P.I. - Lawrence W Harding Jr.

The responses of estuaries to effects of land use on nutrient inputs are increased phytoplankton biomass and productivity, and predictable shifts in species composition. These three indicators strongly express seasonal, annual and secular changes modulated by the interplay of light and nutrient limitation along the estuarine salinity gradient. We propose a three-tiered approach to develop phytoplankton indicators: 1) species composition shifts detected from photopigment composition calibrated with microscopic enumeration, 2) phytoplankton biomass measurements including analyses of historical data, analyses of contemporary data, and extension of remote sensing from aircraft and satellite (companion NASA proposal), 3) primary productivity using archival data spanning two decades and models applied to in-situ and remotely sensed observations. The research will be conducted primarily in Chesapeake Bay and Pamlico Sound study sites, with tests of applicability in Parker River and North Inlet (the ACE-INC estuaries).

P.I. - William Boicourt

We propose to incorporate 0₂ as an important indicator of ecosystem "health" in Atlantic estuaries. The approach consists of an analysis of archived records spanning 1949-present, and of continuous measurements of 0₂ from autonomous moored platforms now deployed on Chesapeake Bay. The focus will be on 0₂ depletion in the deep channel to resolve long-term effects of increased nutrient loading from the physical control of stratification by freshwater flow. The DO indicator will be developed initially in Chesapeake Bay and tested in Pamlico Sound - Neuse River, another system that experiences hypoxia, and in the microtidal Parker River in North Inlet estuaries. Indicators of residence time, stratification, and advective time scales will be developed for the ACE INC estuaries. This effort will be collaborative with R. Luettich of the Pamlico Study. The primary goal will be to construct and test methods to formulate indicators that capture key physical aspects of time and space variability.

P.I. - Mike R. Roman

Coupling phytoplankton production to fish is principally through the micro- and mesozooplankton links in estuaries. We propose to develop indicators of ecosystem "health" from short and long -term trends of zooplankton abundance and species composition in Chesapeake Bay. Hypothesized secular changes in mesozooplankton abundance in response to nutrient over-enrichment will be tested with archival data from monitoring and optical data from contemporary sampling. We propose to develop predictive relationships between optical measurements of phytoplankton biomass from remote and in-situ sensors, with zooplankton abundance and community composition. We will begin analysis using Chesapeake Bat data, then incorporate available data from other ACE INC estuaries. We hypothesize that physical parameters, photopigments, and other optical properties can be used as indicators to predict zooplankton abundance and community composition.

P.I. - Edward D. Houde

Biomass size spectra will be developed and tested as integrative bio-indicators of stress or change in estuarine ecosystems. Data from primary producers to fish are available in Chesapeake Bay Program and other surveys to develop the spectra. We postulate that changes in annual climate, freshwater, and nutrient inputs to Chesapeake Bay and other ACE INC estuaries will be registered as variability in properties of biomass size spectra. Annual, seasonal and regional variability, particularly in the slopes and levels of biomass in the spectra can serve as indicators of change and will related to environmental factors. Specific goals are to identify key species and species groups that contribute importantly to biomass size spectra and thus to interpret trends in trophic status reflected in spectral properties.