The Chesapeake Bay Program maintains an extensive nontidal monitoring network, measuring nitrogen and phosphorus (nutrients) at more than 100 locations on rivers and streams in the watershed. Data from these locations are used by USGS to assess the ecosystem’s response to nutrient-reduction efforts.

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Understanding the temporal and spatial roles of nutrient limitation on phytoplankton growth is necessary for developing successful management strategies. Chesapeake Bay has well-documented seasonal and spatial variations in nutrient limitation, but it remains unknown whether these patterns of nutrient limitation have changed in response to nutrient management efforts.

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Anthropogenic inputs of nutrients via river runoff are the primary drivers of ecosystem degradation in Chesapeake Bay (CB) and the northern Adriatic Sea (NAS). The annual cycle of river flow is typically unimodal in CB (seasonal peak during spring) and bimodal in the NAS (peaks during April–June and October–December). Dissolved inorganic nitrogen accounts for most of the total nitrogen (TN) in both systems.

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Nutrient and sediment transport exhibit strong spatial and temporal inequality, with a small percentage of locations and events contributing to the vast majority of total annual loads. The processes for determining how to reduce total annual loads at a watershed scale often target spatial, but not temporal, components of inequality.

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In the annual IAN Report Card, IAN staff reflect back on accomplishments from 2019. The self-assessment is based on indicators in three categories: social impacts, ecological outcomes, and partner engagement. Overall, IAN received an overall grade of B (84%) which is a slight decrease from the 2018 score of B (86%).

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The Chester River, a tributary of Chesapeake Bay, provides critical habitats for numerous living species and oyster aquaculture, but faces increasing anthropogenic stresses due to excessive nutrient loading and hypoxia occurrence.

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Coastal wetlands, such as saltmarshes and mangroves that fringe transitional waters, deliver important ecosystem services that support human development. Coastal … wetlands are complex social-ecological systems that occur at all latitudes, from polar … regions to the tropics. This overview covers wetlands in five continents. The wetlands … are of varying size, catchment size, human population and stages of economic … development.

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Excessive nitrogen (N) inputs to coastal waters can lead to severe eutrophication and different chemical forms of N exhibit varying levels of effectiveness in fueling primary production. Efforts to mitigate N fluxes from coastal watersheds are often guided by models that predict changes in N loads as a function of changes in land use, management practices, and climate. However, relatively little is known on the impacts of such changes on the relative fractions of different N forms.

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This review aims to synthesize the current knowledge of sediment dynamics using insights from long-term research conducted in the watershed draining to the Chesapeake Bay, the largest estuary in the U.S., to inform management actions to restore the estuary and its watershed. The sediment dynamics of the Chesapeake are typical of many impaired watersheds and estuaries around the world, and this synthesis is intended to be relevant and transferable to other sediment-impaired systems.

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This report card provides a transparent, timely, and geographically detailed assessment of Chesapeake Bay. Since 2016, UMCES has engaged stakeholders throughout the watershed to transform the report card into an evaluation of the Chesapeake Watershed health. Watershed health includes traditional ecosystem indicators, but also social, economic, and cultural indicators. This is the first year the watershed has been scored, using five indicators of ecological and socioeconomic health.

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