The Effects of Habitat Quality on the Secondary

Total Page:16

File Type:pdf, Size:1020Kb

The Effects of Habitat Quality on the Secondary EFFECTS OF HABITAT QUALITY ON SECONDARY PRODUCTION IN SHALLOW ESTUARINE WATERS AND THE CONSEQUENCES FOR THE BENTHIC-PELAGIC FOOD WEB A Dissertation Presented to The Faculty of the School of Marine Science The College of William and Mary in Virginia In Partial Fulfillment Of the Requirements for the Degree of Doctor of Philosophy by David James Gillett 2010 APPROVAL SHEET This dissertation is submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy David J. Gillett Approved, by the Committee, January, 2010 Linda C. Schaffner, Ph.D. Committee Chairperson / Advisor Iris C. Anderson, Ph.D. Elizabeth A. Canuel, Ph.D. Romuald N. Lipcius, Ph.D. Walter R. Boynton, Ph.D. Chesapeake Biological Laboratory University of Maryland Center for Environmental Science TABLE OF CONTENTS DEDICATION..................................................................................................................v ACKNOWLEDGEMENTS............................................................................................ vi LIST OF TABLES......................................................................................................... vii LIST OF FIGURES ...................................................................................................... viii ABSTRACT.................................................................................................................... ix CHAPTER I. ASSESSMENT OF HABITAT DEGRADATION IN THE COASTAL ZONE AND THE CONSEQUENCES FOR RESIDENT BIOTA...................................2 Introduction..............................................................................................................3 Motivations and Investigative Approach...............................................................12 Literature Cited......................................................................................................15 CHAPTER II. THE INFLUENCE OF HABITAT QUALITY ON SECONDARY PRODUCTION IN SHALLOW ESTUARINE WATERS ............................................28 Abstract..................................................................................................................29 Introduction............................................................................................................30 Materials and Methods...........................................................................................33 Site Selection...................................................................................................33 Data Collection................................................................................................34 Analysis............................................................................................................37 Results....................................................................................................................39 Discussion..............................................................................................................41 Interpreting the Saline Estuary.........................................................................42 Interpreting the Tidal Freshwater.....................................................................46 Some Comments on Biodiversity and Productivity.........................................47 Conclusions............................................................................................................49 Literature Cited......................................................................................................50 CHAPTER III. THE INFLUENCE OF HABITAT QUALITY AND MACROBENTHIC COMMUNITY COMPOSITION ON NEKTON UTILIZATION OF SECONDARY PRODUCTION AS A FOOD SOURCE ........................................................................68 Abstract..................................................................................................................69 Introduction............................................................................................................70 Materials and Methods...........................................................................................74 Site Selection...................................................................................................74 Data Collection................................................................................................74 Analysis............................................................................................................77 Results....................................................................................................................80 Site Characterization........................................................................................80 iii Caging Artifacts and Environmental Parameters.............................................80 Production........................................................................................................82 Discussion..............................................................................................................89 Predation Patterns Among Sites.......................................................................90 Predation Patterns Among Faunal Groups.......................................................95 Conclusions.....................................................................................................................97 Literature Cited......................................................................................................99 Appendices...........................................................................................................124 Appendix 1.....................................................................................................124 Appendix 2.....................................................................................................125 Appendix 3.....................................................................................................126 Appendix 4.....................................................................................................127 CHAPTER IV. NATURAL ABUNDANCE 13C AND 15N ISOTOPES OF SHALLOW, SUBTIDAL ESTUARINE MACROBENTHOS AND THEIR RELATION TO HABITAT QUALITY ..................................................................................................128 Abstract................................................................................................................129 Introduction..........................................................................................................130 Materials and Methods.........................................................................................134 Study Sites.....................................................................................................134 Sample Collection..........................................................................................134 Data Analysis.................................................................................................136 Results..................................................................................................................139 Spatial and Temporal Comparisons...............................................................139 Organic Matter-Consumer Relationships ......................................................140 Discussion............................................................................................................144 The Contribution of Salt Marsh Detritus .......................................................146 The Contribution of Phytoplankton ...............................................................147 The Influence of Habitat Quality ...................................................................147 Conclusions..........................................................................................................150 Literature Cited....................................................................................................152 Appendix..............................................................................................................168 CHAPTER V. OVERALL CONCLUSIONS AND IMPLICATIONS.......................169 VITA.............................................................................................................................175 iv DEDICATION This work is dedicated in part to my family, who have always trusted that I knew what I was doing (even if they did not) and in part to Dr. A. Fred Holland, who was the first real mentor I ever had and who taught me how to do ecology. v ACKNOWLEDGEMENTS Field-based, ecosystem-scale benthic ecology is a relatively difficult and time-consuming process that requires the work of many hands. This is further exacerbated when incorporating multiple trophic levels and biogeochemical processes into the structure and functioning of the macrobenthic community. As such, I must first and foremost acknowledge the hard work and support of all the members of the Benthic Processes and Anderson labs for their help with the collection and processing of samples this dissertation is based upon. Alice Brylawski, Leandra Lockwood, Jennifer Buehrle, Shanay Butler, Elizabeth Wells, Payal Dharia, Bill Metcalfe, and Treda Grayson all deserve special recognition for countless hours they spent in the field and the lab with me, putting up with my odd sense of humor and the physical/mental rigors of long days spent slogging through the shallow estuarine waters of Chesapeake Bay. Most of this work would not exist if not for the patience
Recommended publications
  • Do We Need to Use Bats As Bioindicators?
