Paerl Lab Research

EPA-STAR’s Estuarine and Great Lakes Environmental Indicators Program (EaGLe) is supporting Hans Paerl (P.I.), Rick Luettich (Co-P.I.), Rachel Noble and other researchers from IMS, Univ. of Maryland, Univ. of South Carolina, the Marine Biological Laboratory and the NOAA-NOS Beaufort Lab to develop and test broadly-applicable, integrative indicators of ecological condition, integrity, and sustainability across four distinct and representative estuarine systems on the US Atlantic Coast. These include the nation's two largest estuarine complexes, Chesapeake Bay, and Albemarle-Pamlico Sound; a small estuary, the Parker River, situated in the Plum Island NSF Long-Term Ecosystem Research (LTER) site in MA; and a tide dominated estuary in the southeast Atlantic Bight, the North Inlet, SC. These sites are representative of three primary producer bases (intertidal marsh-Plum Island and North Inlet; plankton dominated- and seagrass dominated-portions of Chesapeake Bay and Pamlico Sound) and all contain both pristine and anthropogenically-impacted waters (See Figure 3.11). They also have ongoing, long-term water quality/habitat monitoring programs, serving as the bases for indicator development and testing. These indicators form the backbone of ecosystem, regional and national water quality, habitat assessment and living resources monitoring and modeling efforts. They serve to calibrate and ground truth aircraft and satellite remote sensing of estuarine and coastal resources, including plant community structure, function, and ecological health. Microalgal, marsh and seagrass proxies are linked with metrics of trophic structure to provide indicators of living resources. Our research priorities are to enhance the archive of existing data for these systems with remotely sensed and in situ information on key variables, exploit detailed knowledge of ecosystem structure and function to synthesize this archive and develop candidate indicators, and test the ability of these indicators to gauge ecosystem health and unambiguously detect trends resulting from both natural variability and anthropogenic stresses in multiple estuaries.

• Attenuation of non-point source nitrogen in a coastal watershed: Implications for nutrient management (Piehler, Paerl)

The Neuse River Estuary has shown symptoms of eutrophication throughout the past two decades that have been linked to anthropogenic nitrogen pollution. At least 75% of the total nitrogen load to the estuary has been traced to non-point sources. Varied and evolving land use within the watershed affects the quantities and types of non-point source nitrogen transported to surface waters. Non-point source nitrogen is introduced to estuaries through both distant and proximate sources. We are investigating the transport and transformation of non-point source nitrogen from agricultural and forested lands adjacent to the estuary. We are gathering land-use specific data on transformation and export of nitrogen from various sources to the estuary in agricultural and forested sub-watersheds of the Neuse River Estuary. Particular attention is being paid to processes that either transform or remove non-point source nitrogen prior to being transported to the estuary. Information on land use specific nitrogen transformations is then linked to physical, chemical and biological data for the Neuse River Estuary and Pamlico Sound. We anticipate generating a rigorous analysis of the dynamics of non-point source nitrogen transport for various land uses in the Neuse River Estuary basin. Ultimately, the experimental and field measurements will provide data to construct a model of attenuation of proximate non-point source nitrogen that will be adaptable and applicable to other watersheds.

• Ecology of Infectious Diseases: Ecology of Human Pathogens and Disease (Noble, Paerl)

Accelerating nutrient- and pathogen-enriched wastewater discharge that accompanies coastal development is putting unprecedented pressure on estuaries that receive and process the bulk of land-based runoff. Enhanced nutrient loading has led to increased primary productivity or eutrophication, the symptoms of which pose a significant threat to coastal resources and ecological health. This eutrophication leads to organic matter enrichment of affected waters. Most human pathogens in wastewater discharges are heterotrophs and may thrive under these enriched organic matter conditions. As a result, pathogen populations may increase with enhanced eutrophication. This research focuses on understanding the relationships between nutrient loading in an important watershed (the Neuse River Estuary), growth and fate of microorganisms linked to infectious disease, and subsequent impacts on human health. The long-term goal is the creation of a computational model useful in estimating the effect of watershed protection policies on ecological and human health.

