The Implications of Resource Management in
La Parguera, Puerto Rico
A Thesis
Submitted to the Faculty
of
Drexel University
by
Heidi Hertler
in partial fulfillment of the
requirements for the degree
of
Doctor of Philosophy
November 2002
ã Copyright 2002 Heidi Hertler. All Rights Reserved. ii
Dedication to my family
iii
Acknowledgements
I would like to thank so many people who have been supportive of me and my work in La Parguera. I am especially grateful to Dr. James Spotila and Dr. Daniel
Kreeger, co-advisors, who were both patient and understanding. I will forever be indebted to Dr. Graciela Ramírez-Toro and Harvey Minnigh for their guidance and encouragement as well as a home and great meals after a long field day. Dr. Susan
Kilham has inspired me and Dr. Robert Brulle has encouraged me to make change possible.
This research would not have been possible without the generous financial support from The Gabriella and Paul Rosembalm Foundation, Universidad
Interamericana de Puerto Rico, Centro de Educación, Conservación e Interpretación
Ambiental, the Asociacion de Dueños de Casa Bote de La Parguera, and New Jersey and
Puerto Rico Sea Grant.
I would like to especially thank the students at Universidad Interamericana de
Puerto Rico for their diligent field and laboratory support, particularly Robert Viqueira,
Ana Ruiz, Wilma Vargas, Miguel Viqueira, Arnaldo Pol, Adrián Vicenty, Carol Ferrer,
Odriel Rivera, Jo Anna Santiago, and Janice Franqui. Many thanks go to Academy volunteers and the young women of the Academy of Natural Sciences’ Science
Enrichment and Expansion Curriculum (SEEC), especially Khalilah Love, Batichia
Bullock, DeShanta Miner, Chynelle Singleton, and Zephyr Johnson, who helped with sample preparation and analysis. I would also like to thank Drexel graduate students, iv
Scott Lynn, Sanhita Datta, and Sebastian Interlandi, who have helped with equipment and encouragement.
Juggling a full time job at the Academy of Natural Sciences and working on a dissertation is trying, to say the least. I would like to thank my colleagues at the
Academy, especially Adam Boettner, Nichole Coulter, Deborah Raksany, and Catherine
Gatnsby, for their support and understanding. A million thanks go to my family, for their support, without them I never would have gotten this far. Finally, I want to mention
George, who greets me everyday and is patient and understanding of being shuttled to
“the spa” every time I go to Puerto Rico.
v
Table of Contents
LIST OF TABLES ...... ix
LIST OF FIGURES ...... xii
ABSTRACT...... xiii
CHAPTER 1 – Background and Introduction...... 1
References...... 7
CHAPTER 2 – Effects of Houseboats on Organisms of the La Parguera Reserve, Puerto Rico...... 8
Abstract ...... 8
Introduction...... 9
Materials and Methods...... 11
Houseboat Selection...... 11
Sampling Methodology...... 12
Data Management and Experimental Design...... 13
Results ...... 14
General Observations ...... 14
Biodiversity of the Benthic Community...... 14
Seagrass Abundance ...... 15
Sessile Fauna...... 16
Mobile Fauna ...... 17
Discussion...... 18
References...... 25
vi
CHAPTER 3 – Spatial Variability in Water Quality Associated with Shifting Land Use in La Parguera, Southwest Puerto Rico...... 36
Abstract ...... 36
Introduction...... 37
Materials and Methods...... 40
Study Site ...... 40
Field Methods ...... 42
Laboratory Methods...... 44
Total Suspended Solids and Organic Content ...... 44
Particle Size Distribution...... 45
Sediment Metal Analysis ...... 46
Dissolved Nutrients...... 47
Chlorophyll-a ...... 48
Elemental C:N:P Particulate Analysis ...... 48
Watershed Measurements ...... 49
Statistics ...... 49
Results...... 50
Field Parameters...... 50
Suspended Solids ...... 52
Particle Concentration...... 53
Sediment Metals...... 53
Nutrients and Chlorophyll-a ...... 54
Carbon: Nitrogen: Phosphorous Ratio ...... 55 vii
Discussion...... 55
References...... 62
CHAPTER 4 – Effects of New Land Development on Seagrasses in the Vicinity of La Parguera, Puerto Rico...... 87
Abstract ...... 87
Introduction...... 88
Materials and Methods...... 91
Study Site ...... 91
Field Methods ...... 93
Seagrass Composition...... 93
Seagrass Measurements ...... 94
Epiphytes...... 94
Sediment Trap...... 94
Plaster Ball ...... 95
Statistics ...... 95
Results...... 96
Species Composition...... 96
Growth Rates and Productivity...... 97
Leaf Characteristics and Epiphytes...... 98
Sedimentation...... 98
Discussion...... 99
References...... 104
CHAPTER 5 – Resource Management of a Temperate and Tropical Marine System: Success and Failure...... 123 viii
Introduction...... 123
Environmental Protection in La Parguera and Barnegat Bay...... 126
La Parguera, Puerto Rico ...... 126
Barnegat Bay, New Jersey...... 128
Why the Differences? Environmental Protection and Government Involvement ...... 131
Conclusion...... 132
Summary...... 134
References...... 136
APPENDIX 1 – Field Data for La Parguera, Puerto Rico...... 139
APPENDIX 2 – Lab Data for La Parguera, Puerto Rico...... 152
VITA ...... 164 ix
List of Tables
2.1. Floral2,4 (2.1A) and faunal1,2,3 (2.1B) species encountered during transect sampling of bottom vegetation near houseboats in lagoons at La Parguera, Puerto Rico ...... 30-31
2.2. Fauna and flora encountered within six replicate 0.25 m2 quadrats on the hulls of houseboats near La Parguera, Puerto Rico ...... 32
3.1. Surface and bottom temperatures ± standard error (S.E.) by month in the vicinity of La Parguera, Puerto Rico...... 66
3.2. Surface and bottom salinity in parts per thousand (ppt) for all sampling dates with available rain data in La Parguera, Puerto Rico ...... 67
3.3. Mean surface (3.3A) and bottom (3.3B) dissolved oxygen concentration ± standard error (S.E.), in mg/l, by development class near La Parguera, Puerto Rico...... 68
3.4. Percent of incident light reaching bottom near La Parguera, Puerto Rico....69
3.5. Total suspended solids, mg/l, greater than 0.70 mm in the water column and turbidity by development near La Parguera, Puerto Rico ...... 70
3.6. Total inorganic suspended solids, mg/l, during flood and ebb tidal samples, near La Parguera, Puerto Rico ...... 71
3.7. Number of particles per ml between 2 and 30 mm (fine silts) and 30 and 64 mm (course silts) near La Parguera, Puerto Rico ...... 72
3.8. Concentration of lead, copper, chromium, nickel, zinc and aluminum, µg/g ± S.E., in marine and terrestrial samples of La Parguera, Puerto Rico...... 73-74
3.9. Metal concentrations for samples in and around La Parguera, Puerto Rico, normalized to aluminum concentrations for comparison among samples in the literature ...... 75-76
3.10. Nitrate (NO3), nitrite (NO2), ammonia (NH4) and phosphate (PO4) concentrations compared among different development classes in La Parguera, Puerto Rico ...... 77 x
3.11. Chlorophyll-a concentrations, mg/l, compared among stations in La Parguera, Puerto Rico, from east to west...... 78
3.12. ANOVA results comparing particulate carbon, nitrogen and phosphorous concentration in the water column at sites having different development classes in La Parguera, Puerto Rico...... 79
3.13. Concentrations of particulate carbon, nitrogen and phosphorous in mg/l by development code in La Parguera, Puerto Rico...... 80
3.14. Ratio of carbon to nitrogen weight, carbon to phosphorous weight, and nitrogen to phosphorous weight by development code in La Parguera, Puerto Rico ...... 81
3.15. Ratio of phosphorous to total suspended solids and organic solids by development code in La Parguera, Puerto Rico...... 82
4.1. Seagrass sampled at five stations at La Parguera, Puerto Rico, for species composition, biomass and shoot density...... 109
4.2. Mean percent cover, ± S.E., along transects at stations with seagrass beds near La Parguera, Puerto Rico...... 110
4.3. Number of species per m2 and shoot density (shoots m-2), ± S.E., along transects at stations with seagrass beds near La Parguera, Puerto Rico ....111
4.4. Biomass (g/m2) of seagrass (Thalassia and Syringodium) dominant macro algae along transects at stations with seagrass beds near La Parguera, Puerto Rico ...... 112
4.5. Growth rate (cm/day) for Thalassia in the vicinity of varying stages of development near La Parguera, Puerto Rico...... 113
4.6. Productivity (g/m2day) for Thalassia in the vicinity of varying stages of development near La Parguera, Puerto Rico...... 114
4.7. Blade length (cm) and area (cm2) for Thalassia for stations near La Parguera, Puerto Rico ...... 115
4.8. Total epiphytic load, g/g dry plant mass, in the vicinity of varying stages of development near La Parguera, Puerto Rico ...... 116
4.9 Dissolution of gypsum plaster balls (g/day) in the vicinity of varying stages of development near La Parguera, Puerto Rico...... 117
xi
4.10. Sedimentation rate (g/m2day) and inorganic fraction in the vicinity of varying stages of development near La Parguera, Puerto Rico ...... 118
4.11. Benthic sediment inorganic fraction near La Parguera, Puerto Rico...... 119 xii
List of Figures
2.1 Map of the La Parguera area in Puerto Rico indicating the location of the six study sites...... 33
2.2. Benthic floral community under and near houseboats in La Parguera Reserve in Puerto Rico ...... 34
2.3. Thalassia blade density (A) and blade length (B) under houseboats in La Parguera Reserve, Puerto Rico ...... 35
3.1. Marine study sites in La Parguera, Puerto Rico, indicated by numbers and terrestrial sites indicated by letters...... 83
3.2. Total and inorganic suspended material (mg/l) ± S.E. in the water column during ebb tides near La Parguera, Puerto Rico ...... 84
3.3. Water column fine clay particle concentration (number/ml) ± S.E. in the vicinity of La Parguera, Puerto Rico, increased from east to west...... 85
3.4. Copper enrichment in La Parguera, Puerto Rico, as a result of increased recreational boat use and dockage...... 86
4.1. Map of the La Parguera, Puerto Rico...... 120
4.2. Shoot density (A), biomass (B), and productivity (C) for seagrasses (Thalassia and Syringodium), near La Parguera, Puerto Rico...... 121
4.3. Inorganic epiphytic load (g/g dry plant mass; bars) and productivity (g/m2 day; lines) at stations with seagrass ...... 122 xiii
Abstract The Implications of Resource Management in La Parguera, Puerto Rico Heidi Hertler James R. Spotila and Daniel A. Kreeger
A recent rezoning of La Parguera, southwest Puerto Rico, as a tourist zone has resulted in an imbalance between development and appropriate resource management.
Development associated with tourism is destroying the sub-tropical dry forest and adding pressure on the marine resources through increased boat traffic and marine structures.
Declining water quality and benthic community health are two of the impacts seen in La
Parguera associated with these land use changes.
This study is three-fold. First, I evaluated the effect of houseboats on the benthic community. By comparing seagrass vigor under houseboats and in control areas, the houseboats were not found to be damaging seagrasses through shading nor were they reducing water quality. In fact, these boats may have positively impacted the local marine system by creating an artificial reef environment. However, it was found that seagrass beds had significantly decreased in all areas since the last quantitative benthic study in 1979.
Second, I examined the effect of land use changes on water quality. Declining water quality is a concern to the local town’s people who depend on the resource.
Elevated chlorophyll-a concentrations indicated a source of nutrients entering near the waste treatment facility. Total suspended solids were significantly higher in areas near new development as compared to upstream and downstream sites (31.78 mg/l). Boat ramps were a point source for this material as well as trace metals. xiv
Third, I examined the distribution of seagrass beds near La Parguera. Seagrass beds were reduced or absent near development, and where they were found elevated epiphyte loads were associated with reduced productivity. Sediment composition was not significantly different in areas devoid of seagrasses, suggesting that seagrass might be able to recolonize if other impacts were reduced.
Lower water quality and seagrass vigor in areas near recent development suggest that the changes in local zoning and lack of planning have measurably contributed to reduced water quality. Rapid changes in land use in La Parguera without consideration for best management techniques to control stormwater and nutrient runoff is causing deterioration of water quality, and, in turn, deterioration of the benthic community of this marine system. 0
1
Chapter 1: Background and Introduction
There are over one thousand kilometers of coast in Puerto Rico supporting special features and species such as bioluminescent bays, coral reefs, turtle nesting sites, mangrove lagoons, and caves. Living among these natural resources are nearly four million people (http://www.eia.doe.gov/emeu/cabs/prico.html). Southwest Puerto Rico is unique in that thirty percent of the National Wildlife Refuges in the Caribbean and nearly all of the remaining subtropical dry forests, Guanica Biosphere Reserve, are located in this area.
Unique limestone outcrops covered with swamp deposits of silt and clay dominate the geology of southwest Puerto Rico from Cabo Rojo on the west side of the island to
Guanica on the south side of the island. La Parguera, including its bioluminescent bays is located in this area. There are no rivers in this area; therefore, runoff is the only local source of terrestrial sediment to the marine system (Ewel and Whitmore 1973).
Mountain chains produce a rain shadow effect resulting in a sub-tropical dry forest (Ewel and Whitmore 1973). May through November is typically rainier than other months.
September and October have the greatest precipitation per rain event. Associated with these conditions is an extremely productive marine system.
The unique beauty and natural resources of La Parguera have historically attracted both tourists and fishermen. In 1945 the area experienced its first invasion of new residents when a Social Program Administration formed a rural community in the area.
Project “Parcelas” gave the working class land, materials built their own homes (Krausse
1994). Development was limited, mangrove and utilities, and the people stands were 2
extensive, and salt flats buffered the mangroves from anthropogenic affects. The small village became the center of commercial fishing for the local market.
In 1960, the Planning Board proposed a comprehensive land use plan for La
Parguera. It emphasized the expansion of tourism by forming new public beaches and boating facilities and opening access to bioluminescent bays by the acquisition of nearby land to preserve this natural resource. The plan also included takeover and eventual elimination of stilt houses that were built in the mangroves as summer homes (Planning
Board 1960). This plan was never implemented. After an article on the phosphorescent bays was published in National Geographic Magazine in 1960, the US National Park
Service conducted a feasibility study on establishing a national park in this area (National
Parks Service 1968). Again, the Planning Board prepared a plan for La Parguera
(Planning Board 1968) emphasizing conservation of natural resources and control of development. Again, this plan was not implemented.
Also recognizing the importance of the resources in La Parguera at this time was the Environmental Quality Board. The Board classified the coastal waters surrounding
La Parguera based on established EPA guidelines. Areas around bioluminescent bays and several keys on the outer shelf were established as Class-SA, intended for conservation and research purposes where recreational use would be discouraged. Near- shore areas including the mangrove channels were classified as Class-SB, used for boating, fishing and contact recreation (Environmental Quality Board 1972). In order to comply with established water quality standards, a primary treatment facility (100,000 gallon per day capacity) was built in 1974; however, the stilt houses were not required to connect to the new treatment system because they were built on public property 3
(Aqueduct and Sewer Authority 1973). A number of unsuccessful attempts were made to try to remove the stilt houses based on the potential for impacting water quality (Puerto
Rico Supreme Court 0-72-75; Puerto Rico Supreme Court AA-75-475.)
During the 1970s, a number of federal environmental laws were passed to regulate water quality and pollution. In 1972, recognizing the coast as a significant ecosystem, Congress passed the Coastal Zone Management Act (CZM) to preserve, protect, develop, and, where possible, to restore and enhance the resources of the nation’s coastal zone (16 US §§ 1451-1464). Administered by the National Oceanic and
Atmospheric Administration (NOAA), the Act established a program for states to voluntarily develop comprehensive preservation programs. The intention was to manage coastal development, improve, safeguard and restore the quality of coastal waters and habitats, and to protect natural resources and existing uses of those waters and habitats
(http://www.ocrm.nos.noaa.gov/czm/czm.act.html). Later this act was amended to include controls of nonpoint source pollution (http://www.ocrm.nos.noaa.gov/czm.act).
The Puerto Rico CZM Program was approved in September 1978. The Department of
Natural and Environmental Resources was designated as the administrating agency. A local branch of the Department of Natural and Environmental Resources (DNER) was established in La Parguera as this area was becoming increasingly attractive to local tourism.
The presence of the unique marine resources of southwest Puerto Rico motivated
NOAA to include a 226.5 km2 parcel of marine waters off of southwest Puerto Rico, including La Parguera, as part of the National Marine Sanctuary Program. This program, established in 1972, protects unique marine environments for recreation, science, 4
education, aesthetic and historic purposes (http://www.sanctuaries.nos.noaa.gov). An environmental impact statement and management plan was completed for this area in
1983 (OCRM 1983). In addition to the Commonwealth and Federal laws and regulations, this designation as a sanctuary extended protection to important marine communities such as mangroves and seagrasses. It also required development of a comprehensive management plan, instituted a program of surveillance and enforcement, and provided for resource studies and interpretive programs. Restrictions on taking of coral, wastewater discharge, and cutting of mangroves were included as well as the prohibition of gear for the illegal taking of turtles. Although one of the main goals of this designation was the improvement of fisheries, the attempt to make La Parguera part of the National Marine sanctuary program was met with resistance by the local community who feared greater control over local natural resources by the federal government.
In 1987 the Department of Natural Resource and the US Army Corps of
Engineers, still recognizing the importance of the natural resources in this area, signed an agreement providing for strict pollution control and declared La Parguera a Natural
Wildlife Reserve, with the intention of creating a natural area. The goal of establishing a reserve was to maintain the ecological integrity of the resources and implement management decisions based on science. Such decisions must account for conflict between land use and conservation, since inevitably people, no matter how careful, will have an impact on an ecosystem.
In direct contradiction to the relevant laws and the 1987 Natural Wildlife Reserve status, the Puerto Rico Planning Board rezoned the town in 1994 to encourage development and tourism. This action was not supported by any scientific assessment of 5
the potential ecosystem impact, nor did it consider impact on prior land and resource user groups (e.g. fisheries). In addition, no environmental evaluation of these actions (i.e.
Environmental Impact Statement) was conducted although it is required under both federal and commonwealth law.
A survey conducted in December 1997 revealed 148 new dwellings in La
Parguera with an additional 368 under construction. This represented a population increase of over 200% between 1994 and 1997 and did not include the transient population associated with hotel rentals or tourist facilities. An increase in demand for access to the marine system for recreation, particularly more boat ramps and boat traffic, was associated with the increase in tourism. Near shore ecological effects included the destruction of the seagrass beds that served as nurseries for reef fishes, thus diminishing the health of the reserve. Declining water quality in this area has been and continues to be a concern to the community that depends on this resource for their livelihood.
The local U.S. Army Corps of Engineers (USACE) recognized the decline and, in an attempt to prevent further environmental degradation, ruled that a group of houseboats in the Asociacion de Dueños de Casas Bote de La Parguera was causing degraded water quality in the vicinity of La Parguera. Although seven adverse effects were listed by
USACE, none were documented by scientific study or investigation. This resulted in litigation by houseboat owners (Puerto Rico Supreme Court AA-96-34). As part of my study, I investigated the impact of these floating structures on the seagrass community
(Chapter 2). Although not the result of the houseboats’ presence, the seagrass community was markedly deteriorated compared to that of twenty years ago. Further studies indicated that the rezoning of the dry forest to increase tourism and the associated 6
land-use changes in this area, appeared to be the primary cause of reduced ecological integrity, as indicated by lower water quality, increased turbidity and sedimentation rates, and decreased productivity of the seagrass ecosystem essential for a healthy fisheries industry (Chapters 3 and 4).
The natural resources, on which both local fisherman and the tourist industry depend, are at stake. Many of the other land-use effects observed in La Parguera have occurred from unplanned coastal development elsewhere in the Caribbean. These effects include displacement of traditional users and uses, physical changes and habitat damage, increased pressure on methods of solid waste disposal, increases in sediment loads, and notable visual and aesthetic impacts. Coastal communities can be dramatically harmed by unchecked tourism and poorly managed natural resources. With the increasing demand for land and access, resource management must account for the impact of this sort of rapid development and community change. There is no inherent problem with allowing and even encouraging tourism to flourish. Tourism benefits thousands of destinations, especially economically (Bosselman et al. 1999). However, as demonstrated at La Parguera, sustainable use by a variety of user groups must be carefully balanced and managed based on sound scientific information.
7
References
Aqueduct and Sewer Authority. (1973). Wastewater disposal system – La Parguera (Estudio de viabilidad de Veredas Submarinas en al Area de La Parguera; mimeographed). Department of Marine Science, University of Puerto Rico at Mayaguez
Bosselman, F. P, Peterson, C. A., McCarhty, C. (1999). Managing Tourism Growth. Island Press, Washington D.C.
Environmental Quality Board. (1972). A water quality study of La Parguera and nearby Bahia Fosforescente. Environmental Quality Board, Office of the Governor, San Juan, Puerto Rico
Ewel, J. J., Whitmore, J. L. (1973). The ecological life zones of Puerto Rico and the U.S. Virgin Islands. Forest Service Research Publication. ITF-18, USDA
Krausse, G. H. (1994). La Parguera, Puerto Rico: Balancing tourism, conservation and resource management. 1994 World Congress on Tourism for the Environment, Puerto Rico, May 31 – June 4, 1994
National Park Service. (1968). Bioluminescent Bays in Puerto Rico. U.S. Department of the Interior, Washington, D.C.
Office of Ocean and Coastal Resources Management (OCRM). (1983). Draft Environmental Impact Statement and Management Plan for the Proposed La Parguera National Marine Sanctuary. NOAA, Washington D.C.
Planning Board. (1960). A comprehensive plan for the development of La Parguera, Lajas, Puerto Rico
Planning Board. (1968). La Parguera – Interim Development Plan, PB, Office of the Governor, Santurce, Puerto Rico 8 Chapter 2: Effects of Houseboats on Organisms of the La Parguera Reserve, Puerto Rico
Abstract
As coastal development increases, the number of artificial floating and permanent structures designed to serve the population also increase. It has been postulated that because of their size, houseboats are similar to permanent structures in that they shade a significant portion of the benthos and thereby limit production by benthic flora. On the other hand, these structures can benefit biotic communities by providing substrate for attachment of organisms in a space-limited environment and both habitat and food sources for fish. In this study, we examined whether houseboats benefit or harm the ecological integrity of a topical seagrass dominated system at La Parguera, Puerto Rico.
We performed a benthic survey to compare the diversity and health of seagrasses under houseboats and in control locations. Species diversity (0 - 0.79) varied significantly among sites, but this variability was not attributed to the houseboats. Rather, the variability appeared related to proximity to new development along the shoreline.
Average seagrass blade density and length were 52.7 m-2 and 23.6 cm, respectively.
Neither parameter differed between impacted and control areas; however, both were significant among sites. In addition, boat hulls were heavily encrusted with invertebrates.
The overall averages of species diversity and richness of sessile organisms on hulls of the houseboats were 1.13 and 4.83, respectively. Fish also utilized these structures. Results indicated that houseboats did not directly harm the seagrass communities at La Parguera
9 primarily because of sound environmental management of wastes and mooring techniques.
Introduction
Houseboats are common in bays and lagoons in Florida and the Caribbean. These vessels are anchored in one particular location for long periods of time. While the same is true of many other types of boats, houseboats may shade a larger area of the bottom than a motor or sailing vessel of the same length as a result of their lower length to beam ratio.
By curtailing light availability, it is possible that houseboats could have adverse effects on seagrass ecosystems and benthic communities similar to permanent piers (Loflin 1995,
Czerny and Dunton 1995, Shafer 1999, Kraemer and Hanisak 2000). Floating structures inhibit light to a greater extent than similar structures raised above the water (Burdick and
Short 1999). Mooring systems can also have a severe impact on seagrasses (Walker et al.
1989, Hastings et al. 1995).
On the other hand, these structures may benefit other biota in the area if they act as an attachment surface for sessile organisms and provide habitat and feeding sites for fish (Ibrahim et al. 1996). It is well known that artificial structures in fresh and salt water often provide useful habitat for plants, fish, and invertebrates (Randall 1963, Parker et al. 1974, Helfman 1979, Bohnsack and Sutherland 1985, Bohnsack et al. 1991, Walters et al. 1991, Gregg 1995, Steimle and Figley 1996, Stanley and Wilson 2000). There is a growing awareness in coastal ecology that urban marine structures, such as boat pontoons and pilings, can provide habitat value (Connell 2000). These structures usually support a diverse community of epibiotic organisms (Connell and Glasby 1999). Understanding
10 the nature and function of these man-made structures is important because coastal populations continue to grow and the demand for access to and use of marine resources continues to rise.
Turtle grass, Thalassia testudinum, is the predominant seagrass at La Parguera.
Thalassia grows well on both muddy and sandy bottoms where its roots and rhizomes can establish a good holdfast for the plant. La Parguera is an ideal site for Thalassia growth and in many areas it forms a dense climax community. Temperature, depth, irradiance, and exposure are important factors affecting the distribution of Thalassia. Temperature acts to limit the latitudinal distribution of Thalassia, while depth of light penetration and exposure are important in local distribution (Duarte 1991, Dixon 2000, Koch 2001).
Light availability can also affect the species composition and productivity. The effects of shading on the growth and survival of Thalassia are well documented (Vermaat et al.
1996, Lee and Dunton 1997, Livingston et al. 1998, Gacia 1999, Longstaff and Dennison
1999, Kraemer and Hanisak 2000). Under limiting light conditions, a seagrass- dominated community can shift to a macro algae-dominated community because macro algae can attain maximum productivity at lower light levels (Fong and Harwell 1994).
Communities on an underwater structure are also affected by available light, changing a filamentous algae community to a community dominated by invertebrates (Glasby 1999).
Artificial reefs attract and even enhance fish populations (Hueckel and Buckley
1987, Bohnsack, et. al. 1991, Kurz 1995). Floating structures also attract fish (Klima and
Wickham 1971, Wickham et al. 1973, Prince et al. 1977). National and state governments spend large amounts of money to improve habitats by placing artificial structures in natural waters. It is possible that houseboats have a positive effect by
11 creating substrates upon which attached algae and invertebrates can live and by supplying food and habitat for fish.
The purpose of this study was to determine the effects of houseboats on a marine reserve in southwest Puerto Rico, La Reserva Natural La Parguera. The specific objectives were to determine whether shading from houseboats had a significant effect on the seagrass community, to examine whether houseboat hulls provided habitat for sessile organisms, and to assess whether they served as Fish Aggregating Devices (FADs).
Material and Methods
A quantitative study examined the potential effects of houseboats on a seagrass community at La Parguera, Puerto Rico. We also measured the vigor of the benthic flora under houseboats to deduce shading impacts and surveyed the houseboats as artificial habitats and FADs.
Houseboat Selection
We surveyed the floral and faunal communities under 6 of 16 houseboats (HB1 to
HB6) belonging to the Asociacion de Dueños de Casa Bote de La Parguera between June
10 and 12, 1996. We chose sites that represented locations where houseboats normally moored and were described in historical surveys as dominated by seagrass beds (Figure
2.1). All of the houseboats were moored on a single point anchoring system that allowed them to swing 360o. When groups of houseboats were moored near each other, we surveyed only one or two boats in the group. We avoided sites previously identified as
12 disturbed by boat propellers and general boat traffic (González-Liboy 1979). Aside from these concerns, selection of houseboats was random and not biased by a prior inspection of seagrass health or boat hull biota. The total distance between the eastern- and western- most stations was approximately 2.5 km. We also examined the pier of the Biological
Station on Isla Magueyes in order to observe the effect of a permanent structure on the flora in the Reserve and to compare biota between permanent structures and boats in the
Reserve.
Sampling Methodology
We considered each houseboat an independent site, representing different locations. We recorded the general condition of the houseboat, its mooring system, and its bottom type and measured visibility of the water column with a Secchi disc. We quantitatively assessed the bottom communities at each site along two 30 m transects by
SCUBA diving. One transect extended from the mooring point to the west (270o), which was the direction the houseboats usually oriented in the prevailing wind. The second transect also had its origin at the mooring point, but extended to the north (0o). Along these transects, we defined the following zones: Zone 1 extended 0 – 10 m from the bow and typically included the area under the boat; Zone 2 extended between 10 to 20 m from the bow and was immediately beyond the boat; and Zone 3 was 30 to 40 m from the origin, well removed from the boat. Because Zones 2 and 3 were located beyond the possible shading effect of each moored houseboat, they served as controls for the effects of the houseboats. Zone 3 was also a control for the other two zones in that it was not shaded during the morning, as was the case with Zone 2. We placed three 0.25 m2
13 quadrats systematically within each zone at 3, 7, and 10 m (randomly determined distances) from the starting point of the zone along each transect. This yielded 9 quadrats per transect (three per zone) and 18 quadrats per houseboat.
Using SCUBA, we recorded the species of flora and fauna in each quadrat
(Littler et al. 1989, Humann 1996a, 1996b, 1996c), the proportion of the 25 cells (0.01 m2 sub-quadrats) of each quadrat occupied by each species, and the percent cover of biota in the quadrat. When Thalassia testudinum was present, we counted and measured blades
(Dennison 1990) in five 0.01 m2 sub-cells of each quadrat.
We also examined the effectiveness of the houseboats as artificial habitats for algae and invertebrates by snorkeling. We randomly placed six 0.25 m2 quadrats on the hull of each surveyed houseboat and recorded the number and abundance of flora and fauna. In addition, we recorded invertebrate and fish communities associated with the undersides of each houseboat because they could potentially serve as FADs for many species.
Data Management and Experimental Design
We measured percent cover (visual estimation of covered space) and calculated species richness (Whittaker 1975), species diversity (Shannon-Wiener equitability index,
Ricklefs 1979), blade density, and blade height (cm) for each quadrat. Using
Statgraphics Plus (Version 5 Plus), we tested the data first for normality using the
Shapiro-Wilks W statistic. Percent cover was non-normally distributed and was arcsine transformed. Next, we tested homogeneity of variances using the Levene’s test. Where necessary, data were transformed to meet the assumptions for Analysis of Variance
14 (ANOVA). We determined the effect of houseboats on bottom vegetation using a 2-way
ANOVA in which the main effects were site (n = 6) and zone (n = 3). Variability in the effectiveness of the houseboats to serve as artificial habitat was summarized for algae and invertebrates using a one-way ANOVA design (main effect = houseboat number). For all analyses, we accepted statistical significance at P = 0.05 (Sokol and Rohlf, 1995).
