Nutrient Status Assessment of Two New Brunswick

NUTRIENT STATUS ASSESSMENT OF TWO NEW BRUNSWICK

WATERSHEDS

Erin M. Foster

BSc University of New Brunswick (Fredericton) 2004

A Thesis Submitted in Partial Fulfillment

of the Requirements for the Degree of

Masters of Science

in the Graduate Academic Unit of Biology

Supervisor: Joseph Culp, Ph.D., Canadian Rivers Institute, UNB

Examining Board: Donald Baird, Ph.D., Department of Biology, UNB

Charles Bourque, Ph.D, Department of Forestry, UNB

Dion, Durnford, Ph.D., Department of Biology, UNB (Chair)

This thesis is accepted by the

Dean of Graduate Studies

THE UNIVERSITY OF NEW BRUNSWICK

April, 2010

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1*1 Canada Abstract

Nutrient studies have indicated the importance of nitrogen and phosphorus in the growth of primary producers but excessive amounts of these nutrients have led to enrichment of freshwater ecosystems around the world. In New Brunswick, few studies have examined the nutrient status of the province's rivers or whole watersheds, and so the nutrient status or frequency of nitrogen and/or phosphorus limitation is relatively unknown. This research was conducted within two watersheds, the Kennebecasis and the

Nashwaak watersheds and examined if the nutrient status varied throughout each watershed. The nutrient status, which is an indication if nutrients are limiting growth of algae, was evaluated in relation to point (including tributaries) and nonpoint sources of nutrients in the summer and autumn of 2005. In addition, the frequency in which phosphorus and/or nitrogen limited primary productivity throughout each watershed was determined. Finally, the study compared the results of the two nutrient status approaches and determined the advantages and disadvantages of each.

Based on water column nutrient ratios, phosphorus limitation occurred more frequently (55%) than co-limitation by nitrogen and phosphorus (45%). In contrast, the nutrient diffusing substrates indicated that the algal biomass in the study watersheds was not limited by phosphorus alone. Nutrient saturation was not evident in either watershed as many of the sites had low nutrient concentrations and benthic algal biomass and both of these measures were considered to be oligotrophic. The variability in nutrient status could not be directly linked to land use activities or known point sources by using nutrient ratios. Based on the nutrient diffusing substrates (NDS) results, there were instances where point sources and tributaries appeared to shift downstream nutrient status ii towards potential nutrient saturation or co-limitation. However, the influence of nonpoint sources on nutrient status was less obvious and a direct relationship between the NDS results and surrounding land use could not be drawn. Upon comparison of the methodologies, there were discrepancies between the two nutrient status assessments.

The N: P ratios only successfully predicted the limiting nutrient from the NDS 7% of the time.

The addition of an in-stream bioassay technique like NDS to a nutrient assessment program would be of benefit to environmental agencies as the NDS provided a more direct measurement of nutrient status than water column nutrient ratios by utilizing a biological indicator (benthic algal biomass) as the response variable. If nutrient ratios are used as part of a nutrient status assessment, then more frequent sampling of ambient nutrients would be required in order to improve the reliability of this assessment as increased sampling may lead to a better prediction of the actual nutrient status. Finally, this research made it evident how important it is to control both phosphorus and nitrogen inputs as many sites within the Kennebecasis and Nashwaak watersheds were found to be co-limited by nitrogen and phosphorus. This would likely be the case for many watersheds throughout the province of New Brunswick.

in Acknowledgements

I would like to thank Drs J. M. Culp, R. A. Curry and D. Fox for their guidance and expertise. I would also like to thank the New Brunswick Department of Environment, particularly Darryl Pupek and Rob Hughes, for providing me the opportunity to pursue this master's degree. I would also like to thank my examining committee, Dr. Baird and

Dr. Bourque for reading and reviewing my thesis.

I would like to thank all of those who have helped me with my field and laboratory work as I could not have done it alone. Thanks to L. Duguay, M. Dickson, M.

Finley, and K. Roach. Thanks to Eric Luiker and Dave Hryn for all their technical and logistical help. I would also like to thank Bob Brua for his statistical expertise and

Jordan Erker for his assistance with my GIS land use analysis. I want to thank my friends and family for supporting me during this process. Finally, I want to thank Adam

Douthwright, who has provided me with much encouragement and support. I am very thankful that you are in my life and I am looking forward to our future together.

IV Table of Contents

Abstract ii Acknowledgements iv Table of Contents v List of Tables vii List of Figures viii 1 General Introduction 11 1.1 Environmental concerns related to nutrient enrichment 11 1.2 Nutrient limitation and its role in nutrient enrichment assessments 13 1.3 Benthic algae as water quality indicators 14 1.4 Approaches for nutrient status assessment in rivers 16 1.4.1 Water chemistry 16 1.4.2 Nutrient diffusing substrates 18 1.4.3 Benthic algal community composition 20 1.5 Objectives and Hypotheses 21 1.6 Literature Cited 24 2 Nutrient Status Assessment of Whole Watersheds Utilizing Nutrient Ratios, Benthic Algal Biomass and Community Structure 27 2.1 Abstract 27 2.2 Introduction 28 2.3 Materials and Methods 30 2.3.1 Study Area Description and Site Selection 30 2.3.2 Water Chemistry 35 2.3.3 Algal Biomass and Taxonomy 36 2.3.4 Statistical Methods 38 2.4 Results 41 2.4.1 Nashwaak Watershed 41 2.4.2 Discharge and Flow Duration Curves 41 2.4.3 Kennebecasis Watershed 51 2.5 Discussion 62 2.5.1 Water Chemistry 63 2.5.2 Nutrient Status 63 2.5.3 Algal Biomass and Community Structure 65 2.6 Conclusions 67 2.7 Literature Cited 71 v 3 Assessment of watershed nutrient status using nutrient-diffusing substrate bioassays 76 3.1 Abstract 76 3.2 Introduction 77 3.3 Methods 79 3.3.1 Description of Study Area 79 3.3.2 Site Selection 80 3.3.3 Nutrient Status Assessment - Nutrient Diffusing Substrates 80 3.4 Results 83 3.4.1 Assessment of Nutrient Status Using NDS Bioassays 83 3.5 Discussion 99 3.5.1 Phosphorus as a Limiting Nutrient 100 3.5.2 Potential Influences on Nutrient Status 101 3.5.3 Points of Consideration When Using Nutrient Diffusing Substrates 102 3.6 Conclusions 104 3.7 Literature Cited 106 4 Discussion and Synthesis 109 4.1 Implications of Results 112 4.2 Recommendations on Nutrient Status Research 113 4.3 Literature cited 116 Appendix 1: Historic Nutrient Data 117 Appendix 2: Detection Limits for Nutrient Parameters 119 Appendix 3: Field Measurements 121 Appendix 4: Algal Taxonomy Identification Methodology 124 Appendix 5: Regression Plots Of Land Use and TIN: TP 126 Appendix 6: Eutrophic and Motile Diatoms 130 Appendix 7: Nitrogen and Phosphorus Data 2005 132 Curriculum Vitae

VI List of Tables

Table 1.1 An overview of the questions, hypothesis, and predictions related to each objective 23

Table 2.1: Sampling sites within the Nashwaak watershed. Site name, site identifier, and distance from the reference site are indicated 34

Table 2.2: Sample sites within the Kennebecasis watershed. Site name, site identifier and distance from the reference site are indicated 35

Table 3.1: Nutrient status results for main stem sites within the Nashwaak watershed. Bolded values exceed TN or TP threshold of 0.7mg/L and 0.025 mg/L, respectively. 84

Table 3.2: Nutrient status results for tributary sites within the Nashwaak watershed. Bolded values exceed TN or TP threshold of 0.7mg/L and 0.025 mg/L, respectively. 87

Table 3.3: Nutrient status results for main stem sites within the Kennebecasis watershed. Bolded values exceed TN or TP threshold of 0.7mg/L and 0.025 mg/L, respectively. Substrates could not be installed at KM5 due to high water levels in November.... 92

Table 3.4: Nutrient status results for tributary sites within the Kennebecasis watershed. Bolded values exceed TN or TP threshold of 0.7mg/L and 0.025 mg/L, respectively. 94

Vll List of Figures

Figure 2.1: Location of sampling sites and point sources of nutrients in the Nashwaak watershed 32

Figure 2.2: Location of sampling sites and point sources of nutrients in the Kennebecasis watershed 32

Figure 2.3: Discharge of the Nashwaak River at Durham Bridge in 2005. The arrows indicate when sampling occurred 41

Figure 2.4: Duration curve for the Nashwaak River at Durham Bridge. The arrows indicate when sampling occurred 42

Figure 2.5: Principal component analysis of water chemistry data collected in July throughout the Nashwaak watershed. Major water chemistry patterns are indicated with arrows. Site abbreviations can be found in Table 2.1 43

Figure 2.6: Principal component analysis of water chemistry data collected in October throughout the Nashwaak watershed. Major water chemistry patterns are indicated with the arrows. Site abbreviations can be found in Table 2.1 44

Figure 2.7: The molar ratio of total inorganic nitrogen to total phosphorus in the Nashwaak watershed based on the chemistry data from July and October 2005. Site abbreviations can be found in Table 2.1 45

Figure 2.8: The percent difference observed in nutrient ratios between upstream and downstream sites on the main stem of the Nashwaak River with respect to the influence of major tributaries. Site abbreviations can be found in Table 2.1 46

Figure 2.9: The primary land use in the Nashwaak watershed upstream of each sample is presented along with July (A) and October (B) nutrient ratios. Site abbreviations can be found in Table 2.1 47

Figure 2.10: Mean benthic algal biomass in the Nashwaak watershed based on data collected in July and October 2005. Site abbreviations can be found in Table 2.1.. 48

Figure 2.11: Multi-dimensional scaling of benthic algal taxonomy data from the Nashwaak watershed in July, 2005. Site abbreviations can be found in Table 2.1. 50

Figure 2.12: Multi-dimensional scaling of benthic algal taxonomy data from the Nashwaak watershed in October, 2005. Site abbreviations can be found in Table 2.1. 50

vin Figure 2.13: Discharge (m3/s) of the Kennebecasis River at Apohaqui in 2005. The arrows indicate when sampling occurred 51

Figure 2.14: Duration curve for the Kennebecasis River at Apohaqui in 2005. The arrows indicate when sampling occurred 52

Figure 2.15: Principal component analysis of water chemistry data collected in the Kennebecasis watershed in August 2005. Major patterns in water chemistry are indicated by the arrows. Site abbreviations can be found in Table 2.2 53

Figure 2.16: Principlal component analysis of water chemistry data collected in the Kennebecasis watershed in November 2005. Major patterns in water chemistry are indicated by the arrows. Site abbreviations can be found in Table 2.2 54

Figure 2.17: The molar ratio of total inorganic nitrogen to total phosphorus in the Kennebecasis watershed during August and November 2005. Site abbreviations can be found in Table 2.2 55

Figure 2.18: The percent difference observed in nutrient ratios between upstream and downstream sites on the main stem of the Kennebecasis River with respect to the influence of tributaries. Site abbreviations can be found in Table 2.2 56

Figure 2.19: The primary land use upstream of each site in the Kennebecasis watershed and associated nutrient ratios for August (A) and November (B) in 2005. Site abbreviations can be found in Table 2.2 58

Figure 2.20: Mean benthic algal biomass at sites within the Kennebecasis watershed during August and November 2005. Site abbreviations can be found in Table 2.2.59

Figure 2.21: Multi-dimensional scaling of benthic algal taxonomy data from the Kennebecasis watershed in August 2005. Site abbreviations can be found in Table 2.2 61

Figure 2.22: Multi-dimensional scaling of benthic algal taxonomy data from the Kennebecasis watershed in November, 2005. Site abbreviations can be found in Table 2.2 61

Figure 3.1: The upper photo (A) shows how the nutrient diffusing substrates are constructed and the lower photo (B) is an example of row of substrates that have been removed from a site after deployment 82

Figure 3.2: Mean chlorophyll a concentrations from nutrient diffusing substrates installed at sites along the main stem Nashwaak River during July 2005. Sites are arranged according to increasing agriculture percentage in the watershed (from left to right). 85

IX Figure 3.3: Mean chlorophyll a concentrations from nutrient diffusing substrates installed in the main stem Nashwaak River during October 2005. Sites are arranged according to increasing agriculture percentage in the watershed (from left to right). Substrates were lost at NM7 85

Figure 3.4: Mean chlorophyll a concentrations from nutrient diffusing substrates installed in tributaries of the Nashwaak River during July 2005. Sites are arranged according to increasing agriculture percentage in the watersheds (from left to right) 88

Figure 3.5: Mean chlorophyll a concentrations from nutrient diffusing substrates installed in tributaries of the Nashwaak River during October 2005. Sites are arranged according to increasing agriculture percentage in the watersheds (from left to right). Diffusing substrates were lost at site NT4 88

Figure 3.6: The primary land use in the Nashwaak watershed upstream of each sample site is presented along with NDS results for July (A) and October (B) in 2005. NL= Non-Limited, NP= Co-limitation, N= Nitrogen Limited, P= Phosphorus Limited, I = Nutrient Inhibited by nutrient in brackets and (-) = no data 90

Figure 3.7: Mean chlorophyll a concentrations from nutrient diffusing substrates installed along the main stem of the Kennebecasis River during August 2005 92

Figure 3.8: Mean chlorophyll a concentrations from nutrient diffusing substrates installed along the main stem of the Kennebecasis River during November 2005 93

Figure 3.9: Mean chlorophyll a concentrations from nutrient diffusing substrates installed in tributaries of the Kennebecasis River during August 2005 95

Figure 3.10: Mean chlorophyll a concentrations from nutrient diffusing substrates installed in tributaries of the Kennebecasis River during November 2005 95

Figure 3.11: The primary land use in the Kennebecasis watershed upstream of each sample site is presented along with NDS results for August (A) and November (B) in 2005. NL= Non-Limited, NP= Co-limitation, N= Nitrogen Limited, P= Phosphorus Limited, I = Nutrient Inhibited by nutrient in brackets and (-) = no data. 98

x 1 General Introduction

1.1 Environmental concerns related to nutrient enrichment

In pristine watersheds nutrient loadings may be very low, allowing only minimal algal production to occur. As human activities increase in a watershed, excess nutrients are released which results in a number of negative impacts on the aquatic system.

Activities related to agriculture, forestry, and urban development all can result in excess nutrients being released into watersheds, ultimately leading to eutrophication, which is the process where an aquatic system becomes more productive due to nutrient inputs

(Dodds, 2002). In New Brunswick there are very few rivers that have not been impacted by some degree of human activity, and regulators are now faced with the problem of defining thresholds beyond which nutrient enrichment leads to eutrophication and water quality degradation.

Nutrient enrichment is one of the most common threats to aquatic ecosystems

(Chambers et al., 2001; Scrimgeour & Chambers, 1997). Nutrient enrichment affects the structure and function of an aquatic ecosystem by changing the abundance, biomass, and diversity of various trophic levels (Scrimgeour & Chambers, 1997). Excessive nutrient loadings can cause algal production to increase dramatically (Dodds, Jones, & Welch,

1998). Increased production leads to increased suspended solids and oxygen deficiencies as a result of algal decomposition. Increased primary production can also lead to a buildup of organic carbon causing low dissolved oxygen and high pH (United States

Environmental Protection Agency, 2000). These conditions can impact fish and invertebrate communities by lowering growth rates and causing death (Dodds et al, 11 1998). Community structure may change, as some species become more competitive in these conditions, causing a shift in the community (Dodds et al., 1998). Eutrophication also has implications for public health, as algal blooms can impair surface water drinking supplies (Dodds et al., 1998).

In many of New Brunswick's watersheds, human related activities occur at varying degrees of intensity. These activities are known to elevate nutrients levels compared to watersheds which are undeveloped. There has been minimal research conducted in New Brunswick to confirm if these systems have been modified, in terms of their nutrient status, as a result of the activities taking place. As a result of this observation, this thesis examines the nutrient status in two of New Brunswick's watersheds with the aim of providing a standard assessment protocol for provincial rivers.

Much of the literature in aquatic ecology has indicated that phosphorus is the primary nutrient influencing freshwater productivity (Allan, 1995; Dodds, 2002; Wetzel,

2001). As a result of this generalization, many environmental agencies have been predominately concerned with phosphorus concentrations in lakes and rivers. However, as more land is used for activities such as agriculture, industrial and urban development, the input of other nutrients, such as nitrogen, may become more significant than previously thought and assessing the impacts of nutrients becomes more complex (Dodds

& Welch, 2000). The research presented in this thesis aims to demonstrate that by incorporating various nutrient assessment methodologies in a nutrient management program, a more reliable and comprehensive assessment of a watershed will result. Since each watershed varies from another due to differences in land use patterns, underlying 12 geology, hydrology, and topography, the generalization that phosphorus is the most influential nutrient may not be appropriate for managing nutrients in a watershed.

1.2 Nutrient limitation and its role in nutrient enrichment assessments

A common approach employed by environmental agencies is to assess the concentration of nutrients present in the water column against accepted guidelines. This approach will only provide information on whether the nutrient concentrations are elevated relative to the guideline but it does not indicate whether nutrients are limited.

The assessment of nutrient limitation is a preliminary step in managing nutrient enrichment because it indicates which nutrient(s) most likely regulate primary production

(Dodds, 2002; United States Environmental Protection Agency, 2000). Of the various nutrients required by benthic algae for growth, phosphorus and nitrogen are most frequently studied and have been found to most likely limit growth of benthic algae

(Borchardt, 1996; Dodds, Smith, & Lohman, 2002). Algae require a specific ratio of nitrogen to phosphorus (16:1) in order for growth. This ratio is based on research conducted by Redfield in 1958, who examined the internal cell concentrations of nitrogen to phosphorus of marine phytoplankton at optimal growth rates. Limitation can occur when one, or both, of these nutrients are not supplied at the required ratio, thus limiting the productivity of the algae (Borchardt, 1996; Dodds, 2002). Alternatively, when concentrations of nutrients are available in surplus to the their growth requirements of algae, growth is no longer limited and this is referred to as nutrient saturation and leads to increased algal production. This information is used in defining whether algal production

13 in a section of a river is phosphorus and/or nitrogen limited or nutrient saturated; this is also known as nutrient status. The nutrient status within a river is dependent upon the nutrients available in the water column, thus, factors such as topography, erosion, hydrology, geology and land use that modify nutrient concentration all have the potential to change nutrient status (Wetzel, 2001). In this research, nutrient limitation will be assessed in each of the two New Brunswick watersheds, the Nashwaak and Kennebecasis

Rivers, and this approach will be compared and contrasted to additional assessment approaches including, the analysis of the benthic algal community analysis and the assessment of benthic algal biomass.

1.3 Benthic algae as water quality indicators

In New Brunswick, regulatory agencies currently do not assess benthic algae when conducting nutrient assessments but benthic algae have been used frequently in various types of water quality assessments (Dodds, Jones, & Welch, 1998; Kelly, 1998; Lavoie,

Vincent, Pienitz, & Painchaud, 2004). There are many advantages to incorporating benthic algae into a monitoring program. Benthic algae are the dominant primary producers in most rivers and are found attached to substrates on the river bottom making them easy to sample and integrators of water quality conditions at a specific location.

