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Eutrophication comparisons between Chesapeake Bay and Puget Sound

Eutrophication comparisons between Chesapeake Bay and Puget Sound. Tiffany Huang Oceanography 497 B School of Aquatics and Fisheries. Eutrophication Background. A n ecosystem response to human activities that fertilize bodies of water with N and P.

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Eutrophication comparisons between Chesapeake Bay and Puget Sound

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  1. Eutrophication comparisons between Chesapeake Bay and Puget Sound Tiffany Huang Oceanography 497 B School of Aquatics and Fisheries

  2. Eutrophication Background • An ecosystem response to human activities that fertilize bodies of water with N and P. • Ex: untreated sewage discharge, runoff from farms or lawns • Can often lead to changes in animal and plant populations, degradation of water habitat and quality. • N and P are essential components of structural proteins, enzymes, cell membranes, nucleic acids, etc. • N and P are present at low concentrations in Estuaries. Ecological Consequences: -biodiversity, visibility, mobility functions, fitness, and certain organisms can die off

  3. Chesapeake Bay 1600-1700 – subsistence farming, abandoned, moved onto another plot, low human population 1740-1930 – new agricultural technology, used fertilizers, human population increased, demand for wood, chemically developed nitrogen fertilizers replaced natural fertilizers 1930-present – eastern shore drained for cropland, large increase in anoxia since mid 20th century.

  4. Chesapeake Bay Largest estuary in the U.S. (~300 km ) Land clearing, colonization, erosion of soil led to eutrophication led to hypoxia Hypoxia increased significantly in last 50 years. Eutrophication effects are spreading from near-shore areas and semi-enclosed basins to offshore regions. Spreading of hypoxia may have contributed to major changes in fisheries populations

  5. Chesapeake Bay In 1970’s, discovered first marine dead zone Today the bay’s dead zones estimate to kill 75,000 tons of bottom dwelling organisms Overharvesting, pollution, sedimentation, and disease turned bay’s bottom into muddy wasteland

  6. Puget Sound : Hood Canal Glacial fjord in Puget Sound ~ 80 miles from Seattle Long narrow shape results in estuarine circulation pattern and stratified water columns More susceptible to eutrophication Low oxygen concentrations have been documented since 1950’s, but over last 10 years conditions have worsened Southern HC has experienced up to 12 months of hypoxia & Northern HC exhibited oxygen levels at which biological stress begin to occur.

  7. Puget Sound : Hood Canal September 2002, fish on west side of HC observed to be under stress from low concentration of DO October 2003, DO conditions worsened, 30% rockfish were killed HCDOP studied the causes of low DO concentrations in HC with USGS Found out that the horizontal transport and upward mixing of DIN in the lower layer are driven by physical forces that are not fully understood.

  8. Solutions to Eutrophication Upgrading waste water treatment plants to enhance nutrient removal Improved management of animal waste Reducing and retrofitting impervious surfaces Restoring wetlands Planting forests (nitrogen influx didn’t increase in estuary until ~40% of land was deforested) Prevent fertilizers, pesticides, detergents, and other organic wastes (lawn clippings) from entering streams, groundwater, and other water sources.

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