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2007 Funded Pilot Projects

Hydrodynamics and Transport Pathways for Fecal Microbial Populations in a Salt Marsh and Barrier Beach System

PI: David Ralston (WHOI, Dept of Applied Ocean Physics and Engineering)

We propose to develop and implement a numerical model of flow and transport in a salt marsh and barrier beach system on Cape Cod, MA. The project will focus on Little Sippewissett Marsh and Wood Neck Beach, a system that during summer months frequently experiences high fecal coliform concentrations that indicate potential for significant impacts on human health and lead to restrictions on recreational use. Potential sources of fecal contamination include failed septic systems, birds, or other animals in the marsh. Recent investigations have found that fecal coliform counts are highly variable temporally (tidally, with precipitation events, and seasonally) and spatially across the marsh and beach. A COHH pilot project currently underway has begun to quantify the spatially heterogeneity of microbial communities in the system, intending to distinguish among different sources of fecal contamination and to develop a broader suite of indicator organisms (Sogin, 2006). The project proposed here will work in conjunction with that microbial community mapping project to quantify transport pathways, residence times, and exchange rates in the marsh. Combining transport mechanisms with the spatially heterogeneous source terms will permit calculation of potential exposure and risk to human health associated with the disparate sources of contamination. The model results will also provide guidance for public health officials to redesign of monitoring efforts to sample at times and locations of maximum potential exposure to elevated coliform concentrations, thereby minimizing human health risks. The tasks in the project include acquiring bathymetric data from existing sources and from new field surveys, constructing a numerical grid from the bathymetry, establishing and collecting data for model boundary conditions, and initial calibration and testing of the model based on available observations in the marsh. The model is intended to serve as a basis for future interdisciplinary studies at the study site – model results will aid in design of field observations, and more extensive field studies will aid in refinement of the model. The salt marsh and barrier beach of the study site represent a common coastal environment, and the impacts on human health of fecal contamination in coastal settings are of concern regionally and nationally. The pilot project will provide a step toward building an integrated program in Little Sippewissett to study linkages among physical, chemical, and biological processes in salt marshes and very shallow estuaries, coastal environments where frequent human interactions make potential health impacts particularly significant.

BMAA, a cyanobacterial neurotoxin, in marine food webs: a pilot project

PI(s): Carl Lamborg, Mak Saito, Paul Drevnick (WHOI, Dept. of Marine Chemistry and Geochemistry)

ß-methylamino-L-alanine (BMAA) is a neurotoxic amino acid produced by cyanobacteria. High concentrations of BMAA in human brain tissue have been linked to neurodegenerative diseases (ALS, Alzheimer’s, Parkinson’s) in Guam and Canada. The source of BMAA in Guam is cyanobacteria in the roots of cycad plants and biomagnification through a unique food web. The source of BMAA in Canada is unknown. A recent study, however, reported that many marine cyanobacteria also produce BMAA. Cyanobacteria are ubiquitous in the ocean and especially abundant in coastal areas that have experienced harmful algal blooms, representing a potentially significant source of BMAA to marine food webs. Fish or shellfish that eat cyanobacteria or otherwise accumulate BMAA may thus pose a health risk to human consumers of seafood. We propose to address the most fundamental question concerning the distribution of BMAA in the temperate coastal ocean: Are BMAA concentrations in seafood high enough to be of concern for human health? We will examine fish and shellfish of commercial, recreational, and subsistence importance for BMAA concentrations. If we find BMAA concentrations that pose a human health risk, (i) this could form the basis of a human health risk assessment for BMAA and (ii) we will have preliminary data to generate a full proposal for further study.

Using signature tagged mutagenesis (STM) to investigate how pandemic Vibrio parahaemolyticus persists in the bacterioplankton and associates with epithelia in the marine environment

PI: Janelle Thompson (MIT, Dept of Civil and Environmental Engineering)

This study will estimate the costs-of-illness associated with human respiratory ailments that arise as the consequence of the aerosolization and coastal to inland transport of brevetoxins from blooms of the marine dinoflagellate, Karenia brevis, in the Gulf of Mexico. The research will develop models to link the occurrence of HAB events in the coastal-ocean with exposures to aerosolized brevetoxins. The researchers will compile datasets and develop models of illness rates that would permit historical estimates of these kinds of impacts and the simulation of future potential impacts. This is a proof-of-concept Pilot Project designed to develop an analytical framework that can be used on a larger scale, using more extensive datasets in the future. It is critical that we understand the costs of natural hazards such as HAB events for at least two reasons. First, the nature of the costs (their effect) and their incidence (who is affected and at what rate) will enable the characterization of feasible actions to mitigate the costs. Second, the scale of the costs will help resource managers, scientists, and the general public to gauge the levels of and need for potential mitigation.