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study Description: 



Six replicate 0.04 square meter benthic samples are be 

 collected at all long-term, regional stations during each 

 sampling cruise and double-sieved at 500 and 300 microns. 

 Subsamples for grain size and carbon-hydrogen-nitrogen 

 analyses are removed from these samples prior to their 

 sieving and preservation. An additional six replicate 

 samples sire collected at these stations using a 0.1 

 square meter grab. These samples are preserved and archived. 

 Infauna samples are sorted and specimens identified to 

 the lowest possible taxonomic level and counted. Wet weight 

 biomass is determined for each taxanomic group, for each 

 replicate sample, and for each station. Alalyses of this 

 information includes (1) measures of species diversity, 

 (2) measures of temporal and spatial abundance, (3) descriptions 

 of the life stages of individuals of each species, and (M) 

 measures of faunal affinity and appropriate multivariate 

 techniques to define species and station patterns. Relationships 

 between changes in community and population structures and 

 changes in sediment texture and chemistry resulting from drilling 

 activities are then interpreted. 



Six replicate O.OU square meter benthic samples are 

 collected at all site-specific stations. These samples are 

 double-sieved at 500 and 300 microns and preserved for 

 subsequent cinalysis. 



Epifauna samples are collected during all cruises by 

 dredge and/or trawl at the "mud patch," the head of Lydonia 

 Canyon, and station 2 (control). Sufficient organisms are 

 collected to perform the chemical analyses of trace metals 

 and hydrcarbons. Special consideration is given to 

 commercially- important species that represent a variety of 

 feeding mechanisms. 



Still photographs of the bottom are taken at all stations 

 where infaunal grab samples are collected. These photographs 

 display the large-scale surface topography and the 

 structure and composition of epifaunal assemblages at these 

 sites. 



Measurements of salinity, temperature, and dissolved oxygen 

 are made at all long-term, regional stations on each 

 sampling cruise. 



Information Use: 



A final report containing the results of the first year 

 of this study was submitted to MMS in April 1982. The 

 information from this study was presented to used by the 

 Biological Task Force to evaluate the effects of DCS exploratory 

 operations on the benthic communities of the Georges Bank area. 

 The information will be used in future pre- and post-sale 

 decisions related to environmental sensitivity of benthic 

 communities to DCS discharges, platform siting, discharge 

 requirements, and the adeauacy of mitigating measures. 



