Georgian Court University

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As well as the study of invasive species that now forms the core of my research, over the last two decades or so I have been afforded the opportunity to particpate in research on a wide variety of topics including:
bulletMycology
bulletHydrothermal vent ecology
bulletBenthic diatom population structure
bulletMangrove ecology
bulletUse of flocculent material as food by estuarine organisms
bulletProblems caused by swimmers in sediment traps
bulletMeasures of macrophyte detrital food quality
bulletEffects of nutrient enrichment and species diversity upon detrital food quality
bulletSeagrass ecology in Barnegat Bay
bullet Polybrominated diphenyl ethers (PBDEs)

bulletMycology

My first taste of research science came during 1983 when I worked as a research assistant to Dr. Darryl Grund at Acadia Univeristy (Nova Scotia, Canada). My tasks during this period included collection and identification of macrofungi and testing various colorimetric indicators of toxins present in the fungal tissues.

bulletHydrothermal Vents

Funded by a National Sciences and Research Council (NSERC) undergraduate research assistantship in 19984, I worked as a research assistant to Dr. Verena Tunnicliffe at the University of Victoria (British Columbia, Canada). During this summer I was assigned to identifying and counting meiofauna collected during research trips to the Challenger Ridge Hydrothermal Vents. I was also responsible for preparing a 3-D slide show using negatives from cameras mounted on the Pisces submersible, and for preparing maps of vent and animal distributions.

bulletBenthic Diatoms

During 1985 I carried out research for my honors thesis, funded again by NSERC. For this project I collected samples of benthic diatoms from a salt-marsh edging the Bay of Fundy, Nova Scotia, Canada. I used these collections to analyse changes in community structure over the summer and between exposed areas of mud and that shaded by macrophyte vegetation.
bulletMangrove ecosystems and stable isotope tracers

Between my undergraduate and masters degrees I worked as a research assistant for Dr. Michael Risk at McMaster University (Ontario, Canada). During this project I travelled to Costa Rica to samples a mangrove ecosystem in the Gulf of Nicoya. I collected as many of the primary producers (mangroves, macro-algae, marsh-grasses and benthic diatoms) and animals (from amphipods to fish, snails and crabs) as possible. These I transported back to Canada and analysed for their stable isotope composition (carbon and nitrogen) in order to assess the importance of mangrove detritus in the diets of species sustaining subsistance fiseries or having commercial importance in that ecosystem.

bulletFlocculent Organic Matter as Food for Estuarine Organisms

During my Masters degree I investigated the role of material flocculated from river water by mixing with salt-water as a food source for animals in that system. I found that animals did eat floc, and could (in the absence of better foods) assimilate carbon from that material. Ingestion of the floc was strongly enhanced by microbial colonisation. However not all strains of bacteria isolated from floc enhanced ingestion of pasteurised floc, implying that effect is dependent on the species composition of the colonising bacteria.

bulletProblems caused by "swimmers" in marine sediment traps

During my Masters I gained cruise experience by volunteering to work on monthly cruises to Saanich and Jervis Inlets (British Columbia, Canada). On these cruises I collected zooplankters with nets, and from water overlying sediment traps being deployed by other members of the research team. Animals were identified and fecal pellets were recovered from individuals maintained in unfiltered water after collection. Attempts were then made to attribute fecal pellets of certain size ranges and shapes to their "source" organisms. The idea was to try to assess the importance of each of these source animals in producing the pellets found in the sediment traps. Pellet size, shape and longevity were found to be too variable to allow this approach to succeed.

bulletMeasures and implications of changes in food quality of macrophyte detritus as a consequence of source and degradation time

During my doctoral dissertation I developed a technique to asssess the food quality of various macrophyte detrital materials using in vitro enzyme digestion. I then evaluated the performance of this new techniques using growth and choice bioassays and compared the results with those derived from other available techniques. Using all these techniques the food qualities of six types of macrophyte detritus at eight different stage of degradation was evaluated. The implications of these initial and long term food qualities and source plant species diversity on the quality of the spectrum of food available for ingestion in the estuary over time were assessed.

 

bulletEffects of nutrient enrichment and species diversity upon detrital food quality

Since my graduation my research has veered towards an interest in the impacts of eutrophication and competition (species diversity) upon detrital food quality in marshes. This research has primarily been conducted in collaboration with Dr. J. Court Stevenson at Horn Point Laboratory, using an array of mesocosms built as part of the MEERC project. This suite of 12 marsh mesocosms was set up in 1996-7 with 6 high diversity and 6 low diversity tanks and each scale of diversity was then divided into 3 high nutrient and 3 low nutrient treatments. The growth, relative productivities and diversities of species in these tanks has been followed ever since. Using tagging, senescing shoots from the main species present in the tanks were followed and harvested at various stages of degradation and the detrital food quality of the various materials was assessed.

 

bulletSeagrass ecology in Barnegat Bay

Together with my graduate students (OK, mostly as a result of their hard work!) I have started to collect data on the seasonal changes in abundance of seagrasses in Barnegat Bay, on the reasons for seasonal seagrass die offs and on the changes in above- and below-ground biomass in those plants.  We have also started to investigate the differences in habitat-value between the various species of seagrasses that form extensive beds within Barnegat Bay and little Egg Harbor.