Fisher’s least significant difference (LSD) procedure determined statistical differences between means at a 95% confidence interval.
Results
General Observations
In general, the visibility in and around the houseboats was good with Secchi disk readings reaching to the bottom in 2 to 3 m of water. In one of the six cases an anchor chain scoured approximately 3 m2 of the bottom, but in general there was no damage to the bottom from mooring systems. Five of the six boats had fish living under them and all had communities of sessile organisms on their hulls.
Biodiversity of the Benthic Community
For all parameters, we found no significant zone effect, indicating that the health of benthic organisms, including seagrasses, was not different directly under houseboats
(Zone 1), as compared to intermediate shading (Zone 2) or unshaded controls (Zone 3).
There were significant site effects for species diversity, species richness and percent cover among the houseboats (Figure 2.2). Benthic species diversity ranged from
15 0 at HB4 to 0.87 ± 0.07 at HB3. Although there was a significant difference among sites
(df = 5, F = 29.71, P < 0.0001), there were no differences between the three zones under any houseboat (df = 2, F = 0.16, P = 0.86). Species richness also varied significantly by site (df = 5, F = 35.30, P < 0.001) ranging from 0.22 ± 0.12 at HB4 to 2.61 ± 0.18 at HB3 but not by zone (df = 2, F = 1.61, P = 0.21). Both diversity and species richness were significantly greater at HB1 and HB3 (LSD) as compared to all other sites. Percent cover ranged from essentially zero at HB4 and HB5 to 97.0 ± 4.00 at site HB6. There was a significant difference among sites with respect to percent cover (df =5, F = 103.83, P <
0.001), however, not among zones (df = 2, F = 1.58, P = 0.21).
Seagrass Abundance
Seagrass beds, dominated by Thalassia testudinum, were present only at three of the sites (HB 1, HB 2, and HB 6). Blade density varied significantly by site (df = 2, F=
32.81, P < 0.0001) but not by zone (df = 2, F = 1.27, P = 0.30). Average blade density ranged from 12.2 ± 5.0 m-2 at HB1 to 103 ± 5.0 m-2 at HB6 (Figure 2.3A). Blade density was different among all sites where Thalassia occurred (HB1 < HB2 < HB6,
LSD). Blade length also varied by site (df = 2, F = 8.49, P = 0.0013) but not by zone (df
= 2, F = 0.88, P = 0.42). Blade length ranged from 18.5 ± 0.8 cm at HB6 to 26.9 ± 0.8 cm at HB1 (Figure 2.3B). Blade lengths were greater at HB1 and HB2 as compared to
HB6 (LSD). Houseboats 1, 2, 3 and 6 were anchored over sandy bottoms and houseboats
4 and 5 were anchored over thick (>0.5 m) mud.
Halimeda incrassata dominated the benthic flora near HB1 and HB3 (Table
2.1A). Thalassia dominated the benthic floral community at HB 2 and HB6. The HB4,
16 although near HB2, was distinct. A boat ramp was located directly across the channel from this site. The bottom was unconsolidated mud, with color and texture similar to the terrestrial sediment in the salt flats behind the boat ramp. This area was essentially devoid of benthic flora. Only Caulerpa racemosa and Halimeda incrassata occurred in Zone 3.
We extended our visual survey in this area. No additional vegetation occurred between
Punta Parguera and the mangrove key. HB5 was also located near a boat ramp. The bottom was similar to that of HB4. With the exception of sparse Caulerpa and Halimeda the bottom at HB5 was devoid of any substantial vegetation.
Between HB6 and the mangrove keys, there was a large rectangular area devoid of bottom vegetation that appeared to be the result of shade from a stilt house located there until two years prior to the survey. The houseboat floated over part of this area when it swung on its mooring, however, it did not appear to be the cause of this problem since the bottom was being recolonized by Halimeda incrassata and Thalassia.
Sessile Fauna
While sampling along the bottom transects, we observed six species of invertebrates, of which four were in Zone 1 under the houseboats (Table 2.1B). These included the spiny lobster, (Panullrus argus), the fire sponge (Tedania ignis), the social feather duster worm (Bispira variegata), and the spaghetti worm (Eupolymnia crassicornis).
Houseboat hulls were heavily covered with complex algal and invertebrate communities. The lowest diversity and richness were at HB3, 0.51 ± 0.61 and 3.00
± 0.52, respectively. Species diversity was significantly different among the houseboats
17 (df = 5, F = 6.05, P = 0.0006). However, only HB3 was different from all other sites
(LSD). The average diversity for all other sites was 1.25 ± 0.13. Species richness did not vary among sites (df = 5, F = 2.42, P = 0.06). There was a significant difference in percent cover among the houseboats (df = 5, F = 5.40, P = 0.0012). Cover ranged from
33 ± 4 on the hull of HB3 to 59.2 ± 4.45 on the hull of HB4. The overall average percent cover was 44.8. Both HB1 and HB3 had significantly less coverage than HB4 (LSD).
The red algae Ceramium sp. was present on all hulls, and another red algae,
Callithamnion sp., was the second most common plant (Table 2.2). Sponges (five species) and tunicates (five species) dominated the faunal community; bryozoans (three species) were also common (Table 2.2).
Mobile Fauna
We observed 22 species of fish, of which 8 were found in Zone 1 under the houseboats. Schooling juvenile bar jack (Caranx ruber) were under HB1. Gray snapper
(Lutjanus griseus), French grunts (Haemulon flavolineatum) and yellow tail snapper
(Ocyurus chrysurus) were under HB2. Yellow tail snapper, gray snapper, and tomtates
(Haemulon aurolineatum) were under HB3. No fish were under HB4. Juvenile French grunts, gray snapper, and porkfish (Anisotremus virginicus) were under HB5. Yellow tail snapper, foureye butterfly fish (Chaetodon capistratus) and schooling silversides
(Families Atherinidae, Clupeidae, and Engraulididae) were under HB6.
We examined the pier of the University of Puerto Rico Biological Station on Isla
Magueyes to determine whether the biota was similar to that observed under houseboats in the La Parguera area. The shaded area under the pier had some patchy areas of H.
18 incrassata on the bottom but no Thalassia. The depth in this area (2 m) appeared to be maintained to accommodate the draft of the research vessel that docked there. A dense bed of Thalassia bordered the dredged area. Under the pier was a school of silversides, some gray snappers (Lutjanus griseus) a few gray angelfish (Pomacanthus arcuatus) and two barracudas (Sphyraena barracuda). The pilings of the pier were covered with many of the same organisms seen on the pontoons of the houseboats.
Discussion
There were no statistically significant effects of the houseboats of the Asociacion on the bottom vegetation in the La Parguera reserve. Within each site, both the species composition and vigor of the bottom vegetation were similar under the houseboats and in control locations up 30 m away from the houseboats. There were no salinity differences among sites, depth ranged between 2-3 m, and wave action was minimal at all locations.
There were significant differences in species diversity, species richness, percent cover, blade density and blade length among the different sites within the reserve at La
Parguera. Species diversity and richness were highest at HB1 and HB3, located in the same general area, and lowest at HB4 and HB5, which were both essentially unvegetated.
There was a considerable decline in the distribution of Thalassia in the area of these particular houseboats (HB4 and HB5) since González-Liboy (1979) studied the seagrass beds. For example in 1979, the area in the vicinity of HB5 was covered with dense
Thalassia seagrass beds, but in 1996 there was no Thalassia in this area.
19 Shading by houseboats of the Asociacion did not produce observable changes among zones with regard to the presence of Thalassia or the blade length of Thalassia, an indicator of decreased light (Czerny and Dunton 1995, Lee and Dunton 1997). This was probably a function of the mooring system used by these boats that allowed them to swing 360°. Plants were also starting to recolonize the area near HB6 that had been nearly devoid of vegetation due to a stilthouse that had been removed from the cay two years before this study. The houseboat swung over this area but did not inhibit the growth of Thalassia or other macro algae. In addition, the Thalassia spread into this area since 1979. At that time Thalassia reached just to the northeast edge of the cay, but it now covered the bottom all the way to the west end of the cay including the area under the houseboats (except for the area that was in the shadow of the former stilthouse at this location).
It is well known that sedimentation and resuspension of sediments increase turbidity and reduce irradiance to the plants and, in turn, inhibit photosynthesis. In
Galveston Bay, Texas, dredging and shore development caused the dramatic decline of
Thalassia and Ruppia maritime between 1958 and 1990 (Pulich and White 1991). Similar activities contributed to the decline of submerged vegetation in Chesapeake Bay (Kemp et al. 1983), Cockburn Sound, Australia (Cambridge and McComb 1984), Tampa Bay,
Florida (Lewis et al. 1985), and Apalachee Bay, Florida (Livingston 1984). In all of these cases, various agents that reduce water column light penetration caused serious damage to submerged vegetation. Similar light reducing agents were present in La
Parguera and appeared to be the cause for the Thalassia decline.
20 While this study was not a quantitative study of sources of sedimentation in the
La Parguera area, it was obvious that new construction on the shore was causing erosion and that this led to runoff into the waters of the Reserve (see Chapter 3). At La Parguera rain events moved large amounts of sediment from areas under new construction on land into the shallow marine system through boat ramps that existed near both HB4 and HB5.
These events were reported to us by local residents as well as observed during subsequent visits to the area. The lack of a salt marsh and the cutting of mangroves along the shore allowed the sediment-laden water to reach the water of the Reserve unfiltered.
We postulated that a combination of increased turbidity from sediment runoff and continuous resuspension of sediments by boat propellers was the likely cause of reduced irradiance to the benthic community at HB4 and HB5 to the point where Thalassia growth was severely inhibited. Sediment deposition on leaves significantly interfered with the growth rates of Thalassia in Florida (Iverson and Bittaker 1986, Phillips 1980,
Pulich and White 1991) and has the potential to bury plants. Plants in La Parguera with inhibited growth rates might be unable to withstand sediment deposits on their leaves, unable to outgrow sedimentation rates or might even be buried. In addition, it was also possible that the thick mud at HB4 and HB5 was too soft for Thalassia roots and rhizomes to hold the plant to the substrate.
Houseboats were found to provide benefits to the reserve by serving as habitat to both sessile species encrusting the hulls and to mobile species such as fish that were more abundant under hulls than adjacent open waters. Organisms on the hulls were native to the area and were those expected for locations in the leeward side of the mangrove cays.
The hulls were not painted with anti-fouling paint, making them good substrates for the
21 settlement of larval organisms. The species diversity on the hull of HB3 was significantly lower than on other houseboats, probably related to when the boat was last out of the water for service. Fish were found under HB3, but HB4 with the highest percent cover had no fish. This suggests that although the structure may function to protect individuals, the benthic community composition may influence the presence of fish.
It is well known that artificial structures in fresh and salt water often provide habitat for plants, fish and invertebrates (Randall 1963, Parker et al.1974, Bohnsack and
Sutherland 1985, Walters et al. 1991, Gregg 1995, Steimle and Figley 1996). Our data indicated that the houseboats acted as floating artificial reefs or FADs that attracted and possibly even enhanced fish populations (Hueckel and Buckley 1987, Bohnsack et al.
1991). These structures protected individuals from predators by providing direct shelter and camouflage (reviewed in Rountree 1989). For example, Buckley et al. (1989) reported that FADs were an effective method for enhancing the troll fishery in American
Samoa. Feigenbaum et al. (1989) found that fish are attracted to FADs within days of deployment in waters off northeastern Puerto Rico. They concluded that FADs could have a positive effect on recreational and commercial fisheries in Puerto. Friedlander et al. (1994) reported that FADs were an effective method of enhancing recreational fisheries in the U.S. Virgin Islands, and Higashi (1994) finds that FADs contributed to increased fish catches in Hawaii. In addition, larval and juvenile fish colonized vertical surfaces associated with pilings and remained through reproductive maturity (Lindeman
1989).
22 Roundtree (1989) concluded that the attraction of fish to FADs and other floating structures was due to the protective advantage provided to fish by these structures.
Helfman (1981) showed that fish in freshwater lakes were attracted to shade produced by floating objects. A shaded observer has a visual advantage over a sunlit observer. A shaded observer saw a sunlit target at more than 2.5 times the distance at which a sunlit observer saw a shaded target Helfman (1981). Therefore, a fish hovering in shade was better able to see approaching objects and was simultaneously more difficult to see. Thus the houseboats gave fish a behavioral advantage over fish that were swimming in the open. In addition, more fish were observed under boats that had seagrass in the benthic community. It appeared that this productivity might have also been a factor in attracting fish to the houseboats.
Our data supported the report of Hair et al. (1994) that pontoon like structures were particularly effective in providing valuable habitat for juvenile fish and that artificial habitats served a mitigative function in estuaries where natural habitats are damaged or destroyed. Although there was little or no vegetation in the water below
HB4 and HB5, these houseboats provided the only substrate for invertebrates and cover for fish in this area of La Parguera.
In many areas, boating activities affected shallow marine communities such as seagrass beds (Zieman 1976, Walker et al. 1989, Kruer 1993, Sargent et al.1995).
However, at La Parguera, the houseboats did not appear to have any significant adverse impact on the benthic community because they did not shade the bottom for long periods of time. The Asociacion de Dueños de Casa Bote de La Parguera mandated environmentally protective policies, such as use of permanent, single point moorings, a
23 thirty day maximum stay at any location, and managed removal of waste water. Their single point moorings allowed them to avoid the shading problem. Houseboats also provided habitat for complex benthic communities on their hulls and attracted many species of fish. They appeared to enhance the habitat of the Reserve near the cays along which they were anchored. The seagrass community of La Parguera was in a general state of decline as compared to the finding of González- Liboy (1979), and it appeared that the primary cause of this decline was runoff from nearby on-shore development. Further investigation is necessary to quantify the environmental degradation that is occurring as the result of development and other anthropogenic activities.
The rich natural areas of La Parguera, southwest Puerto Rico, have supported healthy tourism and fishing industries for many years. However, declining water quality and disappearing seagrasses in this area was of increasing concern to the La Parguera fishing community that depended on these resources for their livelihood. A study by
Environmental Quality Laboratories (1993) indicated that the water quality in areas frequented by houseboats was high and had not deteriorated since 1979. The 1993 study indicated high levels of dissolved and suspended solids in the water, confirming a problem observed in 1979 (González-Liboy, 1979). However, there was nothing to suggest that the houseboats caused sedimentation, unlike the newly rezoned area under construction on the west side of La Parguera (see Chapter 4). In addition, the houseboats of the Asociacion did not anchor on coral reefs, did not tie up to mangroves, and did not anchor in or near bioluminescent bays. Since they did not reside in the dry forest area, they were not responsible for impacting the endangered yellow-shouldered blackbird
(Agelaius xanthomus xanthomus). The houseboats of the Asociacion de Dueños de Casa
24 Bote de La Parguera did not harm the Reserve. Nevertheless, the U.S. Army Corps of
Engineers and U.S. Fish and Wildlife Service declared that the houseboats harmed the
Reserve and ordered them to leave. After losing a federal court case (Puerto Rico
Supreme Court AA-96-34) the members of the Asociacion removed their houseboats from the Reserve.
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30 Table 2.1. Floral1,4 (1.1A) and faunal1,2,3 (1.1B) species encountered during transect sampling of bottom vegetation near houseboats in lagoons at La Parguera, Puerto Rico. Zones 1, 2, and 3 correspond to linear distances 0-10 m, 10-20 m and 20-30 m, respectively, from the edge of the houseboat nearest its mooring
Table 2.1A
HB1 HB2 HB3 HB4 HB5 HB6 Zone Zone Zone Zone Zone Zone 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 Caulerpa racemosa X Caulerpa mexicana X Caulerpa sertularioides X X X Halimeda incrassata X X X X X X X X X X X X X X X Acanthopora spicifera X X X X X X X X X Thalassia testudinum X X X X X X X X X Penicillus capitatus X X X X X X X X X Padina jamaicensis X X X Batophora oerstedii X X
31 Table 2.1B.
HB1 HB2 HB3 HB4 HB5 HB6 Zone Zone Zone Zone Zone Zone 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 Panulirus argus X Tedania ignis X X X Bispira variegata X X X X Holothuria Mexicans X X Ircinia stobilina X Eupolymnis crassicornis X X X Chaetondon capistratus X X X Lutjanus grisus X X X X X Lutjanus cyanopterus X Stegastes variablilis X Stagastes leucostictus X X Stagastes fuscus X X Haemulon aurolineatum X X X X X X Haemulon flavolineatum X X X X Haemulon chrysargyeum X Haemulon melanurum X Holocentrus ascensionis X Pomacanthus peru X X Pomacanthus arcuatus X Acanthurus chirurgus X X X Acanthurus coeruleus X Acanthurus bahianus X Ocyurus chrysurus X X X X X Scarus taeniopterus X Hypoplectrus puella X Anisotremus virginicus X Synodus saurus X Synodus intermedius X
1Humann, P. (1996a). Reef Coral Identification. Ned Deloach (ed.) Jacksonville: Paramount Miller Graphics, Inc., Jacksonville 2Humann, P. (1996b). Reef Creature Identification. Ned Deloach (ed.) Jacksonville: Paramount Miller Graphics, Inc., Jacksonville. 3Humann, P. (1996c). Reef Fish Identification. Ned Deloach (ed.) Jacksonville: Paramount Miller Graphics, Inc., Jacksonville. 4Littler, D. S., Littler, M. M., Bucher, K. E., Norris, J. N. (1989). Marine Plants of the Caribbean. Smithsonian Institution Press, Washington, D.C.
32 Table 2.2. Fauna and flora encountered within six replicate 0.25 m2 quadrats on the hulls of houseboats near La Parguera, Puerto Rico.
HB 1 2 3 4 5 6 Ceramium sp. X X X X X Acanthophora spicifera X Callithamnion cordatum X X Padina sanctae-crucis X Flora 1,4 Unidentified filamentous brown algae X Dictyota sp. X Unidentified feather green algae X Unidentified bushy green algae X Favia fragum X Clathria sp. X Phorbas amaranthus X X Tedania ignis X X X X X X Iotrochota birotulata X X X X X Strongylacidon sp. X X Dentitheca dendritica X Caulibugula dendrograpta X Schizoporella sp. X X X X X X Trematooecia aviculifera X X Fauna 1,2 3 Filograma huxleyi X X X X Bispira variegata X X Sesarma cinereum X X X X Callinectes sapidus X Unidentified barnacle X X X Ecteinascidia turbinata X X Clavelina picta X Botrylloides nigrum X X X X Distaplia corolla X Trididemum solidum X Isognomon alatus X
1Humann, P. (1996a). Reef Coral Identification. Ned Deloach (ed.) Jacksonville: Paramount Miller Graphics, Inc., Jacksonville 2Humann, P. (1996b). Reef Creature Identification. Ned Deloach (ed.) Jacksonville: Paramount Miller Graphics, Inc., Jacksonville. 3Humann, P. (1996c). Reef Fish Identification. Ned Deloach (ed.) Jacksonville: Paramount Miller Graphics, Inc., Jacksonville. 4Littler, D. S., Littler, M. M., Bucher, K. E., Norris, J. N. (1989). Marine Plants of the Caribbean. Smithsonian Institution Press, Washington, D.C.
33
HB1
HB3 HB4 HB2 HB6 HB5
N W E
S
1 0 1 Ki l om e t e r s
Figure 2.1. Map of the La Parguera area in Puerto Rico indicating the location of the six study sites.
34
1 3 0.71/A 2.61/A 0.79/A A 2.49/A B 0.8 2.5
2 0.6 1.67/B 1.5 1.33/B 0.4 0.25/B 0.22/B 1 0.08/BC Species Diversity Species Richness 0.49/C 0.2 0/C 0.5 0.22/C
0 0 HB1 HB2 HB3 HB4 HB5 HB6 HB1 HB2 HB3 HB4 HB5 HB6
125 C 97.0/A 100 89.4/B 75.1/C 75
47.0/D 50 Percent Cover 25 0.20/E 0.63/E 0 HB1 HB2 HB3 HB4 HB5 HB6
Figure 2.2. Benthic floral community under and near houseboats in La Parguera Reserve in Puerto Rico. Species diversity (A), species richness (B), and percent cover (C) for bottom vegetation at six houseboats sites. Vertical bars indicate the mean for a 0.25 m-2 area ± SE. Differences in the letter designation beside the mean indicate significant differences among the sites as determined by LSD test.
Figure 2.3A 125 102.8/A 100 +/- S.E.) 2 75
43.0/B 50
12.2/C 25 Blade Density (#/m
0 HB1 HB2 HB6 Site
Figure 2.3B
30 27.0/A 25.2/A 25
20 18.5/B
15
10
Blade Height (cm +/- S.E.) 5
0 HB1 HB2 HB6 Site
Figure 2.3. Thalassia blade density (A) and blade length (B) under houseboats in La Parguera Reserve, Puerto Rico. Thalassia was only under HB1, HB2 and HB6. Vertical columns indicate the mean blade density and blade length ± SE for 1 m2 area at each houseboat site. Letters indicate significant differences as determined by LSD test.
36 Chapter 3: Spatial Variability in Water Quality Associated with Shifting Land Use in La Parguera, Southwest Puerto Rico
Abstract
The shallow marine system at La Parguera, southwest Puerto Rico, is increasingly impacted by changes in land use. Rapidly escalating development is out- pacing the ability of existing upland flora, salt flats, and mangroves to intercept sediment and nutrient runoff flowing toward the adjacent marine system. Beginning in the spring of 1998, I initiated a comparative study to examine the effects of new development in a tropical dry forest on the water quality of adjacent shallow waters. I found considerable variability in important water quality parameters among sites.
Significant changes in surface salinity after rain events occurred near developed as compared to undeveloped areas. Concentrations of total suspended solids were significantly higher in the vicinity of developing areas (34.8 mg/l) compared to similar sites without extensive development (31.8 mg/l). This material appeared to be exported from mangroves during ebb tidal cycles. Sediments nearest marinas and most developed locations had the highest metal concentrations. Some of the sites showed concentrations of Cu, Ni, and Zn that exceeded values reported to cause biological impairment.
Chlorophyll-a measurements in the vicinity of the waste treatment facility (2.57 mg/l) averaged two times the level of other areas with similar topography and stage of development (1.36 mg/l). It was apparent from this study that water quality was impacted by new development in La Parguera. Since the natural resources are the
37 primary attraction fueling new development, protection of these systems should receive greater attention in land use planning and decision making processes.
Introduction
Changing land use and its impact on marine communities is of growing concern as coastal populations increase at tremendous rates (Fortes 1990, Coles et al. 1993, Dale et al. 2000, Goenaga and Boulon 1992). This trend is magnified in tropical and sub- tropical islands where land is scarce. In recent years, we have become more aware of the ecological importance of coastal ecotones, particularly mangrove forests and seagrass beds. Biotic communities that exist at this interface are among the most productive aquatic systems, and often serve as filters for anthropogenic nutrients and sediments (Levin et al. 2001). As such, they are essential for the maintenance of healthy marine environments, e.g. coral reefs that exist just offshore.
Often land use changes are associated with the attraction of tourism to a pristine destination (Island Resources Foundation 1996). Poorly managed development decisions threaten the ecological structure and function of these areas. This is the situation at La Parguera, Puerto Rico, where a recent rezoning of the sub-tropical dry forest as a tourist zone has led to rapid uncontrolled development. This is one of the few remaining sub-tropical dry forests in the Caribbean. Impacts of this rezoning include physical changes to the landscape and habitat damage, increased pressure on existing infrastructure, increased sediment loading, and notable visual and aesthetic impacts such as increased boat and vehicle traffic. La Parguera often suffers from water shortages,
38 electrical outages, overflowing sewers and snarled water and road traffic (Krausse
1994).
Anthropogenic sediment and nutrient inputs to aquatic systems associated with urbanization are commonly cited as threatening water quality and ultimately overall ecosystem stability and productivity (Comeleo et al. 1996, Valiela et al. 1997, Dauer et al. 2000). However, few studies have addressed the relationships between land use and levels of sediments, nutrients and contaminants in estuarine ecosystems (Comeleo et al.
1996, Valiela et al 1997, Dauer et al. 2000). Even fewer have addressed the environmental effects of land use change in a tropical or sub-tropical setting (Leitch and
Harbor 1999), and no studies have assessed the effects of land use change in a dry-forest environment such as La Parguera. Decision makers are often challenged with balancing environmental quality with economic productivity (Perry and Vanderklein 1996).
In most of the world, deterioration of water quality is more commonly associated with increases in sediment loads than with decreases (Perry and Vanderklein 1996).
Increased sediment release is almost always associated with landscape manipulation such as clearing or movement of earth for new uses. Sediments are transported to marine systems through surface runoff. Increased turbidity from high sediment and solids loading decreases available light for aquatic species, which in turn decreases seagrass productivity and leads to reduced plant growth and diversity (Perry and
Vanderklein 1996).
Changes in land use can also have a substantial impact on levels of trace metals in marine systems (Windom et al. 1989). Trace metals are essential for metabolism and photosynthesis in marine flora; however, elevated levels become toxic in marine
39 systems (Kennish 2000). Metals, similar to sediments, are filtered from storm water by seagrass and mangrove systems where they are taken up by roots, leaves, and epiphytes
(Ragsdale and Thorhaug 1980, Schroeder and Thorhaug 1980). Metals can bioaccumulate in plant material, which in turn can be transferred through the food web.
Effects–based sediment quality guidelines identify and prioritize potential problem areas where the potential for adverse biological effects are greatest (MacDonald et al. 1993,
Long et al. 1995).
As areas urbanize, growth can eventually exceed the capacity of the existing infrastructure and cause additional problems. Nitrogen is usually the limiting nutrient in marine systems and the addition of this nutrient through waste waster can cause changes in the species composition (Kennish 1992, Valiela 1984, Alongi 1998). Anthropogenic nutrients also affect the systems they enter by increasing algal epiphytic growth on benthic plants (Masini et al. 1995). Phytoplankton blooms, stimulated by the addition of nutrients, decrease available light to benthic macrophytes thus lowering their productivity (Chambers and Kalff 1985; Kautsky et al. 1986, Pierce et al. 1986) and depleting oxygen upon their decomposition. Epiphytes shade and weigh down leaves decreasing their productivity. Increased eutrophication progressively results in a shift of species from macrophytes to macro algae to phytoplankton, and in turn the structure and function of the system is vastly altered (Sand-Jensen 1989, DeVries et al. 1996, Duarte and Cebrea 1996). Nutrient concentrations are usually low in tropical and sub-tropical systems, particularly in the photic zone where marine plants scavenge the resource
(Valiela 1984). Seston associated chlorophyll-a is often used as an indicator of eutrophication in areas where high nutrient inputs are suspected (Smith et al. 1981,
40 Valiela et al. 1990). Without an appropriate plan to manage the by-products of an increasing population, the natural resources that originally attracted people to the area will eventually be lost.
The principle hypothesis of this study was that the addition of anthropogenic sediments, metals, and nutrients to a shallow seagrass/mangrove system through storm water runoff impairs the water and sediment quality, light availability, and fitness of the benthic community. I took a comparative approach to contrast these parameters among
9 stations differing in levels of predicted runoff from the adjacent land. Water quality metrics included total suspended solids, trace metals, dissolved nutrients, and particulate nitrogen, phosphorus, and carbon. The sampling regimen accounted for day of week, tidal cycle, time of day and rain events.
Materials and Methods
Study Site
La Parguera is located in the sub-tropical dry terrain of southwest Puerto Rico.
The Palmarejo Mountains to the north produce a rain shadow effect (Figure 3.1; Ewel and Whitmore 1973). The average tidal range is less than 0.25 m. The prevailing shoreline faces south and the long shore current runs from east to west (Avila et al.
1979). Using existing information and general observations, I selected 9 marine study sites near La Parguera to measure water quality (Figure 3.1). Stations were based on their proximity to small watersheds having varying stages of old and new development.
41 · Station 1 was east of La Parguera and adjacent to an undeveloped, naturally
vegetated hill. An extensive mangrove system fringed the terrestrial system. This
station served as an upstream-vegetated control.
· Station 2 was also upstream of La Parguera; however, it was adjacent to an
unvegetated, undeveloped hill. The hillside was steep and rock was exposed. There
were no mangroves in this area. This station served as an upstream unvegetated
control.
· Station 3 was adjacent to a low density, established development, which has existed
since the 1960’s. An extensive fringe mangrove system was present between the
houses and the sea. Some areas of the mangroves were cut to fit boats, docks, and
houses.
· Station 4 was located between Isla Magueyes and La Parguera. There was extensive
development on the land, a public boat ramp, and a ferry to the University of Puerto
Rico Marine Lab, Isla Magueyes. Mangroves were present between houses but had
been extensively cut to fit boats, docks, and houses.
· Station 5 was to the east of a popular tourist hotel. There were permitted and non-
permitted boat ramps in this area. The hillsides behind this area were extensively
developed and drainage from newly developed areas into the marine environment
was not being managed. Mangroves were present but had been extensively cut for
boats, docks and houses.
· Station 14 was located near the local fisherman’s dock. Vegetation was extremely
sparse in this area (Spotila et al. 1996). New land development was extensive on the
42 hill directly north of this station. Boat ramps in this area acted as channels for
sediment runoff from the ongoing construction on adjacent hillsides.
· Station 11 was located west of La Parguera in a channel that had high boat use. A
marina was located on the mainland. Similar to Station 14, sediment from new
development entered the marine system in this area.
· Station 6 was located further west of La Parguera. Mangroves were present on the
mainland and on the keys located to the south. There was no development in this
area, however, secondary effluent from the waste treatment facility flowed through
the mangrove.
· Station 22 was located to the west of Boquirón. There was no development on the
mainland near this site, and it served as the downstream control.
For Statistics, I also classified stations by level of development: Stations 1 and 2 were undeveloped, upstream control; Stations 3 and 4 were grouped as old development;
Stations 5, 14, 11, and 6, were classified as new development; and Station 22 was an undeveloped downstream control.
