CHAPTER 9. PART I 



FIGURE 9.1-3. — Temporal variations in C. tripos cell density. January to August 1976. (Fire Island data by Sylvia Weaver; New Jersey coast data 



by Myra Cohn. Paul Hamer, Paul Olsen, and Frank Takacs.) 



Bight, but remained high within the Apex owing to the 

 growth of nannoplanicton populations (fig. 9.1-14). Dur- 

 ing May the isopleths of cell density roughly paralleled 

 isobaths off the Long Island and New Jersey coasts. In 

 June this pattern persisted only off the Long Island coast. 

 Off New Jersey, isopleths of cell density were roughly 

 normal to isobaths, and high cell densities intruded closer 

 to the coastline. Consequently, high cell densities were 

 distributed over a larger area of the New Jersey shelf in 

 relatively shallow water (2C)-40 m). Comparable cell dens- 

 ities over the Long Island shelf were in waters 40 to 60 

 m deep. 



Growth and Respiration of Ceratium tripos 



Measurements of photosynthesis in the Apex during 

 February and March and off Long Island in late April- 

 early May 1976 indicate that C. tripos was growing at a 

 mean euphotic zone growth rate of 0.04 doublings/d (car- 

 bon specific growth; C:Chl = 275), which is in the range 

 of rates reported by Elbriichter (1973). Light-saturated 

 rates were 0.3 to 0.4 doublings/d, in agreement with the 

 cell division rates reported by Nordli (1957). Photosyn- 

 thetic growth could account for the increase in population 

 size observed before thermal stratification in 1976 (Jan- 

 uary-March). 



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