    biology Perspective Do We Need to Use Bats as Bioindicators? Danilo Russo * , Valeria B. Salinas-Ramos , Luca Cistrone, Sonia Smeraldo, Luciano Bosso * and Leonardo Ancillotto Wildlife Research Unit, Dipartimento di Agraria, Università degli Studi di Napoli Federico II, Via Università, 100, 80055 Portici, Italy; [email protected] (V.B.S.-R.); [email protected] (L.C.); [email protected] (S.S.); [email protected] (L.A.) * Correspondence: [email protected] (D.R.); [email protected] (L.B.) Simple Summary: Bioindicators are organisms that react to the quality or characteristics of the environment and their changes. They are vitally important to track environmental alterations and take action to mitigate them. As choosing the right bioindicators has important policy implications, it is crucial to select them to tackle clear goals rather than selling specific organisms as bioindicators for other reasons, such as for improving their public profile and encourage species conservation. Bats are a species-rich mammal group that provide key services such as pest suppression, pollination of plants of economic importance or seed dispersal. Bats show clear reactions to environmental alterations and as such have been proposed as potentially useful bioindicators. Based on the rel- atively limited number of studies available, bats are likely excellent indicators in habitats such as rivers, forests, and urban sites. However, more testing across broad geographic areas is needed, and establishing research networks is fundamental to reach this goal. Some limitations to using bats as bioindicators exist, such as difficulties in separating cryptic species and identifying bats in flight from their calls.
    [Show full text]
  • Annual Report for the College of Marine Science Dean Jacqueline E. Dixon
    ANNUAL REPORT FOR THE COLLEGE OF MARINE SCIENCE DEAN JACQUELINE E. DIXON JANUARY 1 – DECEMBER 31, 2015 Locally Applied, Regionally Relevant, Globally Significant! TABLE OF CONTENTS Contents The View from the Bridge ____________________________________________________________ 2 College of Marine Science Snapshot_______________________ __________________________________3 College of Marine Science Leadership Team_______________________________________________4 Events and Highlights _______________________________________________________________ 7 Highlighted Research ______________________________________________________________ 10 Research Overview ________________________________________________________________ 15 Faculty Highlights _________________________________________________________________ 19 Facilities ________________________________________________________________________ 28 Graduate Education and Awards _____________________________________________________ 29 Education and Outreach ____________________________________________________________ 34 Development_____________________________________________________________________ 37 Publications ______________________________________________________________________ 39 Active Research Awards ____________________________________________________________ 49 Page | 1 THE VIEW FROM THE BRIDGE The View from the Bridge Florida is an ocean state. In Florida, coastal tourism contributes over 200,000 jobs and $50 billion annually. Seafood sales contribute more than $30 billion annually. The
    [Show full text]
  • Coastal and Marine Ecological Classification Standard (2012)
    FGDC-STD-018-2012 Coastal and Marine Ecological Classification Standard Marine and Coastal Spatial Data Subcommittee Federal Geographic Data Committee June, 2012 Federal Geographic Data Committee FGDC-STD-018-2012 Coastal and Marine Ecological Classification Standard, June 2012 ______________________________________________________________________________________ CONTENTS PAGE 1. Introduction ..................................................................................................................... 1 1.1 Objectives ................................................................................................................ 1 1.2 Need ......................................................................................................................... 2 1.3 Scope ........................................................................................................................ 2 1.4 Application ............................................................................................................... 3 1.5 Relationship to Previous FGDC Standards .............................................................. 4 1.6 Development Procedures ......................................................................................... 5 1.7 Guiding Principles ................................................................................................... 7 1.7.1 Build a Scientifically Sound Ecological Classification .................................... 7 1.7.2 Meet the Needs of a Wide Range of Users ......................................................