Benthic algae are a useful indicator of water quality as they are constantly interacting with the physical, chemical and biological components of the aquatic ecosystem (Barbour et al., 1999; Lowe & Laliberte, 1996). Benthic algae can indicate effects that may only be indirectly observed in the fish and macroinvertebrate community such as the effects of

14 herbicides, which enter aquatic systems from adjacent agricultural lands (Barbour et al.,

1999). They are generally sessile organisms and because of this fact they cannot move when pollutants are present, so they must either tolerate the conditions or die (Lowe &

Laliberte, 1996). Benthic algae have a short life cycle and thus have a rapid response to any changes in their environment (Barbour et al., 1999; Lowe & Laliberte, 1996).

Sampling benthic algae requires only limited resources, has minimal impact on the surrounding environment, and standard methods exist to assess algal taxonomy and biomass (Barbour et al, 1999).

Many variables can affect the accrual of benthic algae and these variables must be considered when using algae as biotic indicators in water quality assessments. Algal growth is primarily affected by nutrient availability, the temperature of the surrounding water, and by the quantity of light (Biggs, 1996; United States Environmental Protection

Agency, 2000). In addition, factors that cause disturbance, such as high flow events and grazing by fish and macroinvertebrates, can prevent algal accrual (Stevenson & Peterson,

1990). High velocity is a primary abiotic factor affecting algal distribution and abundance as it can cause substrate instability and increased levels of suspended solids, thereby causing algae to be scoured from the substrate (Biggs, 1996).

As indicated above, algal communities can provide valuable information with regards to impacts of nutrients on an aquatic ecosystem. Thus, a primary goal of my research will be to examine how benthic algae can be used, in conjunction with other nutrient assessment approaches, to provide improved guidance to regulatory agencies on how to incorporate benthic algae into monitoring program designs.

15 1.4 Approaches for nutrient status assessment in rivers

In order to understand the impacts of nutrients on a watershed, various assessment approaches may need to be incorporated in a nutrient management program. There are numerous methodologies which can be used to assess the nutrient status of a river. My research compares the effectiveness of four methodologies to determine if these approaches are appropriate for characterizing the nutrient status in New Brunswick's watersheds. Although the methodologies that were chosen have all been used in previous studies, they have not been used in conjunction with one another and therefore a comparison of the effectiveness has not been carried out. My thesis will investigate the degree of agreement amongst the approaches chosen.

The assessment approaches chosen for this research includes the measurement of ambient water chemistry, the direct determination of nutrient limitation through the use of nutrient diffusing substrates, and the measurement of benthic algal biomass and community composition. An overview of each of these three approaches is provided below as is a discussion of how each approach contributes to nutrient status assessments.

1.4.1 Water chemistry

Surface water quality can be analyzed for any number of chemical and physical variables. For the assessment of nutrient status in rivers, nitrogen and phosphorus are the main water chemistry variables of interest and various components of these elements can be analyzed. Phosphorus is commonly measured as total phosphorus which consists of dissolved and particulate portions, whereas nitrogen can be measured as total nitrogen,

16 ammonia, nitrate and nitrite. Nitrogen and phosphorus ratios can be used to predict nutrient limitation by using total or dissolved fractions of nitrogen and phosphorus.

As indicated earlier, nutrient ratios were initially studied by Redfield in 1958, who found that marine phytoplankton required a specific ratio of nitrogen and phosphorus (16:1) for growth. The concept has since been applied to freshwater systems and various types of experiments have been conducted. Some experiments have attempted to relate nutrient ratios to nutrient status conditions of benthic algal communities (Francoeur, Biggs, Smith, & Lowe, 1999), but only a few experiments have used nutrient ratios in conjunction with nutrient diffusing substrates. Nutrient ratios based on water column nutrients have frequently been compared to benchmarks proposed by

Schanz & Juon (1983) as an alternative to the Redfield ratio: ratios <10 are considered nitrogen limited, ratios >20 are considered phosphorus limited, and ratios 10-20 can be limited by N or P or considered to be co-limited. This research by Schanz and Juon

(1983) was based on algae growth potential bioassays which examined the nutrient ratios that limited growth. My research evaluates how well nutrient ratio data based on Schanz and Juon's (1983) benchmarks agree with other nutrient assessment approaches. It also provides information on integrating nutrient ratios with other nutrient assessment approaches.

Water chemistry data may provide limited information on the specific nutrient that is influencing river productivity. Surface water quality monitoring is considered a

'snap shot' view of what is occurring in the river at the time the sample is taken. There may be situations where this type of sampling may not provide enough information for the purpose of monitoring. For example, in a watershed which has minimal development, 17 a regulatory agency may want to assess the baseline nutrient status prior to any further development. In this situation, using multiple nutrient status approaches may be more appropriate. If, however, the purpose of monitoring is to have a rapid assessment of a watershed's nutrient status, water chemistry may be more suitable, as it would still give a general indication of the nutrient status.

Currently, there is a need for guidance documentation that regulatory agencies can refer to when conducting nutrient status assessments. This thesis will provide both guidance and practical examples on which assessment approaches are the most appropriate for a particular monitoring objective.

1.4.2 Nutrient diffusing substrates

Nutrient diffusing substrates (NDS) are used as an alternative approach to assess nutrient status for the purpose of determining if a site is nutrient-limited or nutrient- saturated. The nutrients (nitrogen and/or phosphorus) are dissolved in an inert media and are held within a container. The nutrients slowly diffuse across a permeable surface in which the benthic algae can colonize. The nutrient diffusing substrates provide a surface for the benthic algae to colonize a substrate similar to what they would use under natural conditions. The artificial substrates allow the colonizing algal community to interact with other environmental variables while controlling the nutrients supplied to them (Pringle &

Triska, 1996). These experiments have minimal impact on the surrounding environment compared to historic whole lake experiments where the entire systems were enriched.

18 Nutrient diffusing substrates have been used in a wide range of experiments ranging from investigating seasonality patterns in algal biomass (Allen & Hershey, 1996;

Francoeur et al., 1999) to determining the differences in nutrient limitation among algal species (Fairchild, Lowe, & Richardson, 1985). There have been many variations of the technique from the use of plastic Petri dishes (Corkum, 1996); terra cotta clay pots

(Fairchild, Lowe, & Richardson, 1985; Scrimgeour & Chambers, 1997) and, recently, small plastic containers which are topped with porous glass discs (Tank & Dodds, 2003).

This latest variation was used for this research to determine the nutrient status of two watersheds. Nutrient diffusing substrates have been used to assess spatial and temporal patterns in nutrients in both lakes and rivers. They have been used in studies to answer questions on land use effects, algal succession or trophic interaction (Scrimgeour &

Chambers, 1997). Depending on the objective of the monitoring program, these in-stream bioassays can be used under a number of scenarios. Nutrient diffusing substrates can be used to assess the impact of known point sources on nutrient status by deploying them above and below effluent discharges. Also, they can be used to assess the impacts of diffuse sources of nutrients by placing the nutrient diffusing substrates in areas of the watershed of contrasting land use.

While a considerable amount of research has been conducted using nutrient diffusing substrates, very few studies have compared standard nutrient status assessment approaches, such as water chemistry and community composition, to nutrient diffusing substrate assessments. Nutrient diffusing substrates have not been used in New

Brunswick to assess the nutrient status of entire watersheds, thus, this research provides guidance for future use of nutrient diffusing substrate studies. 19 1.4.3 Benthic algal community composition

The taxonomic information obtained from benthic algal samples can be used in a number of ways to gain a better understanding of the impacts on a benthic algal community. Indices can be used to provide useful information on the trophic status of a location, the tolerance of the algal community to types of pollution (e.g., organic pollution) as well as to give an indication of the richness and evenness of a site (Barbour et al., 1999). In addition to using biotic indices, changes in community structure can provide important information with regards to environmental stressors (Barbour et al.,

1999). The dominance of certain species can indicate the nutrient status for a particular location; for example, an abundance of blue green algae may indicate nitrogen limitation

(Peterson & Porter, 2002).

For this research, benthic algal community data was used to investigate whether the community composition at sites within each watershed differed from one another and if the variability seen in the data could be attributed to nutrients. It was of specific interest to investigate how much variability was explained by phosphorus as it is the nutrient most often indicated in the literature as affecting benthic algal composition and abundance.

Variables other than nutrients have been found to describe the variability in benthic algal communities. Conductivity was found to be the variable most strongly related to benthic algal communities in New Zealand rivers (Biggs, 1990). Suspended solids, pH and conductivity were the most significant environmental variables that explained the variability in benthic algal communities in southern Quebec (Lavoie,

Vincent, Pienitz, & Painchaud, 2004). These variables, along with the nutrients discussed 20 above, were also assessed to determine their importance in affecting algal community structure in the study watersheds.

1.5 Objectives and Hypotheses

Many of New Brunswick's watersheds are influenced by human activities which occur on lands adjacent to the Province's rivers. A number of these activities result in the release of nutrients into aquatic ecosystems. In order to understand this potential impact, the main objective of the thesis was to evaluate the nutrient status of two New Brunswick watersheds (Table 1.1).

The research will focus on the Kennebecasis and the Nashwaak watersheds. These watersheds were selected based on the amount of agriculture and urban development present and also on the type and number of point sources of nutrients. These sources of nutrients were of interest because they may modify a watershed's nutrient status. The

Kennebecasis watershed has a higher percentage of agricultural land use, numerous point sources and urban areas. The Nashwaak watershed has a higher percentage of forested land, only a few point sources of nutrients and two municipalities. The impact of the major sources of nutrients as well as tributary influence on the watersheds' nutrient status was addressed by choosing monitoring sites that were located upstream and downstream of the nutrient sources.

The second objective in the study was to investigate the ability of an in situ bioassay method to be used to assess the watersheds' nutrient status compared to various standard approaches (Table 1.1). The standard approaches included the measurement of

21 ambient water chemistry, the assessment of the benthic algal community composition as well as the analysis of benthic algal biomass. This information will be used as guidance for agencies working in NB who wish to incorporate nutrient status assessments in their surface water quality programs.

The final objective of the thesis was to determine which nutrient was more influential in affecting the water quality of the two study watersheds (Table 1.1). In New

Brunswick, there is minimal information on which nutrient more frequently limits algal growth in rivers. Although phosphorus is generally cited as the primary limiting nutrient in freshwater systems, recent results from various nutrient status experiments indicate that both nitrogen and/or phosphorus can limit algal growth in lotic systems.

The final chapter of the thesis discusses the effectiveness of nutrient bioassays compared to the other standard approaches and provides a synthesis as to how these approaches can be used in nutrient management. The differences in nutrient status among sites of the two watersheds are discussed in terms of each nutrient assessment approach used. Guidance is provided on the benefits and limitations of these approaches.

Conclusions based on the initial research questions are forwarded and suggestions for future research discussed. Please note that Chapters 2 and 3 of this thesis have been written as independent scientific articles.

22 Table 1.1 An overview of the questions, hypothesis, and predictions related to each objective.

Chapter Question Hypothesis Predictions 2&3 Is a river's nutrient status The nutrient status of A river's nutrient status will change as result of the modified by major sources a river is influenced following reasons: of nutrients and nutrient by point and diffuse Nutrient status will change downstream of a point source supplements from sources of pollution as which contains nutrients. tributaries? well as by major Nutrient status of the main stem will change below tributaries joining the the confluence of a major tributary which contains main stem. elevated nutrients. The nutrient status will change as a result of diffuse sources of pollution such as agriculture and urban development 2&3 Will an in-stream bioassay Nutrient diffusing If the nutrient ratio is greater than 20 it will indicate method (nutrient diffusing substrates will phosphorus limitation and will correspond to the NDS substrates NDS) more determine the nutrient results. accurately depict the status in a more If the nutrient ratio is less than 10 it will indicate nitrogen nutrient status of a river accurate manner limitation and will correspond to the NDS results. compared to determining compared to what can If the nutrient ratio is between 10 and 20, NDS will be able nutrient status determined be determined from to accurately depict if co limitation is occurring. In the from nitrogen to nitrogen to literature this range is considered to be open to phosphorus ratios? phosphorus ratios interpretation.

2&3 Is phosphorus the limiting Phosphorus will limit Phosphorus may be the limiting nutrient in headwater nutrient in a watershed? algal growth regions of a watershed or in minimally disturbed areas of depending on the the watershed activities, which are Downstream of point and diffuse sources of pollution, occurring on land with nitrogen may be the limiting nutrient or nutrient saturation the watershed. may occur. 1.6 Literature Cited

Allan, J. D. (1995). Stream ecology structure: Structure and function of running waters. London: Chapman & Hall. Allen, N. S., & Hershey, A. E. (1996). Seasonal changes in chlorophyll a response to nutrient amendments in a north shore tributary of Lake Superior. Journal of the North American Benthological Society, 15(2), 170-178.

Barbour, M. T., Gerritsen, J., Snyder, B. D., & Stribling, J. B. (1999). Rapid bioassessment protocols for use in streams and wadeable rivers: Periphyton, benthic macroinvertebrates and fish No. EPA 841-B-99-002). Washington, D.C.: U.S. Environmental Protection Agency.

Biggs, B. J. F. (1990). Periphyton communities and their environments in New Zealand Rivers. New Zealand Journal of Marine and Freshwater Research, 24, 367-386.

Biggs, B. J. (1996). Patterns in benthic algae of streams. In R. J. Stevenson, M. L. Bothwell & R. L. Lowe (Eds.), Algal ecology freshwater benthic ecosystems (pp. 31-56)

Borchardt, M. A. (1996). Nutrients. In R. J. Stevenson, M. L. Bothwell & R. L. Lowe (Eds.), Algal ecology freshwater benthic ecosystems (pp. 184-227). New York: Academic Press.

Chambers, P. A., Guy, M., Roberts, E. S., Charlton, M. N., Kent, R., & Gagnon, C, et al. (2001). Nutrients and their impact on the Canadian environment. Environment Canada.

Corkum, L. D. (1996). Patterns of nutrient release from nutrient diffusing substrates in flowing water. Hydrobiologia, 355(1), 37-43.

Dodds, W. K. (2002). Freshwater ecology: Concepts and environmental applications. San Diego: Academic Press.

Dodds, W. K., Jones, J. R., & Welch, E. B. (1998). Suggested classification of stream trophic state: Distribution of temperate stream types by chlorophyll, total nitrogen and phosphorus. Water Resources, 52(5), 1455-1462.

Dodds, W. K., Smith, V. H., & Lohman, K. (2002). Nitrogen and phosphorus relationships to benthic algal biomass in temperate streams. Canadian Journal of Fisheries and Aquatic Science, 59, 865-874.

Dodds, W. K., & Welch, E. B. (2000). Establishing nutrient criteria in streams. Journal of North American Benthological Society, 19(1), 186-196.

24 Fairchild, G. W., Lowe, R. L., & Richardson, W. B. (1985). Algal periphyton growth on nutrient-diffusing substrates: An in situ bioassay. Ecology, 66(2), 465-472.

Francoeur, S. N., Biggs, B. J. F., Smith, R. A., & Lowe, R. L. (1999). Nutrient limitation of algal biomass accrual in streams: Seasonal patterns and a comparison of methods. Journal of North American Benthological Society, 18(2), 242-260.

Kelly, M. G. (1998). Use of the trophic diatom index to monitor eutrophication in rivers. Water Resources, 32(1), 236-242.

Lavoie, I., Vincent, W. F., Pienitz, R., & Painchaud, J. (2004). Benthic algae as bioindicators of agricultural pollution in the streams and rivers of southern Quebec. Aquatic Ecosystem Health and Management, 7(1), 43-58.

Lowe, R. L., & Laliberte, G. D. (1996). Benthic stream algae: Distribution and structure. In F. R. Hauer, & G. A. Lamberti (Eds.), (pp. 269-293). New York: Academic Press.

Peterson, D. A., & Porter, S. D. (2002). Biological and chemical indicators of eutrophication in the Yellowstone River and major tributaries during august 2000. USGS National Monitoring Conference.

Pringle, C. M., & Triska, F. J. (1996). Effects of nutrient enrichment on periphyton. In F. R. Hauer, & G. A. Lamberti (Eds.), Methods in stream ecology (pp. 607-624). New York: Academic Press.

Redfield, A. C. (1958). The biological control of chemical factors in the environment. American Scientist, 46, 1-221.

Schanz, F., & Juon, H. (1983). Two different methods of evaluating nutrient limitations of periphyton bioassays using water from the river Rhine and eight of its tributaries. Hydrobiologia, 102, 187-195.

Scrimgeour, G. J., & Chambers, P. A. (1997). Development and application of a nutrient- diffusing bioassay for large rivers. Freshwater Biology, 38, 221-231.

Stevenson, R. J., & Peterson, C. (1990). Post-spate development of epilithic algal communities in different current environments. Canadian Journal of Botany, 68(10), 2092-2102.

Tank, J. L., & Dodds, W. K. (2003). Nutrient limitation of epilithic and epixylic biofilms in ten North American streams. Freshwater Biology, 48, 1031-1049.

United States Environmental Protection Agency. (2000). Nutrient criteria technical guidance manual rivers and streams No. EPA-822-B-00-002)

25 Wetzel, R. C. (2001). Limnology: Lake and river ecosystems (3rd ed.). New York: Academic Press.

26 2 Nutrient Status Assessment of Whole Watersheds Utilizing Nutrient Ratios, Benthic Algal Biomass and Community Structure 2.1 Abstract

This study assessed the nutrient status of the Kennebecasis and Nashwaak watersheds from headwaters to their mouths, and established which nutrient (nitrogen or phosphorus) most influenced ecological condition of these watersheds. In addition, I determined if point and non-point sources of pollution influenced nutrient status of the rivers. Nutrient ratios, benthic algal biomass and benthic algal community composition were used to investigate these objectives over the summer and autumn of 2005. Based on water column nutrient ratios, phosphorus limitation occurred more frequently (55%) than co-limitation by nitrogen and phosphorus (45%). Nutrient saturation by both nitrogen and phosphorus was not evident in either watershed. Many of the sites had low nutrient concentrations and benthic algal biomass and were considered to be oligotrophic. The variability in nutrient status could not be directly linked to land use activities or known point sources. Higher sampling frequency and more sampling locations may be needed to determine the influence of land use activities on the nutrient status of these and other watersheds. While it was not clear whether using nutrient ratios provided superior results compared to using algal biomass or community structure, each method provided additional information about the sites that would aid environmental agencies in making management decisions regarding land use and nutrients.

27 2.2 Introduction

The quantity of nutrients entering aquatic systems is a concern for regulatory agencies who manage aquatic systems (Chambers et al., 2001; Environmental Protection

Agency, 2000; Mainstone, 2002). As the land surrounding aquatic ecosystems is altered from its natural state and is used for forestry or agriculture and developed for urban and residential purposes, the amount of nutrients entering the water often increase (Carpenter et al., 1998; Kemp & Dodds, 2001; Sharpley, McDowell, & Kleinman, 2001; Smith,

Tilman, & Nekola, 1999; Walsh et al., 2005). The impacts from these nutrient sources along with point sources of nutrients are assessed by evaluating water chemistry (Grimm

& Fisher, 1986), and typically by observing the ratio of nitrogen to phosphorus (N:P) to measure nutrient status. The reliance on water chemistry has arisen because water samples are easy to collect, requires minimal field equipment, and samples are relatively inexpensive to process. However, assessments based on a snapshot of river water chemistry may not correlate well to the status or condition of the aquatic ecosystem

(Allen & Hershey, 1996; Francoeur, Biggs, Smith, & Lowe, 1999). Adding a biological indicator, such as benthic algal biomass or information on the community composition, to water quality monitoring program may help compensate this potential weakness.