Field Methods
Between June 8 and August 3, 1998, my assistants collected water samples twice a week for eight weeks. They sampled 6 stations: Stations 1, 2, 3, 4, 5, and 6. From
August 1998 through May 2000, they collected samples at least monthly, with few exceptions (i.e. no samples were collected between 8/3/98 and 10/22/98 due to
Hurricane George). They collected samples on 62 days. I added three additional stations for the monthly sampling that began in August 1998. I added Stations 11 and
43 14 to target areas that appeared to be receiving increased runoff and added Station 22 as an additional downstream control. We took surface measurements 0.5 m below the surface, and bottom measurements 0.25 m from the bottom where benthic flora were absent and 0.25 m from the top of the canopy when present so as not to disturb the community. We took samples between 11 AM and 2 PM. I compared the time of sampling to Tides and Currents Nautical Software (Version 2.5) to calculate the actual stage of tide, flood vs. ebb. Eighteen sampling trips were during ebb tide, 44 during flood tide.
I obtained rainfall and air temperature data during the study period from the
University of Puerto Rico, Marine Biology Station on Isla Magueyes. Data at the station were recorded only during workdays; no weekend or holiday data were available. Of the 62 sampling dates, 14 were associated with a significant rain event, defined as total precipitation exceeding 0.75 cm or greater for 72 h prior to sampling. In an attempt to capture the effect of rain events, we sampled a subset of six stations after rain events in addition to scheduled monthly samplings.
We used a YSI-85 meter to measure temperature (± 0.1oC), dissolved oxygen (±
0.03 mg/l), conductivity (± 0.5% full scale), and salinity (± 0.1 ppt). We measured light using a LI-COR–185B Quantum/Radiometer with underwater quantum sensor (Li-
192SA; ± 5%) and terrestrial sensor (LI-190SB; ± 5%) to measure photosynthetically active radiation. Using the underwater quantum sensor, we measured light 0.25 m below the water surface and 0.25 m above the bottom with the sensor facing both up and down. We calibrated all instruments according to operations manuals.
44 We collected surface water samples from the forward, windward side of the boat using clean acid-washed polyethylene bottles according to the sampling and storage procedures of Crompton (1989). Samples were transported to Inter American
University and placed in a refrigerator or cool room until processed, within 24 h of collection. Filtered samples were placed in a freezer and shipped frozen to the Academy of Natural Sciences (ANS).
Laboratory Methods
We cleaned all glassware used at Inter American University with 10% hydrochloric acid, rinsed it with DI water, and dried it completely before use. I prepared
Whatman GF/F glass fiber filters (0.70 mm) at ANS by combustion at 500oC for 4 h using a muffle furnace. I rinsed pre-weighed filters with DI water, dried for them 24 h, placed them in a desiccator for 6 h, and then weighed them to the nearest 0.00001 g. I used Nucleopore polycarbonate membrane filters (0.2 mm) for particulate phosphate analysis.
Total Suspended Solids and Organic Content
One liter of water was filtered through each of three pre-weighed filters. Filters
(GF/F) were returned to the pre-numbered petri dish, frozen and shipped to ANS. At
ANS, I dried filters at 105 oC to a constant mass and weighed them. I calculated dry mass of particulate material captured on each filter by subtracting the filter mass from the dried mass. I ashed samples at 450oC for 4 h and re-weighed them (Crompton
1989). The material remaining on the filter constituted the inorganic fraction, including
45 any carbonate material. I determined the organic mass by subtracting the ashed mass from dried mass. Turbidity was measured using a Turner nephelometer (APHA 1995) at
Inter American University.
Particle Size Distribution
Three 250 ml samples of water per station were collected and preserved with
Lugol's solution (APHA 1995). Samples were shipped to ANS in a box. I diluted samples 1:1 with Isoton II and then counted particles between 2-64 um using a
Multisizer Coulter Counter with a 100 um aperture (Part No. 6102033). I counted each replicate sample twice. I placed samples under the Coulter Counter aperture nozzle, where a mercury manometer pulled approximately 750 µl of sample through the small opening. Electronic sensors attached to the mercury manometer started and stopped the counting of particles so that exactly 500 µl of sample was counted. As the water sample was drawn through the small aperture, particles disrupted the electronic field around the aperture and these disruptions were translated into counts. I repeated the count if the two values differed by >10 %. I only accepted concentrations between 500 and 20000 cells per 500 µl because this range resulted in most efficient counting. If counts were above
20000, I diluted samples to achieve concentrations in this range. I also counted the particle concentration of the Isoton II to correct for any particles added with the dilution.
Particles from 2 - 30 mm (fine silts) and 30 – 64 mm (course silts) were counted separately.
46 Sediment Metal Analysis
We collected superficial sediment samples throughout the bay area using an
Eckman grab sampler between June 16 and 22, 2000, during clear weather. Each sample consisted of a composite of three to five separate grabs. We also collected terrestrial samples from above the development and within the town. Samples were frozen until prepared for metal analysis at the Environmental Geochemistry Lab at ANS.
Assistants prepared the samples by removing Halamida platelets and shell fragments and drying at 60oC for 48 hours to assess percent solids. I crushed the dried material and digested approximately 0.2 g using a combination of HNO3, HCl, and HF in conduction with a CEM 2000 microwave digestion system. Acids were evaporated and samples were brought up to 50 ml volume in 2% HNO3. Samples were analyzed by the
ANS Environmental Geochemistry Lab on a Perkin Elmer Optima 3000XL ICP-OES for Cd, Pb, Cu, Cr, Ni, Zn, Fe, and Al. I calculated organic matter by Loss on Ignition
(LOI) at 450oC for 24 hours.
I compared surface sediment concentrations of trace metals from La Parguera
Bay to concentrations in marine sediments from Hungry Bay, Bermuda, a non- anthropogenically impacted bay (Lyons et al. 1983). I also compared values with those calculated by Long et al. (1995) to have biological effects. Effects range-low (ERL) and effects range-median (ERM) delineated three concentration ranges for a particular metal in marine and estuarine sediments. Areas with values greater than ERL, but less than
ERM, had incidents of adverse biological effects occurring occasionally (Long et al.
1995). Areas with values greater than ERM had incidents of adverse biological effects occurring frequently (Long et al. 1995).
47 I normalized metal data to aluminum (Al) to compare concentrations in sediments with varying matrix. In carbonate systems, metal:Al ratios were accepted over other normalizing techniques because aluminum is not affected by human activities, it is the most abundant metal in the Earth’s crust, and it exhibits good relationships to grain size (Ryan and Windom 1988). I determined the enrichment factor according to Ryan and Windom (1988) for each metal:
EF (Enrichment Factor) = (Metalsample/Alsample)/(Metalbackground/Albackground).
Ideally the background values used would be site specific and come from locations thought to have no anthropogenic inputs. However, these conditions were not met in La
Parguera where sediment matrices were heterogeneous and no previous work was available. The average metal:Al ratios in the hill slope sediments above the town and the in literature were quite similar, indicating that sediments on the hillside were close to what was accepted as background in other studies on pristine areas. Therefore, for this study I chose to use the average ratios from the known uncontaminated sites from the literature as our metal and aluminum background values.
Dissolved Nutrients
Nitrate, nitrite, ammonia, and phosphate concentrations were analyzed according to Strickland and Parson (1972) at Inter American University within 24 h of their collection.
48 Chlorophyll-a
I determined chlorophyll-a levels with a procedure modified from Strickland and
Parson (1972). My assistants filtered 1 L of water through an ashed Whatman filter while working in the dark. They immediately wrapped the filters in aluminum foil, froze them, and shipped them to ANS. At ANS, I extracted the chlorophyll-a from the sample in subdued light using 10 ml of 90% acetone diluted with distilled water. I refrigerated the samples overnight (approximately 18 hours) then centrifuged them at
3000 rpm for 20 minutes. I used a clean Pasture pipette to transfer approximately 9 ml of the solution to a fluorometer cuvette which I analyzed using a Turner DesignTD-700
Fluorometer. I added two drops of a 5% HCl solution and mixed. After two minutes, I re-analyzed the sample.
Elemental C:N:P Particulate Analysis
One liter of water from each sample was filtered through a Whatman GF/F filter, frozen, and shipped to ANS by my field assistants. At ANS, I dried the samples for 24 hours, placed them into a chamber with undiluted HCl for 24 h to remove inorganic carbon, re-dried them in an oven for 24 h, and packed the filters into aluminum boats for analysis (Velinsky and Fogel 1997). I analyzed samples using a Carlo Erba 1106 CHN elemental analyzer (Bertoni 1978).
I analyzed total particulate phosphorous according to Strickland and Parson
(1972). Two hundred and fifty to 500 ml of water was filtered through a membrane filter (0.45 mm) at Inter American University. At ANS, I digested the filters using a 5%
49 w/v persulfate solution at 121oC for 30 min and analyzed them using the ascorbic acid method (APHA 1995) on a Molecular Devices Thermomax Microplate Reader.
Watershed Measurements
Using the most recent aerial photographs (1997) and topographic maps (1960), I delineated watershed boundaries using a planimeter. I measured urbanized areas from the aerial photograph to determine the percent of watersheds that were urbanized. The extent of urbanization determined the development code. Stations 1 and 2 received runoff from areas with no development and they were classified as “Undeveloped -
Upstream”. Stations 3 and 4 received runoff from areas that had been developed since the 1960’s with no recent development activity. These stations were classified as “Old
Development”. Stations 5, 14, 11, and 6 (from east to west) received runoff from areas that were under construction during the time of this work and they were classified as
“New Development”. Station 22 was down current of La Parguera and received runoff from undeveloped farmland; this station was classified as “Undeveloped –
Downstream”.
Statistics
I entered data in Microsoft Excel (97) and coded it for statistical analysis. The main effects included date, station, weather, time of day sampled, day of week sampled, tidal cycle, and season. Using Statgraphics Plus (Version 5), I first tested data for normality using the Shapiro-Wilks W statistic. If the data were not normally distributed,
I transformed the data to normalize them. The Levene’s test for homogeneity of
50 variances tested homoscedasticity. I tested correlations using the Pearson product moment correlation between paired variables. I used an analysis of variance (ANOVA) to examine spatial variability among the data. Fisher’s least significant difference
(LSD) procedure clarified differences among means at a 95% confidence interval
(Statgraphics Plus Version 5). Statistical significance was accepted at the 95% confidence interval (P < 0.05). Second order polynomial models were used to describe relationships between parameters.
Results
Field Parameters
Water surface and bottom temperatures did not differ significantly; however, both varied among sampling months (Surface: df = 11, 316; F = 88.97; P < 0.0001;
Bottom: df = 11, 295; F = 72.02; P < 0.0001; Table 3.1). The overall mean surface temperature was 29.3oC, and ranged between 25.9oC in January and 30.8oC in August.
The overall mean bottom temperature was 29.3oC, and ranged from an average of
26.2oC in January and February to 30.7oC in August. The mean surface and bottom salinity at all stations was 37.4 ppt. There was a trend for salinity to be lower after rain accumulations greater than 0.75 cm over the three days prior to sampling (37.0 ppt) as compared to samples collected in clear weather (37.7 ppt), but these differences were not statistically significant. Bottom salinity was also lower after rain, 37.1 ppt, as compared to samples taken after clear weather, 37.8 ppt; however, these differences were also not significant. Surface salinities were significantly lower after rain events in
51 the vicinity of old development (df = 1, 42; F = 4.19; P = 0.047) and new development only (df = 1, 64; F = 5.00; P = 0.0288; Table 3.2). Bottom salinities were only significantly different after rain events in the vicinity of new development (df = 1, 65; F
= 5.16; P = 0.0264; Table 3.2).
The overall mean dissolved oxygen (DO) at the surface and on the bottom for all sampled dates were 5.42 mg/l and 5.31 mg/l, respectively. The mean surface dissolved oxygen after a rain event, 5.27 mg/l, was less than that for samples collected during clear weather, 5.64 mg/l. Bottom dissolved oxygen followed a similar trend, 5.28 mg/l after a rain event and 5.53 mg/l on clear days. Dissolved oxygen only differed among development class when rain accumulation was less than 0.75 cm for the three days prior to sampling (Surface: df = 3, 70; F = 6.81; P = 0.0040; Bottom: df = 3, 70; F =
5.31; P = 0.0024). The lowest bottom and surface DO measurements were always in the vicinity of new development; whereas the highest were from near old and undeveloped areas (Tables 3.3 and 3.4).
There were no differences in conductivity or pH among sites. Overall surface conductivity was 60.5 mS/m, and ranged from 48.3 mS/m to 65.1 mS/m. Bottom conductivity ranged from a low of 51.6 to a high of 65.0, with an overall mean of 60.6 mS/m. The mean pH was 8.3 and the pH range was 7.9 to 8.9.
The percent of measured incident light reaching the benthic community varied significantly among development classes (df = 3, 37; F = 6.36; P = 0.0014; Table 3.4).
At the upstream undeveloped site, 45.7% of the incident radiation reached the benthic community as compared to developed sites and the downstream undeveloped sites,
52 mean = 20.2%. The overall mean for all sites was 26.9%. A complete set of the field data is included in Appendix 1.
Suspended Solids
In general, total suspended solids (TSS) in the water column were significantly different among sites with varying degrees of development (df = 3, 291; F = 5.71; P =
0.0008; Table 3.5; Appendix 2). The overall average TSS was 32.9 mg/l. Sites in the vicinity of new development had significantly higher TSS (34.8 mg/l) than all other areas (mean = 31.8 mg/l). Turbidity followed a similar trend to TSS. The overall mean turbidity was 2.35 NTU, ranging from 0.12 NTU to 10.5 NTU. Turbidity was different among sites (df = 3, 272; F = 15.95; P < 0.0001; Table 3.5). There was no difference in
TSS between samples taken during rain and clear weather.
Although the tidal fluctuation in La Parguera was less than 0.25 m, there was a significant difference in total suspended solids with respect to tidal cycle. The overall mean TSS during flood tides was less than during ebb tides, 32.0 mg/l and 34.6 mg/l respectively. The TSS was not significantly different among sites during flood tides; however, during ebb tides, sites in the vicinity of new development had significantly greater TSS concentrations than old development sites and undeveloped upstream sites
(df = 1, 112; F = 9.91; P = 0.0021; Table 3.6). Turbidity did not follow a tidal trend.
Suspended organic material averaged 9.71 mg/l, ranging from 1.39 mg/l to 36.8 mg/l. There was no significant difference in suspended organic material with respect to site. Suspended inorganic material averaged 23.1 mg/l and ranged from 1.42 mg/l to
36.8 mg/l. The inorganic material was significantly greater during ebb tide, averaging
53 25.7 mg/l near developed sites as compared to all other sites (df = 1, 110; F = 9.93; P =
0.0020; Table 3.6). This difference did not exist for flood tide samples, which averaged
21.7 mg/l.
Particle Concentration
Total particle concentrations (sizes 2 – 63 µm diameter) ranged from 68 particles/ml to 25200 particles/ml, mean = 3150 particles/ml. Although sites in the vicinity of new development had slightly greater concentrations than other sites, there were no differences in particle concentration among stations (Table 3.7; Appendix 2).
However, concentrations did differ between flood and ebb tides for all data (df = 1, 122;
F = 12.37; P = 0.0006; Table 3.7).
Sediment Metals
Surface sediments near the town of La Parguera consisted mainly of mangrove and salt marsh sediments and alluvium from run-off from the adjacent hillsides. Bay sediments consisted of calcareous mud, terrigenous clays, calcareous silty sands and
Halimeda sp. sands (http://sr6capp.er.usgs.gov/gwa./ch-n/N-PR_Vltex1.html).
Cadmium concentrations were below instrument detection limits for all samples.
Marine sediment metal concentrations were elevated at sites near new development as compared to the other marine sites in La Parguera and Bermuda (Table 3.8). Copper concentrations occurred above the ERL in one sample from Station 3 (n = 4), two samples from Station 4 (n = 3), four samples from Station 5 (n = 5), one sample from
Station 11 (n = 2) and one sample from Station 14 (n = 1). Thirteen samples had
54 concentrations of nickel above the ERL: two from Station 3 (n = 4); two from Station 4
(n = 3); three from Station 5 (n = 5); two from Station 11 (n = 2); one from station 14 (n
= 1); and three from Station 22 (n = 3). In addition three samples, one from Station 4 (n
= 3) and two from Station 5 (n = 5), were above the ERM. The highest sediment metal concentration was in the salt flat area. Lead levels were elevated in all new development sites.
Sediment metals were normalized to aluminum. Enrichment was determined for each metal to compare to other sediment matrices (Table 3.9). With the exception of lead, marine sediments were enriched with respect to metals as compared to the values found in the literature and La Parguera terrestrial samples. Copper was three times more enriched than other estuarine samples and five times more enriched than samples taken from the salt flats; zinc was enriched more than ten times the level of the salt flats (Table
3.9).
Nutrients and Chlorophyll-a
Concentrations of nitrate (NO3), nitrite (NO2), ammonia (NH4) and phosphate did not vary among sites or with respect to site, weather or tide (Table 3.10; Appendix
2). The overall nitrate (1.36 mg-N/l), nitrite (0.004 mg-N/l), and ammonia (0.05 mg-
N/l), concentrations were low. Phosphate concentrations (0.04 mg-P/l) were also low.
Chlorophyll-a did vary significantly among stations (df = 3, 284; f-ratio = 12.22; p-value < 0.0001; Table 3.11). The overall mean chlorophyll-a concentration was 1.26 mg/l. Highest concentrations were at Station 6 (mean 2.57 mg/l) near the waste treatment
55 facility (Table 3.11). Lowest concentrations were near undeveloped and old development sites (mean, 0.72 ± 0.11 mg/l and 0.78 ± 0.11 mg/l, respectively).
Carbon: Nitrogen: Phosphorous Ratios
Particulate carbon, nitrogen and phosphorus were each significantly different among sites of different development classes (Table 3.12; Appendix 2). The overall mean carbon concentration was 395 mg/l, ranging from 54.8 to 977 mg/l. The highest concentration was near new development (Table 3.13). The overall mean nitrogen concentration was 67.9 mg/l, ranging from 9.07 to 194 mg/l. Nitrogen followed a similar trend as carbon with the highest value recorded near new development (Table 3.13).
Particulate phosphate varied between 33.9 and 3030 mg/l, mean = 617 mg/l. The highest concentration was near new development (Table 3.13).
There was no difference among development classes with respect to the C:N weight ratio; however, the C:P weight ratio did differ among development classes (df =
3, 224; F = 4.54; P = 0.0041; Table 3.14). The ratios of phosphorous to TSS and organic solids were both greater near new development as compared to upstream sites (df = 3,
120; F = 7.51; P = 0.001; df = 3, 120; F = 3.44; P = 0.02; Table 3.15)
Discussion
La Parguera is located in a unique subtropical dry forest. The high productivity of the near and off shore reefs attracts commercial and sport fishermen as well as
56 recreational SCUBA divers. Unique resources such as the phosphorescent bays also attract tourists. Recognizing the importance of the resources in this area, the U.S. Army
Corps of Engineers and Department of Natural and Environmental Resources classified
La Parguera and the surrounding waters as a marine reserve with the intention of protecting the biodiversity. However, the recent rezoning of this area increased development and tourism. This new development has caused substantial deterioration of the same natural resources that attracted tourism to the area. In addition, associated with new development was a number of declining water quality parameters, including increased suspended material, decreased available light for benthic organisms and elevated metal concentrations in benthic sediments. Water quality was impacted at sites near new development as compared to both control locations and sites near old development.
As expected, there was a difference in water temperature, ranging from 30.8oC in
August to 25.9oC in January (Table 3.1). Water temperature was the only parameter that differed with respect to time of year. Surface salinity was significantly lower at sites near old and new development after rain, suggesting a source of freshwater runoff
(Table 3.2). In addition, bottom salinities were significantly different at sites near new development. This suggests that although both new and old development sites receive runoff from similar areas, more freshwater was entering near new development. Salt flats and mangroves were not able to contain the freshwater, thus the significant changes in salinity. There were no differences between surface and bottom dissolved oxygen
(Table 3.3A and 3.3B).
57 Development appeared to have a significant effect on the available light reaching the benthic community. Areas near and downstream of development had less light reaching the benthic community than the undeveloped site upstream (Table 3.4).
Variability in light data was extremely high and only a limited number of samples were considered for this analysis, i.e. only samples collected on clear days between 10 AM and 2 PM. Areas near new development had the least amount of incident light reaching the bottom. Although the mean was enough to meet the minimum amount required for seagrass growth reported by Duarte (1991), the value was often below 11% of the incident radiation.
Light was limited by suspended material in the water column. Both the overall total suspended solids and turbidity were higher near new development than at all other sites (Table 3.5). Boat ramps directed runoff directly into the marine systems.
Concentrations of TSS were higher in samples collected on ebb tidal cycles suggesting that this material was continuously exported from mangroves (Figure 3.2). In addition, this material was predominantly inorganic. Turbidity, similar to TSS, was highest at new development areas. Unlike TSS, turbidity did not vary by tidal cycle. This might be a function of the type of material in the water, i.e. inorganic vs. organic. It appeared that new development was a point source for suspended solids and inorganic material in particular.
Transport of sediment into the marine system occurred after rain events and was reported by the local community to the Inter American University. However, there was no relationship between TSS and rain events. This was an artifact of the sampling
58 methods. A significant amount of time elapsed between the end of a rain event and the actual sampling.
A majority of the particles in the water column in this area were between 2 and
30 µm. During ebb tides the concentration of the fine silts in the water column were significantly higher as compared to flood tide. Although there were no significant differences among development classes, there was a significant trend in the concentration of fine silt material from east to west within La Parguera suggesting some effect from land use (Figure 3.3).
Metal concentrations in sediments of La Parguera Bay appeared to be affected by run-off from urbanized areas within the town of La Parguera. Concentrations increased adjacent to new development where the population has rapidly increasing over the past
10 years. By comparing metals data from La Parguera Bay to sediment quality guidelines from Long et al. (1995), it was apparent that Cu, Ni, and possibly Zn, concentrated in locations near development may be of biological concern. Copper, commonly found in anti-fouling bottom paint, was five times more enriched in the marine samples than in samples from the adjacent salt flats. Both new and old development sites had public boat ramps, marinas, and stilt houses with docked boats.
Metal concentrations in soils taken from the hills (Figure 3.1, Stations A, B, and
C) behind development in La Parguera were lower than in samples collected from salt flats (Station D, E, and F) and marine sediments. Upland sediments were the most likely reason behind the high Ni values (above ERL and ERM values) within the bay sediments closest to shore. Samples taken at Station E had the highest lead concentration, 120 mg/g, which may have resulted from contamination by a gas station
59 located near this area until early 1970s. In addition, all new development sites were located down stream of Station E and exhibited significantly elevated lead concentrations.
I determined an enrichment factor for each metal by normalizing data to an inert metal, aluminum. Aluminum, not greatly affected by human activities, is the most abundant metal in the Earth’s crust, and exhibits a good relationship to grain size (Ryan and Windom 1988). By comparing metal:aluminum ratios in sediments of La Parguera, it was possible to assess the overall enrichment of a particular metal at specific sampling sites. When enrichment factor values were assessed for La Parguera, copper showed the greatest anthropogenic influence (Figure 3.4). Both nickel and zinc were also elevated from naturally high concentration in this area. This enrichment was probably due to the heavy boat traffic in the bay and the use of bottom paints, known to contain Cu. Further studies are necessary in order to properly identify site-specific background values, and to better understand the geochemistry of sediments at La Parguera. Both local and federal governments should act to control metal pollution in areas where communities are dependent on seafood for their livelihood.
All nutrient concentrations were low in waters along La Parguera shoreline as compared to similar environments (Santoro 1998, Boyer et al. 1999, Boesch et al. 2001).
This was not surprising for this sub-tropical marine system since these systems are known to be nutrient poor and quite efficient at absorbing nutrient inputs. Nitrate (NO3) concentrations decreased with increased dissolved oxygen concentrations. As temperature decreased, ammonia concentrations increased and NO3 concentration decreased.
60 Phytoplankton can bloom rapidly in response to nutrient inputs and maintain low nutrient concentrations by sequestering them in algal biomass. Chlorophyll-a concentration was a good indicator of terrestrial nutrient inputs in this area, as has been shown elsewhere (Smith et al. 1981; Valiela et al. 1990). Chlorophyll-a was invariable between tidal cycles and with changes in weather conditions but was nearly double near the waste treatment facility (Table 3.11). There have been numerous complaints that the waste treatment infrastructure at La Parguera cannot support the expansion of the town.
Stilt houses often disconnect themselves from the treatment plant to prevent back-ups into their homes, particularly on weekends when use is highest. High fecal coliform counts were also found at this station (Ramirez-Toro et al. 2001). It was clear that excess nutrient inputs associated with a supersaturated waste treatment infrastructure was leading to higher algal blooms in this area.
Carbon to nitrogen weight ratios did not differ among sites. On the other hand, the carbon to phosphorous weight ratio did vary significantly in the vicinity of new development, suggesting a source of phosphorous in this area. The source may be the use of fertilizers in the landscaping of new homes. The addition of phosphorous can lead to algal blooms, in particular blue-green algae and other noxious species, and alter the natural algal species composition.
Between 1960 and 1997 the urbanized area in and around La Parguera increased from 4.7 to 25.2 km2, with most of the new development occurring to the west of La
Parguera. This trend continues today as expansive areas of dry forest are converted to subdivisions. Stations 5, 11, 14, and 6 (from east to west) received runoff from newly developed areas, and this was clearly reflected by reduced water quality. Benthic
61 sediments indicated elevated runoff in this area and an increased boat use appeared related to elevated metal concentrations.
In the early 1990s, citizens of La Parguera and Lajas petitioned the
Commonwealth and Municipal governments to control the unplanned, non-regulated use and development in the area, but to no avail. Little data were available to support the community’s position that this development was affecting water quality. The data presented here can be used to develop new strategies that minimize the impact to natural resources in this area without compromising associated tourism. A rigorous monitoring program would be prudent to ensure that anthropogenic impacts are detected.
Community involvement would strengthen sampling and increase awareness of the impacts management decisions have on the ecosystem. Results from such monitoring should be disseminated widely within the community to instill awareness and foster more sound stewardship of this delicate and vital natural resource.
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66 Table 3.1. Surface and bottom temperatures ± standard error (S.E.) by month in the vicinity of La Parguera, Puerto Rico. Data were square-root transformed to equilibrate differences in standard deviations. Months indicated by different letters are significantly different in temperature as indicated by Fisher’s least significant differences procedure (LSD).
Surface Temperature (oC) Bottom Temperature (oC) Month LSD LSD Mean ± S.E. Mean ± S.E Jan 25.9 ± 0.1 A 26.1 ± 0.3 A Feb 26.4 ± 0.1 B 26.4 ± 0.2 A Mar 27.3 ± 0.1 C 26.7 ± 0.4 AB Apr 28.8 ± 0.1 D 28.6 ± 0.2 C May 29.4 ± 0.1 E 29.2 ± 0.2 D Jun 29.9 ± 0.1 F 29.8 ± 0.1 E Jul 30.1 ± 0.1 F 30.0 ± 0.1 E Aug 30.8 ± 0.1 G 30.7 ± 0.2 F Sep 30.1 ± 0.1 F 29.9 ± 0.2 E Oct 30.1 ± 0.1 F 30.0 ± 0.2 E Nov 29.3 ± 0.1 E 29.2 ± 0.1 D Dec 27.7 ± 0.1 C 27.5 ± 0.2 B
67
Table 3.2. Surface and bottom salinity in parts per thousand (ppt) for all sampling dates with available rain data in La Parguera, Puerto Rico. Asterisk indicates significant differences between rain and clear for a particular development class. Surface salinities differed significantly at both old and new development sites between rain and clear sampling days. Bottom salinities only differed at new development sites between rain and clear sampling days.
Surface Salinity (ppt) Bottom Salinity (ppt) Clear Rain Clear Rain Mean ± S.E. Mean ± S.E. Mean ± S.E. Mean ± S.E. Undeveloped - Upstream 37.7 ± 0.3 37.0 ± 0.2 37.7 ± 0.3 37.1 ± 0.2 Old Development 37.6 ± 0.3* 37.0 ± 0.2B* 37.8 ± 0.2 37.2 ± 0.2 New Development 37.5 ± 0.2* 36.9 ± 0.2* 37.5 ± 0.2* 36.9 ± 0.2* Undeveloped - Downstream 37.5 ± 0.4 37.1 ± 0.5 37.3 ± 0.5 37.7 ± 0.4
68
Table 3.3. Mean surface (3.3A) and bottom (3.3B) dissolved oxygen concentration ± standard error (S.E.), in mg/l, by development class near La Parguera, Puerto Rico. Differences in the letter designation indicate significant differences among sites as determined by a Fisher LSD test.
Table 3.3A.
Clear Weather Rain Period Surface DO Surface DO Surface DO (mg/l) (mg/l) (mg/l) Mean ± S.E LSD Mean ± S.E LSD Mean ± S.E LSD Undeveloped - Upstream 5.61 ± 0.14 B 6.11 ± 0.20 B 5.30 ± 0.34 A Old Development 5.64 ± 0.13 B 6.08 ± 0.20 B 5.32 ± 0.33 A New Development 5.18 ± 0.11 A 5.26 ± 0.14 A 5.21 ± 0.29 A Undeveloped - Downstream 5.23 ± 0.25 AB 5.27 ± 0.28 A 5.18 ± 0.94 A
Table 3.3B.
Clear Weather Rain Period Bottom DO Bottom DO Bottom DO (mg/l) (mg/l) (mg/l) Mean ± S.E LSD Mean ± S.E LSD Mean ± S.E LSD Undeveloped - Upstream 5.54 ± 0.15 B 6.16 ± 0.28 B 5.16 ± 0.39 A Old Development 5.68 ± 0.15 B 6.08 ± 0.27 B 5.62 ± 0.37 A New Development 5.06 ± 0.12 A 5.05 ± 0.19 A 5.05 ± 0.33 A Undeveloped - Downstream 5.42 ± 0.29 AB 5.31 ± 0.39 A 5.78 ± 1.04 A
69 Table 3.4. Percent of incident light reaching bottom near La Parguera, Puerto Rico. Data were transformed using arc sine transformation to normalize the data. Significant differences by month were detected by Fisher’s least significant differences procedure (LSD).
