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Hydroid Bed (Biotic Group)

Component: Biotic

Unique Identifier: 531

Biotic Setting Benthic/Attached Biota
Biotic Class Faunal Bed
Biotic Subclass Soft Sediment Fauna
Biotic Group Hydroid Bed
Biotic Community Sertularia Bed
Tubularia Bed

Definition Areas dominated by hydroid species that are not attached to a hard substrate. These animals may be resting on the sediment surface or may be partially embedded in the sediment. Hydroids are the benthic life stage of planktonic jellyfish medusae, and most are predators on small life forms. Hydroids are colonies of individual polyps usually arranged in a branching or bushy pattern. The polyps are specialized for various roles, and defensive/prey capture polyps are armed with nematocysts (stinging capsules in specialized cells). Hydroids may form large mounds or mats in some soft sediment areas.