Food Chain Dynamics 



Smith, S.L. 



$398,000 



Brookhaven National Laboratory 



Department of Applied Science 



C: 516-282-7697; F: 666-7697; 



C: 516-282-2835; F: 666-2835 



The food chain dynamics project provides information on the transfer of energy and material among various pelagic 

 and benthic trophic levels and on factors that alter the pathways or rates of these transfers. Intensive ecosystem 

 studies, coordinated with laboratory experimentation, provide the base for predictive models and evaluation of 

 potential effects of human activity in the coastal environment. Study of the food chains uses an integrated field 

 program of biological rate measurements, standing stock estimates, and remote sensing to infer the cycling and 

 transfer of pollutants and organic material to higher trophic levels. Earlier studies suggest that the spring bloom 

 phytoplankton is not consumed, but based on our recent test of this hypothesis, we find that all rates of processes, 

 including accumulation, if calculated on a time (seasonal) and space-adjusted basis, are greater on the shelf than on 

 the slope. If the test of the export hypothesis is constrained only to the area of Shelf Edge Exchange Processes 

 (SEEP) Program experiments, there is little evidence in favor of accepting the hypothesis because during summer- 

 stratified conditions animal consumption exceeds plant production (i.e., shelf food chains are more or less closed 

 systems). The implication is that the energy-related by-products (pollutants) that enter food chains on the shelf will 

 not be dispersed into the deep sea if the transport relies on fluxes of biogenic particles. Rapid recycling of organic 

 material on the shelf is evidenced in the low-oxygen events in the New York Bight apex during the summer. The as- 

 similative capacity of coastal ecosystems is dependent on cycling and fate of pollutants by food chains if physical ex- 

 port is minor. 



Moored Sensing Systems 



Wirick, C. 



$155,000 



Brookhaven National Laboratory 



Department of Applied Science 



C: 516-282-3063; F: 666-3063 



This project involves deploying fluorometers across the shelf break in the Mid- Atlantic Bight for a period of several 

 months. High-frequency time series of fluorescence will be obtained. Data will be analyzed in conjunction with 

 transmissometers, sediment traps, zooplankton grazing, wind events, and other dynamics to estimate the short-term 

 vectors of motion of chlorophyll and phaeopigments. The fluorometric measurements should provide statistically 

 significant results concerning (1) the seasonality of the standing stock of phytoplankton, (2) the importance of 

 storms in resuspending and transporting phytoplankton, and (3) the transport of phytoplankton across the shelf- 

 slope front. 



Coastal Ocean Margins Program A7 December 1988 



