Chronic seasonal low oxygen condition (hypoxia) occurs in the deep waters of Chesapeake Bay as a result of eutrophication-induced phytoplankton blooms and their subsequent decomposition. Summertime hypoxia has been observed in Chesapeake Bay for over 80 years, with scientific attention and understanding increasing substantially during the past several decades after rigorous and routine monitoring programs were put in place.

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Chesapeake Bay has undergone profound changes since European settlement. Increases in human and livestock populations, associated changes in land use, increases in nutrient loadings, shoreline armoring, and depletion of fish stocks have altered the important habitats within the Bay. Submersed aquatic vegetation (SAV) is a critical foundational habitat and provides numerous benefits and services to society.

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This report card provides a transparent, timely, and geographically detailed assessment of Chesapeake Bay. In 2016, the report card includes five water quality indicators and two biotic indicators. In 2016, the overall grade for Chesapeake Bay is a 54%, a C. This means the Bay is in moderate health. Long term trends of each reporting region health and a fisheries index are also presented. For further details, visit the Report Card Website.

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The Chesapeake Monitoring Cooperative (CMC), as part of the Indicator Effectiveness Matrix objective, produced 12 factsheets describing 14 tidal water quality indicators. These indicators are part of the CMC's tidal water quality Quality Assurance Project Plan and Method Manuals. The factsheets are intended for nontraditional and volunteer monitoring groups to include as part of their water quality monitoring programs as education materials for their volunteers.

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The aim of this report card was to complete IAN's first annual report. IAN staff reflected back on accomplishments from 2015 and developed indicators in 3 categories: social impacts, ecological outcomes, and partnership satisfaction. IAN received an overall grade of a B+.

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Regression-based approaches are often employed to estimate riverine constituent concentrations and fluxes based on typically sparse concentration observations. One such approach is the recently developed WRTDS (‘‘Weighted Regressions on Time, Discharge, and Season”) method, which has been shown to pro- vide more accurate estimates than prior approaches in a wide range of applications.

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The influence of sea level rise and warming on circulation and water quality of the Chesapeake Bay under projected climate conditions in 2050 were estimated by computer simulation. Four estuarine circulation scenarios in the estuary were run using the same watershed load in 1991-2000 period. They are, 1) the Base Scenario, which represents the current climate condition, 2) a Sea Level Rise Scenario, 3) a Warming Scenario, and 4) a combined Sea Level Rise and Warming Scenario.

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Interactions among global change stressors and their effects at large scales are often proposed, but seldom evaluated. This situation is primarily due to lack of comprehensive, sufficiently long-term, and spatially extensive datasets. Seagrasses, which provide nursery habitat, improve water quality, and constitute a globally important carbon sink, are among the most vulnerable habitats on the planet.

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Derived from river monitoring data, concentration-discharge (C-Q) relationships are powerful indicators of export dynamics. Proper interpretation of such relationships can be made complex, however, if the ln(C)-ln(Q) relationships are nonlinear or if the relationships change over time, season, or discharge. Methods of addressing these issues by “binning” data can introduce artifacts that obscure underlying interactions among time, discharge, and season.

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This report card provides a transparent, timely, and geographically detailed assessment of Chesapeake Bay. In 2015, the report card includes five water quality indicators and two biotic indicators. In 2015, the overall grade for Chesapeake Bay is a 53%, a C. This means the Bay is in moderate health. Long term trends of each reporting region health and a fisheries index are also presented. For further details, visit the Report Card website.

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