• Profiling Buoy System for Shallow Waters (Rick Luettich, H. Paerl, students) (EPA).

Luettich has developed a profiling buoy system for shallow inner shelf and estuarine studies. It is comprised of a buoy mounted, computer controlled winch system that raises and lowers a CTD/multi-parameter probe. Cell phone communications enable near real time transmission of data to shore. Two of these systems have been deployed in the Neuse River Estuary over the past several years and have documented the occurrence of wind driven upwelling along the shores of the estuary and the role that this plays in bringing low oxygen water to the surface (potentially impacting pelagic fisheries populations in the system). These profiling buoys have also documented a pervasive vertical migration of the chl-a maximum in the water column from near surface to near bottom on a daily time scale and characterized the meteorological conditions for which the system becomes well-mixed over the depth. Under these mixing conditions the chl-a maximum is completely disbanded and bottom resuspension is widespread.

• ModMon: a Comprehensive, Long Term Water Quality Modeling and Monitoring Program for the Neuse River Estuary (Hans Paerl, Rick Luettich) (North Carolina Department of Environment and Natural Resources)

ModMon is a coordinated, multidisciplinary state, university and industry estuarine environmental modeling and monitoring program. This effort is a result of the Senate Select Committee hearings on River Water Quality and Fish Kills, legislative requests for assistance from university scientists in solving state environmental problems, and university initiatives to enhance research in areas of critical importance to state water quality management and planning. ModMon has been designed to provide a water quality model of the Neuse River Estuary (NRE) that is evaluating alternatives for reducing nitrogen loading. ModMon is also a crucial source of data for evaluating a Total Maximum Daily (nitrogen) Load (TMDL), required by the EPA for controlling unwanted symptoms of eutrophication in the NRE (algal blooms, hypoxia, food web disruption). To achieve these goals, the monitoring component is obtaining field data for calibrating and verifying the model and advancing our understanding of relationships between nutrient loading, eutrophication and water quality. Field data are obtained by both ship-based and in stream continuous multiple sensor (YSI 6800) measurements of temperature, salinity, pH, turbidity, dissolved oxygen and chlorophyll (fluorescence), complemented by laboratory analyses of inorganic and organic nutrients (C, N, P), diagnostic (of algal taxonomic groups) photopigments, and molecular markers for microbial groups involved in nutrient cycling and production dynamics.

• Water Quality Monitoring by NC Ferry (FerryMon), (Hans Paerl) (NCDENR, NCDOT)

North Carolina’s Albemarle-Pamlico Estuarine System (APES) is the US’s second largest estuary and a critical habitat for its southeastern Atlantic fishery. Three ferries that traverse APES (see Figure 3.36) have been equipped with a flow-through system that includes a multi-probe sensor and an automated water sampler to assess surface water quality trends. This program, FerryMon (www.ferrymon.org) also provides salinity, temperature, dissolved oxygen, turbidity, pH, nutrient and diagnostic photopigment data for calibrating and verifying modeling and remote sensing of APES. GPS-based data are downloaded nightly. Intensive temporal and spatial data obtained from the ferry routes provide an environmental baseline and are used to assess the patterns and variability in surface water hydrography, nutrients and phytoplankton biomass and composition. The three ferry routes currently being monitored include the Cedar Island-Ocracoke ferry which crosses the southern Pamlico Sound and Ocracoke Inlet, the Swan Quarter-Ocracoke ferry which crosses the central Pamlico Sound, and the Neuse River ferry, which makes 40 crossings crossing per day between Cherry Point and Minnesott Beach. FerryMon is evaluating ecosystem-level responses to environmental perturbations, including hurricanes, and is being used to calibrate remote coastal ocean color sensors. This also provides a model system for assessing water quality over a wide range of spatial and temporal scales.