Information Concept in Ecology 



151 



Biomass was estimated as ash-free dry weight of suspended 

 soHds. The inethod involved filtering water through tared Millipore 

 filters (type HA), desiccating" filters plus residues, weighing for 

 total solids, then ashing at 600 °C., rehydrating the ash, desic- 

 cating, and weighing again to obtain the ash weight. 



Counts of phytoplankton units (chains, colonies or individual 

 cells) were made from Sedgwick-Rafter mounts of fresh samples 

 obtained from the various depths. All flagellates and diatoms were 

 counted; ciliates and other animals, when present, were excluded. 



COMMUNITY ADAPTATIONS FOR MAXIMUM BIOMASS 



The York River water column at the station sampled was 

 comparatively unstratified from surface to bottom during the 

 summer of 1960. This is illustrated by the graphs in Figure 3. 



MAN DIUOLVIO OXTMII 



1 



MEM eitMLVto rHOtrORU* 



MCAN NITRATE 



Fig. 3. Mean vertical distribution of chlorinity, temperature, and the dissolved 

 substances oxygen, phosphorus and nitrate. 



