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Contents contributed and discussions participated by Megan Ghrist

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Megan Ghrist

Marine Ecosystems | Biological Indicators of Watershed Health | US EPA - 0 views

www.epa.gov/...marine.html

shared by Megan Ghrist on 09 Nov 11 - No Cached
    • Megan Ghrist
      Megan Ghrist on 09 Nov 11
       
      The average salinity in the oceans is approximately 3.5%. The more dense the salt in the water, the more dense the water is for its supporting life ecosystems. The composition of the salinity within the water contains: 1.9% chloride salts 1.1% sodium salts .3% sulfate salts .1% magnesium salts .04% calcium salts .04% potassium salts .01% hydrocarbonate salts Nitrogen and phosphorous are important nutrients for sustaining plant and animal life within marine ecosystems, so the salinity and nutrients are very important factors to consider.
  • hese species require more constant levels of salinity, forcing them to either migrate to new areas when fluctuations in salinity levels occur or to seek out areas where salinity change is minimal
    • Megan Ghrist
      Megan Ghrist on 09 Nov 11
       
      These estuaries are bodies of water that allow rivers to flow into the ocean. Typically in shallow, warm waters, the freshwater and ocean water will often mix, causing the salinity of the water to fluctuate due to runoffs, tides, and seasons in the environment. The salinity not only effects the plant growth of the marine ecosystem but also the diversity of specie's populations.
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  • In areas such as estuaries, tidal marshes, and mangrove forests, tidal and freshwater influences from river and streams makes it necessary for marine organisms to adapt to a wide range of salinity levels.
    • Megan Ghrist
      Megan Ghrist on 09 Nov 11
       
      The depth zones of the ocean are an important factor to consider, because the the euphotic zone (the uppermost layer) is not only the warmest but also contains the highest levels of dissolved oxygen, which effects the marine ecosystems plant life. Without the euphotic zone, the plant life within the marine ecosystem is unable to produce dissolved oxygen for living organisms, so this depth layer is an important layer due to the amount of oxygen that is produced from the photosynthesis that occurs in the phytoplankton. 
  • Like other aquatic ecosystems, marine ecosystems require nutrients and light to produce food and energy.
  • Marine ecosystems contain several unique qualities that set them apart from other aquatic ecosystems, the key factor being the presence of dissolved compounds in seawater, particularly salts.
  • However, the amount of light penetrating the ocean surface tends to decrease with increasing water depth, therefore photosynthesis can only take place within a small band near the surface of the water (called the photic zone).
  • estuaries and marshes are often rich in nutrients
    • Megan Ghrist
      Megan Ghrist on 09 Nov 11
       
      Upwellings within the ocean are important because they bring cold nutrient rich bottom water to the surface, providing nutrients for living organisms in photic regions within the marine ecosystem. These circulations, either surface or deep water currents, support the food chain.
  • increased human activities such as overfishing, coastal development, pollution, and the introduction of exotic species have caused significant damage and pose a serious threat to marine biodiversity
    • Megan Ghrist
      Megan Ghrist on 09 Nov 11
       
      Due to the effects of global warming, thermal expansion is a subject that needs to be addressed. It has many damaging effects on the marine ecosystem, including: slowing of circulation (which brings nutrients), faster melting of glaciers (effects habitats within the ecosystem), and messes with the carbon cycle ( which releases more methane into the atmosphere). A lot of issues concerning global ocean problems which may effect marine ecosystems are the erosion, salt water intrusion into aquifers and low lying areas, and increased flooding as well as storm damage. 
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