Percent Light
Reaching Bottom Mean ± S.E LSD Undeveloped - Upstream 45.7 ± 3.6 B Old Development 22.5 ± 2.7 A New Development 17.5 ± 1.7 A Undeveloped - Downstream 21.3 ± 3.5 A
70 Table 3.5. Total suspended solids, mg/l, greater than 0.70 mm in the water column and turbidity (3.5A) by development near La Parguera, Puerto Rico. Samples collected during flood and ebb tidal cycles were separated (3.5B). Differences in the letter designation indicate significant differences among the sites as determined by a Fisher LSD test.
Table 3.5A.
Total TSS Turbidity
(mg/l) (NTU) Mean ± S.E LSD Mean ± S.E LSD Undeveloped - Upstream 31.3 ± 0.7 A 1.8 ± 0.17 A Old Development 32.3 ± 0.7 A 1.9 ± 0.17 A New Development 34.8 ± 0.6 B 3.1 ± 0.14 B Undeveloped - Downstream 31.8 ± 1.3 A 1.83 ± 0.30 A
Table 3.5B.
Flood Tide TSS Ebb Tide TSS (mg/l) (mg/l) Mean ± S.E LSD Mean ± S.E LSD Undeveloped - Upstream 30.9 ± 0.8 A 32.0 ± 1.4 A Old Development 31.7 ± 0.8 A 33.5 ± 1.3 A New Development 33.2 ± 0.7 A 37.3 ± 1.1 B Undeveloped - Downstream 30.7 ± 1.5 A 33.4 ± 2.3 AB
71
Table 3.6. Total inorganic suspended solids, mg/l, during flood and ebb tidal samples, near La Parguera, Puerto Rico. Samples collected during ebb tide were significantly different. Differences in the letter designation indicate significant differences among the sites as determined by a Fisher LSD test.
Total Inorganic Flood Tide Ebb Tide Suspended Solids Inorganic Inorganic (mg/l) Suspended Solids Suspended Solids (mg/l) (mg/l) Mean ± S.E LSD Mean ± S.E LSD Mean ± S.E LSD Undeveloped - Upstream 22.0 ± 0.8 A 20.6 ± 1.2 A 24.7 ± 0.6 A Old Development 23.0 ± 0.8 A 21.3 ± 1.1 A 24.9 ± 0.6 A New Development 24.4 ± 0.7 A 22.8 ± 1.0 A 27.3 ± 0.5 B Undeveloped - Downstream 22.5 ± 1.5 A 21.2 ± 2.2 A 24.4 ± 1.1 A
72 Table 3.7. Number of particles per ml between 2 and 30 mm (fine silts) and 30 and 64 mm (course silts) near La Parguera, Puerto Rico. Total particle concentration for all , stations was significantly greater during ebb tides as compared to flood tides (Table 3.7B)
Table 3.7A.
Particle Concentration Particle Concentration 2 – 30 mm 30 - 64 mm (particles/ml) (particles/ml) Mean ± S.E Mean ± S.E Undeveloped - Upstream 2240 ± 616 23.9 ± 9.9 Old Development 2800 ± 549 23.8 ± 8.8 New Development 3570 ± 452 38.1 ± 7.3 Undeveloped - Downstream 4100 ± 887 17.6 ± 14.3
Table 3.7B.
Particle Concentration Particle Concentration 2 - 30 mm 30 - 64 mm (particles/ml) (particles/ml) Mean ± S.E Mean ± S.E Flood Tide 2400 ± 345 28.1 ± 5.8 Ebb Tide 4430 ± 465 30.4 ± 7.8
73
Table 3.8. Concentration of lead, copper, chromium, nickel, zinc and aluminum, µg/g ± S.E., in marine and terrestrial samples of La Parguera, Puerto Rico. Overall sample mean for marine and terrestrial samples also included as values for Bermuda (Lyons et al 1983) and those determined by Long et al. (1995) as having effects on biological systems.
Pb (µg/g) Cu (µg/g) Cr (µg/g) Ni (µg/g) Mean ± S.E Mean ± S.E Mean ± S.E Mean ± S.E Undeveloped - Upstream 2.76 ± 3.94 8.01 ± 20.0 18.7 ± 8.37 16.0 ± 7.78 Old Development 9.15 ± 2.16 39.9 ± 11.0 38.0 ± 4.58 25.4 ± 4.26 New Development 13.6 ± 2.28 63.9 ± 11.6 48.7 ± 4.83 39.2 ± 4.49 Undeveloped – Downstream 9.50 ± 3.94 22.8 ± 20.0 44.9 ± 8.37 30.4 ± 7.78
La Parguera Marine Samples 10.0 ± 2.69 42.6 ± 6.15 40.3 ± 4.07 29.8 ± 3.87 Range 1.26 – 25.1 4.83 – 139 14.6 – 73.7 10.7 – 68.8
Bermuda (Lyons et al. 1983) 9.9 11.0 15.0 11
ERL (Long et al. 1995) 46.7 34.0 81.0 20.9 ERM (Long et al. 1995) 218.0 270.0 370.0 51.6
La Parguera hill slope 2.60 ± 1.52 37.4 ± 3.07 171.1 ± 13.9 149.4 ± 13.6 La Parguera salt flats 45.1 ± 8.08 77.9 ± 28.1 357.9 ± 13.1 287.6 ± 12.6 La Parguera Terrestrial Mean 23.8 ± 47.4 29.1 ± 5.4 264.6 ± 14.3 218.5 ± 13.5
74
Table 3.8. Metal Concentrations (continued).
Zn (µg/g) Fe (µg/g) Al (µg/g) Mean ± S.E Mean ± S.E Mean ± S.E Undeveloped - Upstream 39.0 ± 23.2 0.65 ± 0.67 1.21 ± 0.71 Old Development 68.4 ± 12.7 1.64 ± 0.26 2.93 ± 0.35 New Development 96.9 ± 13.4 2.18 ± 0.22 3.89 ± 0.33 Undeveloped - Downstream 50.7 ± 23.2 1.45 ± 0.39 2.55 ± 0.58
La Parguera Marine Samples 73.0 ± 6.6 1.42 ± 0.64 3.05 ± 1.24 Range 35.1 – 181 0.53 – 2.89 1.07 – 4.99
Bermuda (Lyons et al. 1983) NA NA NA
ERL (Long et al. 1995) 150.0 NA NA ERM (Long et al. 1995) 410.0 NA NA
La Parguera hill slope 89.2 ± 5.35 3.31 ± 0.78 5.30 ± 1.32 La Parguera salt flats 163.5 ± 8.85 4.42 ± 0.63 5.46 ± 1.16 La Parguera Terrestrial Mean 126 ± 8.26 3.86 ± 0.95 5.38 ± 1.19
NA – Not Available.
75
Table 3.9. Metal concentrations for samples in and around La Parguera, Puerto Rico, normalized to aluminum concentrations for comparison among samples in the literature (Browen 1979; Martin and Whitfield 1983; Windom et al. 1989).
Pb Cu Cr Mean ± S.E Mean ± S.E Mean ± S.E Undeveloped - Upstream 2.11 ± 1.12 5.81 ± 5.85 14.9 ± 2.45 Old Development 3.46 ± 0.56 14.2 ± 2.92 13.8 ± 1.22 New Development 3.58 ± 0.53 16.0 ± 2.76 12.9 ± 1.15 Undeveloped - Downstream 3.79 ± 0.92 9.03 ± 4.77 17.5 ± 2.00
La Parguera Marine Samples 3.42 ± 1.24 13.5 ± 2.89 14.0 ± 1.88 Range 0.31 – 6.31 4.11 – 34.3 6.02 – 19.6
La Parguera hill slope 0.20 ± 0.44 1.55 ± 0.34 4.57 ± 2.55 La Parguera salt flats 3.11 ± 2.16 3.30 ± 1.32 7.64 ± 2.11 La Parguera Terrestrial Mean 1.66 ± 1.83 2.43 ± 1.21 6.10 ± 2.29
Literature 3.3 ± 1.0 4.6 ± 1.5 9.3 ± 1.2
76
Table 3.9. Metal Enrichment (continued).
Ni Zn Mean ± S.E Mean ± S.E Undeveloped - Upstream 12.1 ± 2.49 31.4 ± 6.27 Old Development 9.57 ± 1.24 25.6 ± 3.13 New Development 10.4 ± 1.17 25.3 ± 2.95 Undeveloped - Downstream 12.0 ± 2.03 20.7 ± 5.12
La Parguera Marine Samples 10.5 ± 1.84 25.3 ± 2.93 Range 3.47 – 15.2 11.2 – 44.7
La Parguera hill slope 6.63 ± 3.16 1.26 ± 0.54 La Parguera salt flats 10.01 ± 2.54 2.42 ± 1.25 La Parguera Terrestrial Mean 8.32 ± 2.78 1.84 ± 1.19
Literature 5.7 ± 2.0 15.3 ± 3.9
77
Table 3.10. Nitrate (NO3), nitrite (NO2), ammonia (NH4) and phosphate (PO4) concentrations compared among different development classes in La Parguera, Puerto Rico. There were no significant spatial differences for any nutrients.
NO3 (mg-N/l) NO2 (mg-N/l) NH4 (mg-N/l) PO4 (mg-P/l) Mean ± S.E Mean ± S.E Mean ± S.E Mean ± S.E Undeveloped - Upstream 1.38 ± 0.08 0.005 ± 0.001 0.07 ± 0.02 0.04 ± 0.01 Old Development 1.37 ± 0.08 0.006 ± 0.001 0.06 ± 0.02 0.03 ± 0.01 New Development 1.37 ± 0.06 0.003 ± 0.001 0.06 ± 0.02 0.03 ± 0.01 Undeveloped - Downstream 1.31 ± 0.14 0.003 ± 0.001 0.04 ± 0.02 0.06 ± 0.01 Overall Mean 1.36 0.005 0.06 0.036 Range 0.05-4.20 0.001-0.025 0.001-0.75 0.001-0.237
78 Table 3.11. Chlorophyll-a concentrations, mg/l, compared among stations in La Parguera, Puerto Rico, from east to west. Data were transformed using the log function to correct for unequal variances. Differences in the letter designation indicate significant differences among sites as determined by a Fisher LSD test.
Chlorophyll-a Station Mean ± S.E LSD 1 0.80 ± 0.15 AB 2 0.65 ± 0.14 A 3 0.79 ± 0.15 AB 4 0.77 ± 0.14 AB 5 0.89 ± 0.14 B 14 1.60 ± 0.21 C 11 1.59 ± 0.24 C 6 2.57 ± 0.15 D 22 1.25 ± 0.20 BC
79 Table 3.12. ANOVA results comparing particulate carbon, nitrogen and phosphorous concentrations in the water column at sites having different development classes in La Parguera, Puerto Rico.
Degrees of F - Ratio P - Value Freedom Carbon 3, 224 3.51 0.0160 Nitrogen 3, 224 5.43 0.0013 Phosphorous 3, 224 10.53 <0.0001
80
Table 3.13. Concentrations of particulate carbon, nitrogen and phosphorous in mg/l by development code in La Parguera, Puerto Rico. Differences in the letter designation indicate significant differences among sites as determined by a Fisher LSD test.
Carbon Nitrogen Phosphorous
(mg/l) (mg/l) (mg/l) Mean ± S.E LSD Mean ± S.E LSD Mean ± S.E LSD Undeveloped - Upstream 350 ± 20.9 A 55.3 ± 4.92 A 14.7 ± 1.59 A Old Development 392 ± 20.2 AB 63.3 ± 4.77 A 15.9 ± 1.54 A New Development 436 ± 17.8 B 80.4 ± 4.20 B 25.1 ± 1.36 B Undeveloped - Downstream 361 ± 42.4 AB 69.3 ± 10.0 AB 19.7 ± 3.23 A
81
Table 3.14. Ratio of carbon to nitrogen weight, carbon to phosphorous weight, and nitrogen to phosphorous weight by development code in La Parguera, Puerto Rico. All ratios were log transformed to satisfy assumptions of one way ANOVA. Differences in the letter designation indicate significant differences among sites as determined by a Fisher LSD test.
Carbon:Nitrogen Carbon:Phosphorous Nitrogen:Phosphorous Mean ± S.E Mean ± S.E LSD Mean ± S.E Undeveloped - Upstream 7.24 ± 0.40 38.7 ± 5.89 B 5.89 ± 0.79 Old Development 7.45 ± 0.39 46.2 ± 5.71 B 6.50 ± 0.77 New Development 6.14 ± 0.34 23.5 ± 5.03 A 4.19 ± 0.68 Undeveloped - Downstream 6.31 ± 0.81 23.6 ± 12.0 AB 3.92 ± 1.61
82
Table 3.15. Ratio of phosphorous to total suspended solids and organic solids by development code in La Parguera, Puerto Rico. All ratios were log transformed to satisfy assumptions of one way ANOVA. Differences in the letter designation indicate significant differences among the sites as determined by a Fisher LSD test.
Phosphorous:TSS Phosphorous:Organic Solids Mean ± S.E LSD Mean ± S.E LSD Undeveloped - Upstream 0.37 ± 0.07 A 2.34 ± 0.52 A Old Development 0.48 ± 0.06 AB 2.66 ± 0.47 AB New Development 0.74 ± 0.05 C 4.05 ± 0.39 C Undeveloped - Downstream 0.71 ± 0.10 BC 4.18 ± 0.76 BC
83
New Development Old Development Station A Station B No Development No Development
Station C Station D Station E
X Station F X X Station 6 Station 11 X X X Station 5 X Station 14 X Station 3 Station 2 Station 4 Station 1 Station 22
N W E
S
1 0 1 Ki l om e t e r s
X = Boat Ramp
Figure 3.1. Marine study sites in La Parguera, Puerto Rico, indicated by numbers and terrestrial sites, indicated by letters.
84
Inorganic 40 Total 38 36 34 32 30 28 26
Suspended Material (mg/l) 24 22 20 1 2 3 4 5 14 11 6 22 Station
Undeveloped Old Undeveloped New Development Upstream Development Downstream
Figure 3.2. Total and inorganic suspended material (mg/l) ± S.E. in the water column during ebb tides near La Parguera, Puerto Rico. Land development indicated below station.
85
8000 7000 6000 5000 4000 3000 2000 1000 Particle Concentration (number/ml) 0 1 2 3 4 5 14 11 6 22 Station
Undeveloped Old New Undeveloped Upstream Development Development Downstream
Figure 3.3. Water column fine clay particle concentration (number/ml) ± S.E. in the vicinity of La Parguera, Puerto Rico, increased from east to west. Land development indicated below station.
86
5
4
3
2 Cu Enrichment
1
0 1 2 4 5 14 11 6 22 Station
Undeveloped Old New Undeveloped Upstream Development Development Downstream
Figure 3.4. Copper enrichment in La Parguera, Puerto Rico, as a result of increased recreational boat use and dockage. Land development indicated below station
87 Chapter 4: Effects of New Land Development on Seagrasses in the Vicinity of La Parguera, Puerto Rico
Abstract
New land development at La Parguera, Puerto Rico, has impacted the shallow benthic community by increasing sediment runoff. In areas near new development, seagrass shoot density and percent cover were reduced or absent compared with reference locations upstream in the long-shore current. Reduced seagrass health was associated with increased epiphyte load. Elevated epiphyte loads (0.49 g/g dry plant mass) were associated with reduced productivity near development. Total suspended solids, in particular the inorganic fraction, were significantly higher in waters sampled near new development. Areas near boat ramps also had elevated metal concentrations in the sediments. Despite the terrestrial source, the overall sediment composition was not significantly different in areas devoid of seagrass compared with sites with abundant seagrass. Seagrasses might therefore be able to re-colonize disturbed areas near new development if nutrient and sediment inputs can be reduced, thereby reducing epiphyte fouling and increasing water clarity, respectively. Despite the wealth of research showing the negative impacts of development and associated water quality degradation on seagrass beds, little integrative analyses have examined the sum of these impacts at one location. Further, virtually nothing has been done to study such relationships along rapid development trajectories such as that at La Parguera.
88
Introduction
Throughout the world, many seagrass beds are in a stressed state, and losses of seagrass acreage have been extensive (Short et al. 1991, Short and Burdick 1996, Short and Wyllie-Echeverrria 1996, Zieman et al. 1999). The overall decline of seagrasses is attributed to a variety of light attenuating processes related to watershed development and the associated degradation of water quality (den Hartog and Polderman 1975; Cambridge and McComb 1984; Chambers and Kalff 1985; Cambridge et al. 1986; Iverson and
Bittaker 1986; Dennison 1987; Orth and Moore 1983; Dennison et al. 1993; Tomasko et al. 1996). This situation is alarming to both coastal managers and ecologists since seagrass meadows serve as nurseries for reef fish communities and provide habitat for fish, shrimp and other invertebrate species (Heck and Thoman 1984, Lee Long et al 1996,
Lipcius et al. 1998, Nagelkerken et al. 2000, Nagelkerken et al. 2001).
In most of the world, declining water quality is often associated with increases in sediment loads (Perry and Vanderklein 1996). Sediment input results from the clearing of land, i.e. forested to residential and commercial, and the channelizing of surface runoff. Suspended solids in the water column decrease available light reaching the benthic plant community. Changes in depth, distribution, size, and biomass of seagrass meadows can occur in response to changes in levels of light (Dawes 1998; Dennison et al. 1993; Czerny and Dunton, 1995). Light reduction also impacts seagrasses by impairing their growth rate (Czerny and Dunton 1995; Lee and Dunton 1997; Kraemer
89 and Hanisak 2000), blade length (Czerny and Dunton 1995; Lee and Dunton 1997), blade density (Tomasko and Dawes 1989; Shafer 1999) and the availability of oxygen reaching the roots (Smith et al. 1984). The physical structure of the seagrass bed is usually lost first; this is followed by changes in the food web and dissolved oxygen (Deegan 2002).
If irradiance is resumed normal growth rates can return (Kraemer and Hanisak 2000).
Increased turbidity is associated with the decline in Thalassia along the Florida Keys
(Lapointe et al. 1994). Species within a seagrass ecosystem have different light requirements; therefore composition can be affected by reduced light (Fourqurean et al.
1995; Davis and Fourqurean 2001).
The impact of increased suspended solids is two-fold. First, as water velocity decreases by the seagrass bed, suspended solids settle out of the water. Thalassia is one of the most effective seagrasses in trapping fine suspended particles because of its broad leaves (Wood et al. 1969; Zieman 1972; Burrell and Schubel 1977). The growth of
Thalassia is significantly decreased as a result of sediment deposited on leaf surfaces
(Phillips 1980). Second, deposition of suspended solids can result in physical burial of benthic plants, which may already be at growth levels below optimum due to low light levels.
In addition to total suspended solids, phytoplankton blooms and epiphytic loads decrease the available light reaching seagrasss (Durako and Moffler 1985; Duarte 1991;
Dennison et al. 1993). Tomasko et al. (1996) reviewed the effect of anthropogenic nutrient enrichment on seagrass community decline. Production and health of seagrasses
90 is impacted by epiphytes by shading the photosynthetically active portion of seagrass blades (Orth and Van Montfrans 1984; Jernadoff et al. 1996). In many areas, epiphytes represent a significant portion (20%) of the mean annual net production in seagrass communities (Phillips 1980). Leaf size affects the type and abundance of epiphytes
(Jernakoff et al. 1996).
The impacts of changing land use are seen in the water quality of the marine system near La Parguera, Puerto Rico. La Parguera was traditionally a small village with an economy based on fishing and small-scale, local tourism. In 1994, the Puerto Rico
Planning Board created a Tourist Zone in and around La Parguera. This created an entirely new town, allowing development in a large portion of the dry forest and salt flat area. Since this rezoning, development has encroached on salt flats and mangroves and destroyed much of dry forest habitat. Impacts of this rezoning include physical changes to the landscape and habitat damage, increased pressure on infrastructure, an increase in sediment loads and increased boat and vehicle traffic. Little data have been collected on the impact of these changes on the shallow marine system (Corredor and Morell 1994).
The mangroves and seagrasses are the first defense as terrestrial runoff enters the marine system. These systems are critical in the survival of the fragile coral systems offshore La Parguera, and are one of the many tourist attractions in this area. Seagrass beds near La Parguera are in a state of decline. A map of the 1979 distribution of seagrass meadows near La Parguera indicated a system dominated by Thalassia
91 (González-Liboy 1979). Spotila et al. (1996) reported that a significant portion of the
1979 seagrass meadow no longer existed.
With this in mind, my goal was to determine if sediment from the new development and increased tourism in La Parguera was impacting the seagrass ecosystem. My first hypothesis was that coastal development in La Parguera had a negative impact on the seagrass health. To test this I measured growth rates and productivity at sites that represented varying stages of development where seagrass beds were found. I also measured epiphytic biomass on the leaves of Thalassia where plants were found. My second hypothesis was that sedimentation rates were higher in areas near development. To test this hypothesis I compared sedimentation rates among different areas experiencing different development activities at La Parguera
Materials and Methods
Study Site
La Parguera is located in the subtropical dry terrain of southwest Puerto Rico.
The Palmarejo Mountains, to the north, produce a rain shadow effect. The average tidal range is less than 0.25 m. The prevailing shoreline faces south and the long shore current runs from east to west (Avila et al. 1979). Using existing information and general observations, I selected 9 marine study sites near La Parguera to measure seagrass health
92 and sedimentation (Figure 4.1). Stations were selected based on their proximity to small watersheds having varying stages of old and new development.
· Station 1 was east of La Parguera and adjacent to an undeveloped, naturally vegetated
hill. An extensive mangrove system fringed the terrestrial system. This station
served as an upstream vegetated control.
· Station 2 was also upstream of La Parguera; however, it was adjacent to an
unvegetated, undeveloped hill. The hillside was steep and rock was exposed. There
were no mangroves in this area. This station served as an upstream unvegetated
control.
· Station 3 was adjacent to a low density, established development that existed since
the 1960’s. An extensive fringe mangrove system was present between the houses.
Some areas of the mangroves were cut to fit boats, docks, and houses.
· Station 4 was located between Isla Magueyes and La Parguera. There was extensive
development on the land, a public boat ramp, and a ferry to the University of Puerto
Rico Marine Lab, Isla Magueyes. Mangroves were present between houses but had
been extensively cut to fit boats, docks, and houses.
· Station 5 was to the east of a popular tourist hotel. There were permitted and non-
permitted boat ramps in this area. The hillsides behind this area were extensively
developed and drainage from newly developed areas into the marine environment was
not being managed. Mangroves were present but had been extensively cut for boats,
docks and houses.
93 · Station 14 was located near the local fisherman’s dock. Vegetation was extremely
sparse in this area (Spotila et al. 1996). New land development was extensive on the
hill directly north of this station. Boat ramps in this area acted as channels for
sediment runoff from the ongoing construction on adjacent hillsides.
· Station 11 was located west of La Parguera in a channel that had high boat use. A
marina was located on the mainland. Similar to Station 14, sediment from new
development entered the marine system in this area.
· Station 6 was located further west of La Parguera. Mangroves were present on the
mainland and on the keys located to the south. There was no development in this
area, however, secondary effluent from a waste treatment facility flowed through the
mangrove.
· Station 22 was located to the west of Boquirón. There was no development on the
mainland near this site, which was the downstream control.
For statistical analysis I also classified stations by level of development: Stations
1 and 2 were undeveloped, upstream control; Stations 3 and 4 were grouped as old development; Stations 5, 14, 11, and 6, were classified as new development; and Station
22 was an undeveloped downstream control.
94 Field Methods
Rainfall and temperature data during the study period were obtained from the
University of Puerto Rico, Marine Biology Station on Magueyes Isla. Data at the station were only recorded during workdays. No weekend or holiday data were available.
Species Composition
Between March 10, 1999 and November 10, 1999, my assistants and I surveyed 4 transects at sites with seagrass beds for species composition, percent cover, and shoot density. At Stations 1, 2 and 3, we surveyed four 100 m transects. Stations 4 and 22 were located between mangrove cays and the mainland and only permitted transects up to
65 m. One meter square quadrats were placed on the east side of the transect at five meter intervals beginning at the origin. Percent cover was visually estimated within the quadrat. Species composition and shoot density were recorded within a 0.25 m2 subdivision of the quad according to Dennison (1990). The above ground biomass, standing crop, for three 0.25 m2 subdivisions of the quad were clipped and returned to the lab (Ott 1990). All laboratory samples were frozen and shipped to The Academy of
Natural Sciences (ANS) for analysis. At ANS, biomass samples were separated by species and dried at 105oC for three day. Samples were then weighed to the nearest mg.
95 Seagrass Measurements
I measured the health of seagrass beds in La Parguera between February 23, 1999 and May 9, 2001. At each station with seagrasses, I measured Thalassia growth rates and productivity according to standard methods (Zieman and Wetzel 1980; Tomasko et al.
1996). I marked at least 5 plants in 2 m of water at the base of the meristem with a 1 mm diameter wire and collected them 14 days later. There were no plants near new development, Stations 5, 14, 11, and 6, at a depth greater than one meter. In the laboratory, I separated plant material into new and old growth and measured, dried and weighed each to determine new production.
Epiphytes
I removed epiphytes by lightly scraping the blades of Thalassia with a razor and collecting the scrapings on a pre-weighed filter. I dried, weighed, then ashed the epiphytes to determine percent organic content. I measured total length as well as blade width for each scraped Thalassia blade according to Bulthuis (1990). From this, I determined total epiphytic load per mass (g epi/g) and leaf area (g/cm2).
Sediment Trap
Sediment traps were similar to those used by Asper (1987). I placed traps in triplicate at all 9 stations and attempted to target rain events. I filled traps with filtered seawater, capped them, and carefully placed them into stands that consisted of permanent
96 PVC pipes with couplings that allowed the traps to sit in an upright position. Care was taken that snorkelers did not kick any seagrasses or sediment while underwater with the traps. The top of the trap was 0.25 m above the bottom, sediment or seagrass canopy.
Once the traps were in position, I removed their covers. I collected the traps after 24 h of exposure. I carefully removed the traps and placed them in a cooler in an upright position. I filtered the material collected in the traps onto pre-weighed filters, froze them and shipped them to ANS. At ANS, I dried the sediments for 48 hours at 105oC and weighed them to 0.00001 g. I ashed the filters to determine organic and inorganic fractions.
I collected benthic sediment samples from each station on one trip. I analyzed samples for inorganic and organic fraction using loss on ignition (LOI).
Plaster Ball
I used gypsum-based, plaster of Paris, “plaster balls”, to compare relative water movement at the stations where sediment traps were placed. Plaster balls were prepared according to Porter et al. (2000). In the field, we hung the balls 0.25 m over the seagrass beds, where present, or over the bottom. We collected the balls after a 24 h exposure period, dried them at 105oC for 48 hours and weighed them to the nearest mg.
Statistics
97 I entered data in Microsoft Excel (97) and coded it for statistical analysis. The main effects coded included date, station, weather, and season. Using Statgraphics Plus
(Version 5), I first tested data for normality using the Shapiro-Wilks W statistic. If the data were not normally distributed, I transformed them to satisfy the normality assumption. The Levene’s test for homogeneity of variances tested for homoscedasticity.
The Pearson product moment correlation tested for correlations between paired variables.
A statistically significant correlation was considered at the 95% confidence interval (P <
0.05). An analysis of variance (ANOVA) examined spatial variability among the data.
Statistical differences among means were determined with Fisher’s least significant difference (LSD) procedure at a 95% confidence interval (Sokol and Rolf 1995).
Results
Species Composition
Seagrass beds were only found at Station 1, 2, 3, 4, and 22. I tried to maintain similar depths in the placement of transects. Data from depths less than 1.75 or greater than 2.25 were not considered. The average depth along the transects was 1.8 m. I recorded Thalassia along all transects (Table 4.1; Figure 4.2). The overall average percent cover for stations with seagrass was 67.7%. Percent cover varied by station,(df =
4, 290; F = 46.53; P < 0.0001; Table 4.2). The overall average species composition was
1.85 species/m2. Species composition was greater at Stations 2 and 4 as compared to all
98 other sites (df = 4, 322; F = 41.67; P < 0.0001; Table 4.3). Shoot density was also different among stations (df = 4, 217; F = 50.56; P < 0.0001; Table 4.3), with an overall average 19.8 shoots/m2.
Above ground biomass at these sites was dominated by Thalassia and Halimedia with averages of 275 and 434 g/m2, respectively. Thalassia biomass varied significantly by station with the greatest amount at Station 1 and least at Station 22 (df = 4, 459; F =
7.47; P < 0.0001; Table 4.4). Halimeda also had the greatest biomass as Station 1; lowest biomass was at Stations 4 and 22 (df = 4, 311; F = 20.16; P < 0.001; Table 4.4;
Figure 4.2).
.
Growth Rates and Productivity
I measured growth rates of Thalassia on fourteen separate sampling trips.
Growth rates differed with varying stages of development (df = 3, 1944; F = 2.71; P =
0.0440; Table 4.5). The overall growth rate for this area was 0.63 cm/day. The highest growth rate was at the downstream site.
Productivity data were collected on five dates between December 21, 1999 and
March 7, 2001. The overall productivity of Thalassia in this area was 3.06 g/m2. The greatest productivity was upstream of development in La Parguera and the least was downstream of the town (df = 3, 163; F = 48.50; P < 0.0001; Table 4.6; Figure 4.2). The overall productivity when rain accumulation was greater than 0.75 cm during the time of the experiment was also significantly lower (2.42 ± 0.36 g/m2) as compared to when there
99 was no rain (3.71 ± 0.36 g/m2; df = 1, 165; F = 6.31; P = 0.0130). Productivity at the upstream undeveloped site was the only area that did not differ significantly between rain and no rain conditions.
Leaf Characteristics and Epiphytes
Overall blade length and area were 40.9 cm and 29.5 cm2, respectively (Table
4.7). Blade length and area varied significantly among stations (blade length: df = 7,
1927; F = 38.73; P < 0.0001; blade area: df = 7, 247; F = 7.14; P < 0.0001). Overall,
25.7% of the blades had bite marks, ranging form 14.8% at Station 3 to 46.7% at Station
22.