    [Show full text]
  • Ctenophore Relationships and Their Placement As the Sister Group to All Other Animals
    ARTICLES DOI: 10.1038/s41559-017-0331-3 Ctenophore relationships and their placement as the sister group to all other animals Nathan V. Whelan 1,2*, Kevin M. Kocot3, Tatiana P. Moroz4, Krishanu Mukherjee4, Peter Williams4, Gustav Paulay5, Leonid L. Moroz 4,6* and Kenneth M. Halanych 1* Ctenophora, comprising approximately 200 described species, is an important lineage for understanding metazoan evolution and is of great ecological and economic importance. Ctenophore diversity includes species with unique colloblasts used for prey capture, smooth and striated muscles, benthic and pelagic lifestyles, and locomotion with ciliated paddles or muscular propul- sion. However, the ancestral states of traits are debated and relationships among many lineages are unresolved. Here, using 27 newly sequenced ctenophore transcriptomes, publicly available data and methods to control systematic error, we establish the placement of Ctenophora as the sister group to all other animals and refine the phylogenetic relationships within ctenophores. Molecular clock analyses suggest modern ctenophore diversity originated approximately 350 million years ago ± 88 million years, conflicting with previous hypotheses, which suggest it originated approximately 65 million years ago. We recover Euplokamis dunlapae—a species with striated muscles—as the sister lineage to other sampled ctenophores. Ancestral state reconstruction shows that the most recent common ancestor of extant ctenophores was pelagic, possessed tentacles, was bio- luminescent and did not have separate sexes. Our results imply at least two transitions from a pelagic to benthic lifestyle within Ctenophora, suggesting that such transitions were more common in animal diversification than previously thought. tenophores, or comb jellies, have successfully colonized from species across most of the known phylogenetic diversity of nearly every marine environment and can be key species in Ctenophora.
    [Show full text]
  • Meiobenthos of the Discovery Bay Lagoon, Jamaica, with an Emphasis on Nematodes
    Meiobenthos of the discovery Bay Lagoon, Jamaica, with an emphasis on nematodes. Edwards, Cassian The copyright of this thesis rests with the author and no quotation from it or information derived from it may be published without the prior written consent of the author For additional information about this publication click this link. https://qmro.qmul.ac.uk/jspui/handle/123456789/522 Information about this research object was correct at the time of download; we occasionally make corrections to records, please therefore check the published record when citing. For more information contact [email protected] UNIVERSITY OF LONDON SCHOOL OF BIOLOGICAL AND CHEMICAL SCIENCES Meiobenthos of The Discovery Bay Lagoon, Jamaica, with an emphasis on nematodes. Cassian Edwards A thesis submitted for the degree of Doctor of Philosophy March 2009 1 ABSTRACT Sediment granulometry, microphytobenthos and meiobenthos were investigated at five habitats (white and grey sands, backreef border, shallow and deep thalassinid ghost shrimp mounds) within the western lagoon at Discovery Bay, Jamaica. Habitats were ordinated into discrete stations based on sediment granulometry. Microphytobenthic chlorophyll-a ranged between 9.5- and 151.7 mg m -2 and was consistently highest at the grey sand habitat over three sampling occasions, but did not differ between the remaining habitats. It is suggested that the high microphytobenthic biomass in grey sands was related to upwelling of nutrient rich water from the nearby main bay, and the release and excretion of nutrients from sediments and burrowing heart urchins, respectively. Meiofauna abundance ranged from 284- to 5344 individuals 10 cm -2 and showed spatial differences depending on taxon.