Trophic status is an indication of biological productivity of a river (Chambers et al., 2001) and is in large part dependent upon the nutrients available in the water column.

The nutrients in a river have many sources, both natural sources and those related to human activities. In terms of natural sources, river bed sediments and decaying organic matter can contribute to the internal nutrient loading of a river (Mainstone, 2002). Human activities can include point sources of nutrients such as industrial and residential 28 wastewater and diffuse sources such as run-off from agricultural and urban landscapes and can contribute to the external loading of a river. These activities influence the amount of nutrients present in the water column and, ultimately, influence riverine nutrient status.

Effluent loadings from pulp mills and wastewater plants, which are enriched with nutrients, were found to influence the nutrient status of two Alberta rivers and cause a shift from limitation to saturation downstream of these nutrient sources (Scrimgeour &

Chambers, 2000). Similar changes in nutrient status were also observed by Bowman,

Chambers, & Schindler (2005).

Watersheds have varying degrees of human activities and each activity can release different amounts of nitrogen and phosphorus. Thus, depending on the human activities which take place within a watershed, one nutrient may be more influential in controlling primary productivity than another. In the past, phosphorus has been thought to have a greater influence on freshwater systems than other nutrients and, therefore, has received more attention in terms of nutrient management, especially in lentic systems

(Chambers, Dale, Scrimgeour, & Bothwell, 2000; Schindler, 1977; Schindler et al.,

2008).

Benthic algae are the dominant primary producers in most rivers and in addition to using water quality to assess nutrient status, benthic algal biomass and community composition have been used in numerous research projects to address a wide range of nutrient-related issues. Peterson & Porter (2002) found that the trophic condition of

Yellowstone River was better represented by algal biomass and nutrient indicator species of algae than by nutrient concentrations in water chemistry samples. They found that changes in the benthic algal biomass and community composition among sites may be a 29 more accurate way of determining the trophic status of a river when nutrient concentrations are low. The composition of benthic algal community has also been used in Quebec streams to determine if agricultural pollution was affecting the benthic community (Lavoie, Vincent, Pienitz, & Painchaud, 2004). This research discovered that variation in the algal community structure was better explained by pH, conductivity and suspended solids than by nutrients. Such examples demonstrate an important advantage to incorporating multiple measures when assessing the nutrient status of riverine ecosystems.

The goal of my research was to assess the value of different tools for measuring nutrient status of New Brunswick rivers. I applied and compared multiple measures, i.e. nutrient ratios, benthic algal biomass and benthic algal community composition. My assessment allowed me to determine if nitrogen or phosphorus were limiting in these systems and evaluate whether tributary inputs along with point and diffuse sources of nutrients were influencing the nutrient status of these watersheds.

2.3 Materials and Methods

2.3.1 Study Area Description and Site Selection

My research focused on assessing the nutrient status of two large sub-basins of the Saint John River, NB that have contrasting land use patterns. The Nashwaak River, located in central NB, has a drainage area of approximately 1700 km . The bedrock geology of the upper third contains mainly igneous rock while the remaining watershed is comprised of sedimentary rock with areas of calcareous sedimentary rock. Nutrient status of the Nashwaak River was assessed on the main stem as well as on the major tributaries 30 including Penniac Stream, Dunbar Stream, Tay River, Youngs Brook, Cross Creek and

Napadogan Brook.

The Kennebecasis River is located in southeastern New Brunswick and has a drainage area of approximately 2086 km . The bedrock geology is comprised of mostly calcareous sedimentary rock while in the lower quarter of the watershed there are areas of igneous rock. Sampling sites were located on the main stem and on four tributaries;

Smith's Creek, Millstream, Trout Creek, and South Branch Kennebecasis River.

Land use was determined based on data provided by the New Brunswick

Department of Natural Resources. The Nashwaak watershed is comprised of forest

(92.3%o) and a small percentage of agricultural (2.8%) and human occupied lands (1.0%), with the remaining 4% as wetlands and surface water. Point sources of nutrients in the

Nashwaak include two municipal wastewater treatment facilities that discharge to the main stem and a fish hatchery effluent source to the Tay River (Figure 2.1). Land use in the Kennebecasis consisted of forested (78%), agricultural (15.4%) and human occupied

(1.8%) lands. Point sources of nutrients in the Kennebecasis include three municipal wastewater treatment facilities and an aquaculture facility (Figure 2.2).

31 Figure 2.1: Location of sampling sites and point sources of nutrients in the Nashwaak watershed.

Figure 2.2: Location of sampling sites and point sources of nutrients in the Kennebecasis watershed.

32 The 16 monitoring sites chosen for the Nashwaak watershed and the 12

Kennebecasis sites (Tables 2.1 and 2.2) were selected to span the range of nutrient concentrations observed in the historical water chemistry data (Appendix 1). Fine scale location of the sites was determined in terms of proximity to tributaries, point and diffused sources of nutrients were factors which influenced the location of monitoring sites. Land use information upstream of each site was acquired from the New Brunswick

Department of Natural Resources. The land use layer was divided into 5 categories, namely forested, agricultural, occupied land, wetlands and other, which combined roads, utility lines, trails, mines and quarries. ArcMap (version 9.3.1, 2009) was used to determine the percentage of each land use category upstream of each monitoring site.

33 Table 2.1: Sampling sites within the Nashwaak watershed. Site name, site identifier, and distance from the reference site are indicated.

Site Name Site Distance From Latitude Longitude Identifier Reference (km) Haul Road NM1 0 (Reference) 46.291190 -67.022450 Giants Glen NM2 22 46.293929 -66.771298 MacGlaggan NM3 32 Bridge 46.268822 -66.663304 Nashwaak NM4 37 Bridge 46.240319 -66.612372 Downstream NM5 45 of Tay River 46.179170 -66.619850 Durham NM6 51 Bridge 46.141441 -66.618463 Downstream NM7 63 of Penniac Stream 46.015918 -66.577740 Marysville NM8 70 45.979304 -66.590956 Nashwaak River Tributaries Distance From Tributary Mouth (km) Napadogen NT1 6 Brook 46.343170 -67.000610 Cross Creek NT2 0.5 46.267410 -66.641920 Youngs Brook NT3 1 46.238139 -66.607148 Tay River NT4 16 Headwaters 46.228150 -66.813980 Tay River NT5 2 Mouth 46.187300 -66.637610 Dunbar Stream NT6 0.5 46.141441 -66.618463 Penniac NT7 7 Headwaters 46.054990 -66.510749 Penniac NT8 1 Stream 46.031968 -66.570190

34 Table 2.2: Sample sites within the Kennebecasis watershed. Site name, site identifier and distance from the reference site are indicated. Site Name Site Distance From Latitude Longitude Identifier Reference (km) Goshen KM1 0 (Reference) 45.793702 -65.169783 Four Corners KM2 31 45.744602 -65.497235 Fox Hill KM3 38 45.714193 -65.556072 Riverbank KM4 50 45.652326 -65.675852 Bloomfield KM5 61 45.580087 -65.756660 Kennebecasis River Distance From Tributaries Tributary mouth (km) South Branch KT1 0.5 45.776594 -65.371038 Smith's Creek KT2 17 Headwaters 45.870109 -65.391378 Smith's Creek KT3 6 Near Mouth 45.747968 -65.512553 Trout Creek KT4 15 Headwaters 45.682507 -65.372436 Trout Creek KT5 4 Near Mouth 45.721540 -65.500872 Millstream KT6 17 Headwaters 45.867283 -65.542779 Millstream KT7 4 Near Mouth 45.703717 -65.599463

2.3.2 Water Chemistry

Water samples were collected during the summer (July-August) and fall (October-

November) of 2005 by wading into the main stream flow. High-density polyethylene

(HDPE) bottles were filled with stream water and placed on ice while they were transported to the Analytical Services Laboratory at the New Brunswick Department of

Environment. The unfiltered samples were processed within 24 h of collection for total phosphorus, nitrates, nitrites, ammonia, suspended solids, metals, bacteria and a suite of general chemical indicators (alkalinity, conductivity, pH and major ions). The

35 methodology used by the laboratory generally followed the procedures described in

Standard Methods for the Examination of Water and Wastewater, 20th Edition (American

Water Works Association, 1998). Detection limits for the nutrients used in this Chapter are presented in Appendix 2.

Additional measurements were taken at each site at the same time as the water chemistry samples (Appendix 3). Temperature (°C), pH, conductivity (uS/cm) were measured using an YSI 63 pH salinity conductivity temperature meter. Dissolved oxygen was measured using an YSI 95 dissolved oxygen meter and flow was determined using a

Marsh-McBirney Inc. Flo-Mate Model 2000 portable flow meter. Flow measurements were taken at 60% of the water depth. Discharge information is also presented along with flow duration curves for each watershed. Duration curves were calculated based on all discharge data collected in the last 30 years. Discharge data was obtained from Water

Survey of Environment Canada.

2.3.3 Algal Biomass and Taxonomy

At each monitoring site, twenty rocks (7-9 cm diameter) were randomly chosen from a section of a run with a minimum depth of 40 cm. Runs were selected because the flow was less turbulent than in riffles but moving faster than in pools. Algal biomass, which was used as an indicator of nutrient enrichment, was removed from a 9 cm area using a scalpel. Biomass from 5 rocks was placed in a 20 ml vial, for a total of 4 vials per site. Vials were placed on ice and in the dark until they were returned to the laboratory where they were frozen for later chlorophyll a analysis. Chlorophyll a biomass was estimated using a hot ethanol extraction technique, adapted from Sartory (1982). Each

36 vial was thawed and homogenized with 200 ml of de-ionized water. An aliquot of 10 ml was passed through a glass fiber C grade (GF/C) filter. The GF/C filter was placed in a centrifuge tube with 10 ml of 90% ethanol, transferred to an 80°C hot water bath for 7 minutes and placed in the dark for 30 minutes. The sample's volume was recorded, then diluted to 1:100 using 90% ethanol and the liquid's fluorescence was measured using a

Turner Designs model 10 series fluorometer. The amount of biomass was determined by accounting for initial volume that was homogenized, the volume that was extracted, the dilution factor and the fluorometer reading for that sample vial. The chlorophyll a biomass formula (mg/m ) is as follows (all volumes are in ml):

2 Chlorophyll a (mg/m ) = (((Ca*0.001) * v * (V, / V2/a) * 0.001,

Where

Ca - reading from the fluorometer (|xg/liter)

v - extract volume (ml)

Vi - volume of original sample (ml)

V2 - volume of sample filtered (ml)

a - area of substrate from which sample was taken (m2).

The benthic algal community was also sampled and this information was used as an additional indicator of nutrient enrichment. An additional five rocks were chosen from the same area as the algal biomass samples and scraped with a sharp scalpel, as above. This material was preserved for taxonomic identification in a 4% formalin solution in the field and later identified according to the methodology in Appendix 4.

37 2.3.4 Statistical Methods

A Principal Components Analysis (PCA) was used to evaluate patterns in water chemistry among sites. Alkalinity, conductivity, dissolved oxygen, total inorganic nitrogen (TIN), total ammonia, pH, total organic carbon, total phosphorus (TP), turbidity,

TIN:TP ratio, water temperature and stream velocity were included. The TIN: TP ratio was included in the PCA to determine if there were any additional trends that were not observed in the bar graphs. All variables were normalized prior to the PCA analysis as this places all variables on the same scale. The data was normalized by subtracting the mean and dividing by the standard deviation for each parameter. A log (0.1+x) transformation was conducted on all parameters with the exception of water temperature and stream velocity as they were not skewed and thus did not require transformation.

Nutrient status was determined by examining the molar ratio of TIN:TP. TIN was used instead of TN as most TN measures were less than the limit of detection. TIN was the sum of nitrite, nitrate and total ammonia concentrations. Nutrient status was determined by comparing the nutrient ratios against benchmarks proposed by Schanz &

Juon (1983): nutrient ratios <10 are considered nitrogen limited, ratios >20 are considered phosphorus limited, and ratios 10-20 can be limited by N or P or considered to be co-limiting. This research by Schanz and Juon (1983) was based on algae growth potential bioassays which examined the nutrient ratios that limited growth. Only a few studies have indicated the growth limiting concentrations of N and P (Borchardt, 1996) and most have expressed these concentrations in the form of soluble reactive phosphorus, phosphate or nitrate rather than TN or TP (Bothwell, 1989; Grimm & Fisher, 1986;

Welch, Jacoby, Horner, & Seeley, 1988). So, as an alternative, TN and TP were 38 considered to be no longer limiting benthic algal biomass when they were greater than

0.7 mg/L and 0.025 mg/L respectively. These nutrient levels correspond to the oligotrophic/mesotrophic trophic status boundary for streams proposed by Dodds, Jones,

& Welch (1998). The influence of tributaries and point sources of nutrients was assessed by calculating the percent difference in nutrient ratios between upstream and downstream sites on the main stem. In order to determine the influence of nonpoint sources of nutrients, a linear regression was completed on the nutrient ratios and the percentage of forestry, agriculture and occupied land upstream of each site. These graphs are presented in Appendix 5.

Average and maximum benthic algal biomass were compared against the stream trophic status guidelines proposed by Dodds et al. (1998). Patterns in benthic algal community structure were examined in relation to water chemistry using the BIO-ENV procedure in PRIMER (PRIMER-E version 6, 2006). This was used to test the null hypothesis that no relationship existed between the abiotic and biotic information. Bi- plots of all environmental variables were used to examine if any of the variables were highly correlated. If a correlation coefficient was >0.95, then only one of the two variables was included. Environmental data was log (0.1+x) transformed and normalized while biotic data was square root transformed. A permutation test was performed to ensure that variables which were selected as the best predictors of the biotic community structure were in fact better than chance.

Examination of patterns amongst the algal communities of main stem and tributary sites was undertaken by using PRIMER. Sites which plotted close together on multi-dimensional scaling (MDS) graph were interpreted to have similar community 39 composition. The analysis of similarity (ANOSIM) tested the null hypothesis that there were no assemblage differences between the main stem and tributary sites. Finally, if differences existed between sites, a similarity percentages routine (SIMPER) was used to examine the contribution of the different genera to differences within and between main stem and tributary sites. Bubble plots of genera that were found to have influenced

SIMPER results were added to the MDS graphs. The trophic state of the algal community was assessed by determining the relative abundance of algal genera that were associated with trophic status indicator groups (Van Dam, Mertens, & Sinkeldam, 1994). However, information on genera level trophic status was limited, so the trophic status category for a particular diatom genera was calculated based on the average tropic status of the species found in that genera. From this information, the percentage of eutrophic diatoms was calculated by summing the relative abundance of genera which were found in the mesotrophic to eutrophic categories (Peterson & Porter, 2002). This information is presented in Appendix 6.

The percent of motile diatoms was also included as part of the watershed interpretation. This metric is an index of siltation and was included as an indirect measure of the impact of erosion. Erosion from land can carry nutrients into local waterways and the percent motile diatoms may provide an indication if this is an issue in the study watersheds. The index is calculated based on the percentage of three diatom genera,

Navicula, Nitzschia, and Surirella (Barbour, Gerritsen, Snyder, & Stribling, 1999) and results are presented in Appendix 6.

40 2.4 Results

2.4.1 Nashwaak Watershed

2.4.2 Discharge and Flow Duration Curves

During the July sampling period, discharge was on average 19 m /s, a value that was exceeded approximately 50% of the time based on the recorded data for the last 30 years (Figures 2.3 and 2.4). Discharge for the October sampling period was on average

21 m3/s and was exceeded 40% of time in the last 30 years of recorded data (Figures 2.3 and 2.4).

600

500

5s 400

6X) 300 - C3 m U' iri o 200 -

100

in m m in m in m in in in in o O o o o o o o o o o o A -O •— tJj Q, > CJ 03 >, <*" — o re 1—> o 1 O i i 2 < • 2 Q

Date

Figure 2.3: Discharge of the Nashwaak River at Durham Bridge in 2005. The arrows indicate when sampling occurred.

41 1000 j

800 -

^ 600 •

f* 400 -

cs u ucTODer jury

5 200 V V

0 n 1 1 1 1 r 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Exceedance (%)

Figure 2.4: Duration curve for the Nashwaak River at Durham Bridge. The arrows indicate when sampling occurred.

2.4.2.1 Water Chemistry

The PCA of water chemistry for July produced two axes which explained 55.4% of the variability in the data. Axis 1 (31.9%) was related to general water chemistry variables such as pH, alkalinity and conductivity. Nutrients were the dominant variable of axis 2 (23.5%; Figure 2.5). For main stem sites, alkalinity, conductivity, pH, total inorganic nitrogen, and turbidity were observed to increase towards the river mouth.

Total organic carbon and the total inorganic nitrogen/total phosphorus ratio (TEST: TP) decreased towards the mouth of the river (Figure 2.5). Total inorganic nitrogen, total ammonia and turbidity were in lower concentrations in tributaries that were in the lower portion of the watershed. The TIN: TP ratio also differed, as tributary sites in the upper portion of the watershed had lower nutrient ratios than sites in the lower portion of the

42 watershed. Alkalinity, conductivity and pH had concentrations that were elevated in tributaries in the lower portion of the watershed while total organic carbon was lower at these sites.

The PCA from the October sampling period resulted in two axes which explained

62.7% of the variability in the environmental data. Axis 1 explained 44.1% of the variability in the data and was largely related to total phosphorus and turbidity. The second axis explained 18.5% of the variability in the data and was dominated by nutrient variables, alkalinity, conductivity and pH. Unlike the July sampling period, there were no clear patterns for the main stem or tributary sites (Figure 2.6).

Location • Mamstem s|c Tributary Nt3 Nt5 Nt4Nm4 * Nml Nil* "^t2 • " Nt6 Nm6 -Usrti Nm3 sj- sf * • '2 o u a PH Nm8 a < -2

Nt8

Nt7

+0 2 PCI Total Organic Carbon

2- Nt3 Nm7 Nt7 Nt4 Nm5 Nt8,

Nm4 CM d, *ml Nm6 Nil * Nt2 -2 * CI o O Nm3 h- -6 -2 0 PCI <

Total Phosphorus, Turbidity

2.4.2.2 Nutrient status

The ratio of total inorganic nitrogen to total phosphorus (TIN: TP) was >20 at many of the main stem sites indicating phosphorus limitation during July and October.

Co-limitation by nitrogen and phosphorus was present at a few main stem sites and this condition occurred more frequently at tributary sites (Figure 2.7). Only one site, NT7, had phosphorus levels at the saturation benchmark of 0.025 mg/L, all other sites were confirmed as being nutrient limited (Appendix 7). Tributaries can be considered a point source of nutrients for the main stem and therefore may influence the main stem's nutrient ratios. Differences in nutrient ratios were observed at each set of upstream and downstream sites that were associated with the tributaries. Many of these differences

44 were small and appeared to have minimal influence on main stem nutrient ratios (Figure

2.7 and 2.8). Some tributaries had considerable influence on main stem nutrient ratios.

For example, NTl and NT8 both had large percent differences in nutrient ratios between upstream and downstream main stem sites in relation to these tributary inputs (74 % in

July and 46 % in October, respectively).

