Aquatic Sciences Meeting, Albuquerque 2001

SS40 Long-Term Research Programs in the Twenty-first Century (Spatial and Temporal Connections)

Date: Thursday, February 15, 2001, Time: 2:45:00 PM

Location: Ruidoso/Pecos

Sharp, J, H, Graduate College of Marine Studies/University of Delaware, Lewes, DE, USA, jsharp@udel.edu

NUTRIENTS AND PHYTOPLANKTON PRODUCTION - INFORMATION AND INFERENCES FROM LONG-TERM RESEARCH AND MONITORING IN THE DELAWARE ESTUARY

Results of our research projects over 23 years linked with a consistent long-term agency monitoring program (34 years) and sporadic older data allow an assessment of the interaction between nutrients and primary production in the estuary of the Delaware River and Bay system. A large increase is seen around 1970 in the ratio of dissolved inorganic nitrogen to total phosphorus throughout the estuary. In the past 15 years, a decrease has occurred in the ratio of dissolved inorganic nitrogen to dissolved inorganic phosphorus. Resource management to improve water quality was probably responsible for both the increase and then decrease in these critical nutrient ratios; although these changes were not intentional. While not monitored directly in the past, long-term responses of primary production have occurred and can be assessed from our shorter-period research and from modeling of monitoring data. With increased interest in nutrient influences on primary production in the nearshore ocean, it is critical that we measure and assess the changes in nutrient ratios that are direct or indirect consequences of human use activities.

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Aquatic Sciences Meeting, Albuquerque 2001

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