Review of the oceanography of Long Island Sound 



229 



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PHOSPHATE- P 



ZOOPLANKTON VOLUMES 

 ^ 10 NET 



1952 



1953 



1954 



Fig. 3. Average phosphate, nitrate, and chlorophyll at the surface (solid lines) and bottom (dotted 

 lines) at inshore stations 1, 6, 7 and 8. Zooplankton displacement volumes, also at inshore stations. 

 are averages for the water column obtained by oblique tows with a No. 10 net. 



until September. The autumn increase in nutrients was interrupted in October, 1953, 

 presumably because of plant growth. While there was not a pronounced autumn 

 flowering in the ordinary sense of the term, both phytoplankton and zooplankton 

 crops were larger than in the autumn of 1952. 



Phosphate and nitrate increased slightly from surface to bottom during most of 

 the spring and summer. Stability was loo slight to permit the accumukilion of a large 

 store of regenerated nutrients in the bottom water. It was reasonable, then, lo tind 

 neither a pronounced summer period of phytoplankton impoverishment nor a marked 

 flowering following destruction of the summer thermocline. It was common in autumn 

 and early winter to find a significant reduction in phosphate and nitrate in the bottom 

 water. The reason for this peculiar phenomenon will be discussed later. 



