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Mar 23 / USGS Newsroom

From Fingerprints and Water Quality to Intersex Fish: USGS at the Chesapeake Bay Ecosystem Conference

Editors and Reporters: The conference runs from March 23-25 at the Baltimore Inner Harbor Marriott, 110 S. Eutaw St. For more info, see the Ecosystem Based Management in the Chesapeake and Other Systems Web site.

A Plague of Hormone-Mimicking Compounds and Other Contaminants Adversely Affecting Chesapeake Bay Fish: Fish health and reproductive issues in the Chesapeake Bay drainage may be associated with fish exposure to hormone-mimicking compounds and other chemicals. USGS scientists have studied yellow perch, a species that has declined in recent years, and found that differences in the egg quality of these fish is occurring in some sites they sampled.  In addition, scientists sampled smallmouth bass and other species from major fish kills in the South Branch of the Potomac and the Shenandoah River. They found the fish were infected with a variety of types of skin lesions and a number of disease-causing bacteria, viruses and parasites. These findings suggest that the immune systems of these fish are weakened, reducing their resistance to disease. Researchers also found high numbers of intersex bass collected in the same areas as the fish kills. Intersex fish, as well as the measurement of the female yolk protein, vitellogenin, in male fishes, have been most commonly associated with exposure to estrogen-mimicking compounds. The co-occurrence of fish kills with these other reproductive effects suggests that endocrine-disrupting chemicals may affect not just individual fish, but also entire populations due to decreased disease resistance and reproductive effects.  The distribution of bass with intersex and the possible association with land-use practices will be discussed. For more information, contact Vicki Blazer at vblazer@usgs.gov or 304-724-4434. Title of talk: Potential effects of endocrine-disruptors and other emerging contaminants on fish species in Chesapeake Tributaries

From Marsh to Open Water: Nutria Eating the Way to Ecosystem Change: South American nutria, an invasive species in the Chesapeake Bay, have long been implicated in the alarming loss of emergent marsh bordering the Blackwater River in Dorchester County, MD. Since their introduction in the1940s, vast acreages of marsh have been converted to open water. No remedial action was taken until the passage by Congress of the 2003 Nutria Control Act, an act that launched a large-scale federal nutria eradication program. This presentation summarizes over a decade of field observation and measurement of vegetative change and reflects on the complex dynamic of interactive physical factors likely to control vegetative expansion and loss. Although no exact history of the process of marsh loss can be reconstructed, important insights arise as to the role of nutria herbivory, tidal erosion, and ultimately the delicate structure of the marsh itself, as factors underlying the rapid conversion to open water that seems irreversible today. Finally, measurements of marsh vegetation before and after nutria removal provide valuable insight into the recovery potential of emergent marsh even under the threat of continued sea-level rise. For more information, contact Mike Haramis at  mharamis@usgs.gov or 301-497-5651. Title of talk: Nutria as a catalyst of change in the tidal marshes of the Blackwater River basin, Maryland

They’re Blooming Harmful: Here Today, Gone Tomorrow, and Then Here Again: Harmful algal and cyanobacteria bloom events are a sign of the undesirable consequences of environmental degradation in the Chesapeake Bay system. Such blooms have been linked with submerged aquatic vegetation declines due to reduced light availability, fish kills from toxic activity or acutely lethal swings in dissolved oxygen, bird kills, and even human health-related events. Other underappreciated and unanticipated consequences of such blooms are their economic impacts by negatively affecting laboratory studies, aquaculture operations, fishery community activities and reduced harvest success, or waves of social response to uncertainty about risks, real or imagined, about seafood safety or beach closures. Oxygen-starved conditions, linked with some blooms, continue to occur throughout the Bay. While Chesapeake Bay watershed States remain committed to water quality protection and ecosystem restoration, recurrent blooms pose further challenges to conducting successful restoration activities. For more information, contact Peter Tango, ptango@chesapeakbay.net or 410-267-9875. Title of talk: Impacts of HABs in Chesapeake Bay 

How to Find Sediment and Nutrient Culprits? Use Fingerprints and Budgets: Sediment and associated nutrients are degrading the living resources and habitat of the Chesapeake Bay and its watershed. Consequently, to deal with this degradation, managers must know the significant sources, storage areas, and transport processes of watershed-derived sediment and nutrients.  To help do this, USGS has developed the SPARROW model (Spatially-Referenced Regression on Watershed Attributes) for the Chesapeake Bay Watershed and its major rivers. At smaller watershed scales (~300 square kilometers), the USGS has been developing a sediment fingerprinting approach to identify significant sources and locations of retention of nutrients and sediment. With this approach, researchers can identify the sources of fine-grained suspended sediment and associated phosphorus by comparing physical and chemical properties of the transported suspended sediment to potential sources in the watershed. Sediment sources can even be determined for individual storm events. Another approach that USGS has developed — the sediment-budget approach – helps managers understand the linkages among source areas, depositional sites, and sediment export. Measurements made in the sediment budget approach, such as streambank erosion, can be used to identify areas of high erosion in the watershed where management actions may be directed. The identification of sediment sources and long-term storage zones is a key product of both approaches. For more information contact Allen Gellis at agellis@usgs.gov or 443-498-5581. Title of talk: Understanding the sources of nutrients and sediment in the Chesapeake Bay Watershed

