Noble Research

• ACE InC –(Paerl, Noble)

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.

• 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.

• Rapid Microbial Detection in Recreational Waters (Rachel Noble)

Monitoring of recreational beaches for fecal contamination is currently performed using culture-based technology that requires >1 day for laboratory analysis. New methods have been developed that have the potential to reduce the measurement period to < 1 hour. These methods generally involve two steps, target capture and detection. Target capture refers to removal, tagging, or amplification of the microbial group of interest (or some molecular/chemical/or biochemical signature of the group) to differentiate it from the remaining material in the sample. Three classes of capture methods have been explored: 1) Surface and whole-cell recognition methods, including immunoassay techniques and molecule-specific probes; 2) Nucleic acid methods, including polymerase chain reaction, quantitative PCR, nucleic acid sequence based amplification and microarrays; and 3) Enzyme/substrate methods utilizing chromogenic or fluorogenic substrates. Detection involves optical, electrochemical or piezoelectric technologies to quantify the captured, tagged or amplified material. The biggest technological hurdle for all these methods is sensitivity, as EPA’s recommended bathing water standard is less than one cell per ml and most detection technologies measure sample volumes less than 1 ml. This challenge is being overcome through addition of pre-concentration or enrichment steps, which have the potential to boost sensitivity without the need to develop new detector technology. The second hurdle is demonstrating a relationship to health risk, since most new methods are based on measuring cell structure without assessing viability, and may not relate to current water quality standards that were developed in epidemiology studies using culture-based methods. Enzyme/substrate methods are most likely to be the first rapid methods adopted because they are based on the same capture technology as currently-approved EPA methods and their relationship to health risk can be established by demonstrating equivalency to existing procedures. Demonstration of equivalency may also be possible for some surface and whole-cell recognition methods that capture bacteria in a potentially viable state. Nucleic acid technologies are the most versatile. However, they measure nonviable structure and will require inclusion in an epidemiological study to link their measurement with health risk.