Total epiphytic load varied among development class (df = 3, 26; F = 3.16; P =
0.0416; Table 4.8; Figure 4.3). The overall average was 0.36 g epi/g, ranging from a 0.17 g epi/g upstream of development to an average of 0.55 g epi/g near development. The overall average inorganic fraction was 77.7%, ranging from 69.8% downstream of development to 79.8% near old development (Table 4.8). The inorganic fraction varied significantly with respect to development class (df = 3, 26; F = 2.84; P = 0.0521)
Sedimentation
Water movement, quantified by the dissolution of the plaster balls, was significantly greater at Stations 1 through 3 as compared to all other sites (df = 8, 275; F
= 21.98; P = 0.0001). The overall loss in ball mass was 0.56 g/day, ranging from 1.12
100 g/day at Station 2 to 0.47 g/day at Station 5 (Table 4.9). There was no difference in sedimentation rates among stations or the percent inorganic fraction (Table 4.10). The overall sedimentation rate near La Parguera was 1.91 g/m2 day with an average inorganic fraction of 77.3%.
Station 6 had the overall highest inorganic fraction of the benthic sediments
(95.0%). Averages ranged from 76.6% at Station 4 to 97.9% and 98.1% at Stations 5 and
11 (Table 4.11). There was a significant difference among Stations (df = 8, 22; F =
52.83; P < 0.0001).
Discussion
Declining water quality associated with uncontrolled development appeared to impact the health of the seagrasses in La Parguera. Total suspended solids were significantly higher near new development in La Parguera (mean, 34.8 mg/l) as compared to both upstream and downstream sites (mean, 31.5 mg/l) (Chapter 3). The light attenuation at sites near new development (17.5%) (Chapter 3) was also greatest among all development codes and often fell below the minimum required for seagrass growth
(Duarte 1991). This in combination with elevated sedimentation rates appeared to be contributing to the declining distribution of seagrass in La Parguera.
The species composition in La Parguera was typical for shallow Caribbean systems. The seagrass community near La Parguera was a mix of macro algae and
101 flowering plants. Although Thalassia was the dominant seagrass, Syringodium made up a large portion of the plant community at Station 2, which had the greatest degree of wave exposure. At both Station 1 and 2, the calcareous macro algae Halimeda sp. represented a greater portion of the biomass than Thalassia and Syringodium combined.
Macro algal species are pioneers in the successional sequence of bare sediment suggesting that these areas were more exposed to wave action (den Hartog 1971; Zieman
1982).
In 1979, González-Liboy surveyed the benthic community near La Parguera.
Although the survey was limited to the area between Stations 3 and 5, most of this was covered with extensive seagrass beds. Dense seagrass beds still covered most of the areas that were surveyed in 1979, and in some areas the beds increased in size. In fact, standing biomass increased from 61.2 g/m2 in 1979 to 264 g/m2 near Station 4 and 173 to 312 near Station 3. However, in 1979, areas near Station 5 had 128 g/m2, whereas by
1997, all of the seagrass beds with the exception of a few patch communities at a depth of less than one meter disappeared from Station 5 west up to a kilometer.
Thalassia blade length, blade area, growth rates, and productivity were measured to assess the health of the seagrass beds. Shoot density, seagrass biomass, and Thalassia productivity declined along the development gradient in La Parguera to Station 5 (Figure
4.2). At Station 2, the seagrass community was a mix of Thalassia and Syringodium, and this may explain the higher shoot density and lower biomass in this area. There were no seagrasses at 2 m depth at any of the stations near new development. The small leaf
102 length and area for Thalassia at Stations 1 and 2 are probably the result of increased wave exposure and not light limitation.
Available light appeared to limit productivity near new development. In 1979 the productivity of seagrass was 5.47 g/m2day near Station 5 but there was no seagrass at this site in this study. Productivity near old development was similar between 1979 (2.99 g/m2day) and this study (3.07 g/m2day). The combination of light attenuation and elevated sedimentation rates in the area near new development appeared to reduce the distribution of seagrass in this area.
Although there were no significant spatial differences in sedimentation rates,
Station 5 had the highest rate in this area (2.58 g/m2 day) followed by Station 14 (2.56 g/m2 day). The inorganic fraction for all stations near new development was above the overall area average (77.3%). Elevated sedimentation rate and reduced light attenuation appear to suppress productivity and growth rates which in turn may be the primary reason that Thalassia was obliterated near new development.
Nutrient and light limitations impact species interactions even if dissolved nutrients are not abundant (Davis and Fourquean 2001). Available dissolved nutrients are efficiently taken up and converted to particulate biomass such as phytoplankton and epiphytes. Nutrient concentrations around La Parguera were low (Chapter 3). Seston chlorophyll-a was elevated near new development and exceeded twice the overall average (1.26 mg/l) at sites near the waste treatment facility (2.57 mg/l). Epiphytes were analyzed for organic and inorganic fractions. There was no difference in the organic
103 fraction of the epiphytes on the leaf blades near varying stages of development (Table
4.8). This suggests that nutrients did not play as significant a role in epiphytic growth in this area, as compared to phytoplankton growth..
The loss of seagrass as a result of anthropogenic impacts is well documented
(Short et al. 1991, Short and Burdick 1996, Short and Wyllie-Echeverrria 1996, Zieman et al. 1999). It is estimated that 20 -100% of the seagrasses in parts of the Gulf of
Mexico have disappeared in the past 50 years as a result of natural and human-induced effects, e.g. increased turbidity and decreases in water quality from dredging, boating, and development (Handley 1995). In Apalachicola Bay, Florida, water and sediment quality determine the distribution of seagrasses and macro algae, which, in turn, influence seasonal successions of animal populations and trophic interactions within the system
(Livingston 1984). Water quality and preservation of the natural resources are often major concerns to local communities that depend on both for their livelihood. The relationship between anthropogenic nutrient inputs and the degradation of the seagrass ecosystem is well documented for the Chesapeake Bay (Dennison et al. 1993; Dauer et al.
2000; Moore et al. 2000), Florida Bay (Hall et al. 1999; Zieman et al. 1999), and western
Australia (Cambridge and McComb 1984; Udy et al. 1999). Seagrass beds buffer fragile off shore communities, trap anthropogenic sediments and provide refuge and nurseries for fish and shellfish.
La Parguera has a number of unique resources. Brilliant phosphorescent bays and healthy coral reefs have attracted both local and international travelers. In 1995, the
104 Puerto Rico Planning Board rezoned this area to accommodate the expanding tourism industry. In so doing, most of the tropical dry forest was opened for development. This new development was concentrated in the western portion of the town. Rain events were observed washing large quantities of sediment from the areas under construction into the adjacent bay area. Elevated concentrations of total suspended solids in the water column near new development increased light attenuation to the benthic community, often below the minimum required for seagrass growth (Chapter 3), and appeared to decrease productivity and growth rates. High sedimentation rates placed an increased stress on the ecosystem, potentially burying any plant able to survive. In fact, these conditions were not even favorable for macro algae. In addition, sediments near boat ramps were also contaminated with copper at levels that suggested biological impacts (Chapter 3).
The seagrasses near new development in La Parguera disappeared as a result of anthropogenic inputs. Once the impacts associated with construction of new homes are removed, it may be possible for seagrasses to re-colonize the area now devoid of benthic plants. Seagrass beds near the older development in La Parguera saw an increase in biomass and productivity since 1975. Continued monitoring of this area will increase the understanding of development on seagrass beds.
105 References
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110
Table 4.1. Seagrass sampled at five stations at La Parguera, Puerto Rico, for species composition, biomass and shoot density. There was no seagrass near new development at the two meters depth
Station 1 2 3 4 22 Transect 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 1 2 3 4 Thalassium testudinum X X X X X X X X X X X X X X X X X X X X Syringodium filiforme X X X X X X X Caulerpa sertularioides X X X X X Caulerpa taxifolia X X Caulerpa mexicana X X Caulerpa prolifera X Caulerpa racemosa X X Caulerpa verticillata X X Udotea X X X X Penicillus capitatus X X X X X X X X X X X X X X X X Halimeda copiosa X Halimeda tuna X X Halimedia incrassata X X X X X X X X X X X X X Halimeda monile X X X X X Halimeda optia X X Dictyota X X X X X X X X X X X Avrainvillea X X Green algae mat X X
111 Table 4.2. Mean percent cover, ± S.E., along transects at stations with seagrass beds near La Parguera, Puerto Rico. Data were arc sine transformed before one-way ANOVA. Differences in the letter designation indicate significant differences among the sites as determined by a Fisher LSD test.
Percent Cover Mean ± S.E LSD 1 84.0 ± 4.00 B 2 80.8 ± 3.65 B 3 79.1 ± 3.13 B 4 76.3 ± 4.03 B 22 18.9 ± 4.03 A
112 Table 4.3. Number of species per m2 and shoot density (shoots m-2), ± S.E., along transects at stations with seagrass beds near La Parguera, Puerto Rico. Shoot densities were log transformed before one-way ANOVA. Differences in the letter designation indicate significant differences among the sites as determined by a Fisher LSD test.
Species Composition Shoot density Mean ± S.E LSD Mean ± S.E LSD 1 2.07 ± 0.09 B 23.3 ± 1.94 C 2 2.32 ± 0.09 C 49.1 ± 1.78 D 3 1.32 ± 0.09 A 18.9 ± 1.52 C 4 2.62 ± 0.12 C 6.57 ± 1.97 B 22 0.80 ± 0.12 A 3.34 ± 1.97 A
113 Table 4.4. Biomass (g/m2) of seagrass (Thalassia and Syringodium) and dominant macro algae along transects at stations with seagrass beds near La Parguera, Puerto Rico. Data were log transformed before one-way ANOVA. Differences in the letter designation indicate significant differences among the sites as determined by a Fisher LSD test.
Thalassia testudinum and Halimeda sp. Syringodium filiforme Mean ± S.E LSD Mean ± S.E LSD 1 389 ± 30.2 C 803 ± 47.0 C 2 248 ± 24.9 B 354 ± 43.1 D 3 312 ± 39.7 BC 271 ± 55.0 C 4 264 ± 57.7 BC 192 ± 60.9 B 22 85.8 ± 53.6 A 95.0 ± 56.1 A
114 Table 4.5. Growth rate (cm/day) for Thalassia in the vicinity of varying stages of development near La Parguera, Puerto Rico. Data were log transformed before one-way ANOVA. Differences in the letter designation indicate significant differences among the sites as determined by a Fisher LSD test.
Growth Mean ± S.E LSD Undeveloped - Upstream 0.59 ± 0.02 A Old Development 0.61 ± 0.02 A Undeveloped - Downstream 0.70 ± 0.02 B
115
Table 4.6. Productivity (g/m2day) for Thalassia in the vicinity of varying stages of development near La Parguera, Puerto Rico. Data were log transformed before one-way ANOVA. Differences in the letter designation indicate significant differences among the sites as determined by a Fisher LSD test.
Clear Weather Rain Period
Productivity Productivity Productivity Mean ± S.E LSD Mean ± S.E LSD Mean ± S.E LSD Undeveloped - Upstream 5.56 ± 0.39 C 6.73 ± 0.54 C 4.55 ± 0.51 C Old Development 3.09 ± 0.40 B 4.66 ± 0.59 B 2.01 ± 0.50 B Undeveloped - Downstream 1.18 ± 0.53 A 1.63 ± 0.68 A 0.67 ± 0.74 A
116 Table 4.7. Blade length (cm) and area (cm2) for Thalassia for stations near La Parguera, Puerto Rico. Differences in the letter designation indicate significant differences among the sites as determined by a Fisher LSD test.
Blade Length Blade Area Mean ± S.E LSD Mean ± S.E LSD 1 34.1 ± 1.31 B 32.6 ± 3.68 B 2 28.2 ± 1.17 A 22.2 ± 2.14 A 3 47.2 ± 1.18 D 38.6 ± 2.18 B 4 48.3 ± 1.14 D 44.0 ± 2.67 B 22 46.9 ± 1.03 D 39.4 ± 3.68 B
117
Table 4.8. Total epiphytic load, g/g dry plant mass, in the vicinity of varying stages of development near La Parguera, Puerto Rico. Differences in the letter designation indicate significant differences among the sites as determined by a Fisher LSD test.
Total Load Percent Inorganic Percent Organic Mean ± S.E LSD Mean ± S.E LSD Mean ± S.E Undeveloped - Upstream 0.17 ± 0.09 A 76.4 ± 2.32 AB 23.6 ± 2.32 Old Development 0.55 ± 0.09 B 79.8 ± 2.48 B 20.2 ± 2.48 Undeveloped - Downstream 0.39 ± 0.12 AB 69.8 ± 3.28 A 30.2 ± 3.28
118 Table 4.9. Dissolution of gypsum plaster balls (g/day) in the vicinity of varying stages of development near La Parguera, Puerto Rico. Differences in the letter designation indicate significant differences among the sites as determined by a Fisher LSD test.
Dissolution Mean ± S.E LSD 1 0.96 ± 0.05 C 2 1.12 ± 0.05 D 3 0.83 ± 0.05 C 4 0.66 ± 0.05 B 5 0.55 ± 0.05 AB 14 0.56 ± 0.05 AB 11 0.66 ± 0.05 B 6 0.47 ± 0.05 A 22 0.56 ± 0.04 AB
119 Table 4.10. Sedimentation rate (g/m2day) and inorganic fraction in the vicinity of varying stages of development near La Parguera, Puerto Rico.
Sedimentation Rate Inorganic Fraction Mean ± S.E Mean ± S.E 1 2.49 ± 0.55 76.8 ± 3.67 2 1.56 ± 0.78 79.9 ± 4.49 3 2.33 ± 0.49 77.6 ± 2.84 4 1.50 ± 0.37 77.8 ± 2.25 5 2.58 ± 0.39 78.2 ± 2.40 14 2.56 ± 0.64 77.8 ± 3.67 11 1.17 ± 0.64 80.5 ± 3.67 6 1.12 ± 0.55 79.0 ± 3.18 22 1.62 ± 0.42 71.6 ± 2.59
120 Table 4.11. Benthic sediment inorganic fraction near La Parguera, Puerto Rico. Differences in the letter designation indicate significant differences among the sites as determined by a Fisher LSD test.
Inorganic Fraction Mean ± S.E LSD 1 89.3 ± 1.57 BC 2 89.9 ± 1.57 C 3 86.0 ± 1.36 B 4 76.6 ± 1.36 A 5 97.9 ± 1.22 E 14 91.1 ± 1.57 D 11 98.1 ± 1.57 E 6 95.0 ± 1.57 C 22 80.2 ± 1.57 A
121
New Development Old Development
No Development No Development
Station 6 Station 11 Station 5 Station 3 Station 2 Station 4 Station 1 Station 22 N
W E S 1 0 1 Ki l o me t er s
Figure 4.1. Map of the La Parguera, Puerto Rico. Seagrass beds were present from Station 1 through 4 then reappear near Station 22. .
122
500 60 388/C B 49.1/D A 400 312/BC 263/BC 247/B 40 300 23.3/C 200 18.9/C 20 85.8/A
6.57/B Biomass (g dry wt/m2) 100 3.34/A Shoot Density (Shoots/m2) 0 0 1 2 3 4 5 14 11 6 22 1 2 3 4 5 14 11 6 22 Station Station
Undeveloped Old New Undeveloped Undeveloped Old New Undeveloped Upstream Development Development D Upstream Development Development D o o 10 w w C 8 6.82/C
6 4.15/B 3.53/B 4 1.89/A 2 1.18/A
Productivity (g/m2 day)
0 1 2 3 4 5 14 11 6 22 Station
Undeveloped Old New Undeveloped Upstream Development Development D o w
123
Figure 4.2. Shoot density (A), biomass (B), and productivity (C) for seagrasses (Thalassia and Syringodium), near La Parguera, Puerto Rico. Light columns indicate productivity measured at 1 m. Differences in the letter designation indicate significant differences among sites as determined by a Fisher LSD test.
Undeeloped Old New Undeveloped Upstream Development Development Downstream 0
0.7 8
0.6 7
6 0.5 5 0.4 4 0.3 3 0.2 2 Productivity (g/m2 day)
0.1 1 Inorganic Epiphytes (g/g dry plant)
0 0 1 2 3 4 5 14 11 6 22 Station
Undeveloped Old New Undeveloped Upstream Development Development Downstream
Figure 4.3. Inorganic epiphytic load (g/g dry plant mass; bars) and productivity (g/m2 day; lines) at stations with seagrass. Lighter color bars indicate station where measurement made at 1 m.
124 Chapter 5: Resource Management of a Temperate and Tropical Marine System: Success and Failure
Introduction
Coastal ecosystems are among the most diverse and productive systems; however, until the 1960s it was not clear who was responsible for their protection. During the
1970s environmental laws were passed to regulate air contaminants, water pollution, and hazardous waste. More then twice as many federal acts were passed in the 70’s (sixteen) compared to the 60’s (seven) or the 80’s (six; Lester 1995). New Federalism was shifting authority from federal to state governments and responsibility for the environment fell to local agencies. However, state and local governments often lacked the technical expertise available to the national government. In addition, during the Reagan and Bush administrations, the states were subject to budgetary cuts particularly in water pollution control (Buck 1996). States were forced to revise constitutions, strengthen the governor’s office, increase revenues through tax, and provide greater opportunities for citizen participation (Lester 1995). Environmental institutions were formed, staffed with capable personnel, and funded. Ultimately, New Federalism depended on environmental protection activities and the institutional capabilities (Lester 1995). Some were successful; others were not.
It is difficult to measure the success or failure of environmental policy and whether it achieved its stated objectives (Buck 1996; Vig and Kraft 2000). Environmental policy is
125 usually fragmented and spread over several different federal agencies and departments; there is no single federal agency in charge of coordinating the different programs and laws and there is no comprehensive, unified national coastal management plan or program
(Beatley et al. 1994). Federal policy is often too broad to adequately protect the environmental resources. Although federal environmental policies mandate state and local compliance with environmental standards, they often do not establish a basis for intergovernmental cooperation (Beatley et al. 1994). Interpretation of federal policy, including subsidized flood insurance, disaster assistance monies, income tax code provisions and a host of infrastructure subsidies, influence state interpretation and coastal development. State environmental agencies are usually the parties responsible for environmental quality; however, state standards are intended to address large areas and therefore are not tailored to meet the needs of particularly sensitive areas (Beatley et al.
1994). Land use decisions are local in nature and therefore responsibility is placed on the local governments and citizenry. Through police power and state-enabling legislation, local governments are responsible for land use planning, zoning, and subdivision regulations (Beatley et al. 1994).
The success or failure of environmental policy is dependent on a number of criteria including: the capacity of state government to support and implement environmental regulations, ecological consciousness at both the state and local levels, and the availability of scientific resources to agencies making management decisions. Resources (monetary, land and personal), interpreting directives rules and regulations, planning programs,
126 organizing activities, extending benefits and applying restrictions are essential in the successful implementation of environmental policy (Buck 1996). Each contributes to a sound environmental policy designed to protect the natural resources of communities.
Policy design and commitment by policy makers to environmental policy are the first steps in the implementation of federal policy by state and local governments (Buck
1996). Bureaucratic interest in economic growth is one of the main reasons for inadequate and noncompliant environmental policy (Desai 1992). Fund-raising for environmental programs may be shouldered by the states, but some are more able and willing to do so than others (Vic and Kraft 2000). Insufficient budget and staffs greatly inhibit the success of environmental policy (Kamieniecki and Sanasarian 1990).
Compliance, defining property rights, and enforcement are measures of commitment to environmental policy.
The second crucial link between policy and expropriation of the environment resources by the public is ecological consciousness. This is measured by public participation, access to information, and the level of organized environmental groups
(Kamieniecki and Sanasarian 1990). Public concern and support for environmental protection spur new policies that increase the government’s responsibility for the environment and natural resources (Vig and Kraft 2000).
The final measure of successful environmental policy implementation is the support and availability of scientific resources (Lester and Lombard 1990). The number
127 of academic institutions receiving funding for research, community awareness and participation, and information dissemination are measures of this.
In this chapter, I conduct a comparison of the government actions to protect the natural resources in two different states – La Parguera, Puerto Rico, and Barnegat Bay,
New Jersey. I first describe the two sites and the differing degrees of environmental protection afforded to each one. I then describe why this difference occurs. I conclude with some observations regarding the government actions necessary to protect coastal ecosystems.
Environmental Protection in La Parguera and Barnegat Bay
La Parguera, Puerto Rico
Puerto Rico became the Commonwealth of Puerto Rico in 1952. Almost immediately, objectives were reflected in the stimulation of labor into formal activities, and conversion of an agricultural economy into an industrialized one (Santiago 1992;
Rivera-Batiz and Santiago 1996). A second shift in labor came in the 1960s as the petrochemical industry expanded in Puerto Rico. During the 70s and 80s, the industrialization process slowed down and the economy became more dependent on US assistance (Santiago 1992; Rivera-Batiz and Santiago 1996). The Puerto Rico Coastal
Zone Management Program was approved in September 1978 with the Department of
Natural and Environmental Resources designated as the administrating agency. The
128 intentions were to manage coastal development, improve, safeguard and restore the quality of coastal waters and habitats, and to protect natural resources and existing uses of those waters and habitats. Ensuing efforts by governmental and non-governmental organizations to conserve both natural habitats and species have achieved very positive results. However, the effects of economic development continue to place heavy pressures on the natural environment and a “no net loss” policy goal is not yet being achieved
(www.oecd.org).
Southwest Puerto Rico was known for its high productivity and most of the commercial fishing in Puerto Rico took place in this area. La Parguera is located in a unique sub-tropical dry forest, very little of which still exists in the Caribbean. The unique beauty and natural resources of this area have historically attracted both tourists and fishermen. Local organizations and groups have long considered this area for special planning. In fact, the Puerto Rico Conservation Trust has effectively purchased a large portion of land surrounding the bioluminescent bay in La Parguera for conservation purposes. Until recently, development within La Parguera was limited, mangrove stands, and salt flats buffered the mangroves from human developments.
In 1983, the National Oceanic and Atmospheric Administration (NOAA) attempted to include La Parguera and the surrounding marine system in the National
Marine Sanctuary Program. Local fisherman who feared the loss of fishing rights met interpretation and translation of the plan with resistance. Department of Natural
Resource (DNER) and the US Army Corps of Engineers, still recognizing the importance
129 of the natural resources in this area, signed an agreement in 1987 that provided for strict pollution control and declared La Parguera a Natural Wildlife Reserve, with the intention of creating a natural area. However, in 1995, the Puerto Rico Planning Board rezoned La
Parguera, southwest Puerto Rico, as a tourist zone. This change was met with resistance from local government and private entities (Tribunal Supremo de Puerto Rico, 99 TSRP
75). Despite these objections and lack of an environmental impact statement, the area was rezoned. The local government was able to pass two ordinances that attempted to control the overcrowding and unruliness associated with the increased tourism.
Development in the sub-tropical dry forest ecosystem threatens both the terrestrial and marine resources. Many of the impacts associated with the changes in land use were apparent in the shallow marine system surrounding La Parguera including increased suspended material, decreased available light to the benthic community, and increased metal concentration in the benthic sediments (Chapter 3). Decreasing water quality is a concern to the local town’s people, many of whom depend on fishing for their livelihood.
Correlations between declines in water quality and seagrass suggest that the development associated with the change in local zoning and lack of planning for an adequate infrastructure system may be responsible for the measured changes (Chapter 3 and 4).
Few data sources on the near shore environment and associated land use changes exist for La Parguera outside of this study, despite the presence of the University of
Puerto Rico Marine Biology Laboratory on Isla Magayez. The Puerto Rico Sea Grant
College Program, in an address to the US Commission on Ocean Policy, recognized the
130 importance of understanding the impacts of urban growth and unplanned development, environmental education, wetland and near shore habitat destruction, and declining water quality. However, none of these issues have been addressed in Sea Grant sponsored research.
Barnegat Bay, New Jersey
Similar to La Parguera, Barnegat Bay in Ocean County New Jersey is a shallow estuarine type system protected by barrier islands. The population in this area has quadrupled between 1960 and 1990 to nearly 450,000, with tourism being the main contributor to the population boom. In fact, it is one of the fastest growing counties in
New Jersey (Barnegat Bay Estuary Program Scientific and Technical Advisory
Committee 2001). The population increases from two- to ten-fold in the summer, depending on the area. This large increase in human population has made the area susceptible to diminished natural resources and increased the susceptibility to storm damage (Nordstrom et al. 1986). Barnegat Bay and its sensitive habitats and endangered species are imperiled by a suite of emerging land use impacts including development pressure, non-point pollution, brown tides, boating conflicts, and personal water craft conflicts. Even small changes in land use have been associated with sizeable impacts on the ecosystem, resulting in part from the shallowness of the bay (Kennish et al. 1984).
Little planning went into initial development of the Bay shoreline and as a result many of the effects on the bay are poorly understood (Wilson and Able 1996). Between
131 1940 and 1970, 28% of Barnegat Bay’s marshes were lost to development. However, federal, state, and local governments recognized the importance of this area and have included a number of acts to protect the bay and surrounding watersheds. Since the
Wetland Law of 1970, only an additional 1.5% of marshes have been lost to development
(Lathrop et al. 1999). The New Jersey Barnegat Bay Study Act of 1987 (PL 1987, Ch.
397) mandated a five-year study by the Department of Environmental Protection of the
Barnegat Bay and its watershed, including the development of a Management Plan for improving the Bay’s environmental and commercial values.
In addition, on July 10, 1995, Barnegat Bay-Little Egg Harbor Estuary and its watersheds, approximately 1,730 km2, were included in the National Estuary Program
(NEP), established under the Federal Clean Water Act, and funds were provided for non- point pollution research and the development and implementation of a comprehensive management plan. Attention was focused on the negative impacts of increased development and recreational use of Barnegat Bay on the environmentally sensitive natural habitats as well as on the health and biodiversity of the marine system. Water quality data and benthic survey of submerged vegetation was available for a variety of locations throughout the bay area (Bochenekand and Tiedemann 1996; McLain and
McHale 1996).
Barnegat Bay is protected under a number of state and local acts. The following legislation regulates land use within the watershed of the bay (Barnegat Bay Estuary
Program 2001):
132 · Coastal Area Development Review Act (NJSE 13:19-1 et seq) and New Jersey Wetlands Act (NJSE 13:9A-1 et seq) regulates development near tidal waters and coastal wetlands.
· Waterfront Development Law (NJSE 12:5-1 et seq), along with the Wetlands Act, attempts to minimize the impact of development near tidal waterways
· Tidelands Management Act and Riparian Land Statues (NJSE 12:3-1 et seq) declare tidal land area owned and managed by the State of New Jersey acting as trustee for the people.
· Shore Protection Act (NJSE 12:6A-1 et seq) is the state version of the Coastal Zone Management Act and addresses man-made improvements to the shore line
· Pinelands Protection Act (NJSE 13:18A-1) established the Pinelands National Reserve, a 1.1 million acre area or 23% of the state’s lands.
· Freshwater Wetlands Protection Act (NJSE 13:9A-1) requires permits for dredging, excavation or removal of soil
· NJ State Planning Act (NJSE 52:18A-196) manages physical growth and infrastructure decisions.
· Barnegat Bay Study Act of 1987 (PL 1987, Ch. 397) mandated DEP’s five-year study of Barnegat Bay and watershed, including the development of a Management Plan for improving the Bay’s environmental and commercial values.
· NJ Coastal Management Program was designed to protect coastal ecosystems, to preserve open space, and to incorporate data in decision-making processes while encouraging residential, commercial and recreational development.
Unlike La Parguera, however, the ecosystem in Barnegat Bay has been well documented and a Comprehensive Conservation and Management Plan exists for this watershed. Kennish and Lutz (1984) summarize historical data. Historical changes in the vigor and distribution of Barnegat seagrasses have been monitored and reported
(Moeller 1964; Taylor 1970; Loveland et al. 1974; Ohori 1982). A limited but useful
133 source of water quality data also exists for this system. Some relationships between seagrass loss and water quality degradation have already been identified for Barnegat
Bay.
Why the Difference?
Environmental Protection and Government Involvement
The same federal environmental policy governs both La Parguera and Barnegat
Bay. Despite this, development in La Parguera continues to damage critical marine habitats. Development decisions were made in the absence of scientific knowledge because that knowledge did not exist or was not available to decision-makers. This was the case in Barnegat Bay in the early 1970’s; however, since then over 60 books, reports and journal articles (ERL WebSpirs) and 8 dissertations (Online Computer Library
Center) have focused on this area’s ecology. Although there has been extensive material published on La Parguera, most of it has focused on specific reef species and the geology of the area. I was not able to find journal publications on the ecology of the near shore area close to La Parguera or the effect of land use.
However, I easily identified ten active environmental organizations supporting conservation in Barnegat Bay. Construction was one of the impacts scrutinized by these groups. Although there were a number of environmental groups active in Puerto Rico, none were involved in La Parguera. Local fishing associations attempted to draw attention to the water quality issues in La Parguera, but were not successful because of
134 their size and organization. Lack of data on the impact of development on the near shore ecosystems has resulted in false accusations by federal agencies in an attempt to improve water quality and lengthy litigations have followed. On the other hand, interest groups for Barnegat Bay were able to develop a Comprehensive Management Plan. The area is currently protected by nine state and local laws enforced by Marine Police and DEP. The
Puerto Rico DEP did have an office in La Parguera until 1998 when it was closed. Local groups around Barnegat Bay publish newsletters and provide workshops to educate the community on environmental issues. Universities receive support from New Jersey State and Federal agencies to conduct research and publish results. Scientific input is required for essentially all aspects of integrated coastal management. Although Puerto Rico Sea
Grant recognized the importance of the near shore ecosystems of La Parguera and the impact of erosion, it has not funded research in this area. Without the governmental and local support seen in Barnegat Bay, La Parguera will be subject to continued environmental degradation.
