412 (BEL-1122-336746) The Chesapeake Watershed Past, Present, and Future (part 1).
Start time: 8:00 AM
Bell, W¹, ¹ Center for the Environment and Society, Washington College, MD, USA
A review of historic land use on the 64,000 sq mi Chesapeake Bay watershed reveals a working landscape with human activity as an integral component of the system. This working landscape perspective, with special regard for changing agricultural practices from the time of pre-colonial contact to the present day, provides important insights into the forces that are working to change the region's predominantly rural communities and their resource-based economies. Communities that take advantage of these forces, as opposed to simply resisting or accommodating them, suggest a promising approach not only to their respective futures, but also to addressing such recalcitrant problems as non-point pollution and a more sustainable quality of life. This presentation will use the history of the Chesapeake Bay watershed to develop the working landscape perspective, identify some of the forces for change that are affecting present-day land use, and show through examples how local leadership-based community visioning can serve as a pro-active rather than reactive approach to a more sustainable future for the region.

413 (BEL-1122-408754) The Chesapeake Watershed Past, Present, and Future (part 2).
Start time: 8:20 AM
Bell, W.¹, ¹ Center for the Environment and Society, Washington College
A review of historic land use on the 64,000 sq mi Chesapeake Bay watershed reveals a working landscape with human activity as an integral component of the system. This working landscape perspective, with special regard for changing agricultural practices from the time of pre-colonial contact to the present day, provides important insights into the forces that are working to change the region's predominantly rural communities and their resource-based economies. Communities that take advantage of these forces, as opposed to simply resisting or accommodating them, suggest a promising approach not only to their respective futures, but also to addressing such recalcitrant problems as non-point pollution and a more sustainable quality of life. This presentation will use the history of the Chesapeake Bay watershed to develop the working landscape perspective, identify some of the forces for change that are affecting present-day land use, and show through examples how local leadership-based community visioning can serve as a pro-active rather than reactive approach to a more sustainable future for the region.

414 (BRU-1122-337227) The Long Term History of the Chesapeake Bay.
Start time: 8:40 AM
Brush, G¹, ¹ Johns Hopkins University, Department of Geography and Environmental, MD, USA
The history of the Chesapeake Bay since its origin some 10,000 years ago is recorded in sediments that have eroded off the land and been deposited in the estuary and tributaries. This history is retrieved from sediment cores. Preserved in the sediment are pollen grains and seeds of terrestrial and aquatic plants, diatoms, ostracods, foraminifera, mandibles of worms, charcoal, chemicals and other entities which serve as indicators of the Bay's environment and biota. During all of this time, the landscape drained by the Bay was about 90% forested. The history contained in the sediment shows the response of forests to climate change over the millennia from species such as spruce and fir present on the landscape when the Bay began to form to hemlock later as climate became warmer to the present oak-hickory-pine forests that have existed over the past 5000 years. During this time, organisms such as diatoms that lived in the estuarine waters were mostly benthic. Submerged grasses were always present. The record indicates that estuarine waters were clear and turbidity low. Dramatic changes began about 300 years ago with the beginning of European settlement. Within a relatively short period of time, the forests were removed and replaced by agricultural fields. This transformation of the landscape was followed by decreased salinity with increased runoff from a deforested landscape, high turbidity from soil erosion resulting in light limitation, increased eutrophication from fertilizers and more widespread anoxia as oxygen in the bottom waters was consumed by decaying biomass. The benthic ecosystem became very stressed, and eventually the mesohaline part of the Chesapeake Bay was converted from a rich benthic ecosystem to one that is now primarily planktonic and in many parts of the Bay heterotrophic.

415 (MAU-1117-749461) Current issues in Maryland land use policy.
Start time: 9:00 AM
Maurer, G.¹, ¹ Chesapeake Bay Foundation, Annapolis, MD, 21403
Sound land use practices are critical to the restoration of water quality in the Chesapeake Bay. Yet, while Maryland is considered a national model for its progressive smart growth policies, we still face a crisis from the adverse effects of suburban sprawl. This presentation will discuss the reasons for this disconnect, by providing an overview of the most important land use related policy issues in Maryland, highlighting successes and failures. Current Maryland policy and practices such as: the priority places initiative, development capacity analyses, annexations, land conservation funding and initiatives, and balanced transportation spending will be summarized and critiqued. The presentation will conclude with an evaluation of the political climate for positive policy changes.

