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Diatom Bloom (Biotic Group)

Component: Biotic

Unique Identifier: 484

Biotic Setting Planktonic Biota
Biotic Class Phytoplankton
Biotic Subclass Diatom Phytoplankton
Biotic Group Diatom Bloom
Biotic Community Skeletonema Bloom

Definition Surface waters where rapid growth and very high densities of diatoms occur. Diatoms are large cells and tend to have high nutrient requirements. Spring diatom blooms occur in many estuarine and coastal waters, as diatoms have low light requirements and are well adapted to the hydrologic period when turbid riverine inputs are highest. They have higher nutrient requirements than other groups and require silica, needed to produce frustules. Land runoff contains silica making the spring period ideal for formation of coastal diatom blooms. The rise of the bloom is important in initiating food webs of zooplankton and other grazers and the decay of the bloom is important in nutrient cycling, and potentially contributes to the later formation of hypoxic bottom water as organic material accumulates in the lower water column.