Integrated Trends Analysis Team Publications
Progress toward the Restoration of Chesapeake Bay in Time and Space
Three decades of monitoring in Chesapeake Bay and tributary rivers has allowed for an examination of the spatial and temporal patterns of water quality change in response to watershed restoration activities. This review of past monitoring data has revealed clear signs of successful water quality remediation in some Chesapeake regions. Upgrades to waste water treatment plants (WWTP) have led to measurable reductions in nutrient concentrations and algal biomass, with associated recoveries of submerged aquatic vegetation and reductions in sediment and nutrient levels. Point-source related improvements were observed in waters local to the WWTP facility, which are generally in oligohaline and tidal freshwater regions of tributaries. Reductions in atmospheric deposition of nitrogen within the Bay watershed has resulted inmarked reductions in nitrogen inputs from the Susquehanna and Potomac Rivers, and these reductions in watershed input have resulted in lower concentrations within the estuary. Coastal plain watersheds with high agricultural intensity continue to yield high amounts of nutrients, and water quality has not improved in the receiving waters of many of these tributaries. Signs of eutrophication remediation are clearest where nutrient load reductions are large and local. In more seaward estuarine reaches, recovery from eutrophication appears to be season- and regionspecific, where the late growing season period in high-salinity waters, which is most vulnerable to nutrient limitation and oxygen replenishment, appear to have recovered first. These findings suggest a refinement of our existing conceptual models of the eutrophication process in Chesapeake Bay, where time of year and proximity to nutrient sources are important to understanding spatial and temporal variation in recovery.
View detailsProgress toward the Restoration of Chesapeake Bay in Time and Space - Executive Summary
Three decades of monitoring in Chesapeake Bay and tributary rivers has allowed for an examination of the spatial and temporal patterns of water quality change in response to watershed restoration activities. This review of past monitoring data has revealed clear signs of successful water quality remediation in some Chesapeake regions. Upgrades to waste water treatment plants (WWTP) have led to measurable reductions in nutrient concentrations and algal biomass, with associated recoveries of submerged aquatic vegetation and reductions in sediment and nutrient levels. Point-source related improvements were observed in waters local to the WWTP facility, which are generally in oligohaline and tidal freshwater regions of tributaries. Reductions in atmospheric deposition of nitrogen within the Bay watershed has resulted inmarked reductions in nitrogen inputs from the Susquehanna and Potomac Rivers, and these reductions in watershed input have resulted in lower concentrations within the estuary. Coastal plain watersheds with high agricultural intensity continue to yield high amounts of nutrients, and water quality has not improved in the receiving waters of many of these tributaries. Signs of eutrophication remediation are clearest where nutrient load reductions are large and local. In more seaward estuarine reaches, recovery from eutrophication appears to be season- and regionspecific, where the late growing season period in high-salinity waters, which is most vulnerable to nutrient limitation and oxygen replenishment, appear to have recovered first. These findings suggest a refinement of our existing conceptual models of the eutrophication process in Chesapeake Bay, where time of year and proximity to nutrient sources are important to understanding spatial and temporal variation in recovery.
View detailsRegional patterns and drivers of total nitrogen trends in the Chesapeake Bay Watershed.
Published on June 30, 2022Link to the document.
Full citation: Zhang, Q., J.T. Bostic and R.D. Sabo, 2022. “Regional patterns and drivers of total nitrogen trends in the Chesapeake Bay watershed: Insights from machine learning approaches and management implications”, Water Research, 218:118443, doi: 10.1016/j.watres.2022.118443.
View detailsMajor point and nonpoint sources of nutrient pollution to surface water have declined throughout the Chesapeake Bay watershed
Published on January 10, 2022Link to the document.
Citation: Sabo, R. D., B. Sullivan, C. Wu, E. Trentacoste, Q. Zhang, G. Shenk, G. Bhatt and L.C. Linker, 2022. “Major point and nonpoint sources of nutrient pollution to surface water have declined throughout the Chesapeake Bay watershed”, Environmental Research Communications, 4:045012, doi: 10.1088/2515-7620/ac5db6.
View detailsNutrient Improvements in Chesapeake Bay: Direct Effect of Load Reductions and Implications for Coastal Management
Published on December 21, 2021Link to the document.
Citation: Rebecca R. Murphy, Jennifer Keisman, Jon Harcum, Renee R. Karrh, Mike Lane, Elgin S. Perry, and Qian Zhang, 2021. "Nutrient Improvements in Chesapeake Bay: Direct Effect of Load Reductions and Implications for Coastal Management", Environmental Science & Technology 2022 56 (1), 260-270. https://pubs.acs.org/doi/10.1021/acs.est.1c05388
View detailsLong‐term trends in Chesapeake Bay remote sensing reflectance: implications for water clarity.
Published on December 13, 2021Link to the document.
Citation: Turner, J.S., C.T. Friedrichs, and M.A.M. Friedrichs, 2021. Long‐term trends in Chesapeake Bay remote sensing reflectance: implications for water clarity. Journal of Geophysical Research: Oceans, 126: e2021JC017959. https://doi.org/10.1029/2021JC017959
View detailsEffects of reduced shoreline erosion on Chesapeake Bay water clarity.
Published on May 15, 2021Link to the document.
Citation: Turner, J.S., P. St-Laurent, M.A.M. Friedrichs, and C.T. Friedrichs, 2021. Effects of reduced shoreline erosion on Chesapeake Bay water clarity. Science of the Total Environment. https://doi.org/10.1016/j.scitotenv.2021.145157
View detailsAn approach for decomposing river water-quality trends into different flow classes.
Published on February 10, 2021Link to the document.
Citation: Zhang, Q., J. S. Webber, D. L. Moyer, and J. G. Chanat, 2021. “An approach for decomposing river water-quality trends into different flow classes”, Science of the Total Environment, 755: 143562, doi: 10.1016/j.scitotenv.2020.143562.
View detailsNutrient limitation of phytoplankton in Chesapeake Bay: Development of an empirical approach for water-quality management
Published on January 1, 2021Link to the document.
Citation: Zhang, Q., T. R. Fisher, E. M. Trentacoste, C. Buchanan, A. B. Gustafson, R. Karrh, R. R. Murphy, J. Keisman, C. Wu, R. Tian, J. M. Testa, and P. J. Tango, 2021. “Nutrient limitation of phytoplankton in Chesapeake Bay: Development of an empirical approach for water-quality management”, Water Research, 188C: 116407, doi: 10.1016/j.watres.2020.116407.
View detailsPatterns and trends in Secchi disk depth over three decades in the Chesapeake Bay estuarine complex
Published on April 15, 2019Link to the document.
Citation: Testa, J.M., Lyubchich V., and Q. Zhang, 2019. “Patterns and trends in Secchi disk depth over three decades in the Chesapeake Bay estuarine complex”, Estuaries and Coasts, 42(4): 927-943, doi: 10.1007/s12237-019-00547-9.
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