(59353) break.
Start time: 9:20 AM

416 (GRO-1117-812083) The bio-geo-socio-chemistry of urban watersheds.
Start time: 10:00 AM
Groffman, Peter¹, ¹ Institute of Ecosystem Studies, Millbrook, NY, USA
Increases in impervious surface associated with urbanization lead to development of an 'urban stream syndrome' with physical degradation of the stream and riparian zone, declines in water quality and changes in biota. This degradation motivates a variety of human responses ranging from regulation to address pollutant delivery to receiving waters (e.g. Chesapeake Bay), to the formation of neighborhood groups concerned about children playing in polluted streams. These groups can serve as catalysts for social cohesion and community action that can foster ecological and socio-economic revitalization of underserved neighborhoods. In the Baltimore Ecosystem Study, one of two urban long-term ecological research (LTER) projects funded by the U.S. National Science Foundation, we are using 'the watershed approach' to integrate ecological, physical and social sciences. Watersheds are a natural (and well-used) physical unit for ecological research and can also function as a focus for human-environment interactions. In this talk I review 1) how urbanization results in degradation of water quality, stream and riparian ecosystems; 2) how this degradation can motivate human action and 3) how restoration can serve as a catalyst for environmental and socio-economic revitalization of underserved areas. Using examples ranging from nitrate dynamics in riparian zones, to the role of urban trees as absorbers of air pollution, to the creation of a trail along a historic stream corridor, I will illustrate how changes in highly visible components of the environment (streams) can be used as a tool to improve the design and implementation of ecosystem restoration to achieve multiple objectives.

417 (BAK-1118-586716) Challenges of assessing and managing persistent bioaccumulative toxins in the Chesapeake Bay.
Start time: 10:20 AM
Baker, J¹, ¹ University of Maryland, Solomons, MD, USA
During the past decade, we have conducted field assessments to determine the concentrations, inventories, and sources of persistent bioaccumulative toxins (PBTs) in the Cheasapeake Bay estuary. Increasingly stringent risk-based thresholds have resulted from improved ecological and human health risk analyses that use sub-lethal endpoints. In the Chesapeake Bay, levels of polychlorinated biphenyls (PCBs) in estuarine fish commonly exceed the most cautious risk-based concentrations, resulting in fish consumption advisories. One goal of our studies is to estimate the magnitudes and relative importance of PCB sources to the Chesapeake Bay. Using the mass balance paradigm, the relative magnitude of storm water, riverine discharge, atmospheric deposition, and point sources are determined. For example, long-term monitoring of the Susquehanna River tributary, which provides 60% of the freshwater flow to the Chesapeake Bay, determined that 76 kg of t-PCB were delivered from the Susquehanna watershed each year. The source of these PCBs to this largely agricultural and forested watershed are unknown. We have developed a spatially-explicit, time-variable model of PBT transport in the estuary to explore the exchange of chemicals between the sediment-water and air-water interfaces, with emphasis on quantifying release of PCBs from contaminated sediments. In addition to 'legacy' PBTs such as PCBs, our recent assessments include the first study of the sources and cycling of brominated flame retardants in the estuary. Current levels of these compounds are quite low in the Chesapeake relative to those documented to cause affects, but their nearly exponential rise in production and use will require continued environmental assessments.