••• Juh -Mamslem I I Jul\ -Tnbulan I ' I October-Mainstem 1/ / I October-Tnbutan

Phosphorus Limited

Co-limited

Nitrogen Limited

^ ^ /> ^ ^ /> ^ ^ ^ ^# Sites

45 100

P"~58 October

it g 60 5 S = 40 4

20 n In *1 m IJ_l •J: NT1 NT2 NT3 NTS NT6 1 l Tributary Sites NT8

Main stem N: P ratios can be affected by point and nonpoint nutrient inputs. The major point sources assessed in the Nashwaak watershed were a municipal wastewater facility that discharges continuously to the Nashwaak River and an aquaculture facility that discharges to the North Tay River (Figure 2.1). Nutrient status downstream of the wastewater facility (NM3) remained phosphorus-limited during both sampling seasons although the percent difference in October was larger (33.5%) compared to a minimal change in July (5%), In contrast, nutrient status in July upstream of the aquaculture facility (NT4) was co-limited but phosphorus limited at the downstream (NT5) site

(Figure 2.7). Nonpoint sources of nutrients within the Nashwaak watershed varied among sites and there seemed to be no clear relationship between nutrient status and land use in 46 either sampling season (Figure 2.9). The linear regression confirmed this as the R was low (< 0.3) (Appendix 5). For instance, co-limitation was found at sites which had the highest percentages of occupied land (NT7 and NT8) and also at sites which had very little agriculture or occupied land (NM1 and NT1).

10% 50 3 Agriculture V////A Occupied 8% • Juh TIN TP 40 Phosphorus Limited 6%

4% - 20 Co-limited

2% 10 Nitrogen Limited 0% o 10% B 50 I I Agriculture V///M Occupied 8% - • Octobci TIN TP 40 Phosphorus Limited 6% ^0

4% - 20 Co-limited

10 Nitrogen Limited 11EL 0% o *> C' £ vN v> \b Vs >F ^N

Main Stem Sites Tributary Sites

Figure 2.9: The primary land use in the Nashwaak watershed upstream of each sample is presented along with July (A) and October (B) nutrient ratios. Site abbreviations can be found in Table 2.1.

2.4.2.3 Algal biomass and Community Structure

Benthic algal biomass was low at all sites in the Nashwaak watershed and there were no clear patterns in algal biomass along the main stem or tributaries (Figure 2.10).

47 The mean benthic chlorophyll a at all sites was less than 20 mg/m and is considered oligotrophic based on (Dodds et al., 1998) trophic classification of rivers. Benthic algal biomass was higher in October at many of the sites, but did not exceed the maximum oligotrophic value of 60 mg/m2 suggested by Dodds et al. (1998). In July, the two highest biomass values were associated with phosphorus-limited sites on the main stem, while in

October the two highest biomass values were associated with sites that were within or near the range of co-limitation. The two tributaries which appeared to influence the nutrient ratios of the main stem (NTl in July and NT8 in October) did not seem to affect main stem algal biomass. Downstream of NTl, there was a slight increase in biomass in

July but downstream of NT8 biomass decreased below the tributary input in October.

25 July October Mesotrophic

20 --

E ra 15 E (A W Oligotrophic (Q S 10 - o m

5 -

X -* Iff I H_ Jl 1~1 I 1 I I1™ Ii ii NM1NM2NM3NM4NM5NM6NM7NM8 NT1 NT2 NT3 NT4 NT5 NT6 NT7 NT8 Main Stem Sites Tributary Sites

Figure 2.10: Mean benthic algal biomass in the Nashwaak watershed based on data collected in July and October 2005. Site abbreviations can be found in Table 2.1.

48 There was no clear relationship between the biotic and abiotic data in July or

October in the Nashwaak watershed as indicate by the BIO-ENV results (P=0.281 and

P=0.138, respectively). This meant that the algal community structure was not co-related with water chemistry or velocity measurements. The results from the ANOSEVI in July and October also indicated that there were no significant differences between main stem and tributary sites (P=0.543 and P=0.407, respectively). The SIMPER test also indicated that there was a low average similarity within groups and high average dissimilarity between groups. The benthic communities of the tributary sites were not found to be significantly different from their nearest main stem sites. MDS plots indicated similarity of the benthic algal communities of upper main stem and tributary sites in July (e.g.,

NM1 with NT1 and NM2 with NT2) but this pattern was not observed downstream

(Figure 2.11). In October, the MDS showed that benthic algal composition of main stem and tributary sites were more closely associated (Figure 2.12). Sites NM7 and NT8 were removed from the MDS in July as they were too dissimilar to the other sites. These sites were the only sites which had the cyanobacteria Merismopedia, which is typically common in saline or acidic water (Bell & Tranvik, 1993; Wehr & Sheath, 2003). A bubble plot of Fragilaria (diatom), which was the genera that influenced the SIMPER results, indicated that this genus appeared to be more abundant at sites in the upper part of the watershed (Figure 2.11). For October, Achnanthes (diatom) was prevalent at many of the main stem and tributary sites which were clustered together (Figure 2.12). The percentage of motile and eutrophic diatoms were also examined but showed no clear pattern (Appendix 6).

49 2D Stress 0 15 Fragilaria sp. Nm6 4 v^l) O « w Nt5 (»*) 160 M&8 Nt3 Nm2 /^~^N Nt6 ( - J 280

( » j 400

Nt7 ™^ Nt4

Figure 2.11: Multi-dimensional scaling of benthic algal taxonomy data from the Nashwaak watershed in July, 2005. Site abbreviations can be found in Table 2.1.

2D Stress 0 13 Achnanthes spp. Nt2 30 N®i6 O

(," ) 120

(Nrn4) ^ ^ ( i ) 210 Nm8

[ '•" ' ) 300 f Nt^NtJ) K_^/ Nt5

Figure 2.12: Multi-dimensional scaling of benthic algal taxonomy data from the Nashwaak watershed in October, 2005. Site abbreviations can be found in Table 2.1.

50 2.4.3 Kennebecasis Watershed

2.4.3.1 Discharge and Flow Duration Curves

During August 2005, mean discharge was 6 m Is, which was exceeded 79% of the time based on the recorded data for the last 30 years and was considered below average

(Figures 2.13 and 2.14). November's discharge was 22.5 m3/s and was exceeded 28% of time in the last 30 years of recorded data and was above average (Figures 2.13 and 2.14).

250

in in O O O o o o o o o o o ex > a c5 ex re to

Date

Figure 2.13: Discharge (m3/s) of the Kennebecasis River at Apohaqui in 2005. The arrows indicate when sampling occurred.

51 f>

~i 1 1 r 0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100% Exceedance (%)

Figure 2.14: Duration curve for the Kennebecasis River at Apohaqui in 2005. The arrows indicate when sampling occurred.

2.4.3.2 Water Chemistry

The August PCA of water chemistry produced two axes which explained 62.8% of the variability in the environmental data (Figure 2.15). Axis 1 (34.8%) was dominated by conductivity, total organic carbon, temperature, turbidity and ammonia while nutrients and alkalinity influenced Axis 2 (28%). For main stem sites, conductivity, total ammonia, total organic carbon, turbidity, temperature, alkalinity, total inorganic nitrogen, and TIN:

TP increased towards the river's mouth (Figure 2.16). Only total phosphorus was found to have concentrations which decreased towards the mouth. The tributary sites showed no definitive patterns with respect to water chemistry.

52 The PC A for November produced two axes which explained 59.5% of the variability in the environmental data (Figure 2.16). Axis 1 (34.6%) was influenced by conductivity, ammonia, TOC, and turbidity, while Axis 2 (24.9%) was dominated by a alkalinity, TIN, TIN:TP and total phosphorus. For main stem sites, alkalinity, conductivity, ammonia, pH, total phosphorus, turbidity, total inorganic nitrogen, TIN: TP and temperature all increased towards the river's mouth. The patterns among main stem sites were not as clear as they were in August. There were no patterns observed in the tributary sites.

6-r Location c • Mamstern % Tributary c PL KT5

KT4 * KM5 KT7 CM * O KM4 H a. 0- KM2 KT2

KT1 KT6

-2 KT3 KM1 *

-4-L 1— 0 PC1 Conductivity, Ammonia, TOC, Turbidity

53 KTl Location * • Mainstem % Tributary

OH H KT2

KM2 1 KT6 KW H f"4 • * (U OoH 0 S-l KM4 3 ctf • —<' D OH

^ -2 H KM3

KT5

—I— 0 PCI Alkalinity, Conductivity, Ammonia, Turbidity,

2.4.3.3 Nutrient Status

In contrast to the Nashwaak system, the ratio of TIN to TP in the Kennebecasis

main stem ranged between 10 and 20 during August and November, indicating co-

limitation by nitrogen and phosphorus. Many of the Kennebecasis tributary sites were

also co-limited, with only a few tributaries exhibiting phosphorus-limitation (Figure

2.17). Three sites, KTl, KT6 and KM3, were at or above the saturation benchmark for

phosphorus saturation; all other sites were confirmed as nutrient limited. Tributaries

appeared to have influenced nutrient ratios of the main stem, although many of these

54 differences were small between upstream and downstream sites (Figure 2.18). Two tributaries, KT3 and KT5, influenced the main stem's nutrient ratio the most, due to their large percent differences.

80 I August Main Stem 70 3 August Tributan 3 November Mam Stem V / J November Tributan 60

.2 50 - « OS a* 40 H Phosphorus Z Limited H 30

20 Co-limited 10 -- Nitrogen Limited I i r^~r KM1 KT1 KM2 KT2 KT3 KT4 KT5 KMi KT7 KT6 KM4 KM5 Sites

Figure 2.17: The molar ratio of total inorganic nitrogen to total phosphorus in the Kennebecasis watershed during August and November 2005. Site abbreviations can be found in Table 2.2.

55 50 •• August 1 .'' A No\ ember 40

20 -

10 -

KT1 KTS KT5 KT7 Tributary Site

The nutrient status effects of three point source municipal wastewater facility on

Kennebecasis main stem were evaluated. These facilities, which discharge continuously, are located on the main stem below Sussex, Apohaqui and Norton (Figure 2.2). The nutrient status of the Kennebecasis downstream of the Sussex wastewater facility (KM3) remained co-limited during both sampling seasons. However, associated with this discharge was the greatest upstream to downstream percent difference (38.5%) in nutrient ratios. Downstream of the Apohaqui (KM4) and Norton (KM5) wastewater facilities, the nutrient status remained co-limited during both sampling seasons and showed only a small percent difference downstream of these facilities (<10%). The nonpoint sources of

56 nutrients or the land use within the Kennebecasis watershed varied among sites and there was no clear relationship between nutrient status and land use in either sampling season

(R2<0.3) (Figure 2.19 and Appendix 5). During August and November, the main stem was primarily co-limited from the headwaters to the mouth even though the percentage of agricultural and occupied land increased towards the mouth. The tributaries were more variable in terms on nutrient status, but this variability did not seem to be related to land use changes. For example, co-limitation occurred at KTl, which had a low percentage of agriculture and occupied lands, as well as at KT5, which had a high percentage of agriculture and occupied lands.

57 50% 80 i i Agriculture V7777A Occupied r 70 40% • August TIN:TP 60

- 50 30% " 40 Phosphorus 20% ,. Limited :>0

20 10% Co-limited iS I- 10 Nitrogen J 0% 0 Limited •a 50% 80 B Agriculture V////A Occupied 70 40% - • November TIN:TP 60

50 30%

Phosphorus 20% . -3,0 Limited

20 10% Co-limited Nitrogen „ Limited 0% P- B- -0* KM! KM2 KM3 KM4 KM5 KTl KT4 KT5 KT6 KT7 KT3 KT2 Main Stem Sites Tributary Sites

2.4.3.4 Algal Biomass and Community Structure

Based on the mean benthic algal biomass, many of the sites were found to be either oligotrophic (< 20 mg/m2) or mesotrophic (20-70 mg/m2), with the exception of

KM3 and KT4 which had eutrophic biomass (> 70 mg/m2) (Figure 2.20). The algal biomass was elevated at KM3 during August and decreased to oligotrophic levels in

58 November. Alternatively, biomass at KT4 was low in August and elevated in November.

These elevated levels were associated with sites that were either co-limited (KM4) or phosphorus-limited (KT4). In August, a decreasing trend in biomass was observed at three of the upper tributaries and this corresponded with increasing nutrient ratios. There was also a slight increasing trend in biomass at the main stem sites in November but this trend was not associated with any changes in nutrient ratios. It is important to note that

KM5 was not sampled due to lack of appropriate substrate and in November KT5 and

KM2 were not sampled due to high water levels.

•• August 180 - I * J No\ ember 160 -

140 -

S 120 - M) s °100 - « Eutrophic S 80 - Cfol 60 - 40 - 1r ™r __ Mesotrophic . JX. T T__ ll Oligotrophia 0 - 1 1 •TT I.TT I.TT W, •. mjTT B.TT KM1 KM2 KM3 KM4 KT1 KT2 KT3 KT4 KT5 KT6 KT7 Main Stem Sites Tributary Sites Figure 2.20: Mean benthic algal biomass at sites within the Kennebecasis watershed during August and November 2005. Site abbreviations can be found in Table 2.2.

59 There appeared to be no clear relationship between the biotic and abiotic data in

August or November in the Kennebecasis watershed. This was indicated by the BIO-

ENV analysis (P=0.35 and 0.767 respectively) which showed that the benthic algal community structure did not correspond to changes in the water chemistry and velocity measurements. ANOSIM results for August and November indicated that there were no significant differences between main stem and tributary sites (P=0.218 and 0.512). The

SIMPER test also indicated a low average similarity within groups and high average dissimilarity between groups. The MDS plots showed no discernable pattern in algal composition among main stem sites with only two sets of sites grouping together

(KT1/KT2 and KT6/KT7) in July (Figure 2.21). In October, more clumping of main stem and tributary sites was evident compared to the August MDS (Figure 2.22). A bubble plot of Melosira varians,, which was a genera that influenced the SIMPER results, indicated that this genus appeared to be more abundant at sites in the upper part of the watershed (Figure 2.21). In October, the majority of sites were grouped together and these sites were found to have the highest amounts of Oscillatoria (Figure 2.22).

Furthermore, the percentage of motile and eutrophic diatoms were also examined but showed no pattern (Appendix 6). Finally, the benthic communities of the tributary sites were not significantly different from their nearest main stem site.

60 2D Stress 0 1 Melosira vanans KN)4 (0) 40

IQJ6 KT*>

KJ7

KT4

Figure 2.21: Multi-dimensional scaling of benthic algal taxonomy data from the Kennebecasis watershed in August 2005 Site abbreviations can be found in Table 2 2

2D Stress 0 04 Oscillatorw sp 1 O 20

KT6 KPi

Figure 2.22: Multi-dimensional scaling of benthic algal taxonomy data from the Kennebecasis watershed in November, 2005 Site abbreviations can be found in Table 2 2

61 2.5 Discussion

Nutrient status of river ecosystems can be affected by many different factors including geology, land use and point source discharges of nutrients. While phosphorus has long been assumed to be the key limiting nutrient in freshwaters (Wetzel, 2001), this assumption has been challenged by increasing evidence that nitrogen may be an equally important driver of river productivity (Francoeur, 2001; Grimm & Fisher, 1986; Lohman,

Jones, & Baysinger-Daniel, 1991). There has been limited research on the nutrient status in New Brunswick rivers, thus, the importance of phosphorus and nitrogen as factors limiting primary production is poorly understood.

The Nashwaak and Kennebecasis watersheds exhibited differences in nutrient ratios and biomass while having similar trends in water chemistry. The Nashwaak watershed was predominately phosphorus-limited, with low algal biomass. In contrast, the Kennebecasis watershed was co-limited by nitrogen and phosphorus and had higher algal biomass. In both rivers the concentration of many water chemistry parameters (e.g., conductivity, alkalinity, turbidity and total inorganic nitrogen) increased from the headwaters towards the river mouth. Compared to other rivers in North America, the

Nashwaak watershed and portions of the Kennebecasis watershed had very low nutrient levels and would be considered oligotrophic under Dodds et al. (1998) trophic classification of streams. There were several areas of the Kennebecasis, including the mouths of major tributaries and downstream of municipalities, where nutrient levels that attained mesotrophic productivity range.

62 2.5.1 Water Chemistry

Many water chemistry parameters measured in the Nashwaak and Kennebecasis watersheds had elevated concentrations towards the mouth of the main stem river. For example, the downstream increase of total inorganic nitrogen in the Nashwaak River corresponded to the higher percentages of agriculture and occupied land use. Carpenter,

(1998) previously established that these types of land use can be an important nonpoint source of both nitrogen and phosphorus for freshwater systems. With this rise in TIN, the nutrient ratio of the Nashwaak was expected to increase. However, nutrient ratios were actually reduced in the lower portion of the watershed. This unexpected outcome likely results from the increase in TIN being insufficient to change the nutrient ratio pattern as the nonpoint and point sources of nutrients may have only been releasing minimal amounts of TIN to the watershed. In the autumn, patterns in water chemistry were less obvious in the Nashwaak, possibly due to the large fluctuations in discharge prior to sampling in October. In the Kennebecasis, differences in discharge between seasons may explain the variability in phosphorus, which decreased towards the mouth in the summer and increased towards the mouth in the autumn. The variations in discharge were due to large precipitation events that occurred in the autumn, these events may in turn increase run off from surrounding land, potentially bringing nutrients to the streams.

2.5.2 Nutrient Status

The nutrient status varied between watersheds, with the Nashwaak being predominantly phosphorus-limited, while the Kennebecasis was commonly co-limited.

Nutrient saturation was not common, with only phosphorus saturation being encountered

63 at only a few sites between the two watersheds. The variation in nutrient status between watersheds was anticipated due to differences in land use patterns. The Nashwaak had a high percentage of forested land, which typically exports fewer nutrients than agricultural or occupied lands (Chambers et al., 2001; Likens & Bormann, 1974). In contrast, higher levels of agriculture and larger municipal wastewater facilities were expected to have influenced the nutrient status of the Kennebecasis watershed. However, there appeared to be no relationship between site specific nutrient ratios and upstream land use percentages.

Differences in nutrient ratios between watersheds could also have been influenced by other factors that affect the transport of nutrients, such as soil type, erosion risk, riparian zone health, in-stream biological processes and precipitation events (Sharpley et al.,

2001). More frequent sampling may have been required in order to determine if the land uses were influencing nutrient status as this study was based on only two water quality sampling events. Furthermore, a better indication of the influence of nonpoint sources may have been observed if sampling occurred during the application of fertilizers or possibly sampling after large precipitation events. Assessing the type of agriculture present, farming intensity and fertilizer rates would have provided a better understanding of potential agricultural impacts.

Headwater reaches were expected to be phosphorus-limited, as these reaches were relatively un-impacted and had very low nutrient concentrations. However, both in the

Nashwaak and Kennebecasis, nutrient ratios in the headwater reaches often indicated co- limitation by nitrogen and phosphorus. The presence of co-limitation indicates that even in the upper most reaches of the watersheds both nitrogen and phosphorus play an important role in primary productivity. 64 Differences in nutrient ratios were observed between upstream and downstream sites that were associated with point sources of nutrients. This provides an indication that these sources of nutrients may have influenced the nutrient ratios and nutrient status of these rivers. In both watersheds, municipal wastewater facilities influenced nutrient ratios, as was evident by large percent differences, but these changes were not large enough to actually shift nutrient status. In addition, tributaries were found to have a minimal influence on nutrient ratios of both main stem rivers. Nashwaak tributaries were not expected to impact the main stems nutrient ratios due to low nutrient concentrations

(Appendix 6) and large amounts of forested land. Similar to the Nashwaak River, there were no changes in the nutrient status of the main stem Kennebecasis that were due the influence of tributaries and the percent differences in the nutrient ratios were low.

