Pennatulid Bed (Biotic Group)

Component: Biotic

Unique Identifier: 537

Biotic Setting	Benthic/Attached Biota
Biotic Class	Faunal Bed
Biotic Subclass	Soft Sediment Fauna
Biotic Group	Pennatulid Bed
Biotic Community	Halipteris Bed Pennatula Bed Stylatula Bed Renilla Bed

Description

Definition

Subtidal soft-bottom habitats that are dominated by sea pens or sea pansies (Phylum Cnidaria, Order Pennatulacea). These are colonial octocorals with a central stem-like support attached to a root-like peduncle, adapted for life in soft sediments. An arrangement of suspension-feeding polyps in a single plane on two sides of the central stem (which is a specialized polyp) gives some sea pens the overall appearance of a feather or quill pen. The root-like peduncle is embedded in soft sediments, but the sea pen can move to a new area if conditions are unfavorable. Sea pansies are more compact and fleshier than sea pens. Pennatulids are often common in deeper waters.