Table 22. Correlation coefficients of linear regressions of nitrate, orthophosphate, 

 silicate, and ammonia on salinity (from Livingston et a1. 1974). 



Species richness and diversity of 

 nekton are directly associated with areas 

 of high environmental stability but low 

 secondary productivity. Infaunal 

 macroinvertebrates show the same general 

 response to salinity (Livingston 1983d). 

 Within a given area of low salinity, 

 however, species richness may increase in 

 areas of relatively high primary 

 productivity and detritus availability. 

 In this way, the influence of salinity may 

 be modified by ambient habitat conditions. 



In low-salinity estuaries, species 

 diversity indices tend to reflect the 

 effects of salinity on recruitment of 



dominant populations. Within a given 

 habitat (such as an oyster bar, 

 unvegetated soft-sediment area, or 

 seagrass bed), the spatial distribution of 

 organisms at any given time may depend on 

 gradients of productivity and salinity. 

 The regulating features may change their 

 relative importance through any given 

 seasonal succession. Temperature and 

 other physical features seasonally modify 

 the productivity-salinity association. 

 Among the phytoplankton, water temperature 

 is the primary limiting factor, although 

 river discharge, nutrients (mainly phos- 

 phorus), turbidity, and light inhibition 

 may control phytoplankton productivity at 



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