2.5.3 Algal Biomass and Community Structure

Benthic biomass was low throughout most of the Nashwaak, but was elevated at several sites in October (i.e., NT2, NT5 and NT8). Nutrient levels were low at these sites

(Appendix 6) and prior to autumn sampling, a large number of precipitation events occurred, which should have led to decreased biomass due to scouring (Francoeur &

Biggs, 2006). However, Humphrey & Stevenson (1992) indicated that increased flow can increase algal metabolism as long as the velocity is not high enough to scour the benthic algae from the substrate. In addition, the precipitation events could have provided pulses of nutrients via run-off that may have gone undetected due to the timing of the water chemistry samples. In comparison, the Kennebecasis experienced higher biomass at several sites, in particular KM3 (August) and KT4 (November). The biomass above

65 KM3 was co-limited and TIN and TP concentrations at KM3 were elevated (Appendix

6). An increase in biomass might be expected considering the sources of nutrients upstream of KM3 (wastewater facilities, agriculture, and occupied lands). By contrast, nutrients were low at KT4 and there were no significant source of nutrients upstream suggesting that KT4 was influenced by discharge increases prior to sampling as discussed previously for Nashwaak River sites.

The lack of a relationship between the environmental and biological data sets observed in the BIO-ENV analysis indicates that other factors such as light availability, macroinvertebrate grazing and site-specific water velocity regimes may have influenced these algal communities (Biggs, 1996). A relationship may have existed between the measured variables and the community but more frequent sampling may have been required in order to see such a relationship. The ANOSIM results indicated that main stem sites were more similar to the nearest tributary site than the closest upstream or downstream site on the main stem. This may give an indication that the tributaries do influence the nearest downstream site in terms of community composition. Kiffney,

Green, Hall, & Davies, (2006) concluded that tributaries influence nutrients, algal biomass and substrate composition of main stem reaches and these effects are dependent on the tributary size. Although the SIMPER results suggested differences between the main stem and tributary sites, it was impossible to test for these differences because the study design did not allow for within-site replication.

Fragilaria was found primarily in upper sites and this genus is known to dominate headwater reaches and is typically present in reaches where there is minimal nutrient enrichment, as was the case for the upper Nashwaak watershed (Biggs, 1996). In 66 October, there were a number of precipitation events which would have affected the algal community however, Achnanthes was present at many sites and is known to be only affected by severe flood events (Douglas, 1958). For the Kennebecasis, Melosira varians was present at sites associated with higher agriculture and this species is typically prevalent in areas of nutrient enrichment and is an indicator of organic pollution (Wehr &

Sheath, 2003). In November, the cyanobacteria Oscillatoria was present at many of the sites and this genus has numerous species that are tolerant to organic pollution (Palmer,

1969). The large precipitation events prior to sampling would have caused increased run off from agricultural and occupied lands that may have brought inputs of organics to the watershed.

2.6 Conclusions

Phosphorous has been viewed historically as the limiting nutrient in freshwater systems (Hecky & Kilham, 1988; Mainstone, 2002; Schindler, 1977). In contrast, this research demonstrates that co-limitation is more common than phosphorus limitation in the Nashwaak and Kennebecasis watersheds. These results illustrate why it is important to manage and regulate the release of both nitrogen and phosphorus from point and nonpoint sources of nutrients. Dodds (2002) determined there was a significant interaction of N and P in lotic systems, suggesting that both nutrients can be limiting nutrients and, therefore, both should be considered when assessing benthic algal biomass in streams and rivers. Nutrient enrichment bioassays have also demonstrated that nitrogen limitation often occurs in river systems (Dodds, Smith, & Lohman, 2002; Francoeur,

2001; Smith et al., 1999).

67 Determination of whether a site is phosphorus, nitrogen, or co-limited by both can vary as a result of the various criteria that can be used to determine the boundaries of each nutrient status. The Redfield ratio (Redfield, 1958), which is based on the growth requirements of marine phytoplankton, indicates phosphorus limitation at ratios greater than 16 and nitrogen limitation at ratios less than 16. Another commonly used nutrient ratio benchmark concludes N limitation if N: P ratios are less than 10, P limitation when ratios are greater than 20 and co-limitation when ratios are between 10 and 20 (Schanz &

Juon, 1983). Most recent researchers used the benchmarks of 10 and 20 and I would recommend that future nutrient status assessments use the same benchmark (Allen &

Hershey, 1996; Grimm & Fisher, 1986; Lohman et al., 1991; Wold & Hersey, 1999). An alternative to using nutrient ratios in nutrient status assessments is the use of nutrient diffusing substrates, which is an in-stream bioassay which provides an indication of nutrient status based on the amount of biomass that accumulates on the various nutrient treatments over a period of time.

Nutrient status results can also differ based on the form of nitrogen or phosphorus which is used to calculate the nutrient ratio. Some studies use dissolved nitrogen and phosphorus rather than total while others have used inorganic rather than organic portions of these nutrients. It is difficult to know which approach is the most accurate as some researchers have indicated that using the ratio of dissolved inorganic nutrient to total phosphorus is a better indicator of potential nutrient limitation than other combinations

(Lohman et al., 1991), while others found that dissolved and inorganic nutrients did not reliably indicate nutrient limitation (Francoeur et al., 1999; Tank & Dodds, 2003; Allen

& Hershey, 1996). Although total nutrients may overestimate the amount of nutrients 68 that are available for benthic biomass growth, a number of studies have indicated that total nutrients were found to correlate well with benthic biomass (Chetelat, Pick, Morin,

& Hamilton, 1999, Dodds, Smith, & Zander, 1997). Therefore, it is suggested that total nutrients should be used in nutrient status assessments, as they appear to be a more reliable indication of nutrient status than dissolved nutrients.

The percentages of agricultural and occupied land use observed in the study watersheds was considered to be low compared to watersheds that have been used in other studies. A study in the United States used watersheds that ranged from 14 to 98% in agricultural land and as a result, higher TIN and TP values were found (3.66 mg/1 and

0.077 mg/1 respectively) (Johnson, Richards, Host, & Arthur, 1997). The agricultural and occupied lands present in my study watersheds may have had a localized or transient impact on nutrient status but this was not evident based on the results from this research.

At some sites, the increases in algal biomass may have been as a result of other factors.

These factors, such as light, temperature, and flow, influence algal biomass but cannot be directly managed, so it becomes important to manage nutrients so that their impacts are minimized.

This study has illustrated the importance of managing both nitrogen and phosphorus in a watershed as they were both found to be limiting. Management options would include best management practices for agriculture, forestry and occupied lands such as erosion prevention, riparian zone protection, along with controls on point sources of nutrients which release effluent in oligotrophic, nutrient limited reaches. Although there was no clear relationship between point/nonpoint sources of nutrients and the

69 pattern in nutrient ratios, it is still important to manage both sources of nutrients to minimize their effects on water quality.

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Schindler, D. W. (1977). Evolution of phosphorus limitation in lakes . Science, 195, 260- 262.

Schindler, D. W., Hecky, R. E., Findlay, D. L., Stainton, M. P., Parker, B. R., Paterson, M. J., et al. (2008). Eutrophication of lakes cannot be controlled by reducing nitrogen input: Results of a 37-year whole-ecosystem experiment. Proceedings of the National Academy of Sciences, 105(23), 11254-11258.

Scrimgeour, G. J., & Chambers, P. A. (2000). Cumulative effects of pulp mill and municipal effluents on epilithic biomass and nutrient limitation n a large northern river ecosystem. Canadian Journal of Fisheries and Aquatic Sciences, 57, 1342-1354.

Sharpley, A. N., McDowell, R. W., & Kleinman, P. J. A. (2001). Phosphorus loss from land to water; integrating agricultural and environmental management. Plant and Soil, 257,287-307.

Smith, V. H., Tilman, G. D., &Nekola, J. C. (1999). Eutrophication: Impacts of excess nutrients on freshwater, marine, and terrestrial ecosystems. Environmental Pollution, 100, 179-196.

Tank, J. L., & Dodds, W. K. (2003). Nutrient limitation of epilithic and epixylic biofilms in ten North American streams. Freshwater Biology, 48, 1031 -1049.

Van Dam, H., Mertens, A., & Sinkeldam, J. (1994). A coded checklist and ecological indicator values of freshwater diatoms from the Netherlands. Netherlands Journal of Aquatic Ecology, 28(1), 117-133.

Walsh, C. J., Roy, A. H., Feminella, J. W., Cottingham, P. D., Groffman, P. M., & Morgan, R. P. (2005). The urban stream syndrome: Current knowledge and the search for a cure. J.N. Am. Benthol. Soc, 24(3), 706-723.

Wehr, J. D., & Sheath, R. G. (Eds.). (2003). Freshwater algae of North America ecology and classification (1st ed.). London: Academic Press.

Welch, E. B., Jacoby, J. M., Horner, R. R., & Seeley, M. R. (1988). Nuisance biomass levels of periphytic algae in streams. Hydrobiologia, 157, 161-168.

74 Wetzel, R. C. (2001). Limnology: Lake and river ecosystems (3rd ed.). New York: Academic Press.

Wold, A. P., & Hersey, A. E. (1999). Spatial and temporal variability of nutrient limitation in 6 north shore tributaries to Lake Superior. Journal of the North American Benthological Society, 18(\), 2-14.

Zoto, A., Dillon, D. O., & Schlichting, E. (1973). A rapid method for cleaning diatoms for taxonomic and ecological studies. Phycologia, 12, 69-70.

75 3 Assessment of watershed nutrient status using nutrient-diffusing

substrate bioassays

3.1 Abstract

Nutrient studies have indicated the importance of nitrogen and phosphorus in the growth of primary producers but excessive amounts of these nutrients have led to enrichment of freshwater ecosystems around the world. Determining the limiting nutrient or the nutrient status of a system can aid in nutrient management. In New Brunswick, few studies have examined the nutrient status of the province's rivers or whole watersheds, and so the nutrient status or frequency of nitrogen and/or phosphorus limitation is relatively unknown. Nutrient diffusing substrates (control, nitrogen, phosphorus, nitrogen

+ phosphorus) were used to determine differences in nutrient status throughout the

Nashwaak and Kennebecasis watersheds in southern New Brunswick. Of particular interest was the influence of point and nonpoint sources of nutrients on watershed nutrient status as well as the influence of tributaries on the main stem's nutrient status.

The frequency of phosphorus versus nitrogen limitation was also examined to determine which nutrient limited growth of periphyton biomass more often. Unlike earlier studies, algal biomass in these watersheds was not limited by phosphorus alone. In the Nashwaak watershed, biomass was largely co-limited by nitrogen and phosphorus in the summer but was non-limited in the fall. Sites within the Kennebecasis watershed were more variable in the summer, with sites being nitrogen-limited, co-limited or non-limited but were non- limited in the fall. There were instances were point sources and tributaries caused shifts in nutrient status towards non-limitation. The influence of nonpoint sources on nutrient

76 status was less obvious and a direct relationship between the NDS results and surrounding land use could not be drawn. Overall, the nutrient diffusing method used in this study appeared to be an effective way to examine the nutrient status of watersheds and would be a useful management tool for environmental agencies.

3.2 Introduction

While the nutrients, phosphorus and nitrogen, are important for the growth of primary producers, the problems associated with excessive nutrient loadings (e.g., oxygen depletion, decreased biotic diversity) are well known in Canada and worldwide

(Chambers et al., 2001; Carpenter, 1998; United States Environmental Protection

Agency, 2000). Although phosphorus has long been viewed as the fundamental limiting nutrient in freshwater systems (Wetzel, 2001), many nutrient limitation studies have shown the importance of both nitrogen and phosphorus in freshwater systems (Lohman,

Jones, & Baysinger-Daniel, 1991). For example, Grimm & Fisher (1986) found that in many Arizona streams, nitrogen limitation was common. Many others have shown the importance of nitrogen limitation in freshwater systems (Hill & Knight, 1988; Lohman et al., 1991; Tank & Dodds, 2003). Additionally, Francoeur (2001) performed a meta analysis of nutrient amendment experiments and found that nitrogen was as likely to limit algal growth as phosphorus. In New Brunswick, there has been very limited research conducted on the nutrient status of the province's waterways, thus, for the development of nutrient management strategies, it is critically important to investigate the relative roles of phosphorus and nitrogen in limiting primary productivity.

77 A common method used to assess nutrients status of freshwater systems has been the calculation of nitrogen phosphorus (N:P) ratios acquired from the ambient water chemistry. This method predicts phosphorus limitation for systems with ratios above 20 and nitrogen limitation when ratios are below 10 (Schanz & Juon, 1983). However,

Francoeur, Biggs, Smith, & Lowe, (1999) recommend more direct methods, such as experimental manipulation, as it would provide more accurate measures of nutrient status. Examples of nutrient limitation experiments include whole system enrichment studies (Schindler, 1977), flow through systems with varying nutrient regimes (Grimm &

Fisher, 1986; Lohman et al., 1991), and the use of nutrient diffusing substrates (Corkum,

1996a; Fairchild, Lowe, & Richardson, 1985; Scrimgeour & Chambers, 1997; Tank &

Dodds, 2003).

In this study nutrient diffusing substrates (NDS) were chosen as an alternative to using nutrient ratios for determination of nutrient status. NDS is an in-stream bioassay where various nutrient treatments consist of having nitrogen, phosphorus or both in combination dissolved in an inert media and added to a container topped with a porous glass disc. The nutrients slowly diffuse across the permeable glass disc surface, upon which benthic algae colonize and grow. The benefit of these artificial substrates is they allow the colonizing algal community to interact with other environmental variables while controlling the nutrients supplied (Pringle & Triska, 1996). Depending on the objective of the monitoring program, the in-stream bioassays can be used under a number of scenarios, including determining the impact on nutrient status of known point or diffuse sources of nutrients (Corkum, 1996b; Scrimgeour & Chambers, 2000), or assessing the temporal variability of watershed nutrient status (Wold & Hersey, 1999). 78 My research determined whether differences existed in nutrient status at a watershed scale based on the accumulation of algal biomass on the NDS. I hypothesized that nutrient status would vary spatially within watersheds in relation to point and nonpoint sources of nutrients as well as tributary inputs. I predicted that phosphorus limitation would occur in headwater areas as well as in areas with minimal human activities. Additionally, shifts in nutrient status were anticipated downstream of nutrient sources with status shifting from phosphorus limitation towards nutrient saturation or nitrogen limitation.

3.3 Methods

3.3.1 Description of Study Area

The research focused on assessing the nutrient status in two New Brunswick watersheds. The Nashwaak and Kennebecasis watersheds, which are sub-watersheds of the Saint John River, were chosen based on their land use patterns and the presence of point sources. The Nashwaak watershed, with a drainage area of 1700 km , is comprised mainly of forested land (92%) with small portions of agricultural (2.8%) and occupied land (1%). In comparison, the Kennebecasis has a larger drainage area of 2086 km and higher percentages of agricultural (15.4%) and occupied lands (1.8%). Point sources of nutrients in the Nashwaak include a municipal wastewater treatment facility that discharges to the main stem and a fish hatchery discharging to the Tay River. In the

Kennebecasis, point sources that were assessed included three municipal wastewater

79 treatment facilities discharging to the main stem. Further characteristics of these watersheds are described in detail in Chapter 2, section 2.3.1.

3.3.2 Site Selection

Sites were selected in each watershed based broadly on the proximity to tributaries, point and diffused sources of nutrients. In addition, historic water chemistry data (Appendix 7) was examined to ensure that the chosen sites included a wide range of nutrient concentrations. This selection process produced 16 monitoring sites in the

Nashwaak watershed and 12 monitoring sites in the Kennebecasis watershed (Tables 2.1 and 2.2).

3.3.3 Nutrient Status Assessment - Nutrient Diffusing Substrates

NDS bioassays were deployed at each site during the summer and fall of 2005.

The methodology used for constructing the substrates was similar to that used by Tank &

Dodds, (2003). Substrates were constructed by filling small plastic containers with agar

(2% by weight) that contained one of four treatments; nitrogen as NaN03 (0.5M), phosphorus as KH2P04 (0.5M), nitrogen and phosphorus combined, or an agar only control. The agar was covered with a Whatman glass fiber fritter, which served as a substrate for the benthic algae to colonize (Figure 3.1). The containers were attached to plastic bars using 10 cm plastic tie wraps. Bars were anchored to the river bottom using

30 cm galvanized nails at depths which ranged from 40-50 cm. Ten replicates of each treatment were deployed at each site and depths and flows were recorded upon deployment (Appendix 3). All substrates were retrieved after 17-21 days; the glass fiber 80 fritters were placed in labeled bags and placed on ice in a cooler for subsequent

chlorophyll a analysis. Chlorophyll a biomass was estimated using a hot ethanol

extraction technique, adapted from Sartory (1982). For the analysis, each fritter was placed in a glass tube with 10 ml of 90% ethanol, placed in an 80°C hot water bath for 7

minutes and placed in the dark for 30 minutes. Sample volume was recorded, then

diluted to 1:100 using 90% ethanol and fluorescence of the liquid measured using a

Turner Designs, model 10 series fluorometer. Chlorophyll a (mg/m2) was determined by using the following formula:

Chlorophyll a (u^/m2) = ((Ca * v * DF* 0.001) /a),

Where

Ca - reading from the fluorometer (ng/liter)

v - extract volume (ml)

a - area of glass fiber fritter (m2)

DF - dilution factor.

81 Figure 3.1: The upper photo (A) shows how the nutrient diffusing substrates are constructed and the lower photo (B) is an example of a group of substrates that have been removed from a site after deployment.

To determine if there was a significant difference between treatments, data was log transformed and a one way ANOVA was completed for each site to test whether algal biomass was significantly different (P<0.05) between treatments. If a significant difference was found, Turkey's HSD multiple comparison technique was used to differentiate which treatment was significantly greater. Significant differences were then interpreted as nutrient limitation. If a significant difference was not observed between any of the treatments, the location was considered to be non-limited. This result could

82 indicate potential nutrient saturation, providing that the nutrient levels at the site were greater than the oligotrophic levels (TN>0.7mg/L and TP>0.025mg/L used in Chapter 2 to indicate saturation). If ambient nutrient concentrations were not above these levels, then biomass was considered to be limited by other environmental factors.

3.4 Results

3.4.1 Assessment of Nutrient Status Using NDS Bioassays

3.4.1.1 Nashwaak Watershed

NDS bioassays indicated that main stem sites on the Nashwaak River were predominantly co-limited by nitrogen and phosphorus in July (Figure 3.2, Table 3.1).

Combined with the observation that N and P concentrations were below the saturation threshold of 0.7mg/L TN and 0.025mg/L TP, it appears that nitrogen and phosphorus were the primary limiting nutrients at these sites. Based on Dodds, Jones, & Welch

(1998) trophic classification of streams, the biomass within the main stem sites ranged from mesotrophic (20-70 mg/m2) to eutrophic (> 70 mg/m2).

