Eutrophication Process

Over the past decade, we have been learning how natural and human nutrient (nitrogen and phosphorus) inputs affect phytoplankton production, algae biomass, dissolved oxygen and seagrass abundance in the Chesapeake Bay.  During this time, we have noticed a link between high nutrient levels and overproduction of planktonic algae called phytoplankton.  Similar to adding fertilizer to agricultural crops for larger yields, high nutrient levels in estuarine waters produce increased numbers and biomass (weight) of phytoplankton.  This process in its most basic form defines eutrophication.  After observing the damage caused by phytoplankton blooms, the Chesapeake Bay Program implemented a 40% nutrient level reduction strategy.  This strategy focused on four important processes related to water quality and nutrient issues, including:

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1.  Phytoplankton production (numbers) and biomass (weight) in many estuaries respond to nutrient inputs. 

2.  High rates of phytoplankton blooms continue through summer and fall because of benthic (bottom) recycling of essential nutrients (Nitrogen and Phosphorus).

  Organic matter that moves from the surface to deeper waters is linked to phytoplankton blooms.

4.  Submerged aquatic vegetation (SAV) respond to water quality conditions, such as light availability. However, our understanding is not complete and research studies continue.

For more information, please contact Renee Karrh at (410) 260-8628.

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