    [Show full text]
  • Features of Formation of Reefs and Macrobenthos Communities in the an Thoi Archipelago the Gulf of Thailand (South China Sea)
    id7363687 pdfMachine by Broadgun Software - a great PDF writer! - a great PDF creator! - http://www.pdfmachine.com http://www.broadgun.com EEnnvviirroonnImSmSN : e0e97nn4 - 7tt45aa1 ll SSccViioleeumnne 8 Iccssuee 8 An Indian Journal Current Research Paper ESAIJ, 8(8), 2013 [297-307] Features of formation of reefs and macrobenthos communities in the An Thoi archipelago the Gulf of Thailand (South China Sea) Yuri Ya.Latypov A.V.Zhirmunsky Institute of Marine Biology, Far Eastern BranchRussian Academy of Sciences, Vladivostok, 690059, (RUSSIA) E-mail : [email protected] ABSTRACT KEYWORDS Macrobenthos communities studied on fringing reefs of the AnThoj Coral; archipelago using SCUBA-diving equipment. The islands are located in Reef; the turbid and highly eutrophic waters of the eastern Gulf of Thailand. We Macrobenthos; researched species composition and settlements densities and biomasses Community; in common species of algae, coelenterates, mollusks and echinoderms, as AnThoi archipelago; well as the degree of substrate coverage by macrophytes and coral. Clear Vietnam. vertical zonation identified in the change of the various communities in macrobenthos. The dominance of massive Porites on almost all reefs of the Gulf of Thailand is due to their ability to survive in stressful for many corals. They predominate over other scleractinian for the productivity of organic matter, the degree of substrate coverage and species diversity. They also constitute the reef skeleton and play a significant role of the expansion of its area in themuddy bottom of the Gulf of Thailand. 2013 Trade Science Inc. - INDIA INTRODUCTION phological zoning and developed powerful reef depos- its, common in structural reefs of the Indo- Pacific.
    [Show full text]
  • An Analysis of the Fish and Macrobenthos Along the Sand Island Ocean Outfall Using Remote Video: Vi
    HANAU-S-96-002 C2 AN ANALYSIS OF THE FISH AND MACROBENTHOS ALONG THE SAND ISLAND OCEAN OUTFALL USING REMOTE VIDEO: VI. 1995 DATA Richard E. Brock PROJECT REPORT PR-96-06 March 1996 WATER RESOURCES RESEARCH CENTER UNIlVERSlTY OF HAWAI'I AT MANOA Honolulu, Hawai'i 96822 AUTHOR: Dr. Richard E. Brock AssociateResearcher and FisheriesSpecialist Sea Grant Extension Service Marine Science Building 204 University of Hawai'i at Mhtoa Honolulu, Hawai'i 96822 Tel.: 808/956-2859 FAX: 808/956-2858 $5.0O/copy Please make remittance in U.S. dollars fmm a U.S. bank or internationalmoney order to: ResearchCorporatha ot the Uaiverekyot Hawaii Mail to. Water Resources Research Center University of Hawai'i at Mmnoa 2540 Dole St., Holmes Hall 283 Honolulu, Hawai'i 96822 ~ U.S.A. Attn: Publications Of6ce NOTE: Pleaseindicate PR-9646 on checkor moneyorder for our reference. AN ANALYSIS OF THE FISH AND MACROBKNTHOS ALONG THE SAND ISLAND OCEAN OUTFALL USING REMOTE VIDEO: VI. 1995 DATA Richard E. Brock Project Report PR-9644 March 1996 PREPARED FOR Departmentof WastewaterManagement City and County of Honolulu Project Report for "The Assessmentof the Impact of OceanSewer Outfalls on the Marine Environment off Oahu, Hawaii" ProjectNo.: C39805 ProjectPeriod: 1 January1995-31 August 1996 Principal Investigator: RogerS. Fujioka WATER RESOURCES RESEARCH CENTER University of Hawai'i at Minoa Honolulu, Hawai'i 96822 Any opinions.findings, and conclusions or recommendationsexpressed in thispublication are those of the author and do not necessarilyreflect the view of the Water ResourcesResearch Center, ABSTRACT Becausethe diffuser of theSand Island Ocean Outfall lies below safe diving depths, a remotely controlled video camerasystem was used to determinethe statusof the fish and diurnallyexposed macrobenthos resident to thediffuser.