October concentrations of nitrogen and phosphorus were well below saturation thresholds and this was also observed in July. However, in contrast to the July results, only site NM2 exhibited N-P co-limitation (Table 3.1). NDS results for the remaining sites showed no difference in biomass accumulation (Figure 3.3). Because nutrients were below the saturation threshold, along with the absence of differences in algal biomass among NDS treatments indicated that other environmental factors besides nutrients were

83 limiting the accumulation of algal biomass. Based on Dodds et al. (1998) trophic classification of streams, the biomass within the main stem sites ranged from mesotrophic

-y ry

(20-70 mg/m ) to eutrophic (> 70 mg/m ) but appeared to be lower compared to July with many sites having less than 60 mg/m2. The NP and P treatments at NM8 in October significantly inhibited biomass. Table 3.1: Nutrient status results for main stem sites within the Nashwaak watershed. Bolded values exceed TN or TP threshold of 0.7mg/L and 0.025 mg/L, respectively. JULY RESUL1r s Site Limitation Inhibition TP(mg/L) TN (mg/L) NM1 N-P,P None 0.019 <0.3 NM2 N-P None 0.009 <0.3 NM3 N-P None 0.009 <0.3 NM4 N-P None 0.009 <0.3 NM5 N-P.N None 0.011 <0.3 NM6 N-P None 0.011 <0.3 NM7 None None 0.014 <0.3 NM8 N-P None 0.01 <0.3 OCTOBER RESULTS NM1 None None 0.012 <0.3 NM2 N-P None 0.009 <0.3 NM3 None None 0.008 <0.3 NM4 None None 0.008 <0.3 NM5 None None 0.009 <0.3 NM6 None None 0.010 <0.3 NM7 - - 0.015 <0.3 NM8 None N-P,P 0.012 <0.3

84 1X0 MH Control 160 I.1...H Nitrogen (N) ^Hi Phosphoais (P) 140 I 1 NP

-^ 120 -

100

« so c _o S 60

20 -

NM1 NM2 NIVH NM4 NM5 NM6 NM7 NM8 Sites Figure 3.2: Mean chlorophyll a concentrations from nutrient diffusing substrates installed at sites along the main stem Nashwaak River during July 2005. Sites are arranged according to increasing agriculture percentage in the watershed (from left to right).

80 I Control D Nitrogen (N) I Phosphorus (P) 60 J NP

WD S 40

20 - II ii NMl NM2 NM" NM4 NM5 NM6 NM7 NM8 Sites

Figure 3.3: Mean chlorophyll a concentrations from nutrient diffusing substrates installed in the main stem Nashwaak River during October 2005. Sites are arranged according to increasing agriculture percentage in the watershed (from left to right). Substrates were lost at NM7.

85 Nutrient diffusing substrate bioassays indicated that tributary sites within the

Nashwaak watershed were predominantly non-limited in both July and October (Figures

3.4-3.5, Table 3.2). Exceptions to this general trend were sites NT2 and NT5 in July which were co-limited, and site NT7 in October which was N-limited. As observed at main stem sites, nutrients were below the saturation threshold thereby indicating that other environmental factors were limiting the algal biomass accumulation. Based on

Dodds et al. (1998) trophic classification of streams, the biomass within the tributary sites ranged from oligotrophic (<20 mg/m ) to eutrophic (> 70 mg/m ) in July, but was lower in October ranging from oligotrophic to mesotrophic. Nutrient diffusing substrates containing phosphorus appeared to significantly inhibit biomass at several sites in both months. Headwater locations were not limited by phosphorus but were either non-limited or nitrogen limited.

86 Table 3.2: Nutrient status results for tributary sites within the Nashwaak watershed. Bolded values exceed TN or TP threshold of 0.7mg/L and 0.025 mg/L, respectively. JULY RESULTS Site Limitation Inhibition TP(mg/L) TN(mg/L) NT1 None None 0.013 <0.3 NT2 N-P None 0.007 <0.3 NT3 None P 0.009 <0.3 NT4 None None 0.012 0.3 NT5 N-P.N None 0.009 <0.3 NT6 None P 0.016 <0.3 NT7 None N-P,P 0.025 <0.3 NT8 None None 0.019 <0.3 OCTOBER RESULTS NT1 None None 0.012 <0.3 NT2 None None 0.012 <0.3 NT3 None N-P,P 0.008 <0.3 NT4 - - 0.008 <0.3 NT5 None None 0.008 <0.3 NT6 None None 0.015 <0.3 NT7 N None 0.021 <0.3 NT8 None P 0.019 <0.3

87 200 • Control 3 Nitrogen (N) • Phosphorus (P) 150 3 NP

100

o ffl

50 -

NTl TNTH NT4 NT7 NTS NT2 NT6 NTS Sites Figure 3.4: Mean chlorophyll a concentrations from nutrient diffusing substrates installed in tributaries of the Nashwaak River during July 2005. Sites are arranged according to increasing agriculture percentage in the watersheds (from left to right).

Control 50 Nitrogen (N) Phosphorus (P) NP 40

01)

>- —' i0 KJ £« o P3 20

W- NTl NT? NT4 NT7 NTS NT2 NT6 NT5 Sites Figure 3.5: Mean chlorophyll a concentrations from nutrient diffusing substrates installed in tributaries of the Nashwaak River during October 2005. Sites are arranged according to increasing agriculture percentage in the watersheds (from left to right). Diffusing substrates were lost at site NT4.

88 Nutrient status of the main stem and the corresponding NDS results may have been affected by point and nonpoint source nutrient inputs. The major point sources assessed in the Nashwaak watershed were a municipal wastewater facility that discharges directly to the Nashwaak and an aquaculture facility that discharges to the North Tay

River (Figure 2.1). In July, the nutrient status remained unchanged downstream (NM3) of the wastewater facility compared to the upstream site (NM2) while in October, the nutrient status shifted from NP limited (NM2) to non-limited (NM3) downstream of the wastewater facility. The nutrient status shifted from non-limited at NT4 to NP limitation downstream of the aquaculture facility (NT5) in July, but in October, a comparison between sites could not be completed as the NDS were lost due to a high water event at

NT4. Tributaries can also be considered a point source of nutrients for the main stem and therefore may influence the main stem's nutrient status. However, many of the tributaries were not associated with nutrient status shifts at downstream main stem sites.

The exception was NT8 in July, where upstream of this tributary the nutrient status was co-limited, while downstream (NM8) it was found to be non-limited. In October, the only nutrient status change in terms of the tributaries was associated with NT1, where nutrient status went from non-limitation to co-limitation. In situations where nutrient status shifted towards non-limitation downstream of a potential nutrient source, the sites were not considered nutrient saturated as the ambient nutrient concentrations were below nutrient saturation thresholds (Table 3.1 and 3.2).

The influence of nonpoint sources of nutrients was assessed by comparing the existing land use percentages to each station's nutrient status. Overall, land use did not appear to influence nutrient status (Figure 3.6). For example, many of the main stem sites 89 with similar percentages of agriculture and occupied land use were NP limited (NM 4, 5,

6, and 8) except for NM7 which was non-limited. For the tributaries, sites that were found to be non-limited (NTl, 4, 8) had low agriculture land use while sites with higher agriculture were NP limited (NT2 and 5).

10% Agriculture V77A Occupied 8% -

6% NP NP l(P) 4% - NP S NP NP NP 2% - NP NP NP w 0% ^ 10% •D B C I I Agriculture (0 V77A Occupied 8% -

4% S - |(NP) l(P) 2% NP N l(NP)

0% IH I In B_ NM1 NM2 NM3 NM4 NM5 NM6 NM7 NM8 NT1 NT3 NT4 NT7 NT8 NT2 NT6 NT5 Main Stem Sites Tributary Sites

90 3.4.1.2 Kennebecasis Watershed

In August, nutrient diffusing substrate bioassays indicated that main stem sites on the Kennebecasis River were either nitrogen-limited or co-limited with exception of KM4

(Figures 3.7, Table 3.3). Combined with the observation that N and P concentrations were below the saturation threshold of 0.7mg/L TN and 0.025mg/L TP, it appears that nitrogen was the primary limiting nutrient at KM2, KM3 while both nutrients limited primary productivity at KMl and KM5. Nutrient concentrations at KM4 were below saturation indicating that other environmental factors were limiting primary productivity.

Based on Dodds et al. (1998) trophic classification of streams, the biomass within the main stem sites ranged from mesotrophic (20-70 mg/m2) to eutrophic (> 70 mg/m2). The phosphorus treatments at KM2 significantly inhibited biomass.

During November, NDS bioassays indicated that main stem sites were either nitrogen-limited or non-limited (Figure 3.8). Similar to August, nitrogen and phosphorus were below saturation thresholds indicating, that nitrogen was the primary limiting nutrient at KM2 and KM4, while other environmental factors were limiting primary productivity at KMl (Table 3.3). Phosphorus concentrations at KM3 were at the nutrient saturation threshold which indicates that this site may be phosphorus saturated. Algal biomass on the NDS was lower in November compared to August, ranging from oligotrophic to eutrophic, with many of the sites having less than 60 mg/m .

91 Table 3.3: Nutrient status results for main stem sites within the Kennebecasis watershed. Bolded values exceed TN or TP threshold of 0.7mg/L and 0.025 mg/L, respectively. Substrates could not be installed at KM5 due to high water levels in November. AUGUST RES1QLT S Site Limitation Inhibition TP(mg/L) TN (mg/L) KM1 N-P.N None 0.020 <0.3 KM2 N P 0.015 <0.3 KM3 N None 0.024 <0.3 KM4 None None 0.016 <0.3 KM5 N-P None 0.016 <0.3 NOVEMBER RESULTS KM1 None None 0.016 <0.3 KM2 N None 0.019 <0.3 KM3 None None 0.025 0.4 KM4 N None 0.023 0.4 KM5 - - 0.024 0.4

••• Contiol * i 250 - I 1 Nitrogen I^^H Phosphorus •i I I NP * ~ 200- r , L

M) J T ' X, 15" - T" T

o T S ioo - i * S 1 * T 1 -r ' i ' 50 - 1L I I 1 • 1 i "| ] i I 1 1 KMl KM2 KJVH KM4 KM5 Sites Figure 3.7: Mean chlorophyll a concentrations from nutrient diffusing substrates installed along the main stem of the Kennebecasis River during August 2005.

92 120 Conlol Nitrogen (N) 100 Phosphorus (P) J NP

^ 80

o 5 40 -I

•Hin i in»n KMl KM2 KM? KM4 Sites Figure 3.8: Mean chlorophyll a concentrations from nutrient diffusing substrates installed along the main stem of the Kennebecasis River during November 2005.

NDS bioassays indicated that tributary sites within the Kennebecasis watershed were either co-limited or non-limited in August (Figures 3.9, Table 3.4). Nitrogen and phosphorus were below saturation thresholds indicating that both nutrients were limiting primary productivity at KT2, KT4 and KT5, while other environmental factors were limiting primary productivity at KT3 and KT7. Phosphorus concentrations were at the nutrient saturation threshold for KT6, indicating phosphorus saturation. Headwater sites were not phosphorus limited but rather co-limited (KMl, KT2, and KT4) or phosphorus- saturated (KT6). Based on Dodds et al. (1998) trophic classification of streams, the biomass within the tributary sites ranged from mesotrophic (20-70 mg/m ) to eutrophic

(> 70 mg/m2).

93 In contrast, November NDS bioassay results indicated that all tributary sites were non-limited (Figure 3.10, Table 3.4). Nitrogen and phosphorus were below saturation thresholds indicating other environmental factors were limiting primary productivity.

Nutrient diffusing substrates that contained either phosphorus alone or phosphorus and nitrogen combined significantly inhibited biomass at KT4, KT6 and KT7 in November.

Compared to August's results, all headwater locations were non-limited. Biomass at tributary sites was lower in November compared to August, and ranged from oligotrophic to mesotrophic.

Table 3.4: Nutrient status results for tributary sites within the Kennebecasis watershed. Bolded values exceed TN or TP threshold of 0.7mg/L and 0.025 mg/L, respectively. AUGUST RESULTS Site Limitation Inhibition TP(mg/L) TN (mg/L) KT1 None None 0.025 <0.3 KT2 N-P None 0.018 0.3 KT3 None None 0.021 <0.3 KT4 N-P, P None 0.008 0.3 KT5 N-P,P None 0.010 0.5 KT6 None None 0.026 0.4 KT7 None None 0.013 0.3 NOVEMBER RESULTS KT1 None None 0.021 0.3 KT2 None None 0.022 0.4 KT3 None None 0.016 <0.3 KT4 None N-P 0.011 <0.3 KT5 None None 0.015 0.3 KT6 None P 0.019 0.4 KT7 None N-P,P 0.015 0.4

94 250 •M Control i y~i Nitrogen (N) 200 - ••• Phosphoais (P) I r~z] NP T 150 - I 100 o 5

KTl KT4 RT5 KT6 KT7 KT"! K.T2 Sites Figure 3.9: Mean chlorophyll a concentrations from nutrient diffusing substrates installed in tributaries of the Kennebecasis River during August 2005.

60 I Conlol J Nilrogen (N) 50 - I Pliosplioms (P) 3 NP

40 s E 30

* 20 H

T 10 - - Ir 111 KTl KT4 KT5 KT6 KT7 KT3 KT2 Sites

Figure 3.10: Mean chlorophyll a concentrations from nutrient diffusing substrates installed in tributaries of the Kennebecasis River during November 2005.

95 Since nutrient status can be affected by point and nonpoint sources of nutrients, three municipal wastewater facilities were assessed for potential effects to the

Kennebecasis main stem. These facilities, which discharge effluent continuously, were located on the main stem below Sussex, Apohaqui and Norton (Figure 2.2). In August, the nutrient status remained unchanged downstream (KM3) of the Sussex WWTP compared to the upstream site (KM2), but a large increase in algal biomass was observed.

Downstream of the Apohaqui wastewater facility, the nutrient status shifted from nitrogen limitation at KM3 to non-limitation at KM4. Nutrient status also shifted from non-limitation (KM4) to co-limitation (KM5) downstream of the Norton wastewater facility. In November, the nutrient status shifted from nitrogen limited upstream of the

Sussex wastewater facility to non-limitation (with phosphorus saturation) based on NDS bioassay and phosphorus saturation based on the ambient nutrient concentrations (Table

3.3). Downstream of the Apohaqui wastewater facility, nutrient status shifted from non- limitation (with phosphorus saturation) to nitrogen limitation. The influence of the

Norton wastewater facility could not be determined as NDS bars were not installed at

KM5 due to high water. In situations where nutrient status shifted towards non-limitation downstream of a potential nutrient source, the sites were not considered nutrient-saturated as the ambient nutrient concentrations were below nutrient saturation thresholds, with the exception of KM3 in November (Tables 3.3-3.4).

Tributaries also shifted nutrient status of the main stem of the Kennebecasis. In

August, the nutrient status shifted from co-limitation to nitrogen limitation downstream of KTl and also shifted downstream of KT7 from nitrogen limitation to non-limitation. In

November, the nutrient status shifted downstream of all tributary inputs. Downstream of 96 KT1 and KT7 the status shifted from non-limitation to nitrogen limitation compared to

KT3 and KT5 where it shifted from nitrogen limitation to non-limitation (with phosphorus saturation). The nutrient status was variable with respect to nonpoint sources.

For example, sites with higher percentages of agriculture were typically non-limited but there were instances where nitrogen limitation also occurred (KM3 in August and KM4 in November) as well as co- limitation (KM5 and KT2 in August) (Figure 3.11). At sites with lower amounts of upstream agriculture, the relationship between nutrient status and land use was less clear. Although it was expected that these sites would be nutrient limited, this did not always occur and non-limitation was found at KT1 in August and at

KM1 andKTl in November.

97 Agriculture Occupied

30% -

NP NP NP NP NP NP IL B Agriculture V777A Occupied 40% -

l(P) l(P) S N -

N l(NP) NP a IH 10 fl_ KM1 KM2 KM3 KM4 KM5 KT1 KT4 KT5 KT6 KT7 KT3 KT2 Main Stem Sites Tributary Sites

Figure 3.11: The primary land use in the Kennebecasis watershed upstream of each sample site is presented along with NDS results for August (A) and November (B) in 2005. NL= Non-Limited, NP= Co- limitation, N= Nitrogen Limited, P= Phosphorus Limited, I = Nutrient Inhibited by nutrient in brackets and (-) = no data.

98 3.5 Discussion

NDS bioassays have been widely used to determine the nutrient status of freshwater systems throughout many parts of the world (Bernhardt & Likens, 2004;

Francoeur et al., 1999; Tank & Dodds, 2003; Winterbourn, Hildrew, & Orton, 1992). By comparison, this methodology has seldom been used in New Brunswick and, in particular, the nutrient status of whole watersheds has not been assessed within the province. Based on NDS results from this study, it was apparent that the nutrient status varied from the headwaters to the mouth of each system. In addition, it appeared that in each watershed there was one nutrient treatment which frequently limited algal biomass.

For instance, the Nashwaak watershed was largely co-limited by nitrogen and phosphorus in the summer but non-limited in the fall. The nutrient status of the Kennebecasis watershed was more variable in the summer compared to the Nashwaak, with sites being nitrogen-limited, co-limited or non-limited. During the fall, sites were predominately non-limited. Non-limitation has been found in other studies using NDS and is known to be a common occurrence during fall (Allen & Hershey, 1996; Wold & Hersey, 1999).

Non-limitation can be due to other factors limiting benthic algal biomass such as temperature, grazing by macroinvertebrates, scouring, inadequate light or a combination of these factors (DeNicola, 1996; Francoeur & Biggs, 2006; Hill & Knight, 1988;

Steinman & Mulholland, 1996; Steinman, 1996).

A comparison of seasonal trends demonstrated differences in algal biomass in both watersheds, with the artificial substrates having less biomass in the fall than in the summer. These results are similar to other studies which have conducted their research in temperate climates (Allen & Hershey, 1996; Francoeur et al., 1999; Winterbourn, 1990). 99 The seasonality in algal biomass can be attributed to seasonal changes in nutrients, flow, light, temperature and macroinvertebrate abundances (Biggs, 1988; Borchardt, 1996;

DeNicola, 1996; Francoeur et al., 1999). For my study, nutrients were similar between seasons but light and macroinvertebrates were not assessed. Seasonal differences in discharge were found in both watersheds, where fall discharge was greater than the summer (Figure 2.3, 2.4, 2.13, and 2.14) and so this factor may have influenced the algal biomass within these watersheds.

3.5.1 Phosphorus as a Limiting Nutrient

Phosphorus has been thought to be the primary limiting nutrient in freshwater systems (Borchardt, 1996; Schindler, 1977; Wetzel, 2001) but other research has shown the influence of nitrogen on algal biomass (Francoeur et al., 1999; Grimm & Fisher,

1986; Lohman et al., 1991). Phosphorus can enter freshwater system naturally through the weathering of rock and soil erosion but the amount that comes from these sources is expected to be low and so the productivity of freshwater systems is expected to be limited by phosphorus (Allan, 1995). Comparatively, nitrogen comes naturally from atmospheric exchange as well as from various biological processes that take place within rivers or in the surrounding watershed (Allan, 1995). In both watersheds, it was apparent that phosphorus was not commonly the limiting nutrient, but rather it was found to be co- limiting with nitrogen and at a few sites in the Kennebecasis, nitrogen was the primary limiting nutrient. This illustrates the value of knowing if differences exist between sites, in terms of nutrient status, so that nutrients can be managed appropriately.

