TERRY E. WHITLEDGE 



Institxite of Marine Science, 

 University of Alaska Fairbanks 



DEAN A. STOCKWELL 



Institute of Marine Science, 

 University of Alaska Fairbanks 



CHAPTER FOUR 



Water Column 

 Productivity 



"In water all hath had its primal source; 

 and water still keeps all things in their 

 course." 



♦ Johann Wolfgang von Goethe (1749-1832) 



INTRODUCTION 



Observations of nutrient and primary productivity 

 changes in aquatic environments have been used to 

 assess many aquatic ecosystems for changes of primary 

 inputs or suspected ecosystem alterations (Boynton et 

 al. 1982; Pennock et al. 1999). Estuarine areas, such as 

 the Nueces Delta, depend upon the mixing of fresh 

 water with sea water to maintain biological 

 productivity. Specifically, fresh water imports nutrients 

 and dilutes salinity of the receiving sea water. 

 Therefore, increased freshwater inflow from the 

 demonstration project should have a large impact on 

 the water column and its biological processes. The re- 

 introduction of fresh water from the Nueces River into 

 the upper Nueces Delta offered an opportunity to 

 monitor nutrient and primary productivity responses in 

 a historic river delta that had been altered by lack of 

 freshwater inflows from small and medium runoff 

 events. In the recent past, fresh water flow has been 

 limited to only large events that have flooded the delta 

 every several years. 



OBJECTIVES 



1) To assess the effect of the demonstration project 

 on salinity and nutrient availability to the water 

 column of the study area; 



2) To assess the response of water column 

 phytoplankton populations to changes in salimty 

 and nutrient availability; and 



Chapter Four ♦ 4-1 



