13-9 



ences as improved water quality (undocumented) and expanded treatment of 

 mxinicipal water discharges. 



BENTHIC STUDIES 



Organisms living on or in bottom substrates in New Haven 

 Harbor occupy intertidal and subtidal muds and sands as well as wood, 

 rock and concrete structures including pilings, old barges, bulkheads 

 and jetties. These benthic assemblages are relatively stationary and to 

 survive must withstand all extremes in physical and chemical parameters 

 that occur in the water column. In this regard, the benthos are unlike 

 plankton, which move with water currents, and unlike pelagic and demersal 

 finfish and large motile epibenthic invertebrates, which may move about 

 in response to physical and chemical parameters. Thus the characteristics 

 of the benthos at a given place and time should reflect the ciomulative 

 conditions prior to that time. Plankton, finfish and mobile epibenthic 

 organisms at a given point in time give less indication of what conditions 

 may have been on the preceding day or weeks . Studies included in this 

 report which directly address components of the benthos are (5) Exposure 

 Panels, (6) Subtidal Infauna and (7) Intertidal Infauna. Larger, motile 

 invertebrates are considered in (8) Epibenthic Invertebrates. Oyster 

 growth and mortality are addressed in (9) Oyster Study. A special study 

 examining accumulation of trace metals by benthic organisms is included 

 in (10) Trace Metal Studies, which also takes a much broader view of 

 trace metal processes in general and throughout Long Island Sound. 



Power generating stations utilizing once-through cooling 

 systems impact the marine benthic environment in a number of ways. The 

 direct impact of the heated effluent may be sufficient to elevate 

 temperatures in the receiving body of water to a point which is detri- 

 mental to the survival of some of the resident species, particularly 

 those that are near their tolerance limits for temperature or other 

 physical factors. This type of impact may affect adults, juveniles, or 

 larvae of benthic infauna. Further, heat may alter competitive advan- 

 tages or behavior, indirectly producing mortality. Added heat may alter 



