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Great Lakes National Program Office Environmental Indicators

Water Indicators

Clean water is fundamental to a healthy Great Lakes ecosystem.

  • Trophic State
    The trophic state of lakes is indicative of their biological productivity, that is, the amount of living material supported within them, primarily in the form of algae.

  • Lake Erie Phosphorus
    Phosphorus is an essential element for all organisms and is found naturally in tributaries and run-off waters. Excessive phosphorus can lead to over-enrichment with algae and aquatic weeds and depletion of dissolved oxygen as the excess plant and animal matter decay.

  • Dissolved Oxygen Depletion in Lake Erie
    Oxygen is essential for all plants and animals to survive, whether they live on the land or in the water. The Central Basin of Lake Erie is susceptible to low dissolved oxygen concentrations

  • Beach Closings
    When bacteria standards are exceeded, local authorities may close swimming at a beach or issue an advisory that water is unhealthful for swimming.

 
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