    [Show full text]
  • Biological Oceanography - Legendre, Louis and Rassoulzadegan, Fereidoun
    OCEANOGRAPHY – Vol.II - Biological Oceanography - Legendre, Louis and Rassoulzadegan, Fereidoun BIOLOGICAL OCEANOGRAPHY Legendre, Louis and Rassoulzadegan, Fereidoun Laboratoire d'Océanographie de Villefranche, France. Keywords: Algae, allochthonous nutrient, aphotic zone, autochthonous nutrient, Auxotrophs, bacteria, bacterioplankton, benthos, carbon dioxide, carnivory, chelator, chemoautotrophs, ciliates, coastal eutrophication, coccolithophores, convection, crustaceans, cyanobacteria, detritus, diatoms, dinoflagellates, disphotic zone, dissolved organic carbon (DOC), dissolved organic matter (DOM), ecosystem, eukaryotes, euphotic zone, eutrophic, excretion, exoenzymes, exudation, fecal pellet, femtoplankton, fish, fish lavae, flagellates, food web, foraminifers, fungi, harmful algal blooms (HABs), herbivorous food web, herbivory, heterotrophs, holoplankton, ichthyoplankton, irradiance, labile, large planktonic microphages, lysis, macroplankton, marine snow, megaplankton, meroplankton, mesoplankton, metazoan, metazooplankton, microbial food web, microbial loop, microheterotrophs, microplankton, mixotrophs, mollusks, multivorous food web, mutualism, mycoplankton, nanoplankton, nekton, net community production (NCP), neuston, new production, nutrient limitation, nutrient (macro-, micro-, inorganic, organic), oligotrophic, omnivory, osmotrophs, particulate organic carbon (POC), particulate organic matter (POM), pelagic, phagocytosis, phagotrophs, photoautotorphs, photosynthesis, phytoplankton, phytoplankton bloom, picoplankton, plankton,
    [Show full text]
  • Meiofaunal Responses to Sedimentation from an Alaskan Spring Bloom
    MARINE ECOLOGY PROGRESS SERIES Vol. 57: 137-145, 1989 Published October 5 Mar. Ecol. Prog. Ser. I Meiofaunal responses to sedimentation from an Alaskan spring bloom. I. Major taxa John W. ~leeger',Thomas C. shirley2,David A. ziemann3 'Department of Zoology and Physiology. Louisiana State University. Baton Rouge, Louisiana 70803. USA 'Juneau Center for Fisheries and Ocean Sciences, University of Alaska Fairbanks, Juneau, Alaska 99801. USA 30ceanic Institute. Makapuu Point. PO Box 25280. Honolulu, Hawaii 96825, USA ABSTRACT: Metazoan meiofaunal comnlunity dynamics and spring phytoplankton bloom sedimenta- tion rates were measured concurrently in Auke Bay, Alaska. from 1985 to 1988. We test the null hypothesis that recruitment and density maxima are unrelated to sedimentation events. Springtime chlorophyll a sedimentation was predictable and episodic, occurring annually at peak rates during mid- May at 35 m; carbon sed~mentationwas continuous through the spring. Cumulative sedimentation varied from year to year, ranging from lowest to highest by a factor of 2. At a 30 m station, seasonal variation in major taxon density was not identifiable, however interannual variations in meiofaunal densities &d occur No consistent relationship between meiofaunal abundances and spring chl a or carbon sedimentation was found, i.e. years with the highest or lowest nematode and harpacticoid abundances did not correspond to years with the highest or lowest values for sedimentation. Other factors must regulate the interannual variation in meiofauna, at least over the range of values for sedimentation in Auke Bay. INTRODUCTION tions may settle quickly to the bottom (Billett et al. 1983, Townsend & Canlmen 1988), and settled cells Although there have been many recent ecological may be in good physiological and nutritional condition studies of the meiobenthos (Coull & Bell 1979), most (Lenz 1977).
    [Show full text]
  • Comparative Composition, Diversity and Trophic Ecology of Sediment Macrofauna at Vents, Seeps and Organic Falls
    Review Comparative Composition, Diversity and Trophic Ecology of Sediment Macrofauna at Vents, Seeps and Organic Falls Angelo F. Bernardino1*, Lisa A. Levin2, Andrew R. Thurber3, Craig R. Smith4 1 Departamento de Oceanografia e Ecologia, Universidade Federal do Espı´rito Santo, Goiabeiras, Vito´ ria, Esp´ı rito Santo, Brazil, 2 Center for Marine Biodiversity and Conservation; Integrative Oceanography Division, Scripps Institution of Oceanography, La Jolla, California, United States of America,3 College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, Oregon, United States of America,4 Department of Oceanography, School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, Hawaii, United States of America communities. Sulfide is toxic to most metazoan taxa [1,2], Abstract: Sediments associated with hydrothermal vent- although some sediment-dwelling taxa have adapted to conditions ing, methane seepage and large organic falls such as of low oxygen and appear capable of tolerating the presence of whale, wood and plant detritus create deep-sea networks sulfide. Due to high local production, metazoans in reducing of soft-sediment habitats fueled, at least in part, by the sediments in the deep sea are often released from the extreme food oxidation of reduced chemicals. Biological studies at limitation prevalent in the background community (e.g. [3]). deep-sea vents, seeps and organic falls have looked at Instead, chemical toxicity may drive infaunal community macrofaunal taxa, but there has yet to be a systematic comparison of the community-level attributes of sedi- structure. In this meta-analysis we ask which taxa are common ment macrobenthos in various reducing ecosystems.