Coasting with COAST: An Online Toolkit for Chesapeake Bay Restoration: The new Chesapeake Online Adaptive Support Toolkit (COAST) is a web-based, decision-support system to assist land management and restoration efforts in the Chesapeake Bay watershed. COAST provides managers and policy-makers a diverse suite of models, monitoring data, and support information to help them better target, implement, and assess the effectiveness of their restoration activities. In addition, COAST uses an adaptive-management framework so managers can make more informed decisions as they learn more about the ecosystem over time. The initial version of COAST focuses on the Chesapeake Bay Program (CBP) water-quality goal. Managers with the USDA Natural Resources Conservation Service are now using COAST to make water-quality decisions related to agriculture and to identify priority agricultural areas within the Chesapeake Bay watershed. The U.S. Environmental Protection Agency is using information from COAST to help select projects to reduce nutrients from urban areas. Likewise, the Chesapeake Bay Foundation and the Maryland Bay Trust Fund are using information from COAST to help identify areas in which to focus and assess efforts to reduce nutrients from agricultural and urban areas. Future uses of COAST include identifying forest areas that provide a water-quality benefit so they can be considered for protection, better focusing efforts to implement streamside buffers, and identifying key habitats for restoration and protection. COAST is a joint product of the U.S. Geological Survey and the Chesapeake Bay Program Office. For more information, contact Scott Phillips at swphilli@usgs.gov or 443-498-5552. Title of talk: Chesapeake Online Adaptive Support Toolkit (COAST)

Location, Location, Location: Forest Buffers and Hydrologic Pathways: Streamside forest buffers are one of the most widely used best-management practices (BMPs) for removing nutrients and suspended sediment from waters of the Chesapeake Bay Watershed. Buffers typically are planted along streamsides to a width that commonly extends 35 to 100 feet from the stream. But studies at several sites have shown that the mere presence of a forest buffer does not necessarily provide effective removal because hydrologic pathways control the effectiveness of the removal processes across stream corridors. Consequently, where forest buffers are located in relation to hydrologic pathways is a key in how effective they are at reducing nutrient and suspended sediment loads to the Bay. Several effects of hydrologic pathways on nitrate concentrations in groundwater exemplify how changes in nutrient and sediment concentrations do not necessarily reflect changes in sediment loads. USGS researchers also found that  the edges of floodplains bordering valley slopes seem to be some of the most effective parts of stream  corridors for nitrate removal. Mapping the geographic distribution of removal processes in relation to pathways for both groundwater flow and surface runoff can help provide managers with tools to target the planting and preservation of forest buffers that effectively remove nutrients and suspended sediment from waters across the Bay Watershed. For more information, contact Gary Speiran at gspeiran@usgs.gov or 804-261-2642. Title of talk: Alternative forest buffer placement for improving water quality

Managing Sediments in the Chesapeake Bay: An application of the watershed model SPARROW (SPAtially Referenced Regressions On Watershed attributes) provides managers with predictions that allow them to quantify, locate, and assess sediment sources and the factors that affect the fate and transport of sediments in the Chesapeake Bay Watershed. Using SPARROW, USGS researchers modeled the estimated average annual flux of suspended sediment from 129 long-term monitoring stations in nontidal streams with sources of suspended sediment and transport factors. The results showed that agriculture, urban development, and small streams outside the Chesapeake Bay Coastal Plain were the predominant sources of suspended sediment throughout the watershed. Agriculture contributed more than half (51 percent) of the suspended sediment that was  transported to the estuary. Another 39 percent originated from developed areas, 8 percent from small stream channels, and 2 percent from forests. On average, urban development yields the greatest amount of suspended sediment per unit area, although agriculture is much more widespread throughout the region and the greatest overall source of suspended sediment. Factors affecting the transport of suspended sediment from uplands to streams include basin slope, physiography, and soil permeability. Managers may find that applying erosion controls in areas of known sediment sources where the combined effects of watershed characteristics on sediment transport have the greatest influence may be most helpful in mitigating sedimentation in the bay and its tributaries. Sediment storage occurs along larger streams in the Coastal Plain where slopes and velocities are lower, and in reservoirs, where residence times are longer. Management actions designed to maintain the ability of floodplains to retain sediment in the Coastal Plain setting may be an effective way to preserve this natural trapping system. For more information, contact John Brakebill at jwbrakeb@usgs.gov or 443-498-5557. Title of talk: Spatially Explicit Estimates of Sources and Transport Processes of Suspended-Sediment Flux in Streams of the Chesapeake Bay Watershed

[Via USGS]

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