Review of the oceanography of Long Island Sound 235 



than the increase in experimental light bottles. The discrepancy may have been due 

 to experimental error, since it is well known that bacterial growth is abnormally 

 large in bottled sea water. However, there are also several possible sources of error 

 in the physical oceanographic calculations, so that there is an uncertainty factor of at 

 least 50% in the results of the productivity compilation. 



The consumption of organic matter by the benthic community was estimated by 

 physical oceanographic computation of the rate of transfer of oxygen downwards 

 through the lower few metres of water and by the rate of upward transfer of phosphate 

 from the bottom. An estimate of the rate of consumption by the plankton community 

 could be obtained from the net rate of utilization of oxygen in the lower part of the 

 water column, since the vertical distribution of plankton was relatively uniform. 

 However, it was a minimal estimate because experiments showed a slight but significant 

 amount of photosynthesis at depths of 15 to 20 m in summer. Dark bottle respiration 

 averaged approximately twice the net rate of change in the lower water column. 

 Experimental values were presumably too high, and therefore an intermediate value 

 was chosen to represent the total oxygen consumption of the plankton community. 

 Results are shown in Table II, together with somewhat similar estimates by Harvey 

 (1950) for the EngHsh Channel. 



Table II 

 Comparison of mean annual standing crops and organic production (grams organic 

 matter per m^) in the English Channel (EC) and central Long Island Sound (LIS) 



* Photosynthetic glucose production and loss of glucose by respiration. 



t Production of phytoplankton of normal organic content in excess of respiratory requirement. 



t Includes bacteria and microzooplankton. For further explanation of this item see text. 



Data for the English Channel were obtained at a station in 70 m of water ofT 

 Plymouth, as compared with a mean depth of 20 m in Long Island Sound. Nutrient 

 concentrations were relatively low in the English Channel, although the total stock 

 in the water column at the time of the winter maximum was about the same in both 



areas. 



The Sound has a larger standing crop of phytoplankton and greater basic pro- 

 ductivity. The zooplankton crop is only slightly greater, in this connection, R. 

 CoNOVER (1955) has pointed out that the dominant copepod Acartia is a relatively 

 inefficient feeder, has a remarkably high respiratory requirement, and probably 