Conclusions
Coastal communities worldwide, especially on islands, recognize the importance of resource management. In the decision making process about resources, deliberate efforts should be directed toward ensuring that action in one area is linked to action in another (Griffith and Ashe 1993). The success of environmental policy involves cooperation and commitment at all three governmental levels (national, state, and
135 municipal), education of stakeholders, and support for research from which decisions should be made. While this recommendation offers the opportunity to shape future growth, it also suggests that there might be opposition to the restrictions by those wishing to reap the economic benefits of development.
Changes in coastal environments often happen gradually, and these cumulative changes should be incorporated into regulatory and management procedures (Daily and
Ehrlich 1992, Spaling and Smit 1993). Maintaining healthy ecosystems that function within the greater land-margin interface requires a landscape approach to assessing ecosystem diversity and integrity (Lapin and Barnes 1995). Managing ecosystems is clearly a social process (Norgaard 1992, Meffe and Viederman 1995). Solving many of our coastal problems may be linked to understanding how people use coastal resources, how they think the resources should be used in the future, and how they view the severity of environmental problems there (Burger 1998).
Changes in the zoning, such as that in La Parguera, should be a communal process that proceeds from general agreement on the goals for use of land resources in the area and includes scientific data. Such an agreement can only come from involving all areas of the community. Planning is comprehensive in that it attempts to deal with many factors; it makes systematic use of information and it involves images of the future and strategies to reach them. ‘Bottom-up’ planning using local knowledge and use patterns could have helped avoid the costs of litigation, promoted successful management, and met the needs of local people (Sanderson and Koester 2000). To empower a community
136 does not have to mean that there be a net loss in power at the higher levels in the government hierarchy (Olsen and Christie 2000).
Balancing resource management and development pressure is a complex processes. Non-use value is seldom considered in development and is often outweighed by the value of conventional uses. Tourism is attracted to pristine natural areas and can play an important role as an incentive for protection (Gossling 1999). Sustainable development requires that societies meet human needs both by increasing productive potential and by insuring equitable potential and opportunities for
(http://www.un.org/esa/sustdev/). It is not the physical differences of an area that determine the success of policy but rather the ability of local government and community organizations to educate stakeholders and implement changes to conserve and manage natural resources. The success of environmental policy is dependent on the “buy in” of state and local stakeholders
Summary
The recent rezoning of La Parguera as a tourist zone increased development in the dry forest, of which very little remains in the Caribbean. Unmanaged development in the dry forest appeared to increase storm-water runoff, high in inorganic material, to the near shore marine system. Although the mangroves and salt flat retained some of this material, sediments were directly entered the marine system through non-permitted boat
137 ramps. This in turn reduced the available light to the benthic community and increased sedimentation rates. Anthropogenic impacts are deteriorating the seagrass community in the vicinity of new development.
A fragile relationship exists between the dry forest, mangroves, seagrasses and coral reefs. Seagrasses are essential to the presence and growth of many species of marine life, especially during the younger stages of their development. In addition, the species that utilize the seagrass beds as nurseries to the greatest extent, the grunts and snappers, are those of most interest to local fisherman. The decline in any one of these will inevitably affect the others.
Barnegat Bay is similar to La Parguera geologically. Although both have seen a population increase, community involvement in environment groups and local awareness has led to a success story in New Jersey where attempts were made to control erosion and seagrasses are returning. The resources that attract tourists to La Parguera are being threatened. Local and state agencies must be educated as to the present situation in La
Parguera. Although state agencies recognized the importance of this area by designating it a Wildlife Reserve, laws and regulations are critically lacking and the consequence is evident in the shallow marine system. The local community must become involved in the decision making process since it is their resources that are being destroyed.
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142
Appendix 1. Field Data from La Parguera Puerto Rico.
Temperature Mean Conductivity pH Salinity Dissolved Oxygen Light % Light
Start Turb Surface Bottom Depth Surface Bottom Field Lab Surface Bottom Surface Bottom Air Surface Bottom Reaching
Date Station Time (NTU) (oC) (m) (ppt) (mg/l) (mE) Bottom
6/8/98 1 8:45 1.2 29.6 29.6 1.25 62.5 62.7 8.3 8.133 38.1 38.2 4.5 4.5 na na na na
6/8/98 2 9:05 0.6 30.0 30.0 1.00 63.5 63.7 8.2 8.224 38.5 38.6 4.7 4.8 na na na na
6/8/98 3 9:35 0.4 29.8 29.8 1.35 63.1 63.1 8.1 8.247 38.4 38.4 5.1 5.5 na na na na
6/8/98 4 9:50 0.6 29.8 29.8 1.60 63.3 63.3 7.7 8.207 38.5 38.5 4.9 4.9 na na na na
6/8/98 5 10:15 1.0 30.2 30.2 2.00 63.7 63.7 6.8 8.225 38.5 38.5 5.0 4.7 na na na na
143
6/8/98 6 10:35 1.2 30.4 30.4 1.80 64.3 64.1 7.4 8.135 38.6 38.6 4.9 5.1 na na na na
6/10/98 1 13:50 na 30.3 30.1 1.25 63.6 63.5 7.9 8.243 38.5 38.5 6.5 6.8 na na na na
6/10/98 2 14:30 na 30.4 30.4 2.25 64.2 64.3 7.2 8.120 38.7 38.8 7.4 7.5 na na na na
6/10/98 3 14:55 na 31.0 30.9 1.50 64.8 64.8 7.0 8.160 38.7 38.7 6.7 7.1 na na na na
6/10/98 4 15:16 na 30.8 30.8 1.65 64.5 64.5 7.2 8.230 38.6 38.6 7.2 7.5 na na na na
6/10/98 5 15:35 na 30.7 30.7 1.90 64.5 64.5 6.6 8.210 38.6 38.6 6.7 6.7 na na na na
6/10/98 6 16:00 na 30.8 30.8 2.50 64.6 64.5 6.5 8.130 38.6 38.6 6.0 6.0 na na na na
6/15/98 1 6:40 1.1 29.6 29.2 1.25 63.0 63.2 8.2 8.201 38.5 38.5 3.8 3.2 na na na na
6/15/98 2 7:05 0.5 29.7 29.7 2.25 63.2 63.2 8.3 8.199 38.6 38.5 4.4 4.1 na na na na
6/15/98 3 7:25 0.8 29.7 29.7 1.25 63.2 63.2 8.3 8.211 38.6 38.6 4.4 4.5 na na na na
6/15/98 4 7:49 0.5 29.3 29.3 1.50 62.9 62.9 8.1 8.184 38.6 38.6 4.1 4.1 na na na na
6/15/98 5 8:07 2.5 29.9 29.9 1.85 63.7 63.7 8.2 8.192 38.7 38.7 4.1 4.3 na na na na
144
6/15/98 6 8:30 1.3 30.0 30.0 2.25 63.5 63.6 8.1 8.138 38.6 38.6 4.5 4.4 na na na na
6/18/98 1 6:43 1.2 29.1 29.2 1.50 62.1 62.0 7.9 8.146 38.2 38.2 4.2 3.6 na na na na
6/18/98 2 7:10 0.5 29.3 29.4 1.25 62.3 62.4 7.6 8.177 38.2 38.2 5.1 5.1 na na na na
6/18/98 3 7:30 0.7 29.0 29.0 1.55 62.1 61.9 7.6 8.139 38.3 38.2 3.4 3.9 na na na na
6/18/98 4 7:53 1.3 29.2 29.1 1.75 61.8 61.8 7.4 8.082 38.0 38.0 3.6 3.7 na na na na
6/18/98 5 8:10 3.3 29.4 29.4 1.85 62.5 62.5 7.5 8.126 38.3 38.3 4.0 4.2 na na na na
6/18/98 6 8:26 1.5 29.9 29.9 2.25 63.0 63.0 7.3 8.131 38.3 38.3 4.4 4.6 na na na na
6/22/98 1 10:25 4.4 28.8 28.7 1.00 60.9 61.0 7.5 8.004 37.8 37.8 8.0 6.7 na na na na
6/22/98 2 11:26 3.1 29.3 29.2 2.50 61.9 62.1 7.7 8.178 38.0 38.1 9.3 9.6 na na na na
6/22/98 3 11:56 2.7 29.2 29.1 1.50 61.7 61.5 7.4 8.214 37.9 37.8 10.2 11.5 na na na na
6/22/98 4 12:37 1.4 29.2 29.2 1.75 61.9 61.9 7.3 8.244 38.0 38.0 10.8 11.0 na na na na
6/22/98 5 12:54 3.0 29.2 29.1 2.25 61.6 61.4 7.1 8.195 37.8 37.8 8.9 10.0 na na na na
145
6/22/98 6 13:22 3.8 29.9 29.8 2.25 62.7 62.7 7.0 8.174 38.0 38.1 9.2 9.7 na na na na
6/24/98 1 14:30 1.5 30.7 30.1 1.35 64.2 63.2 8.6 8.413 38.3 38.3 na na na na na na
6/24/98 2 15:12 1.6 30.6 30.4 0.75 64.0 63.7 8.5 8.425 38.3 38.4 na na na na na na
6/24/98 3 15:33 2.6 30.8 30.7 1.40 64.2 64.1 8.4 8.377 38.3 38.4 11.5 11.6 na na na na
6/24/98 4 15:57 1.5 30.8 30.8 1.25 64.3 64.3 8.4 8.374 38.4 38.4 na 11.5 na na na na
6/24/98 5 16:12 1.9 30.7 30.5 2.00 63.7 63.7 8.3 8.356 38.2 38.3 11.6 10.0 na na na na
6/24/98 6 16:34 3.1 30.7 30.7 2.25 63.6 63.8 8.3 8.311 38.1 38.2 9.8 9.7 na na na na
6/29/98 1 15:13 2.2 30.4 30.0 1.25 63.5 63.7 7.9 8.264 38.3 38.4 6.0 5.4 na na na na
6/29/98 2 15:29 0.8 30.3 30.3 1.00 63.6 63.8 7.9 8.289 38.4 38.5 6.8 7.3 na na na na
6/29/98 3 15:55 1.9 30.4 30.6 1.50 63.8 63.8 7.9 8.352 38.5 38.4 7.1 7.2 na na na na
6/29/98 4 16:18 1.2 30.4 30.4 1.60 63.8 63.8 7.8 8.313 38.4 38.4 6.9 6.9 na na na na
6/29/98 5 16:38 3.9 30.4 30.4 2.00 63.9 64.0 7.8 8.240 38.5 38.5 5.5 6.0 na na na na
146
6/29/98 6 17:00 1.9 30.4 30.4 2.25 63.7 63.9 7.7 8.211 38.4 38.5 5.3 5.3 na na na na
7/1/98 1 8:42 1.9 29.4 29.3 1.00 62.7 62.7 7.7 8.015 38.6 38.7 4.0 2.8 na na na na
7/1/98 2 9:01 1.1 29.6 29.6 1.25 63.0 63.0 7.8 8.015 38.5 38.5 4.7 5.0 na na na na
7/1/98 3 9:24 2.2 29.7 29.6 1.50 62.9 62.9 7.8 8.118 38.4 38.4 4.9 5.0 na na na na
7/1/98 4 9:42 1.2 29.3 29.3 1.50 62.6 62.6 7.7 7.996 38.5 38.5 4.8 4.7 na na na na
7/1/98 5 10:00 2.2 29.7 29.6 2.00 63.0 63.0 7.6 8.022 38.5 38.5 5.0 4.8 na na na na
7/1/98 6 10:16 3.4 30.0 29.7 2.00 63.3 63.2 7.5 7.975 38.4 38.4 4.8 5.0 na na na na
7/6/98 1 7:40 1.7 29.2 29.1 1.00 62.6 62.5 7.2 7.984 38.5 38.7 3.6 2.5 na na na na
7/6/98 2 8:01 1.6 29.2 29.2 1.25 62.3 62.4 7.0 8.086 38.3 38.4 4.5 4.0 na na na na
7/6/98 3 8:18 3.8 29.3 29.3 1.50 62.1 62.6 7.1 8.079 38.5 38.4 4.3 4.2 na na na na
7/6/98 4 8:36 1.9 28.9 28.9 1.50 61.9 62.2 7.2 8.500 38.3 38.5 4.2 4.1 na na na na
7/6/98 5 8:52 7.3 29.4 29.3 1.90 62.6 62.6 7.2 8.037 38.4 38.4 4.1 4.1 na na na na
147
7/6/98 6 9:09 5.0 29.5 29.5 2.75 62.8 62.8 6.8 7.965 38.4 38.5 3.6 3.5 na na na na
7/15/98 1 7:28 2.3 29.7 29.3 1.00 62.1 62.5 8.5 8.146 37.9 38.2 3.4 2.4 na na na na
7/15/98 2 7:46 0.8 29.5 29.6 1.15 62.3 62.6 8.0 8.226 38.0 37.9 4.8 4.1 na na na na
7/15/98 3 8:00 2.4 29.8 29.8 1.50 62.7 62.8 7.9 8.268 38.1 38.2 4.4 4.2 na na na na
7/15/98 4 8:15 1.3 29.7 29.6 1.50 62.1 62.6 7.8 8.234 37.9 38.2 3.9 4.1 na na na na
7/15/98 5 8:30 3.1 29.8 29.8 2.00 62.7 62.7 7.6 8.206 38.1 38.2 4.0 4.0 na na na na
7/21/98 1 8:05 3.3 29.5 29.3 1.00 61.3 62.1 7.9 8.152 37.4 37.9 3.4 2.7 na na na na
7/21/98 2 8:21 1.2 29.7 29.7 1.00 62.3 62.3 8.0 8.277 37.9 37.9 4.3 4.5 na na na na
7/21/98 3 8:35 1.3 29.4 29.4 1.40 61.3 61.9 8.0 8.263 37.5 37.8 4.0 3.6 na na na na
7/21/98 4 8:53 1.4 29.6 29.5 1.60 61.9 61.9 8.0 8.306 37.8 37.8 4.5 4.6 na na na na
7/21/98 5 9:06 3.6 29.9 29.8 2.00 62.5 62.4 8.0 8.285 38.0 38.0 4.0 4.2 na na na na
7/21/98 6 9:22 0.8 29.9 29.9 2.30 62.5 62.4 7.9 8.239 37.9 37.9 4.2 4.1 na na na na
148
7/23/98 1 13:54 1.9 30.7 30.7 0.85 62.8 63.5 7.8 8.361 37.7 37.8 6.0 6.2 na na na na
7/23/98 2 14:14 1.6 31.3 31.2 0.75 63.8 64.0 7.9 8.420 37.9 37.9 7.2 7.1 na na na na
7/23/98 3 14:37 3.0 31.3 31.3 1.50 64.1 64.1 8.0 8.402 37.9 38.0 5.6 5.9 na na na na
7/23/98 4 14:56 2.5 31.4 31.3 1.45 64.2 64.2 7.8 8.366 37.9 37.9 5.9 5.9 na na na na
7/23/98 5 15:14 3.6 31.4 31.4 2.00 64.2 64.3 7.8 8.324 37.9 37.9 5.7 5.9 na na na na
7/23/98 6 15:35 2.5 31.6 31.3 2.25 64.3 64.0 7.8 8.287 37.8 37.9 5.2 5.8 na na na na
7/28/98 1 15:18 1.8 30.4 30.1 0.85 62.8 62.4 7.9 8.281 37.7 37.7 5.7 5.7 na na na na
7/28/98 2 15:50 1.6 30.6 30.2 1.25 62.9 62.5 8.2 8.381 37.8 37.8 7.3 6.9 na na na na
7/28/98 3 16:07 3.3 30.3 30.3 1.35 62.7 62.8 8.2 8.365 37.3 37.8 6.4 6.7 na na na na
7/28/98 4 16:26 1.6 30.1 30.1 1.50 62.5 62.6 8.2 8.355 37.7 37.8 6.0 5.9 na na na na
7/28/98 5 16:44 2.6 30.1 30.1 2.00 62.5 62.6 8.1 8.262 37.8 37.8 5.4 5.2 na na na na
7/28/98 6 17:04 3.6 30.4 30.3 2.75 63.0 63.0 8.0 8.253 37.9 38.0 5.5 5.3 na na na na
149
7/30/98 1 7:53 1.7 29.5 29.7 1.00 61.9 62.0 8.0 8.238 37.8 37.8 3.2 3.4 na na na na
7/30/98 2 8:11 1.0 29.7 29.7 0.85 62.1 62.1 7.8 8.279 37.8 37.8 3.9 4.1 na na na na
7/30/98 3 8:35 1.5 29.8 29.7 1.25 62.2 62.2 7.5 8.295 37.8 37.8 4.0 3.8 na na na na
7/30/98 4 8:55 1.4 29.8 29.7 1.50 62.2 62.2 7.5 8.274 37.8 37.8 4.3 4.2 na na na na
7/30/98 5 9:11 3.6 29.9 29.9 1.75 62.4 62.4 7.5 8.267 37.8 37.8 4.7 5.0 na na na na
7/30/98 6 9:32 2.3 30.3 30.2 2.25 62.8 62.8 na 8.225 37.8 37.8 5.0 4.9 na na na na
8/3/98 1 10:41 1.0 30.4 30.4 1.25 62.6 33.3 7.9 8.295 37.5 37.7 5.9 6.2 na na na na
8/3/98 2 11:28 1.1 30.5 30.4 1.25 62.9 62.9 8.1 8.371 37.7 37.8 6.8 6.9 na na na na
8/3/98 3 11:46 1.8 30.5 30.5 1.50 63.0 62.7 8.0 8.370 37.8 37.6 6.6 6.9 na na na na
8/3/98 4 12:04 2.0 30.8 30.7 1.50 63.4 63.4 8.1 8.309 37.9 37.9 5.5 5.4 na na na na
8/3/98 5 12:23 2.5 30.8 30.8 2.00 63.5 63.6 7.7 8.267 37.9 38.0 4.9 4.0 na na na na
8/3/98 6 12:42 2.3 31.3 31.0 2.50 63.8 63.7 7.5 8.246 37.7 37.8 5.0 5.3 na na na na
150
10/22/98 1 10:34 2.0 28.9 28.9 1.93 58.0 59.0 7.6 8.377 35.7 36.3 4.4 4.0 1804 na 889 49
10/22/98 2 11:03 2.4 29.2 28.8 1.67 58.8 58.9 8.5 8.421 36.0 36.1 4.9 4.3 1907 na 1063 56
10/22/98 3 11:29 1.4 29.0 29.0 1.63 58.7 58.8 8.0 8.504 36.1 36.0 5.2 5.0 1898 na 872 46
10/22/98 4 12:02 1.7 28.9 28.9 1.70 57.9 58.0 8.2 8.441 35.5 35.6 4.5 4.4 1945 na 792 41
10/22/98 5 12:27 2.2 28.9 29.0 1.82 58.1 59.4 8.1 8.407 35.6 36.1 4.1 4.1 1916 na 625 33
10/22/98 6 12:57 3.3 29.3 29.2 2.58 57.8 58.5 8.7 8.338 35.2 36.1 4.0 2.7 1817 na 603 33
10/26/98 11 12:44 2.2 30.1 29.9 2.42 60.1 59.9 6.8 8.400 36.1 36.2 4.6 5.2 1848 na 605 33
10/26/98 14 12:32 2.0 30.5 29.8 1.95 60.1 59.9 6.6 8.400 36.1 36.2 4.9 5.1 1988 na 578 29
10/26/98 22 13:08 0.6 31.2 30.4 1.75 61.0 60.5 7.1 8.279 35.9 36.1 4.6 4.1 1887 na 800 42
11/3/98 1 12:44 1.4 30.6 30.2 1.33 60.2 60.1 6.9 8.398 36.1 36.0 6.3 6.3 na na na na
11/3/98 2 12:27 1.9 30.3 30.3 1.25 60.2 60.1 7.0 8.404 36.0 36.0 6.4 6.6 na na na na
11/3 /98 3 12:04 1.6 30.3 30.3 1.67 60.2 60.1 7.2 8.359 36.0 36.0 6.0 6.0 na na na na
151
11/3/98 4 11:46 1.4 30.1 30.1 1.83 60.1 60.1 7.2 8.297 36.1 36.1 4.9 4.8 na na na na
11/3/98 5 11:24 1.9 30.4 30.2 2.25 60.1 59.5 7.4 8.260 36.0 35.6 4.6 0.0 na na na na
11/3/98 6 10:57 1.5 30.6 30.3 2.82 59.2 59.9 7.2 8.194 35.7 35.9 4.0 4.6 na na na na
11/10/98 1 13:24 2.5 30.8 30.4 1.17 60.7 60.5 7.3 8.440 36.2 36.1 7.4 8.6 na na na na
11/10/98 2 12:58 1.1 30.6 30.6 0.85 60.5 60.5 8.4 8.480 36.1 36.0 8.0 7.9 na na na na
11/10/98 3 13:47 1.1 30.7 30.5 1.57 60.2 60.5 7.3 8.360 35.9 36.2 5.8 6.3 na na na na
11/17/98 11 11:25 2.8 28.6 28.4 2.25 58.5 58.5 7.4 8.216 36.3 36.3 5.0 5.2 na na na na
11/17/98 14 11:43 4.3 28.6 28.5 1.90 58.5 58.5 7.6 8.280 36.2 36.2 4.8 4.7 na na na na
11/17/98 22 10:53 1.2 28.3 28.3 1.52 58.5 58.5 7.2 8.173 36.3 36.4 4.7 4.4 na na na na
12/1/98 4 13:18 1.2 29.0 29.0 1.70 58.9 59.0 7.7 8.190 36.1 36.2 4.3 4.4 na na na na
12/1/98 5 12:55 3.6 29.0 28.9 2.00 59.0 58.7 7.4 8.280 36.2 36.1 4.5 3.5 na na na na
12/1/98 6 12:34 1.8 29.1 29.0 2.42 59.2 59.0 7.8 8.250 36.2 36.2 4.4 5.1 na na na na
152
12/8/98 1 11:36 1.5 27.9 27.8 1.08 58.1 58.0 6.9 8.300 36.4 36.4 5.9 6.2 na na na na
12/8/98 2 11:15 1.2 28.0 27.9 1.00 58.2 58.2 6.8 8.400 36.4 36.4 6.3 6.6 na na na na
12/8/98 3 12:13 1.0 28.0 27.9 1.33 58.2 58.1 7.2 8.300 36.3 36.4 6.7 6.6 na na na na
12/8/98 4 11:55 1.3 28.4 28.0 1.75 58.3 58.2 6.8 8.300 36.3 36.4 5.4 4.8 na na na na
12/8/98 5 12:50 5.3 28.4 28.2 2.13 58.4 58.4 7.4 8.257 36.3 36.4 4.6 4.2 na na na na
12/8/98 6 12:33 1.9 28.6 28.1 2.58 58.5 58.0 7.0 8.300 36.1 36.3 4.8 5.2 na na na na
12/15/98 11 12:48 4.1 28.8 28.5 1.77 59.2 59.0 7.6 8.560 36.6 36.6 5.3 4.8 na na na na
12/15/98 14 11:45 3.1 28.6 28.3 1.80 59.0 58.9 7.6 8.334 36.6 36.6 5.2 5.5 na na na na
12/15/98 22 12:18 1.1 28.9 29.0 1.30 59.0 59.8 7.5 8.620 36.2 36.7 4.3 5.6 na na na na
2/9/99 1 12:45 4.3 25.9 26.0 0.95 57.5 57.1 7.3 8.905 37.3 37.3 6.4 6.7 na na na na
2/9/99 2 10:50 2.8 25.6 25.5 1.33 56.7 56.7 7.9 8.390 37.2 37.2 7.2 7.6 na na na na
2/9/99 3 11:30 3.3 25.8 25.8 1.67 56.8 56.8 7.1 8.400 37.1 37.2 6.2 6.2 na na na na
153
2/9/99 4 12:29 1.8 26.0 26.0 1.63 57.2 57.3 7.2 8.381 37.2 37.3 6.2 6.8 na na na na
2/9/99 5 12:11 2.5 26.1 26.0 2.00 57.3 57.3 7.2 8.351 37.3 37.3 5.5 5.6 na na na na
2/9/99 6 11:57 3.2 26.4 26.1 2.57 57.3 57.0 6.8 8.347 37.0 37.1 5.4 5.6 na na na na
2/22/99 11 11:06 3.8 27.0 25.7 2.58 57.3 57.2 7.3 8.230 37.5 37.5 4.3 4.4 na na na na
2/22/99 14 10:45 5.4 25.8 na 1.87 57.4 55.8 7.3 8.250 37.6 37.5 4.6 4.4 na na na na
2/22/99 22 12:13 1.7 26.6 na 1.50 58.3 57.8 5.9 8.320 37.7 37.4 5.2 3.2 na na na na
3/8/99 1 11:32 0.1 27.0 na 1.23 59.1 59.1 7.3 8.450 37.8 37.9 4.7 4.3 na na na na
3/8/99 2 11:16 0.3 26.9 na 1.08 58.7 58.8 8.3 8.490 37.7 37.7 5.0 5.2 na na na na
3/8/99 3 12:21 2.8 27.4 na 1.62 59.3 59.2 6.9 8.470 37.9 37.7 4.7 4.7 na na na na
3/8/99 4 11:50 2.8 27.3 na 1.67 59.3 59.4 7.8 8.380 37.8 37.8 3.8 4.0 na na na na
3/8/99 5 12:53 3.4 na na 2.00 59.8 58.7 8.4 8.450 37.8 37.2 4.3 2.8 na na na na
3/8/99 6 12:39 2.4 27.5 na 2.53 60.2 51.6 7.6 8.380 36.6 33.0 4.2 1.1 na na na na
154
3/22/99 11 12:54 10.5 28.2 na 1.83 60.9 60.4 7.7 8.300 38.1 37.4 6.1 0.5 na na na na
3/22/99 14 11:19 na 27.9 na 2.28 60.4 60.5 7.5 na 38.1 38.2 6.5 6.7 na na na na
3/22/99 22 13:17 3.0 29.0 na 1.52 61.8 60.9 7.1 na 38.1 37.9 7.0 7.9 na na na na
4/5/99 1 12:35 4.3 28.9 na 1.17 60.7 61.9 7.3 8.666 38.0 37.8 6.4 6.4 na na na na
4/5/99 2 11:43 3.9 28.9 na 1.52 61.4 61.3 7.2 8.622 38.0 38.0 5.8 5.9 na na na na
4/5/99 3 12:23 2.7 28.9 na 1.43 61.1 60.8 7.3 8.578 37.9 38.0 4.3 4.9 na na na na
4/5/99 4 11:15 4.0 28.6 na 1.67 61.4 61.7 7.3 8.458 38.2 38.1 4.0 3.0 na na na na
4/5/99 5 10:49 4.3 28.3 na 2.38 61.1 56.7 6.8 8.368 38.2 27.9 3.3 0.1 na na na na
4/5/99 6 12:04 1.3 28.8 na 2.45 61.7 60.1 7.1 8.416 37.6 38.1 4.1 4.9 na na na na
4/19/99 11 11:16 1.1 28.6 na 1.75 61.5 59.6 7.4 8.277 38.2 38.2 5.0 2.6 na na na na
4/19/99 14 12:24 3.8 29.3 na 2.33 62.0 62.3 7.7 8.284 38.2 38.4 5.3 0.7 na na na na
4/19/99 22 12:04 2.7 29.2 na 1.25 62.3 62.4 7.8 8.312 38.4 38.4 5.2 5.4 na na na na
155
5/18/99 1 12:05 0.1 29.5 29.6 1.08 62.4 62.6 7.4 8.300 38.1 38.2 4.3 5.9 na na na na
5/18/99 2 11:50 0.2 29.5 29.6 2.00 62.0 62.5 7.0 8.320 37.8 38.1 5.8 5.8 na na na na
5/18/99 3 12:19 2.2 29.6 29.5 1.50 62.1 62.2 7.4 8.340 38.1 38.0 5.5 6.0 na na na na
5/18/99 4 11:25 0.2 29.2 29.2 1.42 62.0 62.0 7.1 8.290 38.1 38.1 4.8 4.7 na na na na
5/18/99 5 12:38 4.2 29.3 29.7 2.08 62.7 62.7 7.4 8.280 38.2 38.2 4.7 4.6 na na na na