418 (RAT-1117-053295) Environmental Contaminant Exposure, Effects, and Ecotoxicological Research Needs for Chesapeake Bay Wildlife.
Start time: 10:40 AM
Rattner, Barnett¹, McKernan, Moira¹, Ackerson, Betty¹, McGowan, Peter², ¹ USGS-Patuxent Wildlife Research Center, Beltsville, MD, USA² Chesapeake Bay Field Office, U.S. Fish and Wildlife Service, Annapolis, MD, USA
Environmental contamination in Chesapeake Bay ranges from a moderate to potentially significant stressor on waterbirds and terrestrial wildlife. A search of the Contaminant Exposure and Effects-Terrestrial Vertebrates database (www.pwrc.usgs.gov/contaminants-online) revealed 839 data records for terrestrial vertebrates in the Chesapeake Bay region. Recent studies in waterfowl, terns, herons, and ospreys indicate that legacy organochlorine contaminants have declined in eggs and tissues, although p,p'-DDE, total PCBs and coplanar PCB congeners still exert sublethal and reproductive effects in parts of the Bay. Contemporary contaminants (alkylphenols, ethoxylates, perfluorinated compounds, polybrominated diphenyl ethers) are detectable in osprey eggs from regions of concern (Anacostia River, Elizabeth River, Baltimore Harbor) but interpretation of these exposure data are difficult because adverse effect levels are unknown in wildlife. With the possible exception of Cd, concentrations of other metals (e.g., Hg, Pb and Se) in tissues and eggs are below toxic effect thresholds of waterbirds. Since 1990, two moderate-sized oil spills have occurred resulting in the death of several hundred birds; records of the U.S. Fish and Wildlife Service and the U.S. Coast Guard indicate that about 500 smaller spill events occur annually in the Chesapeake Bay region. Exposure and potential effects of dioxins, dibenzofurans, cholinesterase-inhibiting pesticides, rodenticides, and lead shot have not been adequately assessed in the past 15 years, and relatively little is known about impacts of algal toxins on waterbirds in the Bay. In addition, future ecotoxicological research and monitoring activities should focus on amphibians and reptiles throughout the region, and avian species in upper bay tributaries.

419 (PAY-1122-409496) Oyster Restoration in Maryland.
Start time: 11:00 AM
Paynter, K¹, ¹ Department of Biology, University of Maryland
Oysters were an integral part of the Chesapeake Bay ecosystem that was almost entirely removed during the last century. Stocks are now thought to be less than 1% of historic levels and two diseases threaten rehabilitation efforts. Maryland waters, however, are generally low in salinity, which retards disease virulence and enhances oyster survival. Strategies to restore oyster populations include planting the native species, Crassostrea virginica, in high densities in low salinities to create large reef structures and testing a non-native species, Crassostrea ariakensis, for disease resistance and reef formation. Restoration efforts to date show that oysters planted in low salinities and protected from fishing will live relatively long lives and create substantial reef structure. These reefs may have far-reaching ecological value. Low salinity reefs protected from fishing experience 10 to 15% mortality annually and grow 2 to 3 cm/yr. When planted densely (250 to 500 seed oysters/m2) they create substantial and complex benthic structure. These structures, in turn, serve as valuable habitat to a variety of benthic species whose abundances are much higher on restored reefs compared to non-restored reefs. Because these reefs are composed of large animals in dense aggregations, the potential contributions of the oysters in a spatial context (/m2) may be quite high. Calculations based on literature values for filtration rates, nitrogen removal and larvae production suggest these reefs may filter vast quantities of water, remove ecologically-relevant amounts of nitrogen and produce billions of larvae on a per acre basis.

420 (LUD-1122-335711) Historical and Current Impacts and Issues Affecting Chesapeake Bay Fisheries.
Start time: 11:20 AM
Ludwig, D¹, Iannuzzi, T¹, ¹ BBL Sciences, Annapolis, MD, USA
For Native Americans in pre-Columbian times and scattered early European settlements, the Chesapeake Estuary provided abundant resources of fish and shellfish. Soon after, agriculture, industry, development, and harvest began the cycles of impact that continue today. Exploitation depleted some species, such as shortnose and Atlantic sturgeon, during the colonial period. Since then, populations of commercial and recreational fish and shellfish, including American shad and river herrings, Atlantic croaker, striped bass, blue crab, soft clam, and American oyster have drastically declined and, in some cases (for example, striped bass) recovered. In this presentation, we summarize historical changes in Chesapeake Bay fish and shellfish populations and describe the ecosystem alterations, harvest technologies, and management methods that provide much of the context for those changes. We provide a fresh perspective regarding the effects of invasive species, disease organisms, commercial and recreational harvest, landscape modifications, point-and non-point source pollution, and habitat degradation on fish and shellfish resources. We develop and present a general model illustrating the linked nature of human and aquatic ecosystems in the Chesapeake, incorporating both the directed management of fish and shellfish resources and the undirected constraints imposed on the ecology of the Bay by ongoing anthropogenic modification of the biosphere.