Some are benthic, but most are pelagic.

These services include food production and provision of habitats for aquatic invertebrates, fish, benthic infauna and plants.

The benthic zone is the ecological region on, in and immediately above the seabed, including the sediment surface and some sub surface layers.

Most live pelagically in open water, although some live as surface films at the water sediment interface (benthic), or even under damp atmospheric conditions.

Based on the results of this survey, Saudi Arabia states that impacts of the 1991 oil spills persist in near shore subtidal benthic environments.

In South Africa, the Southern African Scoring System (SASS) method was developed as a rapid bioassessment technique, based on benthic macroinvertebrates, and is used for the assessment of water quality in Southern African rivers.

Anthropogenic activities and accumulation of solid wastes (e.g. discarded fishing nets, traps, anchors, debris and tyres) can be a threat to the marine habitats, creating anoxic conditions for benthic fauna and having a negative impact throughout the marine ecosystem.