5/18/99 6 11:05 0.2 29.7 29.6 2.67 61.8 62.2 7.2 8.250 37.5 38.0 4.4 5.2 na na na na
6/21/99 5 11:02 4.0 29.0 28.7 2.25 60.4 60.9 7.8 8.145 37.1 37.8 4.4 3.9 na na na na
6/21/99 6 12:01 1.8 29.9 29.4 2.67 62.1 61.6 7.5 8.133 37.7 37.7 4.4 5.0 na na na na
6/21/99 11 11:40 1.8 29.3 29.2 2.33 61.7 61.6 7.8 8.171 37.9 37.9 4.7 5.0 na na na na
6/21/99 14 11:21 3.9 29.3 29.1 2.08 61.6 61.5 7.9 8.144 37.9 37.9 4.3 4.3 na na na na
6/21/99 22 12:51 0.8 29.9 29.8 1.50 62.5 62.5 7.9 8.237 37.9 38.0 5.4 5.3 na na na na
6/29/99 1 10:30 0.8 29.1 28.9 1.08 60.2 61.1 8.1 8.151 37.0 37.7 5.5 5.1 1800 na 1200 67
156
6/29/99 2 10:44 1.2 29.3 29.2 1.25 61.7 61.7 8.1 8.230 37.8 37.9 6.0 5.5 1800 na 1200 67
6/29/99 3 10:57 1.6 29.3 29.2 1.33 61.6 61.6 8.1 8.281 37.8 37.8 5.5 5.6 1900 na 1150 61
6/29/99 4 11:15 1.6 29.0 28.4 1.67 61.3 61.3 8.1 8.195 37.8 37.9 5.2 5.0 2000 na 900 45
6/29/99 5 11:30 1.9 29.5 29.4 2.00 61.9 61.8 8.1 8.253 37.8 37.9 5.6 5.3 1900 na 450 24
6/29/99 6 12:10 1.6 30.1 29.7 2.50 62.6 62.3 8.1 8.215 37.9 37.9 5.0 5.4 1850 na 750 41
6/29/99 11 11:56 1.4 29.8 29.7 2.25 62.3 62.2 8.1 8.235 37.8 37.9 5.1 5.5 1950 na 800 41
6/29/99 14 11:44 2.3 29.8 29.7 1.83 62.2 62.1 8.0 8.213 37.8 37.9 5.2 4.6 2000 na 900 45
6/29/99 22 12:29 0.9 30.3 30.1 1.42 63.2 63.3 8.1 8.265 38.2 38.3 5.5 5.3 2100 na 850 40
7/30/99 1 11:00 0.5 30.2 29.9 1.25 61.0 61.0 8.0 8.144 36.8 36.9 5.8 5.7 1900 na na na
7/30/99 2 11:27 0.8 30.0 30.1 0.92 61.8 61.8 8.1 8.326 37.3 37.3 7.0 6.7 1900 na na na
7/30/99 3 11:58 1.2 30.2 30.2 1.50 62.0 62.0 8.1 8.326 37.4 37.4 6.7 6.7 1350 na na na
7/30/99 4 12:12 1.4 30.3 30.3 1.50 62.2 62.2 8.0 8.247 37.4 37.4 5.7 5.7 2100 na na na
157
7/30/99 5 12:32 3.0 30.6 30.2 2.08 62.3 62.3 8.0 8.325 37.3 37.4 5.5 5.0 2100 na na na
7/30/99 6 13:20 1.7 31.6 30.5 2.75 63.4 62.5 8.1 8.325 37.3 37.4 6.1 6.2 1650 na na na
7/30/99 11 13:07 1.2 30.9 30.8 2.42 62.8 62.9 7.9 8.293 37.4 37.5 5.9 5.8 2000 na na na
7/30/99 14 12:52 2.8 30.7 30.6 2.25 62.7 62.7 8.0 8.247 37.5 37.5 4.9 4.5 2000 na na na
7/30/99 22 13:37 0.7 31.7 31.4 1.58 64.5 64.4 7.9 8.200 37.8 38.0 4.7 6.1 1300 na na na
8/27/99 1 12:00 0.9 30.4 30.4 1.50 61.9 62.0 8.2 na 37.1 37.3 5.0 5.1 2100 na 1100 52
8/27/99 2 13:55 0.9 30.8 30.6 1.25 62.0 62.2 8.2 na 37.0 37.1 6.2 6.4 1900 na 1050 55
8/27/99 3 11:19 2.1 30.5 30.5 1.50 61.7 61.7 8.1 na 36.9 36.9 6.5 6.8 2000 na 900 45
8/27/99 4 11:43 1.2 30.7 30.5 1.58 61.8 62.0 8.1 na 36.9 37.1 6.1 5.6 2100 na 1150 55
8/27/99 5 12:04 3.0 31.0 30.7 2.17 62.3 62.2 8.1 na 37.0 37.1 5.4 5.2 2100 na 450 21
8/27/99 6 13:04 2.1 31.9 31.3 2.75 63.2 63.0 8.0 na 36.9 37.2 5.4 6.4 2100 na 600 29
8/27/99 11 12:45 1.8 31.3 31.2 2.33 62.9 63.0 8.1 na 37.2 37.3 6.2 5.6 2100 na 500 24
158
8/27/99 14 12:26 1.9 31.2 31.2 2.25 62.7 62.7 8.1 na 37.1 37.2 5.5 5.4 2100 na 250 12
8/27/99 22 13:22 1.6 32.6 32.2 1.50 65.1 65.0 8.0 na 37.6 37.7 5.0 6.0 2100 na 900 43
8/29/99 1 8:40 1.4 28.1 28.1 1.17 56.4 56.4 7.9 7.950 35.0 35.0 3.0 3.2 na na na na
8/29/99 2 9:10 1.2 29.2 29.3 1.33 58.2 58.6 7.9 8.087 35.6 35.6 3.5 4.2 na na na na
8/29/99 3 9:18 1.1 28.9 28.8 1.58 57.8 57.8 8.0 8.099 35.5 35.5 4.4 4.2 na na na na
8/29/99 4 9:38 0.9 28.4 28.3 1.58 56.9 56.9 8.0 8.040 35.3 35.3 4.1 4.3 na na na na
8/29/99 5 9:57 4.7 29.0 29.0 2.17 58.1 58.0 8.0 8.101 35.5 35.5 4.0 3.9 na na na na
8/29/99 6 10:16 2.1 29.8 29.5 3.02 59.0 58.9 7.9 8.106 35.6 35.8 3.3 4.5 na na na na
9/12/99 1 8:45 0.7 30.4 30.1 1.33 59.8 59.3 8.1 8.202 35.7 35.6 4.0 3.5 1200 na 700 58
9/12/99 2 9:08 0.8 30.6 30.5 0.83 60.5 60.5 8.1 8.253 36.0 36.1 4.3 4.3 1650 na 900 55
9/12/9 9 3 9:29 0.4 30.7 30.6 1.75 60.6 60.5 8.0 8.274 36.0 36.1 4.3 4.0 1650 na 750 45
9/12/99 4 9:50 1.0 30.7 30.6 1.92 60.8 60.8 8.0 8.273 36.1 36.2 4.5 4.7 1550 na 600 39
159
9/12/99 5 10:12 2.6 31.1 30.8 2.33 60.6 61.3 7.9 8.300 35.8 36.3 4.5 4.2 1850 na 325 18
9/12/99 6 10:34 1.1 31.6 31.3 2.42 61.9 61.6 8.0 8.251 36.3 36.4 4.7 4.5 2100 na 750 36
9/14/99 1 9:44 na 29.2 29.2 1.17 57.5 58.6 7.6 8.017 35.5 35.8 3.0 3.1 1500 na 350 23
9/14/99 2 10:19 2.8 29.6 29.9 2.00 59.4 59.6 7.8 8.190 35.8 36.0 4.5 4.2 1800 na 750 42
9/14/99 3 10:46 1.0 29.5 29.5 1.50 59.0 59.1 7.9 8.262 35.8 35.8 4.3 4.3 850 na 550 65
9/14/99 4 11:08 2.0 28.9 29.0 1.75 56.9 56.9 7.8 8.173 34.8 34.9 4.0 4.0 925 na 325 35
9/14/99 5 11:25 2.3 29.5 29.7 2.25 58.0 59.2 8.0 8.260 34.8 35.8 4.3 4.1 1100 na 325 30
9/14/99 6 11:45 3.6 29.6 30.0 2.67 56.7 59.8 7.9 8.215 34.1 35.8 4.0 3.6 1800 na 350 19
9/19/99 1 8:40 1.1 30.0 30.1 1.08 58.0 59.5 9.0 8.300 34.7 35.8 4.6 4.5 1200 na 525 44
9/19/99 2 9:02 0.8 30.3 30.2 1.50 59.4 59.7 9.3 8.300 35.5 35.7 4.4 4.2 1350 na 650 48
9/19/99 3 9:24 1.5 30.4 30.3 1.42 59.9 60.1 9.2 8.300 35.8 36.0 3.5 3.6 1525 na 575 38
9/19/99 4 9:44 0.9 30.7 30.6 1.58 60.2 60.3 8.5 8.300 35.8 35.9 4.6 4.4 1500 na 600 40
160
9/19/99 5 10:08 5.6 31.1 30.8 2.25 60.7 60.3 8.5 8.300 35.8 35.9 4.3 4.3 1900 na 700 37
9/19/99 6 11:06 1.1 31.6 31.1 2.25 61.0 60.8 7.9 8.300 35.4 35.9 4.6 5.4 1500 na 775 52
9/19/99 11 10:45 2.7 31.8 31.0 2.25 60.0 60.4 8.0 8.400 34.9 35.8 4.1 4.5 2000 na 450 23
9/19/99 14 10:27 1.3 31.4 30.9 1.75 61.0 60.5 8.1 8.400 35.8 35.9 4.6 4.9 1500 na 750 50
9/19/99 22 11:29 0.9 31.8 na 1.50 61.2 60.8 na 8.300 35.7 35.9 4.2 5.5 2250 na 900 40
10/18/99 1 10:35 na 29.6 29.5 0.97 59.7 59.6 8.1 8.119 36.2 36.2 6.0 5.9 1750 na 800 46
10/18/99 2 10:57 0.8 29.6 na 1.00 59.6 59.6 8.0 8.224 36.2 36.2 6.1 6.2 1925 na 750 39
10/18/99 3 10:25 0.9 29.8 29.8 1.50 59.8 59.8 8.1 8.313 36.1 36.1 6.4 6.8 1900 na 800 42
10/18/99 4 11:47 1.8 29.9 na 2.00 59.7 59.9 8.0 8.221 36.0 36.2 5.3 5.6 1650 na 1125 68
10/18/99 5 12:06 na 30.0 29.7 2.00 59.9 59.6 8.0 8.229 36.1 36.1 5.1 4.6 1900 na 117.5 6
10/18/99 6 13:01 na 30.5 30.0 2.67 59.9 59.6 8.0 8.246 35.7 36.0 5.1 5.7 2225 na 212 10
10/18/99 11 12:39 2.0 30.1 30.1 2.50 60.0 60.0 8.0 8.213 36.0 36.1 5.5 5.2 950 na 78 8
161
10/18/99 14 12:24 4.0 30.1 30.0 2.25 59.0 59.8 8.0 8.179 35.4 36.0 4.7 4.6 1100 na 680 62
10/18/99 22 13:20 1.8 31.2 30.9 1.58 60.8 60.6 8.0 8.241 35.7 35.9 5.1 5.6 2250 na 240 11
11/15/99 1 11:05 0.8 27.7 27.7 0.92 56.8 57.2 8.0 7.900 35.7 35.9 3.3 2.5 207.5 na 110 53
11/15/99 2 11:45 0.8 28.1 28.1 1.58 57.6 57.6 8.1 8.100 35.9 35.9 4.7 4.6 240 na 147.5 61
11/15/99 3 12:01 1.1 28.0 28.0 1.50 57.5 57.8 8.2 na 35.8 35.9 5.2 4.8 240 na 125 52
11/15/99 4 12:17 1.8 27.9 27.9 1.67 57.6 57.5 8.0 7.900 36.0 36.0 3.9 3.7 207.5 na 155 75
11/15/99 5 12:34 3.4 28.2 28.2 2.42 58.0 58.0 8.0 8.000 36.1 36.1 3.7 3.1 210 na 145 69
11/15/99 6 13:35 3.2 28.3 28.3 2.67 58.1 58.0 8.1 8.200 36.1 36.1 3.5 4.2 2150 na 900 42
11/15/99 11 13:16 2.8 28.2 28.2 2.50 58.1 58.2 8.2 8.200 36.2 36.2 4.3 3.8 2400 na 710 30
11/15/99 14 12:56 3.6 28.1 28.2 2.42 57.9 58.1 8.1 8.060 36.1 36.0 4.9 3.5 1700 na 620 36
11/15/99 22 13:57 0.8 27.9 28.3 1.75 57.4 58.9 8.1 8.200 36.1 36.5 4.5 3.6 1050 na 350 33
12/20/99 1 10:30 0.9 26.7 26.3 1.50 56.9 56.5 8.1 8.330 36.5 36.6 5.4 4.6 1650 na 750 45
162
12/20/99 2 10:45 1.2 26.7 26.6 1.00 56.9 57.0 8.1 8.350 36.6 36.6 5.4 6.0 1600 na 900 56
12/20/99 3 10:55 1.2 26.5 26.4 1.50 56.8 56.8 8.1 8.330 36.6 36.6 5.1 5.1 1650 na 900 55
12/20/99 4 11:10 1.4 26.4 26.4 1.75 56.4 56.7 8.1 8.286 36.4 36.6 5.2 5.1 1500 na 750 50
12/20/99 5 11:27 4.0 26.8 26.4 2.08 57.1 56.8 8.1 na 36.5 36.4 4.9 4.6 1350 na 180 13
12/20/99 6 12:21 2.2 27.3 26.7 2.78 57.0 56.6 8.1 8.358 36.2 36.3 5.7 5.4 1800 na 180 10
12/20/99 11 12:09 4.0 27.0 26.8 2.42 57.0 56.7 8.0 8.325 36.4 36.5 5.2 5.6 1530 na 180 12
12/20/99 14 11:54 3.5 27.1 26.6 2.33 57.1 56.7 8.0 8.264 36.5 36.5 5.0 5.0 1650 na 180 11
12/20/99 22 12:41 2.2 27.5 27.0 1.50 57.6 57.2 8.1 na 36.5 36.6 5.3 5.1 1740 na 780 45
1/26/00 1 11:30 16.0 25.8 27.7 1.42 55.4 55.6 7.9 8.300 36.3 36.3 5.3 5.1 900 na 180 20
1/26/00 2 11:55 6.9 26.0 25.9 1.50 56.1 56.1 7.9 8.400 36.4 36.5 6.0 6.0 1200 na 210 18
1/26/00 3 12:12 6.0 26.1 26.0 1.75 55.6 56.1 8.0 8.400 36.0 36.5 5.7 6.4 450 na 150 33
1/26/00 4 12:25 2.2 25.8 25.7 1.58 54.0 55.4 8.0 8.300 35.1 36.1 5.9 5.8 690 na 500 72
163
1/26/00 5 12:40 2.2 25.8 25.8 2.08 54.4 55.3 8.0 8.500 35.4 36.0 5.2 5.4 1650 na 800 48
1/26/00 6 10:30 5.0 25.9 25.8 2.90 55.6 56.0 8.0 8.287 36.2 36.5 5.5 5.4 3300 na 1110 34
1/26/00 11 13:13 3.0 26.0 na 2.50 55.3 55.4 8.0 8.354 35.9 36.1 5.7 5.4 2250 na 1100 49
1/26/00 14 12:56 3.2 25.9 25.9 2.33 55.8 56.1 8.0 8.324 36.3 36.4 5.6 5.5 4500 na 2100 47
1/26/00 22 13:51 2.2 26.2 26.1 1.67 56.6 56.7 7.9 8.300 36.8 36.8 5.5 5.7 990 na 120 12
2/16/00 1 10:30 2.1 26.0 25.6 1.25 57.4 57.0 8.0 8.200 37.5 37.5 5.7 8.6 1560 na 500 32
2/16/00 2 10:49 1.1 26.0 26.1 0.92 55.3 56.3 7.9 8.300 35.9 36.6 6.4 7.1 1740 na na na
2/16/00 3 11:04 2.2 26.2 26.1 1.67 57.6 57.5 7.9 8.300 37.3 37.3 5.6 6.1 1470 na 510 35
2/16/00 4 11:20 2.2 26.1 26.2 1.75 57.5 57.5 7.9 8.300 37.4 37.4 5.8 6.1 1890 na 180 10
2/16/00 5 11:40 4.6 26.5 26.2 2.17 58.1 57.8 7.9 8.300 37.4 37.5 5.3 5.2 1290 na na na
2/16/00 6 12:24 3.1 26.8 26.4 2.50 57.8 57.8 7.8 8.276 37.0 37.4 6.0 6.2 2220 na 1800 81
2/16/00 11 12:11 3.4 26.8 26.3 2.33 58.0 57.8 7.8 8.214 37.3 37.4 5.6 5.4 2010 na 250 12
164
2/16/00 14 11:56 3.4 26.6 26.2 2.33 57.9 57.7 7.9 8.300 37.3 37.4 5.2 5.3 1950 na na na
2/16/00 22 12:41 2.2 27.0 26.7 1.67 58.6 58.4 7.9 8.297 37.5 37.5 6.0 5.5 2160 na na na
3/16/00 1 14:10 na 27.5 27.0 1.25 60.4 59.1 8.0 na 37.9 37.8 8.0 6.4 1100 na 950 86
3/16/00 2 13:57 na 26.5 26.3 2.08 58.5 58.5 8.1 na 37.8 37.0 7.6 7.5 1900 na 1000 53
3/16/00 3 13:40 na 27.0 26.8 1.67 58.7 58.6 8.1 na 37.6 37.6 8.6 8.6 1900 na 1500 79
3/16/00 4 13:20 na 26.9 26.9 1.67 58.2 58.8 8.0 na 37.3 37.7 6.9 6.9 1800 na 1150 64
3/16/00 5 13:04 na 27.0 26.6 2.25 58.6 58.4 7.9 na 37.7 37.7 6.6 6.5 2000 na 1250 63
3/16/00 6 12:05 na 27.0 26.2 2.92 58.4 57.9 7.8 na 37.5 37.6 6.4 6.9 2000 na 1150 58
3/16/00 11 12:25 na 26.7 26.5 2.42 57.8 58.5 7.8 na 37.3 37.8 6.2 6.4 2000 na 1900 95
3/16/00 14 12:45 na 26.9 26.6 2.08 56.7 58.5 7.7 na 36.3 37.7 5.6 5.3 2000 na 1200 60
3/16/00 22 11:40 na 26.9 26.6 1.75 57.4 58.4 7.9 na 36.7 37.7 5.9 5.8 2000 na 950 48
4/12/00 1 12:28 1.5 28.0 28.0 1.08 60.3 60.3 8.3 8.200 39.9 37.9 6.1 5.8 2000 na 1550 78
165
4/12/00 2 12:57 2.0 28.0 27.8 1.58 60.5 60.2 8.3 8.300 38.0 38.0 6.5 5.8 700 na 600 86
4/12/00 3 13:25 6.6 28.4 28.5 1.42 60.8 62.0 8.4 8.400 37.9 38.0 6.7 5.2 1900 na 1800 95
4/12/00 4 13:54 2.6 28.8 28.8 1.75 61.5 61.7 8.5 8.300 38.1 38.2 6.2 6.2 1900 na 1650 87
4/12/00 5 14:38 1.9 28.7 28.6 2.08 61.3 61.3 8.3 8.300 38.1 38.1 6.1 5.6 1700 na 710 42
4/12/00 6 16:20 8.5 28.7 28.3 2.83 61.2 60.3 8.2 8.300 38.0 38.1 5.6 5.3 750 na 200 27
4/12/00 11 15:38 4.0 28.6 28.6 2.08 61.3 61.4 8.4 8.300 38.1 38.2 5.6 4.6 1600 na 750 47
4/12/00 14 15:10 6.9 28.6 28.6 2.17 61.0 61.3 8.6 8.300 37.9 38.1 5.5 5.3 390 na na na
4/12/00 22 16:50 3.0 29.4 29.3 1.50 62.3 62.8 8.6 8.400 38.2 38.6 5.2 5.5 150 na na na
5/22/00 2 11:35 1.0 30.2 30.2 1.58 62.4 62.3 8.5 8.200 37.6 37.6 6.1 6.1 2000 1500 1200 80
5/22/00 4 12:20 3.0 37.5 37.5 1.50 64.5 64.5 8.4 8.200 37.9 37.9 4.5 4.6 2000 150 1100 733
5/22/00 5 13:05 4.2 30.9 30.7 2.08 63.4 63.1 8.3 8.200 37.8 37.9 4.7 4.3 2000 450 1000 222
5/22/00 14 13:50 5.2 31.7 31.0 1.67 63.0 62.5 8.3 8.300 37.0 37.1 5.0 4.7 1900 500 250 50
166
6/19/00 2 11:30 2.9 29.3 29.2 1.58 59.3 60.8 na 8.100 37.2 37.3 5.6 5.6 2400 670 380 57
6/19/00 4 12:12 3.1 29.8 29.8 1.50 61.7 61.9 8.0 8.200 37.5 37.6 5.6 5.6 2900 1500 1200 80
6/19/00 5 12:50 2.3 30.1 29.7 1.92 61.5 61.9 8.0 8.100 37.3 37.6 5.5 4.9 2000 1000 700 70
6/19/00 14 13:35 5.3 30.2 30.1 1.92 62.4 62.4 8.0 8.200 37.7 37.7 5.0 5.1 1500 550 230 42
6/19/00 22 14:16 2.8 31.2 31.1 1.50 64.0 64.1 8.0 8.200 38.0 37.9 5.7 6.1 1500 200 140 70
7/10/00 2 11:40 1.6 29.2 29.2 1.50 60.3 60.2 7.9 8.300 36.9 36.9 7.0 7.1 1700 1700 1500 88
7/10/00 4 12:30 1.8 30.0 29.9 1.58 61.6 61.6 7.9 8.300 37.3 37.3 6.7 6.2 1950 1600 1450 91
7/10/00 5 13:10 4.0 30.1 29.9 2.25 61.9 61.8 7.8 8.400 37.4 37.4 6.1 5.6 1900 1400 900 64
7/10/00 14 13:55 4.1 30.3 30.1 2.08 61.8 61.8 7.8 8.300 37.3 37.3 6.0 5.6 1800 1500 1800 120
7/10/00 22 14:40 1.9 31.4 31.3 1.58 64.0 64.0 7.8 8.300 37.8 37.9 5.7 6.0 670 420 300 71
8/21/00 1 11:00 1.0 30.2 30.2 1.25 60.7 60.5 8.0 8.300 36.4 36.3 4.4 4.7 na na na na
8/21/00 2 12:52 1.0 30.7 30.7 2.67 61.2 61.1 8.1 8.500 36.5 36.2 6.0 6.2 na na na na
167
8/21/00 3 13:20 1.6 n 31.0 1.67 61.2 61.8 8.1 8.500 36.3 36.0 6.3 6.6 na na na na
8/21/00 4 13:45 0.9 31.5 31.4 1.92 61.8 62.4 8.1 8.400 36.3 36.7 9.9 6.1 na na na na
8/21/00 5 14:10 2.4 31.5 31.3 2.33 62.3 62.4 8.1 8.400 36.6 36.8 6.0 5.3 na na na na
8/21/00 6 15:06 3.6 31.9 31.3 3.00 63.0 62.5 8.0 8.400 36.9 36.9 5.7 5.9 na na na na
8/21/00 11 14:50 2.4 31.8 31.6 2.50 63.1 62.9 8.0 8.400 36.9 36.9 5.5 5.6 na na na na
8/21/00 14 14:33 3.6 31.8 31.5 2.67 62.6 62.7 8.0 8.400 36.6 36.8 5.3 5.0 na na na na
8/21/00 22 15:35 1.3 32.7 32.6 1.75 64.7 64.9 8.0 8.500 37.3 37.4 5.5 5.7 na na na na
8/23/00 1 12:15 5.0 29.2 29.6 na 58.0 59.3 8.0 8.000 35.5 35.9 5.6 4.7 na na na na
8/23/00 2 12:30 9.0 29.5 29.5 na 57.5 59.0 8.0 8.100 37.0 35.7 5.3 5.3 na na na na
8/23/00 3 12:50 1.7 29.3 29.4 na 53.4 58.2 8.0 8.300 37.5 35.5 5.4 5.6 na na na na
8/23/00 4 13:12 1.7 29.1 29.1 na 57.0 56.9 8.0 8.100 34.8 34.9 5.8 4.7 na na na na
8/23/00 5 13:37 na 29.6 29.4 na 57.7 57.6 8.0 8.200 34.9 34.9 5.8 5.1 na na na na
168
8/23/00 6 14:03 3.0 29.8 29.3 na 56.2 58.3 8.0 8.200 33.8 33.8 5.3 4.9 na na na na
9/18/00 1 11:45 2.6 29.5 25.3 1.25 58.9 59.3 8.0 8.200 35.9 36.0 5.4 5.0 na na na na
9/18/00 2 12:05 1.4 29.5 29.5 2.50 59.2 59.2 8.0 8.300 35.9 36.0 5.4 5.5 na na na na
9/18/00 3 12:35 1.1 29.2 29.2 2.00 58.5 58.7 8.1 8.300 35.7 35.3 5.7 5.0 na na na na
9/18/00 4 13:35 1.0 28.8 29.0 1.92 57.7 57.3 8.0 na 34.9 34.9 5.3 5.6 na na na na
9/18/00 5 13:55 1.8 29.7 29.7 2.42 58.9 59.4 8.0 8.200 35.5 35.8 4.2 4.5 na na na na
9/18/00 6 15:20 1.8 29.9 29.3 2.92 58.3 59.3 8.0 8.300 35.2 35.7 4.9 4.8 na na na na
9/18/00 6 12:55 1.8 29.3 29.3 4.33 59.0 59.0 8.2 8.300 35.9 35.9 5.5 5.5 na na na na
9/18/00 11 15:00 1.9 30.0 29.8 2.75 59.2 59.3 8.0 8.300 35.6 35.8 4.8 4.7 na na na na
9/18/00 14 14:40 1.5 30.0 30.0 2.42 58.6 59.6 8.0 8.300 35.1 35.8 4.7 4.0 na na na na
9/18/00 22 16:00 1.5 29.9 29.8 1.58 57.4 58.3 8.0 8.100 34.4 35.1 4.6 5.5 na na na na
10/16/00 1 11:59 1.4 30.2 30.2 1.33 60.8 60.7 8.4 8.200 36.6 36.5 6.2 6.1 2100 1500 1000 67
169
10/16/00 2 12:22 2.4 30.4 30.4 1.08 60.8 60.9 8.5 8.300 36.4 36.4 7.4 7.7 2200 1200 800 67
10/16/00 3 12:45 2.6 30.5 30.5 1.83 60.9 60.9 8.6 8.400 36.4 36.4 7.1 7.1 2400 1700 800 47
10/16/00 4 13:10 4.5 30.8 30.7 1.92 61.5 61.4 8.6 8.300 36.6 36.5 5.7 5.5 2000 1400 200 14
10/16/00 5 13:50 1.6 30.9 30.6 2.50 61.5 61.2 8.7 8.300 36.5 36.5 6.1 4.6 1800 1500 300 20
10/16/00 6 15:10 4.2 31.2 30.8 2.92 61.9 61.6 8.2 8.300 36.5 36.5 5.8 5.8 1800 1000 340 34
10/16/00 11 14:46 3.2 31.2 30.8 2.67 61.8 61.8 8.2 8.300 36.5 36.5 5.1 5.5 490 300 240 80
10/16/00 14 14:21 4.9 31.1 30.6 2.58 61.7 61.4 8.7 8.300 36.5 36.6 4.8 4.5 1900 1300 600 46
10/16/00 22 15:38 1.5 32.0 32.0 1.75 63.4 63.3 8.0 8.300 36.9 36.9 6.6 6.5 1000 1000 500 50
11/14/00 1 11:15 0.5 29.3 28.8 na 59.0 53.6 8.0 8.600 36.0 36.1 5.3 6.7 2150 1500 1000 67
11/14/00 2 11:39 0.7 29.2 29.2 na 59.0 59.1 8.0 8.700 36.1 36.1 6.0 4.9 2100 1500 1000 67
11/14/00 3 11:57 0.7 29.4 29.1 na 59.2 58.8 8.0 8.600 36.1 36.0 6.1 6.2 2100 1400 600 43
11/14/00 4 12:18 1.0 28.8 29.3 na 59.2 59.2 7.9 8.600 36.1 36.1 5.3 5.4 2000 1400 1000 71
170
11/14/00 5 12:43 2.5 28.8 29.4 na 59.8 59.4 7.9 8.600 36.2 36.2 4.8 4.7 2000 1100 500 45
11/14/00 5 15:07 2.5 29.3 29.7 5.50 59.5 59.0 8.0 8.600 36.1 36.1 5.9 5.8 2000 1400 750 54
11/14/00 6 14:00 2.0 30.0 29.5 na 60.2 59.5 7.9 8.600 36.2 36.2 4.5 5.1 2100 1400 600 43
11/14/00 11 13:40 1.5 30.1 29.7 na 60.3 59.8 8.0 8.600 36.2 36.2 5.1 5.6 2000 1500 1600 107
11/14/00 14 13:02 2.3 29.6 29.2 na 59.8 59.3 7.9 8.600 36.2 36.2 4.5 4.3 2000 1000 500 50
11/14/00 22 14:16 0.5 30.0 29.9 na 60.5 60.7 8.0 8.800 36.4 36.7 5.4 5.0 2000 1500 1000 67
2/20/01 1 13:00 na 27.0 26.8 na 58.6 58.4 8.0 8.545 37.6 37.5 6.2 6.8 2200 1700 1000 59
2/20/01 2 13:32 na 26.8 26.8 na 58.1 58.3 7.8 8.352 37.3 37.4 6.6 6.9 2200 1700 1200 71
2/20/01 3 13:52 na 27.2 27.1 na 58.6 58.8 7.9 8..496 37.4 37.6 6.5 6.4 2200 1700 1000 59
2/20/01 4 14:11 na 27.0 27.0 na 58.6 58.7 7.8 8.488 37.5 37.6 6.5 6.5 400 350 200 57
2/20/01 5 14:47 na 26.9 26.7 na 58.3 58.5 7.8 8.393 37.3 37.5 5.4 5.5 370 240 120 50
2/20/01 6 15:51 na 26.8 26.8 na 58.4 58.4 7.8 8.380 37.4 37.5 5.2 5.1 160 72 28 39
171
2/20/01 11 15:29 na 26.8 26.8 na 58.6 58.6 7.8 8.410 37.6 37.6 5.1 4.0 400 110 40 36
2/20/01 14 15:11 na 26.9 26.9 na 58.7 58.7 7.8 8.500 37.6 37.6 5.1 4.7 450 160 50 31
2/20/01 22 16:12 na 27.1 27.0 na 59.2 59.3 7.8 8.390 37.7 37.9 5.4 4.7 320 200 120 60
4/24/01 1 13:18 2.2 28.7 28.1 na 61.2 61.0 8.1 na 38.2 38.2 6.7 6.1 2100 1700 1400 82
4/24/01 2 13:36 1.2 28.5 28.2 na 61.4 61.2 8.1 8.490 38.3 38.2 7.5 7.1 1500 1800 1400 78
4/24/01 3 13:53 3.6 28.8 28.7 na 61.7 61.5 8.1 8.530 38.2 37.8 7.0 6.8 2300 1500 500 33
4/24/01 4 14:11 0.9 28.9 28.9 na 61.5 61.8 8.1 8.500 38.0 38.0 7.0 7.3 2100 1500 1000 67
4/24/01 5 14:40 2.5 28.7 28.3 2.00 61.4 61.3 8.0 8.500 39.1 38.2 6.1 5.1 2100 1200 500 42
4/24/01 6 15:35 4.4 29.4 28.8 2.92 62.3 61.6 8.0 8.400 38.2 34.9 5.9 6.8 2200 500 230 46
4/24/01 11 15:15 3.9 28.9 28.9 2.33 62.0 62.0 8.0 8.400 38.3 38.3 5.1 5.6 1700 1400 400 29
4/24/01 14 14:58 4.3 28.9 28.8 2.08 61.8 61.7 8.0 8.420 38.3 38.1 5.1 5.2 2200 1300 400 31
4/24/01 22 15:57 3.5 30 30.0 1.58 63.4 63.5 8.0 8.470 38.5 38.5 5.6 8.1 2100 1500 400 27
172
5/7/01 1 12:46 20.0 29.3 29.0 1.08 54.0 55.1 8.0 7.900 32.5 33.5 5.0 5.0 2100 1500 700 47
5/7/01 2 12:06 33.1 28.5 27.9 3.25 53.1 55.0 8.0 8.100 31.4 33.4 5.8 5.5 2000 1500 300 20
5/7/01 3 11:35 8.6 27.5 27.6 1.75 53.7 55.6 8.0 8.100 33.6 34.9 5.5 6.1 2100 1500 400 27
5/7/01 4 11:10 6.2 27.8 27.6 1.75 51.2 56.8 7.9 8.100 31.9 35.7 4.9 4.2 2100 1500 400 27
5/7/01 5 10:34 3.2 27.4 27.6 2.08 51.4 57.0 8.0 8.000 32.3 35.8 5.8 4.1 1500 1200 500 42
5/7/01 6 15:40 3.0 29.1 27.6 3.08 51.1 59.6 8.0 8.100 31.2 32.6 5.3 4.7 1800 570 150 26
5/7/01 11 15:25 4.1 29.4 28.4 2.25 51.5 58.6 8.0 8.100 31.0 32.6 5.2 3.7 1200 400 140 35
5/7/01 14 15:13 3.4 28.8 28.6 2.83 53.1 54.4 8.0 8.100 32.4 34.0 5.1 4.2 530 400 110 28
5/7/01 22 15:58 4.5 28.4 28.1 1.75 48.3 52.3 7.8 8.000 28.6 32.2 5.6 4.4 300 150 34 23
173
Appendix 2. Lab Data for La Parguera, Puerto Rico. Water quality parameters collected between 6/15/98 and 5/10/01 near
La Parguera, Puerto Rico.