 

bullet  Polybrominated diphenyl ethers (PBDEs)

Polybrominated diphenyl ethers (PBDEs) have been dubbed “the PCBs of the 21st century” (Wilbur 2005). Commonly used as flame-retardants, PBDEs are found in a wide variety of products including furniture and electronic equipment. PBDEs are mixed with polymers like plastics and polyurethane as they are being made, but do not bind to the polymers chemically, and so can leach from these materials throughout the life of the product.  Since PBDEs can be a significant component of these materials (e.g. up to 30% in polyurethane cushions), and are highly stable and thus persistent in nature, there is strong potential for environmental contamination by these compounds.   

PBDE residues have been found in the tissues of marine and terrestrial species around the globe (Boer et al. 1998, Lichota et al. 2004, Wolkers et al. 2004) and to have major impacts on animal and human health.  For example, PBDEs are linked to decreased eggshell thickness in peregrine falcons (Sørensen et al. 2004) and decreased bone densities in polar bears (Sonne et al. 2004).  PBDEs have also been found to be potent thyroid disruptors (Ilonka et al. 2000), have been implicated in the development of learning disabilities in mice (Eriksson et al. 2001) and are likely carcinogens (McDonald 2002).  PBDE concentrations in human tissues have increased about 100 fold over the past 30 years, with concentrations in people from the United States being about 20 times higher than in people from Europe, where there has been stronger regulatory control over PBDE manufacture and use (Hites 2004).

Concentrations of PBDEs in New Jersey’s Coastal Ecosystems are poorly known.  To address this data gap, we propose to develop the proficiencies required to monitor PBDEs in sediment, water and biota within the Barnegat Bay.  Once the methodologies have been established and tested within our laboratories, we intend to develop a monitoring program to assess the extent of and changes in PBDE pollution in the Barnegat Bay over time.

Along with Dr. Andrew Weber (Dept of Chemistry, GCU), my students and I are well on our way to being able to assess the concentrations of these important environmental contaminants in New Jersey's Coastal Waters and are looking forward to starting collecting and analyzing water, sediment and tissue samples collected in various New Jersey Estuaries in the Spring of 2006. 

References Cited 

Boer J de, Wester PG, Klamer HJC, Lewis WE, Boon JP. 1998. Do flame-retardants threaten ocean life? Nature 394: 28-9 

Central Arizona- Phoenix Long Term Ecological Research (CAPLTER). 2001. CAPLTER Water sampling protocol. http://caplter.asu.edu/fieldprotocols/WaterSampling.htm  

Eriksson P, Jakobsson E, Fredriksson A. 2001. Brominated flame retardants: A novel class of developmental neurotoxicants in our environment? Environ Health Pers 109:903-8 

Hites RA. 2004.   Polybrominated diphenyl ethers in the environment and in people: A meta-analysis of concentrations.  Environ Sci Technol 38(4): 945-56. 

Ilonka A, TM Meerts, JJ van Zanden, EAC Luijks, I van Leeuwen-Bol, G Marsh, E Jakobsson , Å Bergman and A Brouwer. 2000. Potent competitive interactions of some brominated flame retardants and related compounds with human transthyretin in vitro. Toxicol Sci 56: 95-104. 

Lichota GB, McAdie M, Ross PS.  2004.  Endangered Vancouver Island marmots (Marmota vancouverensis: sentinels of atmospherically delivered contaminants to British Columbia, Canada.  Environ Toxicol Chem 23(2):402-7. 

McDonald TA. 2002. A perspective on the potential health risks of PBDEs. Chemosphere 46 (5):745-755

Rieck RH. 2004 Polybrominated diphenyl ether analysis in fish tissue and other matrices by GC–ECD. LCGC North America 22(9): 914 -925 

Sonne C, Dietz R, Born EW, Riget FF, Kirkegaard M, Hyldstrup L, Letcher RJ, Muir DCG.   2004. Is bone mineral composition disrupted by organochlorines in East Greenland polar bears (Ursus maritimus)? Environ Health Pers 112 (17): 1711-6 

Sørensen PB, Vorkamp K, Thomsen M, Falk K, Møller S. 2004. Persistent organic pollutants (POPs) in the Greenland environment - Long-term temporal changes and effects on eggs of a bird of prey. NERI Technical Report No. 509.

http://www.panda.org/downloads/toxics/preegrinefalcons.pdf  

Wilbur S. 2005.  GC-ICP-MS – A powerful alternative for detection of brominated flame-retardants.   Agilent Separation Times 18 (2):  4-5.  

Wolkers H, Van Bavel B, Derocher AE, Wiig O, Kovacs KM, Lydersen C, Lindstrom G.  2004.   Congener-specific accumulation and food chain transfer of polybrominated diphenyl ethers in two Arctic food chains.  Environ Sci Technol 38:1667-74.

Learn more about the Biology Department at Georgian Court University

Author: Louise Wootton. Ph.D.  Last updated January 15, 2006

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