DMPQ-What is eutrophication and How does it affect the marine ecosystem?

Inorganic plant nutrients are water soluble nitrates and phosphates that cause excessive growth of algae and otheraquatic plants. The excessive growth of algae and aquatic plants due to added nutrients is called Eutrophication.


Impact of Eutrophication on environment:

  • Creation of dense blooms of noxious, foul-smelling phytoplankton known as Algal Blooms that reduce waterclarity and quality.
  • Algal blooms limit light penetration, reducing growth and causing die-offs of plants in littoral zones whilealso lowering the success of predators that need light to pursue and catch prey.
  • Furthermore, high rates of photosynthesis associated with eutrophication can deplete dissolved inorganiccarbon and raise pH to extreme levels during the day.
  • Elevated pH can in turn ‘blind’ organisms that rely on perception of dissolved chemical cues for their survivalby impairing their chemosensory abilities
  • When these dense algal blooms eventually die, microbial decomposition severely depletes dissolvedoxygen, creating a hypoxic or anoxic ‘dead zone’ lacking sufficient oxygen to support most organisms.
  • It may cause the ecosystem to be competitive by making limited nutrients into abundant ones. Thiscauses shifting in species composition of the ecosystem.
  • Some algal blooms produce noxious toxins (e.g., microcystin and anatoxin-a).

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