Nutrient TSS
Date Station NH3 NO3 NO2 PO4 Total Inorganic Organic Chlorophyll a
mg/l mg/l ug/l
6/15/98 3 bdl 1.10 0.01 0.01 30.31 24.05 6.26 0.51
6/15/98 5 bdl 1.20 0.00 0.07 30.20 24.72 5.47 0.38
6/15/98 6 bdl 1.40 0.01 0.01 28.54 23.68 4.86 1.43
10/22/98 1 0.10 3.40 0.00 bdl 30.55 13.20 17.34 1.00
10/22/98 2 0.04 4.20 bdl bdl 27.30 10.49 16.81 1.04
174
10/22/98 5 0.05 2.90 bdl bdl 27.89 13.17 14.73 1.08
10/22/98 6 0.04 1.90 0.02 bdl 29.09 14.50 14.59 2.50
11/3/98 1 0.00 0.30 bdl 0.04 27.49 4.61 22.88 0.60
11/3/98 2 0.01 0.40 0.00 bdl 27.20 5.40 21.79 0.56
11/3/98 3 0.01 0.20 0.00 0.00 32.71 8.81 23.90 0.93
11/3/98 4 0.01 0.50 0.00 0.01 26.17 5.59 20.58 1.07
2/9/99 4 0.13 0.10 0.00 bdl 28.01 3.23 24.78 0.64
3/8/99 1 0.01 0.10 0.00 0.01 35.47 2.70 32.77 1.38
3/8/99 2 0.02 0.25 0.00 0.00 32.17 2.07 30.10 0.47
3/8/99 3 0.02 0.20 0.00 0.01 33.30 2.16 31.14 1.47
3/8/99 4 0.02 0.20 0.00 bdl 35.47 2.81 32.67 1.03
3/8/99 5 0.03 0.10 0.00 bdl 35.75 3.97 31.77 2.07
175
3/8/99 6 0.02 0.30 0.00 bdl 35.00 4.26 30.74 3.19
5/18/99 1 0.00 bdl 0.00 0.18 27.39 23.15 4.24 0.15
5/18/99 2 0.01 bdl 0.00 0.01 31.08 26.76 4.32 0.11
5/18/99 3 0.00 bdl 0.00 bdl 26.00 22.72 3.29 0.19
9/19/99 1 0.05 1.80 0.00 0.01 26.37 23.15 3.22 0.88
9/19/99 2 0.03 1.80 0.00 bdl 27.60 24.35 3.25 0.81
9/19/99 3 0.00 1.80 bdl bdl 26.60 23.40 3.21 0.89
9/19/99 4 0.05 2.30 bdl bdl 25.09 22.10 2.99 1.11
10/18/99 4 0.02 1.30 bdl bdl 26.43 22.93 3.49 0.73
10/18/99 5 0.08 1.30 bdl bdl 27.24 23.58 3.66 1.86
10/18/99 6 0.01 1.05 bdl bdl 26.02 22.57 3.45 3.43
10/18/99 11 0.10 1.30 bdl bdl 28.11 24.31 3.81 2.66
176
10/18/99 14 0.03 1.05 bdl bdl 24.10 20.96 3.14 2.64
10/18/99 22 0.03 1.10 0.00 bdl 28.64 24.96 3.68 2.69
11/15/99 1 bdl 0.70 0.01 0.02 25.96 22.85 3.10 1.10
11/15/99 2 bdl 0.60 0.01 0.01 29.31 25.87 3.44 0.84
11/15/99 3 bdl 1.30 0.01 0.01 26.59 23.46 3.14 1.16
11/15/99 4 bdl 1.20 0.00 0.01 24.52 21.52 3.00 1.32
11/15/99 5 bdl 1.30 0.00 bdl 27.64 24.32 3.32 1.83
11/15/99 6 bdl 1.35 bdl 0.01 24.81 21.54 3.28 4.24
11/15/99 14 bdl 1.00 0.01 bdl 31.95 27.88 4.07 1.87
11/15/99 22 bdl 0.60 0.00 0.01 26.47 23.16 3.31 3.21
12/20/99 1 bdl 1.50 0.00 bdl 30.72 26.40 4.31 1.84
12/20/99 3 bdl 1.40 0.01 bdl 25.72 22.32 3.40 1.27
177
12/20/99 4 bdl 1.50 0.01 bdl 28.67 24.47 4.20 0.94
12/20/99 5 bdl 1.40 0.00 bdl 32.24 27.72 4.52 1.72
12/20/99 6 bdl 1.40 0.00 bdl 44.97 38.73 6.24 3.08
12/20/99 11 bdl 1.60 0.00 bdl 44.75 34.34 10.41 3.14
12/20/99 14 bdl 1.50 bdl bdl 34.70 29.82 4.87 5.68
12/20/99 22 bdl 1.40 0.00 bdl 34.63 29.60 5.03 2.95
1/26/00 1 bdl 1.20 0.00 bdl 41.55 29.42 12.13 2.25
1/26/00 2 bdl 1.30 0.00 bdl 37.68 28.22 9.46 1.27
1/26/00 4 bdl 1.10 0.00 0.01 33.11 24.66 8.45 0.77
1/26/00 5 bdl 1.30 0.00 bdl 29.38 22.75 6.63 0.85
1/26/00 6 bdl 1.05 0.00 bdl 31.88 25.16 6.72 0.91
1/26/00 11 bdl 1.20 0.00 bdl 34.64 26.94 7.70 1.20
178
1/26/00 14 bdl 1.30 0.00 0.01 36.74 26.69 10.05 2.69
1/26/00 22 bdl 1.10 0.00 bdl 30.46 22.78 7.68 1.45
2/16/00 1 bdl 1.30 bdl bdl 23.84 18.65 5.19 0.67
2/16/00 2 bdl 1.00 0.01 bdl 29.88 22.07 7.80 0.40
2/16/00 3 bdl 1.30 0.03 bdl 27.13 21.04 6.10 0.55
2/16/00 4 bdl 1.20 0.01 bdl 34.60 25.32 9.28 2.07
2/16/00 5 bdl 1.10 0.00 bdl 37.13 27.46 9.67 0.97
2/16/00 6 bdl 1.20 0.00 bdl 31.72 24.53 7.20 3.28
2/16/00 11 bdl 1.10 0.00 bdl 38.03 27.99 10.04 1.47
2/16/00 14 bdl 1.10 0.00 bdl 35.70 25.73 9.97 1.04
2/16/00 22 bdl 1.10 0.00 bdl 28.84 22.35 6.49 0.83
3/16/00 1 bdl 1.10 bdl bdl 36.10 28.73 7.37 0.56
179
3/16/00 3 bdl 1.10 bdl bdl 41.98 30.25 11.73 0.44
3/16/00 3 bdl 1.30 bdl bdl 41.98 30.25 11.73 0.44
3/16/00 6 bdl 1.00 bdl bdl 41.85 29.50 12.36 6.14
4/12/00 1 bdl 1.40 bdl bdl 32.74 22.92 9.82 0.40
4/12/00 3 bdl 1.40 bdl bdl 41.70 30.59 11.11 1.48
4/12/00 4 bdl 1.10 bdl 0.01 34.21 22.48 11.74 0.72
4/12/00 5 bdl 1.40 bdl bdl 42.19 30.72 11.46 1.64
4/12/00 6 bdl 1.30 bdl bdl 38.88 28.29 10.60 3.80
4/12/00 11 bdl 1.60 bdl bdl 39.50 29.28 10.22 0.56
4/12/00 22 bdl 1.60 bdl bdl 34.79 23.01 11.78 1.76
6/19/00 2 bdl 0.80 bdl bdl 35.30 26.55 8.74 0.45
6/19/00 4 bdl 1.20 bdl 0.01 37.74 24.43 13.32 0.51
180
6/19/00 5 bdl 1.10 bdl 0.02 46.10 31.98 14.12 1.06
6/19/00 14 bdl 1.20 bdl 0.04 39.46 25.28 14.18 1.29
6/19/00 22 bdl 1.10 bdl 0.02 39.02 26.30 12.72 0.82
7/10/0 0 4 bdl 1.30 bdl bdl 37.94 22.77 15.17 0.57
7/10/00 22 bdl 1.30 bdl 0.21 30.81 21.02 9.79 0.83
8/21/00 1 bdl 2.15 bdl bdl 39.63 25.10 14.53 0.43
8/21/00 3 bdl 2.04 bdl 0.04 31.62 19.46 12.17 0.78
8/21/00 4 bdl 2.03 bdl 0.04 40.36 26.78 13.58 0.42
8/21/00 5 bdl 2.42 bdl 0.03 36.47 24.17 12.30 1.06
8/21/00 11 bdl 2.71 bdl 0.03 43.54 24.91 18.63 1.48
8/21/00 14 bdl 2.50 bdl 0.04 40.36 26.93 13.44 0.88
8/21/00 22 bdl 2.63 bdl 0.04 35.91 23.63 12.28 0.52
181
8/23/00 3 bdl 1.47 bdl 0.02 35.29 23.75 11.54 0.57
8/23/00 5 bdl 2.58 bdl 0.03 29.41 20.16 9.24 1.30
8/23/00 6 bdl 1.27 bdl 0.05 35.34 22.66 12.68 1.19
9/18/00 3 bdl 1.95 bdl 0.03 108.82 95.24 13.58 1.17
9/18/00 5 bdl 2.28 bdl 0.02 96.09 82.79 13.30 1.53
9/18/00 11 bdl 2.30 bdl 0.01 80.38 70.03 10.35 2.72
9/18/00 14 bdl 2.25 bdl 0.01 97.96 83.81 14.15 1.52
10/16/00 4 bdl 2.30 bdl 0.01 23.40 20.01 3.38 0.37
10/16/00 6 bdl 2.03 bdl 0.02 26.27 23.21 3.06 1.48
10/16/00 11 bdl 2.23 bdl 0.03 19.58 16.51 3.07 1.20
11/14/00 1 bdl 2.12 bdl 0.02 26.61 24.27 2.34 0.30
11/14/00 2 bdl 2.48 bdl bdl 23.05 21.66 1.39 0.47
182
11/14/00 2 bdl bdl bdl 0.04 23.05 21.66 1.39 0.47
11/14/00 3 bdl 2.48 bdl 0.03 23.64 20.99 2.65 0.64
11/14/00 4 bdl 2.32 bdl 0.01 22.04 19.89 2.15 0.67
11/14/00 5 bdl 2.24 bdl 0.03 28.15 25.61 2.54 0.65
11/14/00 5 bdl 2.24 bdl 0.03 28.15 25.61 2.54 0.65
11/14/00 6 bdl 1.90 bdl 0.05 24.36 21.95 2.41 2.25
11/14/00 22 bdl 2.59 bdl 0.04 20.39 18.33 2.06 0.69
2/20/01 2 bdl 0.11 bdl 0.24 27.82 24.56 3.26 0.38
2/20/01 4 bdl 0.12 bdl 0.23 24.83 22.10 2.73 0.39
2/20/01 5 bdl 0.12 bdl 0.15 27.15 24.01 3.14 0.91
2/20/01 14 bdl 0.11 bdl 0.16 26.34 23.25 3.09 1.03
2/20/01 22 bdl 0.07 bdl 0.17 30.94 27.08 3.86 0.99
183
4/24/01 1 bdl 0.18 bdl 0.01 173.90 119.10 54.80 0.66
4/24/01 2 bdl 0.21 bdl 0.02 120.86 60.48 60.38 0.50
4/24/01 3 bdl 0.18 bdl 0.01 31.51 25.39 6.12 0.92
4/24/01 4 bdl 0.17 bdl 0.00 39.05 32.24 6.82 0.61
4/24/01 5 bdl 0.16 bdl 0.01 34.85 27.04 7.81 1.23
4/24/01 6 bdl 0.17 bdl 0.01 27.06 21.62 5.44 3.05
4/24/01 11 bdl 0.11 bdl 0.02 28.27 24.99 3.28 1.98
4/24/01 14 bdl 0.18 bdl 0.02 38.83 32.23 6.60 1.44
4/24/01 22 bdl 0.16 bdl 0.03 24.57 20.13 4.45 2.56
5/7/01 4 bdl 0.27 bdl 0.08 60.25 48.96 11.29 0.85
5/7/01 22 bdl 0.13 bdl 0.10 28.97 23.63 5.34 0.11
184
Appendix 2. Lab Data for La Parguera, Puerto Rico. Water quality parameters collected between 6/15/98 and 5/10/01 near
La Parguera, Puerto Rico (continued).
Particulate Particle Concentration Particle Volume
Date Station P C N C:N 2-30 um 30-63 um Total 2-30 µm 30-63 µm Total
µg-P/l µg-C/l µg-N/l #/ml µm/ml
6/15/98 3 146.9 413.7 33.0 12.6 3118.8 61.0 3179.8 94095 199850 293945
6/15/98 5 1051.6 366.5 49.8 7.2 14616.3 145.0 14761.3 423505 348150 771655
6/15/98 6 949.9 478.0 81.5 5.9 4518.8 143.5 4662.3 168755 409000 577755
10/22/98 1 503.2 512.8 47.4 11.1 1519.3 120.5 1639.8 66794 554650 621444
10/22/98 2 153.3 544.3 69.1 8.1 2972.3 134.5 3106.8 99835 903650 1003485
10/22/98 5 187.2 339.6 60.2 5.9 3693.3 145.5 3838.8 99402 1137350 1236752
185
10/22/98 6 144.8 461.4 78.9 5.8 3914.3 187.0 4101.3 70909 1633000 1703909
11/3/98 1 414.2 394.9 43.3 9.1 3178.8 79.5 3258.3 77083 330150 407233
11/3/98 2 109.3 403.7 45.4 8.9 2253.8 49.0 2302.8 51081 212300 263381
11/3/98 3 1019.7 361.2 42.2 8.5 4059.8 98.0 4157.8 90896 565950 656846
11/3/98 4 276.7 397.9 42.2 9.5 3399.3 77.5 3476.8 82944 361400 444344
2/9/99 4 157.9 428.7 43.2 10.5 1898.1 9.5 1907.6 385433 68143 453576
3/8/99 1 200.2 441.0 125.6 3.5 2918.6 16.5 2935.1 400033 503800 903833
3/8/99 2 126.9 338.4 67.9 5.2 1846.1 8.0 1854.1 264733 200100 464833
3/8/99 3 212.1 462.0 121.1 4.3 2692.1 2.0 2694.1 307733 108006 415739
3/8/99 4 140.9 436.3 89.9 5.0 3821.6 4.5 3826.1 454083 96808 550891
3/8/99 5 458.3 647.0 147.1 4.4 4815.6 7.0 4822.6 371233 184400 555633
3/8/99 6 626.2 687.0 143.3 4.9 3632.6 8.0 3640.6 609433 164837 774270
186
5/18/99 1 55.3 331.7 63.0 5.9 3132.1 2.5 3134.6 299433 54176 353609
5/18/99 2 185.9 298.5 37.8 10.4 2478.6 8.5 2487.1 348033 175900 523933
5/18/99 3 537.7 475.3 82.4 5.5 2473.6 7.5 2481.1 348033 161900 509933
9/19/99 1 443.0 440.6 147.6 3.0 1897.5 0.0 1897.5 50631 na 50631
9/19/99 2 288.7 332.2 99.6 3.9 1834.5 0.5 1835.0 20497 na 20516
9/19/99 3 987.6 346.9 147.0 2.4 1305.0 0.0 1305.0 15393 na 15393
9/19/99 4 952.9 366.7 144.6 2.5 2247.0 0.5 2247.5 46035 8367 54402
10/18/99 4 446.3 385.5 129.9 3.0 2310.0 2.5 2312.5 104042 40533 144575
10/18/99 5 1205.3 397.0 151.0 2.6 2584.5 5.0 2589.5 123744 161150 284894
10/18/99 6 837.6 498.3 194.7 2.6 6766.5 6.5 6773.0 350450 134951 485401
10/18/99 11 1013.8 600.2 147.4 4.5 5284.0 3.0 5287.0 381000 65150 446150
10/18/99 14 764.7 665.6 191.3 3.5 2739.0 1.5 2740.5 83129 48709 131837
187
10/18/99 22 565.9 544.1 184.4 3.0 3780.5 4.0 3784.5 153800 147766 301566
11/15/99 1 315.5 338.0 81.8 6.7 656.1 15.5 671.6 95249 na 95249
11/15/99 2 652.3 197.5 68.4 3.4 548.1 81.5 629.6 19036 na 19036
11/15/99 3 435.8 234.7 91.1 3.4 839.6 29.0 868.6 30928 41262 72190
11/15/99 4 827.3 410.4 136.3 3.0 165.6 81.5 247.1 10289 1245750 1256039
11/15/99 5 926.0 435.4 126.1 3.5 1094.1 8.0 1102.1 24793 50579 75372
11/15/99 6 523.6 444.0 165.1 2.7 361.6 44.5 406.1 18223 347827 366050
11/15/99 14 672.2 529.4 158.9 3.5 934.1 75.5 1009.6 61773 na 61773
11/15/99 22 694.2 365.4 77.1 4.9 181.1 45.5 226.6 9233 na 9233
12/20/99 1 479.8 245.3 108.1 2.3 44.0 68.1 8914 609400 618314
12/20/99 3 763.8 291.9 147.3 2.0 1460.6 92.5 1553.1 46109 907000 953109
12/20/99 4 347.5 377.7 134.1 2.9 1940.6 133.5 2074.1 58964 1491650 1550614
188
12/20/99 5 512.4 552.4 177.5 3.1 1775.1 64.5 1839.6 48252 716300 764552
12/20/99 6 472.9 558.0 176.3 3.2 4232.6 136.5 4369.1 1746883 649100 2395983
12/20/99 11 352.4 470.4 170.0 2.8 3446.1 192.0 3638.1 196933 2317650 2514583
12/20/99 14 417.3 728.2 172.4 4.2 1063.6 90.5 1154.1 90210 422150 512360
12/20/99 22 1194.7 422.4 141.0 3.0 2143.6 109.5 2253.1 81322 1029050 1110372
1/26/00 1 269.7 938.0 179.4 5.1 7083.5 7.5 7091.0 1278595 176700 1455295
1/26/00 2 900.2 483.9 114.8 4.2 6722.5 5.5 6728.0 674245 119797 794042
1/26/00 4 432.8 153.3 23.6 6.6 2540.0 0.0 2540.0 252795 na 252795
1/26/00 5 695.5 255.2 67.1 3.8 3447.5 2.5 3450.0 259045 81701 340746
1/26/00 6 1341.3 195.5 46.7 4.5 2012.5 1.0 2013.5 271895 21306 293201
1/26/00 11 694.4 253.5 64.6 3.9 3191.0 2.0 3193.0 248945 59421 308366
1/26/00 14 611.3 415.4 85.2 5.0 4424.0 0.5 4424.5 126499 na 126517
189
1/26/00 22 816.3 354.7 80.5 4.4 1582.0 2.0 1584.0 250645 40338 290983
2/16/00 1 815.4 213.3 46.4 4.6 360.0 1.5 361.5 201245 37862 239107
2/16/00 2 525.9 132.1 38.0 4.4 1172.0 8.0 1180.0 159845 208981 368826
2/16/00 3 412.0 256.4 65.9 4.3 502.5 9.5 512.0 165334 251200 416534
2/16/00 4 1254.4 353.7 100.6 3.6 1128.5 10.0 1138.5 226395 292250 518645
2/16/00 5 1531.3 368.7 91.9 4.0 1319.0 28.5 1347.5 575195 940070 1515265
2/16/00 6 390.8 367.7 64.2 5.7 9490.0 1.0 9491.0 222748 na 222765
2/16/00 11 500.9 290.4 67.9 4.3 2508.5 6.0 2514.5 340895 179000 519895
2/16/00 14 506.6 326.6 70.8 4.7 5156.0 11.0 5167.0 342495 303602 646097
2/16/00 22 254.3 265.2 46.0 5.8 5787.5 18.5 5806.0 484445 480888 965333
3/16/00 1 291.6 279.3 58.7 4.8 2096.1 27.5 2123.6 50794 64215 115009
3/16/00 3 281.9 420.6 110.1 3.9 1259.1 67.0 1326.1 38232 343300 381532
190
3/16/00 3 281.9 420.6 110.1 3.9 1259.1 67.0 1326.1 38232 343300 381532
3/16/00 6 1223.6 593.2 83.1 7.2 3123.6 274.5 3398.1 197183 672100 869283
4/12/00 1 184.4 253.9 52.4 4.7 1576.6 19.5 1596.1 32339 148440 180778
4/12/00 3 807.1 781.1 153.4 5.2 2494.6 17.5 2512.1 59481 114850 174331
4/12/00 4 505.1 225.6 48.9 4.7 1714.1 13.0 1727.1 46073 77868 123940
4/12/00 5 na 378.7 82.5 4.7 7934.1 215.5 8149.6 320783 578050 898833
4/12/00 6 1106.0 643.8 125.9 5.1 3725.1 20.0 3745.1 91982 31859 123840
4/12/00 11 1424.7 557.6 130.7 4.3 3432.6 36.5 3469.1 99571 167150 266721
4/12/00 22 769.7 417.2 66.6 6.3 2273.1 39.5 2312.6 48659 102256 150914
6/19/00 2 569.4 304.3 22.4 139.3 760.0 1.5 761.5 96789 42425 139213
6/19/00 4 1104.7 599.9 49.1 12.2 2622.5 1.0 2623.5 334745 27797 362542
6/19/00 5 1016.7 613.8 71.9 8.8 424.0 1.0 425.0 127495 19209 146704
191
6/19/00 14 441.3 765.2 83.1 8.8 2158.5 1.0 2159.5 328645 15921 344566
6/19/00 22 473.1 469.5 40.8 11.4 871.5 3.5 875.0 270345 82893 353238
7/10/00 4 511.8 505.0 46.9 10.5 1649.0 3.0 1652.0 243795 66721 310516
7/10/00 22 433.4 388.7 77.8 5.4 1110.5 3.0 1113.5 225645 63867 289512
8/21/00 1 444.4 382.3 57.7 8.2 432.0 1.0 433.0 75443 36275 111718
8/21/00 3 339.0 683.5 93.2 9.9 1067.0 4.0 1071.0 206595 164743 371338
8/21/00 4 160.5 139.7 65.1 2.1 341.5 0.0 341.5 105968 na 105968
8/21/00 5 993.7 307.0 60.9 5.3 179.2 2.0 181.2 264545 60450 324995
8/21/00 11 824.1 434.5 51.4 8.5 1270.5 6.5 1277.0 214295 189250 403545
8/21/00 14 787.6 117.2 61.8 1.9 2739.5 1.5 2741.0 349995 44856 394851
8/21/00 22 717.9 82.0 66.1 1.5 1213.0 0.5 1213.5 193695 7846 201541
8/23/00 3 608.6 220.7 62.3 8.6 2081.0 1.5 2082.5 182995 36448 219443
192
8/23/00 5 1628.3 374.4 99.3 4.4 968.0 1.5 969.5 253695 14788 268483
8/23/00 6 1034.2 250.3 62.3 4.3 2071.0 1.0 2072.0 279245 20537 299782
9/18/00 3 883.8 141.0 44.5 3.2 155.5 2.0 157.5 197795 102193 299988
9/18/00 5 836.2 269.3 53.0 4.3 2716.0 3.0 2719.0 396395 94127 490522
9/18/00 11 925.0 97.5 43.8 2.2 1946.5 2.5 1949.0 308295 74647 382942
9/18/00 14 799.9 122.1 41.1 3.0 2020.0 3.0 2023.0 302645 89958 392603
10/16/00 4 33.9 626.3 74.7 8.4 2373.0 4.0 2377.0 411895 101071 512966
10/16/00 6 173.9 186.4 21.3 8.7 1670.5 5.0 1675.5 251895 116025 367920
10/16/00 11 1187.4 176.3 24.7 7.1 4971.5 9.0 4980.5 589145 232800 821945
11/14/00 1 386.4 134.2 24.3 6.2 758.5 1.5 760.0 102854 28665 131519
11/14/00 2 368.0 70.5 12.1 5.9 1126.0 5.0 1131.0 176754 114150 290904
11/14/00 2 368.0 70.5 12.1 5.9 1126.0 5.0 1131.0 176754 114150 290904
193
11/14/00 3 306.6 137.2 16.5 7.6 1996.5 4.0 2000.5 123382 144684 268066
11/14/00 4 159.1 801.2 26.8 29.9 1781.5 2.5 1784.0 205104 73851 278955
11/14/00 5 436.3 287.3 37.4 6.9 1018.0 1.5 1019.5 142154 30406 172560
11/14/00 5 436.3 287.3 37.4 6.9 1018.0 1.5 1019.5 142154 30406 172560
11/14/00 6 134.9 300.0 45.5 6.6 6075.5 3.0 6078.5 367354 121754 489108
11/14/00 22 603.5 459.3 37.2 14.8 1905.5 1.5 1907.0 196104 32661 228765
2/20/01 2 185.4 316.5 37.2 6.7 4524.3 0.0 4524.3 142005 na 142005
2/20/01 4 150.0 484.7 56.0 8.9 5392.8 0.0 5392.8 161655 na 161655
2/20/01 5 447.0 289.6 35.4 8.2 6449.8 0.0 6449.8 276955 na 276955
2/20/01 14 747.4 169.3 27.7 6.0 3658.3 0.0 3658.3 76985 na 76985
2/20/01 22 563.6 388.8 33.8 10.1 7720.8 1.0 7721.8 249855 19699 269553
4/24/01 1 544.3 80.6 12.7 6.4 1879.3 0.0 1879.3 39509 na 39509
194
4/24/01 2 211.6 104.1 16.8 6.2 5237.3 0.5 5237.8 219155 28794 247949
4/24/01 3 503.4 156.2 24.3 6.5 3438.8 2.0 3440.8 95719 42773 138491
4/24/01 4 252.0 54.8 na na 4102.8 0.0 4102.8 197005 na 197005
4/24/01 5 611.3 104.1 16.7 6.2 3801.8 0.0 3801.8 133955 na 133955
4/24/01 6 659.3 154.8 20.4 7.6 2962.3 0.5 2962.8 63595 27018 90613
4/24/01 11 1219.7 151.6 27.7 5.5 9850.8 0.0 9850.8 132705 na 132705
4/24/01 14 712.2 239.7 34.6 6.9 5333.3 0.5 5333.8 99294 11307 110601
4/24/01 22 547.8 275.2 38.4 7.3 11145.8 0.0 11145.8 314005 na 314005
5/7/01 4 1073.8 72.7 10.8 6.8 25148.3 0.0 25148.3 354655 na 354655
5/7/01 22 1192.6 97.6 18.6 5.2 13678.3 0.0 13678.3 267805 na 267805 bdl: Below instrument detection limit na: Data not available
142 Vita
Heidi Hertler
1966 Born October 29, Hackensack, New Jersey.
1985-1989 B.S., Biology, Bates College, Lewiston, Maine.
1989-1992 M.S., Biological Oceanography, Florida State University, Tallahassee.
1992-1994 Research Assistant, Florida Geological Survey, Tallahassee, Florida.
1994-1995 Staff Ecologist, Dames & Moore Environmental Engineers, Tallahassee, Florida.
1995-2002 Staff Scientist, The Academy of Natural Science, Philadelphia
Research Presentation
Quantitative study of the effects of houseboats on the Asociacion de Duenos de Casa Bote de La Parguera on the marine organisms of La Parguera Reserve. Presented at the State of the Environment in Puerto Rico Meeting, San German, Puerto Rico, March 23, 2000
Spatial and temporal variability in water quality associated with shifting land use in Southwest Puerto Rico. Presented at the 15th Biennial International Conference Estuarine Research Federation, New Orleans, Louisiana, September 25-30, 1999.
Effects of new land development on seagrass at La Parguera, Puerto Rico. Presented at American Society of Limnology and Oceanography, Albuquerque, New Mexico, February 12-16, 2001.
A comparison of the effects of nutrient and sediment loadings in temperate and sub-tropical seagrass communities. Presented at the 16th Biennial International Conference Estuarine Research Federation, St. Petersburg Beach, Florida, November 4-8, 2001.
143