r t hie I .—Sampling location:! and depths. Long Uland Sound, 1972-73. 



Sound's east- west axis. Dissolved oxygen was de- 

 termined by the azide modification of the Winkler tech- 

 nique (American Public Health Association 1965), with 

 standard 0.25N phenylarsine oxide substituted for the 

 less stable sodium thiosulfate. Water samples were fro- 

 zen for later colorimetric determination of nitrate, ni- 

 trite, ammonia, urea, iron, and orthophosphorus, using a 

 Technicon Auto Analyser. Nitrate and nitrite were 

 anlyzed using the naphthylenediamine-sulfanilamide 

 system with cadmium reduction of nitrate after Wood et 

 al. (1967). The ammonium analyses, which were based 

 on the phenolhypochlorite Bertelot reaction (Solorzano 

 1969), were run within 15 days of collection. In some 

 cases this is longer than our tests show is permissible 

 without measurable loss (10 days); however, because of 

 the large area surveyed, shorter intervals were some- 

 times not possible. The values represent, therefore, a 

 conservative estimate of ammonium concentration. The 

 urea analysis is an adaptation to seawater of Marsh et 

 al.'s (1965) blood urea method in which diace- 

 tylmonoxime reacts with urea in the presence of thiose- 



micarbizide and ferric ion intensifiers. Orthophosphorus 

 was measured utilizing the molybdate-ascorbic acid pro- 

 cedure after Murphy and Riley (1962). Iron was deter- 

 mined using the essentials of the 2-2' bipyridal pro- 

 cedure of Lewis and Goldberg (1954) as adapted to the 

 autoanalyzer by Henriken (1967). 



Benthic samples were collected with a 0.1 m" Smith- 

 Mclntyre bottom grab. At each station, sediments from 

 one (Cruises 1 and 2) or two (Cruise 3) grabs were sieved 

 to 1 mm. Retained macrofauna were relaxed in a magne- 

 sium chloride-seawater solution, preserved in a 1:9 

 Formalin to seawater mixture and later trasfered to lO'^i 

 ethanol with 5' i glycerin. 



Samples were sorted under dissecting microscopes. All 

 organisms were identified to species when possible. Our 

 macrofauna analysis will concentrate on polychaetes, 

 molluscs, and arthropods, which together comprise the 

 great majorityof species and individuals collected Mc- 

 Call (1977) reported that these three groups accounted 

 for95Tf of the infaunal macrobenthos of central LIS). 



Species diversity was calculated using the Shannon- 



