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What is the "Benthos"?

The term benthos derives from the Greek word bathys, meaning deep. Benthos refers collectively to all aquatic organisms which live on, in, or near the bottom of water bodies. This includes organisms inhabiting both running and standing waters, and also applies to organisms from both saltwater and freshwater habitats.


The term phytobenthos is used when referring to the primary producers (i.e., various algae and aquatic plants), whereas zoobenthos is applied in reference to all consumers (i.e., benthic animals and protozoa). Benthic microflora (i.e., bacteria, fungi, and many protozoa) constitute the decomposer community, and are involved in the recycling of energy and essential nutrients.

The benthos may be further subdivided on the basis of size. Large benthic animals (those readily visible without the use of a microscope) are collectively referred to as macrozoobenthos or macroinvertebrates. Representatives include clams, snails, worms, amphipods, crayfish, and the larvae of many aquatic insects (e.g., dragonflies, mayflies, stoneflies, caddisflies, chironomid midges, and black flies). Microscopes are essential to discern members of the microbenthos (e.g. nematodes, ostracods).

Shredding macroinvertebrates

The benthic macroinvertebrates consume algae, coarse particulate matter (such as fallen leaves) and its associated fungi and bacteria, fine suspended organic matter, and prey organisms. Macroinvertebrates are part of the food supply for many fishes and other vertebrates of lakes and streams.

Thus, the benthos encompasses a huge array of life with many phyla involved. They inhabit such disparate habitats as the small aquaria formed in the bottom of pitcher plant leaves to the bottom of the Mississippi River, the Great Lakes, and the oceans. Some of the benthos spend part of their life cycle in other habitats, such as riparian and shore lands.

Who are bethologists and what do they do?


Members of the Society for Freshwater Science are parimarily scientists mainly interested in freshwater ecosystems and ecosystems at the aquatic-terrestrial interface. These habitats include rivers, streams (both temporary and permanent), lakes, reservoirs, riparian forests and grasslands, wetlands, and bogs. Benthologists study the life histories, population ecology, community ecology, and systematics of the benthos. They also study processes within freshwater habitats that support the benthos. Benthologists work for the conservation of threatened or rare organisms and unimpaired ecosystems, while seeking to rehabilitate degraded habitats. In the area of applied research, benthologists develop pollution monitoring methods, impact assessment techniques, and restoration designs. They study pest and invasive organisms and develop strategies for reducing the health or economic impacts of these organisms. Because many of the benthos are important as fish food, their study is important to fisheries management.

Many SFS members are associated with educational institutions as faculty, students or staff. Others are employed by government agencies where they use their benthic knowledge for impact assessment, pollution control, and resource conservation. Some benthologists are employed in industry, typically environmental consulting firms. They may be concerned with nuisance benthic organisms, environmental monitoring for permitting/licensing of facilities, mitigation of impacts, and restoration of aquatic habitats.

Membership in SFS is open to all. Studies of communities and processes withinin estuarine and marine benthic communities provide important parallels to those occurring in freshwater. All persons interested in benthic organisms are encouraged to join and to participate in the society's activities.

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