100 In the selected study watersheds, phosphorus was expected to be the primary limiting nutrient in areas upstream of point sources of nutrients. Downstream of these sources, it was anticipated that phosphorus would not be limiting but rather nitrogen- limitation or nutrient saturation would be present. However, since sole limitation by phosphorus was not observed within either watershed, this predicted pattern was not observed downstream of any of the point sources of nutrient which were assessed. It was also expected that the headwater sites would be phosphorus limited as these reaches were relatively un-impacted with very low nutrient concentration. However, they were often found to be co-limited in the summer months (NMl, KTl, and KT4) or non-limited in the fall (NMl, NT6, KM1, and KT2). The presence of co-limitation in these headwaters areas reinforces the conclusion that nitrogen is as important as phosphorus in limiting primary productivity.

3.5.2 Potential Influences on Nutrient Status

Many factors can influence the nutrient status of a river such as geology, the state of the riparian zone, in stream processes and surrounding land use (Allen & Hershey,

1996; Biggs, 1990; Lohman et al., 1991; Lowe, Golladay, & Webster, 1986). For the

Nashwaak and Kennebecasis watersheds, the influence of nutrient sources (point sources, nonpoint sources and tributaries) were assessed. Point sources of nutrients were previously found to affect nutrient status of freshwater systems (Chambers, Dale,

Scrimgeour, & Bothwell, 2000) and the NDS results did indicate instances where point sources and tributaries appeared to have influenced the nutrient status downstream causing a shift in nutrient status either towards nitrogen-limitation or phosphorus

101 saturation. However; the majority of shifts downstream of nutrient sources were towards non-limitation and were not considered nutrient-saturated as the nutrient concentration were below the saturation thresholds. The influence of nonpoint sources on nutrient status was less obvious and a direct relationship between the NDS results and surrounding land use could not be drawn. This could have been the result of relatively low percentages of agriculture and occupied lands that may have had such a small impact that changes in nutrient status could not be attributed to these nonpoint sources. Additionally, the influx of nutrients from nonpoint sources of nutrients were likely released intermittently throughout the year, depending on timing of land use activities and the NDS may not have been deployed during times when the bulk of the nutrients were released. Cooper &

Thomsen (1988) assessed nutrient levels in streams that drained from areas of varying land use (agriculture, undisturbed land and forest plantations) and found that the nutrient levels were not consistent throughout the year and were the highest after large precipitation events.

3.5.3 Points of Consideration When Using Nutrient Diffusing Substrates

While the NDS bioassay was found to be a successful approach, several methodological changes would improve the interpretation of the results for future assessments. For instance, the lack of a significant difference between treatments was very common in this study. Non-limited sites were only considered saturated if the ambient TN and TP concentrations were greater than 0.7mg/L and 0.025mg/L respectively. As a result, it was determined that only a few sites within the watersheds were phosphorus saturated, while the remaining non-limited sites were believed to be

102 influenced by other factors such as grazing by macroinvertebrates, light availability, scouring, and water temperature (Allen & Hershey, 1996; Francoeur & Biggs, 2006;

Scrimgeour & Chambers, 1997; Winterbourn, 1990). However, there may have been sites that were in fact saturated or close to it but there was not enough information available on what concentrations of TN and TP saturate the growth of a benthic algae.

For improved interpretation of future nutrient status assessment, I believe it is important that more research is carried out to determine what concentrations of total nitrogen and total phosphorus limit the growth of benthic algae, as information in this area is very limited.

There were instances where the NDS bioassay indicated a site was non-limited but the ambient concentration of phosphorus was at or above the saturation threshold.

This means the NDS should have shown nitrogen limitation at these locations but for some reason did not. This discrepancy may be due to the timing of when the ambient nutrient sampling as nutrients were collected upon installation of the NDS rather than upon retrieval. During this time, nutrient could have fluctuated while the NDS would have integrated the ambient conditions while there were installed. It is recommended that ambient nutrient sampling be conducted upon installation and retrieval so that this type of result is minimized.

Certain nutrient treatments of the NDS bioassay were found to significantly inhibit biomass at several sites. Nutrient inhibition occurs when the biomass on the nutrient enriched substrates are lower than the control substrates. In this study, nutrient inhibition was observed on treatments which contained either phosphorus or phosphorus combined with nitrogen. Inhibition was present in both watersheds and occurred in both 103 sampling seasons. However, it appeared that inhibition was equally common in both the summer and the fall in the Nashwaak watershed, but for the Kennebecasis, nutrient inhibition was more prevalent in fall than in the summer. Francoeur et al. (1999) found that there was a relationship between low water temperatures and the degree of nutrient limitation. Furthermore, Bernhardt & Likens (2004) found that substrates enriched in nitrogen most often caused algal growth to be inhibited. Additionally, they proposed that nutrient inhibition may be caused by grazing invertebrates, toxic levels of nutrients within the amended treatments, nutrient levels present in the substrates that may be stimulating the growth of algae low in chlorophyll a, or that the addition of nutrients might be stimulating bacteria growth which would cause competition for the benthic algae. Since algal growth did occur on all amended substrates at many non-inhibited sites, nutrient toxicity likely was not an issue in my study. The remaining explanations are still possible and could have contributed to the inhibition at the sites.

3.6 Conclusions

The nutrient diffusing method used in this study appeared to be an effective way to examine the nutrient status of watersheds. By using this technique, I was able to determine that nutrient status differed among sites, between watersheds and seasons and was affected by point source effluents. However, the differences in nutrient status found throughout each of the watershed were hard to attribute to the surrounding land use or tributary influences. Although each likely influenced the nutrient status to some degree, it was difficult to indicate by how much each contributed to the observed differences.

104 Due the seasonal variation found in the NDS results in each of the watersheds, nutrient status assessment results should only be applied to the season in which the substrates were installed and not extrapolated to other time periods. To label a reach as nitrogen-limited or co-limited and to state that the nutrient status remains unchanged throughout the year would be inaccurate and would result in mismanagement of the system. Seasonal changes in nutrient status were expected and were also found in other studies using NDS (Allen & Hershey, 1996; Bernhardt & Likens, 2004; Francoeur et al.,

1999; Stanley, Short, Harrison, Hall, & Wiedenfeld, 1990). The algal community also changes from reach to reach, with each species in a community having different nutrient requirements, contributing to the differences that were observed among sites (Francoeur,

2001; Lowe et al., 1986).

The information from this NDS research can be used for environmental management purposes. For instance, knowing the nutrient which limits the algal biomass of a particular reach is useful and this knowledge can be applied when planning for particular land use activities or if an industry wishes to discharge to a reach that is particularly sensitive to nutrient enrichment. The results from the NDS also indicate by how much the biomass of algae may increase if a nutrient source was present. Since nutrient enrichment can affect other aspects of freshwater systems besides algal biomass, it is important that this stressor is minimized when possible.

105 3.7 Literature Cited

Allan, J. D. (1995). Stream ecology structure: Structure and function of running waters. London: Chapman & Hall.

Bernhardt, E. S., & Likens, G. E. (2004). Controls on periphyton biomass in heterotrophic streams. Freshwater Biology, 49, 14-27.

Biggs, B. J. F. (1988). Artificial substrate exposure times for periphyton biomass estimates in rivers. New Zealand Journal of Marine and Freshwater Research, 22, 507- 515.

Biggs, B. J. F. (1990). Periphyton communities and their environments in New Zealand rivers. New Zealand Journal of Marine and Freshwater Research, 24, 367-386.

Borchardt, M. A. (1996). Nutrients. In R. J. Stevenson, M. L. Bothwell & R. L. Lowe (Eds.), Algal ecology freshwater benthic ecosystems (pp. 184-227). New York: Academic Press.

Carpenter, S. R. (1998). Nonpoint pollution of surface waters with phosphorus and nitrogen. Issues in Ecology, 3, 1-12.

Chambers, P. A., Guy, M., Roberts, E. S., Charlton, M. N., Kent, R., Gagnon, C, et al. (2001). Nutrients and their impact on the Canadian environment. Environment Canada.

Cooper, A. B., & Thomsen, C. E. (1988). Nitrogen and phosphorus in streamwaters from adjacent pasture, pine and native forest catchments. New Zealand Journal of Marine and Freshwater Research, 22, 279-291.

Corkum, L. D. (1996a). Patterns of nutrient release from nutrient diffusing substrates in flowing water. Hydrobiologia, 333(\), 37-43.

Corkum, L. D. (1996b). Responses of chlorophyll-a, organic matter, and macroinvertebrates to nutrient additions in rivers flowing through agricultural and forested land. Archiv Fur Hyrdrobiologie, 136(3), 391-411.

106 DeNicola, D. M. (1996). Periphyton responses to temperature at different ecological levels. In R. J. Stevenson, M. L. Bothwell & R. L. Lowe (Eds.), Algal ecology freshwater benthic ecosystems (pp. 150-183). New York: Academic Press.

Fairchild, G. W., Lowe, R. L., & Richardson, W. B. (1985). Algal periphyton growth on nutrient-diffusing substrates: An in situ bioassay. Ecology, 66(2), 465-472.

Francoeur, S. N. (2001). Meta-analysis of lotic nutrient amendment experiments: Detecting and quantifying subtle responses. Journal of the North American Benthological Society, 20(3), 358-368.

Francoeur, S. N., & Biggs, B. J. F. (2006). Short-term effects of elevated velocity and sediment abrasion on benthic algal communities. Hydrobiologia, 561, 59-69.

Grimm, N. B., & Fisher, S. G. (1986). Nitrogen limitation in a Sonoran desert stream. Journal of the North American Benthological Society, 5(1), 2-15.

Hill, W. R., & Knight, A. W. (1988). Nutrient and light limitation of algae in two northern California streams. Journal ofPhycology, 24, 125-132.

Lohman, K., Jones, J. R., & Baysinger-Daniel, C. (1991). Experimental evidence for nitrogen limitation in a northern Ozark stream. Journal of the North American Benthological Society, 10(1), 14-23.

Lowe, R. L., Golladay, S. W., & Webster, J. R. (1986). Periphyton response to nutrient manipulation in streams draining clearcut and forested watersheds. Journal of the North American Benthological Society, 5(3), 221-229.

Pringle, C. M., & Triska, F. J. (1996). Effects of nutrient enrichment on periphyton. In F. R. Hauer, & G. A. Lamberti (Eds.), Methods in stream ecology (pp. 607-624). New York: Academic Press.

Sartory, D. P. (1982). Spectrophotometry analysis of chlorophyll a in freshwater phytoplankton. Technical Report TR1 15). South Africa: Hydrological Research Institute, Department of Environmental Affairs, Pretoria.

107 Schanz, F., & Juon, H. (1983). Two different methods of evaluating nutrient limitations of periphyton bioassays using water from the river Rhine and eight of its tributaries. Hydrobiologia, 102, 187-195.

Schindler, D. W. (1977). Evolution of phosphorus limitation in lakes. Science, 195, 260- 262.

Scrimgeour, G. J., & Chambers, P. A. (1997). Development and application of a nutrient- diffusing bioassay for large rivers. Freshwater Biology, 38, 221-231.

Stanley, E. H., Short, R. A., Harrison, J. W., Hall, R., & Wiedenfeld, R. C. (1990). Variation in nutrient limitation of lotic and lentic algal communities in a Texas (USA) river. Hydrobiologia, 206, 61-71.

Steinman, A. D. (1996). Effects of grazers on freshwater benthic algae. In R. J. Stevenson, M. L. Bothwell & R. L. Lowe (Eds.), Algal ecology freshwater benthic ecosystems (pp. 341-373). New York: Academic Press.

Steinman, A. D., & Mulholland, P. J. (1996). Phosphorus limitation uptake and turnover in stream algae. In F. R. Hauer, & G. A. Lamberti (Eds.), Methods in stream ecology (pp. 161-189). New York: Academic Press.

Tank, J. L., & Dodds, W. K. (2003). Nutrient limitation of epilithic and epixylic biofilms in ten North American streams. Freshwater Biology, 48, 1031-1049.

United States Environmental Protection Agency. (2000). Nutrient criteria technical guidance manual rivers and streams No. EPA-822-B-00-002)

Wetzel, R. C. (2001). Limnology: Lake and river ecosystems (3rd ed.). New York: Academic Press.

Winterbourn, M. J. (1990). Interactions among nutrients, algae, and invertebrates in a New Zealand mountain stream. Freshwater Biology, 23(3), 463-474.

Winterbourn, M. J., HILDREW, A. G., & ORTON, S. (1992). Nutrients, algae and grazers in some British streams of contrasting pH. Freshwater Biology, (173), 173-182.

108 4 Discussion and Synthesis

This research focused on assessing the nutrient status of the Kennebecasis and

Nashwaak watersheds which are located in New Brunswick. As part of this research, the frequency of phosphorus limitation and influence of point and diffuse sources of nutrients on nutrient status were also of interest. Nutrient status was assessed by utilizing an in- stream bioassay method (nutrient diffusing substrates, NDS) as well as through water column nutrient ratios in order to assess the accuracy and degree of agreement of these methodologies.

In Chapter 2, nutrient ratios, benthic algal biomass and benthic algal community composition were used to investigate the objectives mentioned above. While it was not clear whether using nutrient ratios provided superior results compared to using algal biomass or community structure, each method provided additional information about the sites that would aid environmental agencies in making management decisions regarding land use and nutrients. Based on water column nutrient ratios, phosphorus limitation occurred more frequently (55%) than co-limitation by nitrogen and phosphorus (45%).

Nutrient saturation was not evident in either watershed as many of the sites had low nutrient concentrations and benthic algal biomass and were considered to be oligotrophic based on (Dodds, Jones, & Welch, 1998) trophic classification of streams. The Nashwaak and Kennebecasis watersheds exhibited differences in nutrient ratios and biomass while having similar trends in water chemistry. The Nashwaak watershed was predominately phosphorus-limited, with low algal biomass. In contrast, the Kennebecasis watershed was co-limited by nitrogen and phosphorus and had higher algal biomass. Compared to other rivers in North America, the Nashwaak watershed and portions of the Kennebecasis 109 watershed had very low nutrient levels and would be considered oligotrophic under

Dodds (1998) trophic classification of streams. Headwater reaches were thought to be phosphorus-limited, as these reaches were relatively un-impacted with very low nutrient concentration. However, in both watersheds, nutrient ratios in the headwater reaches often indicated co-limitation by nitrogen and phosphorus. Differences in nutrient ratios were observed between upstream and downstream sites that were associated with point sources of nutrients. This provides an indication that these sources of nutrients may have influenced the nutrient ratios and nutrient status of these rivers. In contrast, there was no clear relationship between the nutrient status (N and P limitation) and land use percentages in either watershed.

In Chapter 3, nutrient diffusing substrate (NDS) results indicated that the nutrient status changed from headwaters to the mouth of each system. In addition, it appeared that in each watershed there was one nutrient treatment which frequently limited algal biomass. For instance, the Nashwaak watershed was largely co-limited by nitrogen and phosphorus in the summer and non-limited in the fall. The nutrient status of the

Kennebecasis watershed was more variable in the summer compared to the Nashwaak, although the majority of sites were co-limited. During the fall, sites were predominately non-limited. Additionally, there was an observed difference in algal biomass in both watersheds between seasons, with the artificial substrates having less biomass in the fall than in the summer. Overall, it was apparent that algal biomass was not solely limited by phosphorus; instead co-limitation by nitrogen and phosphorus occurred at 28% of the sites. The majority of the sites (45%) were non-limited. Many of these sites were oligotrophic and so were not considered to be nutrient saturated and algal biomass may 110 have been influenced by other factors such as temperature, macro-invertebrate grazing or scouring. The influence of nutrient sources on the nutrient status of each watershed was variable. There were instances where nutrient status shifted from limitation to potential saturation below point sources of nutrients and tributary inputs. However, there was no apparent relationship between nonpoint sources of nutrients and differences in nutrient status. Overall, the in-stream bioassay technique appeared to be an effective approach to assessing the nutrient status of a whole watershed as differences were observed between sites and these results may lead to more targeted nutrient management in the future.

Upon comparison of the methodologies, there were discrepancies between the nutrient status results acquired from the N: P ratios and the NDS in-stream bioassay. The

N: P ratios successfully predicted the limiting nutrient from the NDS 7% of the time.

Unfortunately, this lack of agreement between methodologies has occurred in a number of other studies (Allen & Hershey, 1996; Francoeur, Biggs, Smith, & Lowe, 1999;

Scrimgeour & Chambers, 2000) and has been attributed to inadequate incubation period, utilizing dissolved nutrient ratios and time between nutrient sample collection and NDS retrieval. In my study, the NDS were installed between 17 and 21 days, which was the proposed time period by Tank & Dodds (2003) but this factor could have still attributed to the lack of agreement. The N: P ratios in my study were calculated based on total nutrient amounts rather than dissolved and therefore were likely not a contributing factor.

Dodds, Smith, & Zander (1997) showed that total nutrient correlate more closely to benthic algal biomass than dissolved nutrients and that they provide a better indication of the portion that is biologically available. I propose that the key factor leading to the disagreement between methodologies is the time lag between measurements. Water 111 column nutrients were only collected upon deployment of the NDS and were compared to

the NDS results after 17-21 days of incubation. Nutrient concentrations may have

fluctuated throughout the incubation period of the NDS but the benefit of using an in-

stream bioassay is that while it is deployed in the stream it integrates ambient nutrient

conditions rather than provide a snap shot of the nutrient status. If nutrient ratios are to be

used in nutrient status assessment, then more frequent sampling of ambient nutrients

would be required in order to improve the reliability of this assessment as increased

sampling may lead to a better prediction of the actual nutrient status. However, based on

the information presented, the NDS in-stream bioassay provides a better estimate of the

nutrient status of a stream.

4.1 Implications of Results

In order to manage nutrients effectively in freshwater ecosystems, it is important to understand which nutrient is limiting primary productivity as this aids in controlling

nutrient enrichment and algal growth (Smith et al., 1999). The differences in nutrient

status observed between sites and seasons in each watershed indicates that there are areas

and time periods within watersheds that may be more sensitive to nutrient additions and management decisions regarding nutrients should take this into consideration. Even though the differences between sites could not be entirely linked to the inputs of point and diffuse sources of nutrients, this does not mean that these sources do not influence the nutrient status and algal biomass production within freshwater systems. This research made it evident how important it is to control both phosphorus and nitrogen inputs, as many sites within the Kennebecasis and Nashwaak watersheds were found to be co-

112 limited by nitrogen and phosphorus. This would likely be the case for many watersheds throughout the province of New Brunswick.

The addition of an in-stream bioassay technique like NDS to a nutrient assessment program would be of benefit to environmental agencies. The NDS provided a more direct measurement of nutrient status than water column nutrient ratios by utilizing a biological indicator (benthic algal biomass) as the response variable as well the artificial substrates allow the colonizing algal community to interact with other environmental variables while controlling the nutrients supplied (Pringle & Triska, 1996). This makes the methodology more ecologically relevant and illustrates the merit of incorporating the

NDS approach into a various riverine monitoring scenarios such as baseline or prior to any proposed development to indicate how sensitive a stream reach may be to nutrient enrichment by comparing the percent increase in biomass of the nutrient treatments to that of the control.