    [Show full text]
  • Ecosystems Mario V
    Ecosystems Mario V. Balzan, Abed El Rahman Hassoun, Najet Aroua, Virginie Baldy, Magda Bou Dagher, Cristina Branquinho, Jean-Claude Dutay, Monia El Bour, Frédéric Médail, Meryem Mojtahid, et al. To cite this version: Mario V. Balzan, Abed El Rahman Hassoun, Najet Aroua, Virginie Baldy, Magda Bou Dagher, et al.. Ecosystems. Cramer W, Guiot J, Marini K. Climate and Environmental Change in the Mediterranean Basin -Current Situation and Risks for the Future, Union for the Mediterranean, Plan Bleu, UNEP/MAP, Marseille, France, pp.323-468, 2021, ISBN: 978-2-9577416-0-1. hal-03210122 HAL Id: hal-03210122 https://hal-amu.archives-ouvertes.fr/hal-03210122 Submitted on 28 Apr 2021 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Climate and Environmental Change in the Mediterranean Basin – Current Situation and Risks for the Future First Mediterranean Assessment Report (MAR1) Chapter 4 Ecosystems Coordinating Lead Authors: Mario V. Balzan (Malta), Abed El Rahman Hassoun (Lebanon) Lead Authors: Najet Aroua (Algeria), Virginie Baldy (France), Magda Bou Dagher (Lebanon), Cristina Branquinho (Portugal), Jean-Claude Dutay (France), Monia El Bour (Tunisia), Frédéric Médail (France), Meryem Mojtahid (Morocco/France), Alejandra Morán-Ordóñez (Spain), Pier Paolo Roggero (Italy), Sergio Rossi Heras (Italy), Bertrand Schatz (France), Ioannis N.
    [Show full text]
  • The Relation of Tidal Height and Sediment Type to the Intertidal Distribution of Marine Oligochaetes in Coos Bay, Oregon
    AN ABSTRACT OF THE THESIS OF David Randall Strehiow for the degree of Master of Science in the School of Oceanography presentedon 3 May 1982 Title: The Relation of.Tidal Height and Sediment Type to the Inter- tidal Distributi Redacted for privacy Abstract approved: .J. Gonor The taxonomy of intertidal oligochaetès, and the relationships between oligochaete species distributions, tidal height, and sediment type, were studied in detail for a sand and mud flat in lower Coos Bay, Oregon. Eighteen species, representing four families, were identified. Three species of Enchytraeidae (Marionina vaucheriae, Marionina callianassae, and Marionina gpnori) and one species of Tubificidae (Aktedrilus oregpnensis) are new to science. A preliminary description of a new family, Psamotheriidae, based on Psarrrnotheriuni hastatus n.g. n.sp. is given. Other species present were Marionina vancouverensis, M. sjaelandica, N. subterranea, and N. achaeta (Enchytraeidae); Aktedrilus locyi, Li.mnodriloides monothecus, L. victoriensis, L. vérrucosus, Tubificoides coatesae, and T. pseudogaster (Tubificidae); and Paranais litoralis (Naididae). Individuals of Enchytraeus sp. and Lumbricillus spp. (Enchytraeidae) were found but were not fully mature, and therefore could not be identified to species. Nine of the eighteen species are known oniy from the northeast Pacific littoral zone, indicating the existence of a distinct regthnal oligochaete fauna. Earlier studies of the Enchytraeidae (Coates and Ellis 1981) and Tubificidae (Brinkhurst and Baker 1979) support this conclusion. Distinct oligochaete species assemblages were closely associated with physical habitat types defined by tidal exposure and sediment type. The distributions of species were not correlated with each other or with physical habitat types, however. Tide levels at which large changes in maximum continuous tidal exposure or submergence occur (critical tide levels) are strongly associated with.
    [Show full text]