4.2 Recommendations on Nutrient Status Research

Environmental agencies have commonly relied on water column nutrient ratios in order to determine the nutrient status of freshwater systems but this approach can be improved by adding the NDS assessment technique to nutrient management program. By doing so, this will provide a better understanding of nutrient limitation and will allow for a more reliable means of assessment. In the end, management decisions based on such information will be more effective.

As with any assessment approach nothing is perfect, there will always be aspects that will need to be considered when interpreting the results of an assessment. In the case

113 of my research, there are features of both the nutrient ratio and the NDS methodologies that I encountered that if shared, may improve the research of others in the future. For instance, in river systems where nutrients are low, using nutrient ratios may pose a problem as one of the nutrients may be below the detection limit, which was the case with TN in my study. It is recommended that the laboratory that completes the analysis should have detection limit of 0.1 mg/L for TN. For my study, the detection for TN was

0.3 mg/L and TN of 0.3mg/L is considered "mesotrophic" under Dodds et al. (1998) trophic classification of rivers. In order to manage nutrients appropriately, it is important to have a low enough detection so that changes can be observed.

When using either nutrient status assessment techniques to determine the effects of point and nonpoint sources of nutrients on a watershed's nutrient status, additional factors may need to be addressed. Assessing only the percentage of general categories of land use activities such as agriculture and occupied lands may not be sufficient and a more detailed assessment is warranted. Specifically the intensity of farming activities should be taken into account (i.e. number of animals/km2 or numbers of dwellings/km2).

Additional factors that can influence the transport of nutrients such as the state of the riparian zone adjacent to the river should also be considered. For a more improved assessment of point sources, the nutrient assessment could be conducted at varying distances downstream to see where nutrient status shifts occur compared to an upstream reference location.

The NDS approach was found to be a more direct form of nutrient assessment than water column nutrient ratios but as with the nutrient ratios, there were aspects which may need improvement or further research. One aspect is in determining whether a non- 114 limited site is in fact nutrient saturated or if the lack of significant difference between treatments was due to other factors. To address this, additional research is needed to understand at what concentration TN and TP saturate the growth of a whole benthic algal community. This information would aid in interpreting nutrient limiting results by comparing them to ambient nutrient concentrations so that nutrient saturation can be either ruled out or accepted as a possibility. Currently, there only exists information on the concentrations of nitrates, phosphates or dissolved nutrients and these have only been assessed on portions of the algal community such as diatoms or filamentous algae

(Grimm & Fisher, 1986; Bothwell, 1989; Welch, Jacoby, Horner, & Seeley, 1988).

Finally, in the fall assessment period, there was a higher incidence of sites where there was no significant difference between treatments; these sites were given the term non- limited. The higher frequency of these sites may be an indication that the response of the benthic algae to nutrient addition may require more time to develop. For future research, it is recommended that incubation time or degree days increase during seasons which experience lower water temperatures in order to increase the likelihood of encountering significant responses.

115 4.3 Literature cited

Dodds, W. K., Smith, V. H., & Zander, B. (1997). Developing nutrient targets to control benthic chlorophyll levels in streams: A case study of the Clark Fork River. Water Resources, 31(7), 1738-1750.

Grimm, N. B., & Fisher, S. G. (1986). Nitrogen limitation in a Sonoran desert stream. Journal of the North American Benthological Society, 5(1), 2-15.

Pringle, C. M., & Triska, F. J. (1996). Effects of nutrient enrichment on periphyton. In F. R. Hauer, & G. A. Lamberti (Eds.), Methods in stream ecology (pp. 607-624). New York: Academic Press.

Smith, V. H., Tilman, G. D., & Nekola, J. C. (1999). Eutrophication: Impacts of excess nutrients on freshwater, marine, and terrestrial ecosystems. Environmental Pollution, 100, 179-196.

Tank, J. L., & Dodds, W. K. (2003). Nutrient limitation of epilithic and epixylic biofilms in ten North American streams. Freshwater Biology, 48, 1031-1049.

Welch, E. B., Jacoby, J. M., Horner, R. R., & Seeley, M. R. (1988). Nuisance biomass levels of periphytic algae in streams. Hydrobiologia, 157, 161-168.

116 Appendix 1: Historic Nutrient Data

117 The data in tables below are based on samples collected from 1988-2004 and are average values. Please note that (-) denotes that historic data for this site was not available.

Nashwaak Watershed

NH3T N03 TN TP Site (mg/L) (mg/L) (mg/L) (mg/L) NM1 - - - - NM2 0.01 0.05 0.3 0.009 NM3 0.013 0.05 0.31 0.014 NM4 0.014 0.05 0.31 0.016 NM5 0.011 0.05 0.31 0.017 NM6 0.014 0.05 0.31 0.016 NM7 0.16 0.05 0.31 0.011 NM8 0.012 0.05 0.31 0.01 NT1 0.01 0.05 0.32 0.012 NT2 0.01 0.05 0.31 0.007 NT3 0.012 0.05 0.3 0.01 NT4 - - - - NT5 0.011 0.05 0.3 0.007 NT6 0.12 0.3 0.013 NT7 - - - - NT8 0.12 0.05 0.3 0.021 Kennebecasis Watershed

NH3T N03 TN TP Site (mg/L) (mg/L) (mg/L) (mg/L) KM1 0.016 0.05 0.3 0.017 KM2 0.013 0.073 0.3 0.021 KM3 0.093 0.111 0.39 0.037 KM4 - - - - KM5 0.027 0.127 0.38 0.022 KT1 0.012 0.072 0.32 0.018 KT2 0.01 0.06 0.3 0.016 KT3 0.017 0.144 0.45 0.03 KT4 0.01 0.149 0.3 0.01 KT5 0.012 0.23 0.34 0.015 KT6 - - - - KT7 0.017 0.11 0.32 0.028 Appendix 2: Detection Limits for Nutrient Parameters

119 Parameter Detection limit (mg/L) Total Phosphorus 0.005 Total Nitrogen 0.3 Total Ammonia 0.01 Total Nitrate 0.05 Total Nitrite 0.05

120 Appendix 3: Field Measurements

121 Nashwaak Watershed - July 2005

Specific Water DO Conductivity Temperature Flow Depth* Site ID (mg/L) pH (US) (°C) (m/s) (m) NM1 7.23 7.37 34.5 19.9 0.76 0.41 NM2 8.56 7.35 40.8 16.6 0.77 0.29 NM3 8.2 7.31 39.9 17 0.45 0.39 NM4 8.08 7.36 43.5 19.4 0.54 0.3 NM5 8.21 7.53 76.4 16.5 0.05 0.54 NM6 8.4 7.53 53.8 18.7 0.60 0.42 NM7 8.42 7.47 59.4 21.2 0.51 0.53 NM8 8.28 7.4 64.2 19.3 0.39 0.58 NT1 8.72 7.07 30.3 14.8 0.36 0.31 NT2 8.22 7.72 69.2 18.8 0.42 0.39 NT3 8.72 7.47 42.4 16.7 0.03 0.44 NT4 7.57 7.58 49.3 20.9 0.30 0.46 NT5 8.06 7.9 89.8 20.4 0.85 0.41 NT6 8.3 7.43 41.1 20 0.60 0.3 NT7 8.7 7.51 53.3 15.5 0.15 0.37 NT8 8.95 7.52 55.7 21.9 0.85 0.28

Nashwaak Watershed - October 2005

Specific Water DO Conductivity Temperature Flow Depth* Site (mg/L) pH (US) (°C) (m/s) (m) NM1 10.25 7.19 28.8 12.9 0.28 0.4 NM2 10.12 7.49 41.8 13.6 0.35 0.3 NM3 9.46 7.41 37.6 14.2 0.3 0.4 NM4 11.15 7.32 42.9 14.1 0.46 0.32 NM5 8.23 7.44 54.9 12.3 0.17 0.53 NM6 8.45 7.23 44.7 12 0.26 0.42 NM7 10.07 7.19 41.5 12.3 0.42 0.44 NM8 10.02 7.22 41 11.6 0.1 0.505 NT1 10.28 7.22 29.8 12.9 0.25 0.26 NT2 9.28 7.59 55.1 13.5 0.24 0.36 NT3 9.51 7.04 34.7 11.4 0.13 0.3 NT4 10.5 7.48 44.8 13.9 0.14 0.49 NT5 9.2 7.71 67.6 13.3 0.38 0.39 NT6 8.52 7.23 34.2 10.1 0.36 0.38 NT7 10.39 6.97 33.7 11.8 0.32 0.37 NT8 11.2 7.09 37.5 10.1 0.11 0.3 122 Kennebecasis Watershed - August 2005

Specific Water DO Conductivity Temperature Flow Depth* Site (mg/L) pH Os) (°C) (m/s) (m) KM1 8.6 7.35 58.5 15.4 0.3 0.53 KM2 6.82 7.47 228.2 20.4 0.27 0.41 KM3 8.35 7.89 251.9 21.9 0.84 0.49 KM4 6.15 7.68 250.1 23.6 0.33 0.39 KM5 6.97 7.71 248.2 25.6 0.27 0.34 KT1 8.72 7.4 165.2 16.1 0.91 0.43 KT2 9.66 8.04 177.5 22.6 1.15 0.39 KT3 9 7.67 172.4 22.6 0.85 0.34 KT4 8.57 7.81 84.2 19.3 1.06 0.27 KT5 8.08 7.63 170.2 20.4 0.39 0.4 KT6 7.54 7.73 81.9 25.8 0.92 0.36 KT7 7.11 7.57 206 22.9 0.31 0.26

Kennebecasis Watershed - November 2005

Specific Water Depth* DO Conductivity Temperature Flow (m) Site (mg/L) pH (uS) (°C) (m/s) KM1 9.95 7.32 45.8 8.7 0.45 0.4 KM2 9.89 7.44 147.9 8.5 0.25 0.57 KM3 9.78 7.44 141 9 0.17 0.36 KM4 10.11 7.53 132.1 7.2 0.7 0.44 KM5 9.85 7.57 130.8 7.1 - - KT1 9.73 7.31 95.3 8.6 0.14 0.32 KT2 10.68 7.36 93.8 5.7 0.37 0.45 KT3 10.23 7.41 91.3 5.4 0.52 0.4 KT4 11.04 7.5 52 8.1 0.26 0.32 KT5 10.58 7.54 88.1 9.6 0.3 0.35 KT6 10.18 7.16 50.2 7.9 0.25 0.36 KT7 10.21 7.27 93.2 6.4 0.3 0.34

* Depth measurements were taken where NDS bars were installed.

- No flow or depth measurements were taken due to high water levels. Appendix 4: Algal Taxonomy Identification Methodology

124 Identification and enumeration of periphyton samples were performed by M.A.

DeSeve Consultants of Outremont, Quebec using the traditional Utermohl settling technique and an inverted microscope equipped with phase contrast at 165-750X magnification. Counting units were individual cells, filaments or colonies depending on the algal organization. A minimum of 400-500 units from randomly selected transects were counted for each sample using multiple magnifications because cell size varied over several orders of magnitude. If a sample had fewer than 400 algal units because of low abundance or high particulate matter, at least 70% of the counting chamber was counted.

Diatoms in the formalin-preserved sample were identified initially without further processing in order to accelerate sample identification. These rapid identifications were confirmed by mounting material in Hyrax media after cleaning using the muffle furnace technique (Zoto, Dillon, & Schlichting, 1973), then viewing the cleaned cells at 1000X magnification under oil immersion. Where it was not possible to separate two or more species in the fresh samples, separation was allocated proportionally from the cleaned sample results.

125 Appendix 5: Regression Plots Of Land Use and TIN: TP

126 Nashwaak Watershed Nutrient Ratios vs. Forested land 40

35 • Summer 1 30 K N:P R2 = 0.0171 •*?•• 1 '•g 25 If Fall N:P

20 • Linear 15 (Summer N:P) 10 Linear (Fall N-P) 5

0 86 90 92 94 96 98 Forested Land (%)

Nashwaak Watershed Nutrient Ratios vs. Occupied 40 Land (%)

35 • Summer 30 N:P • |W • 25 « Fall NP PS 2 ti Ci^W R = 0.0853 20 • 15 R2 = 0.2834 ""--A (Summer N:P) 10 - Linear (Fall N:P) 5

0 0.5 1 1.5 Occupied Land (%)

127 Nashwaak Watershed Nutrient Ratios vs. Agriculture 40 . <%> 35 • „ • Summer N:P 30 • 8 • i ^ • Y *^±3-> - FallN:P •2 25 a PS 0003 £20 1w A^—-^^^i °- "E • (Summer 3 1 | N;P) Z O 1 Llnear If (Fall N:P) 10

u 0 12 3 4 5 Agriculture (%)

r Kennebecasis Watershed Nutrient Ratios vs. 80 Forested Land (%) 70

60 • Summer •S 50 N:P Pi a FallN:P 40

2 • Linear 30 R = 0.0019 i (Summer N:P) 20 _ff--- m. If • R2 = 0.064 • Linear (Fall N:P) 10 • I

0 70 80 90 100 Forested Land (%)

128 Kennebecasis Watershed Nutrient Ratios vs. 80 Occupied Land (%)

60 • Summer N:P ••§ 50 PS • Fall N:P 40 "E 2 • Linear 30 R = 0.0263 (Summer N:P) 20 Linear g* R2 = 0.0951 (Fall N:P) 10 • I

0 0.5 1 1.5 2 2.5 Occcupied Land (%)

Kennebecasis Watershed Nutrient Ratios vs. 80 Agricultural Land (%)

60 • Summer e N:P '•£ 50 OS S FallN:P s 40 R2 = 4E«fl7

• Linear (Summer 20 N:P) •- 0.0658 Linear 10 (Fall N:P)

0 5 10 15 20 25 Agricultural Land (%)

129 Appendix 6: Eutrophic and Motile Diatoms

130 Nashwaak Watershed

Eutrophic Eutrophic Motile Motile Main Diatoms Diatoms Main Diatoms Diatoms Stem (%) (%) Stem (%) (%) Sites Summer Fall Sites Summer Fall NM1 95 9.5 NM1 0 0 NM2 7.8 8.5 NM2 0 0 NM3 38.8 28.1 NM3 0 0 NM4 34.6 26.9 NM4 0.7 1.5 NM5 36.3 18.7 NM5 6.1 2.7 NM6 0 46.8 NM6 0 3.1 NM7 0 61.1 NM7 0 5.5 NM8 80.1 75 NM8 2.4 12.5 Tributary Sites Tributary Sites NT1 3.5 16.7 NT1 0 0 NT2 50 29.3 NT2 25 0.3 NT3 86.4 50 NT3 40.5 0 NT4 0 61.4 NT4 0 3.7 NT5 0 0 NT5 0 0 NT6 100 44.8 NT6 16.6 2.9 NT7 62.5 53.5 NT7 18.1 22.5 NT8 0 40 NT8 0 0

Kennebecasis Watershed

Eutrophic Motile Motile Main Eutrophic Diatoms Main Diatoms Diatoms Stem Diatoms (%) Stem (%) (%) Sites (%) Summer Fall Sites Summer Fall KM1 60.1 58.2 KM1 43.3 31.9 KM2 97.7 KM2 12.1 0 KM3 75.9 100 KM3 0.7 0.5 KM4 75.9 92.9 KM4 6.3 16.3 Tributary Sites Tributary Sites KT3 90.9 100 KT3 12.5 4.5 KT1 91.4 90 KT1 10.8 0 KT2 72.3 81.8 KT2 53.5 76. KT4 65.0 0 KT4 1.6 0 KT5 28.2 KT5 5 0 KT6 70.9 0 KT6 31.3 0 KT7 12.3 0 KT7 5.0 0

131 Appendix 7: Nitrogen and Phosphorus Data 2005

132 Nashwaak Watershed

Summer Fall Main Main Stem TIN TN TP Stem TIN TN TP Sites (mg/L) (mg/L) (mg/L) Sites (mg/L) (mg/L) (mg/L) NM1 0.110 <0.3 0.019 NM1 0.110 <0.3 0.012 NM2 0.112 <0.3 0.009 NM2 0.110 <0.3 0.009 NM3 0.117 <0.3 0.009 NM3 0.137 <0.3 0.008 NM4 0.110 <0.3 0.009 NM4 0.115 <0.3 0.008 NM5 0.113 <0.3 0.011 NM5 0.114 <0.3 0.009 NM6 0.110 <0.3 0.011 NM6 0.115 <0.3 0.010 NM7 0.110 <0.3 0.014 NM7 0.110 <0.3 0.015 NM8 0.127 <0.3 0.01 NM8 0.114 <0.3 0.012 Tributary Sites Tributary Sites NT1 0.111 <0.3 0.013 NT1 0.110 <0.3 0.012 NT2 0.110 <0.3 0.007 NT2 0.116 <0.3 0.012 NT3 0.110 <0.3 0.009 NT3 0.110 <0.3 0.008 NT4 0.110 0.3 0.012 NT4 0.110 <0.3 0.008 NT5 0.110 <0.3 0.009 NT5 0.110 <0.3 0.008 NT6 0.110 <0.3 0.016 NT6 0.110 <0.3 0.015 NT7 0.122 <0.3 0.025 NT7 0.110 <0.3 0.021 NT8 0.120 <0.3 0.019 NT8 0.110 <0.3 0.019

Kennebecasis Watershed

Summer Fall Main Main Stem TIN TN TP Stem TIN TN TP Sites (mg/L) (mg/L) (mg/L) Sites (mg/L) (mg/L) (mg/L) KM1 0.133 <0.3 0.020 KM1 0.110 <0.3 0.016 KM2 0.115 <0.3 0.015 KM2 0.130 <0.3 0.019 KM3 0.179 <0.3 0.024 KM3 0.251 0.4 0.025 KM4 0.140 <0.3 0.016 KM4 0.218 0.4 0.023 KM5 0.134 <0.3 0.016 KM5 0.217 0.4 0.024 Tributary Sites Tributary Sites KT3 0.112 <0.3 0.021 KT3 0.110 0.3 0.021 KT1 0.143 <0.3 0.025 KT1 0.160 0.4 0.022 KT2 0.123 0.3 0.018 KT2 0.118 <0.3 0.016 KT4 0.200 0.3 0.008 KT4 0.120 <0.3 0.011 KT5 0.324 0.5 0.010 KT5 0.260 0.3 0.015 KT6 0.177 0.4 0.026 KT6 0.190 0.4 0.019 KT7 0.175 0.3 0.013 KT7 0.190 0.4 0.015 133 Curriculum Vitae

Candidate's full name: Erin Marie Foster

Universities attended: University of New Brunswick (Fredericton) 2003

Publications: Foster, E.M., Culp, J.M., Curry, R.A., D. Fox. In prep. An assessment of the nutrient status of New Brunswick's watersheds: A comparison of methods.

Conference Presentations:

Foster, E.M., Culp, J.M., Curry, R.A, D. Fox, Nutrient Status Variability in the

Kennebecasis and Nashwaak watersheds. Canadian Rivers Institute Day. May, 2006.

Fredericton, New Brunswick.

Foster, E.M., Hughes, R., D. Fox, Web Reporting on New Brunswick's Watersheds.

CCME National Science and Technology Workshop on Water Quality Monitoring.

February, 2008