benthos

 

Chesapeake & Coastal Bay Life 

Illustration of Benthos book

The benthos is the community of organisms that live in or on the bottom of the Bay and its tributaries. Examples of some benthic animals that live in Chesapeake Bay sediments include clams, amphipods, polychaetes, and isopods. Benthic macroinvertebrates are used as biological indicators because they are reliable and sensitive indicators of habitat quality in aquatic environments and they are ecologically important components of the Chesapeake Bay’s food web.

Common Name:Common Burrower Amphipod
Scientific Name:Leptocheirus plumulosus
Fast Fact:
Many studies have used amphipods as an indicator species for evaluating the acute and chronic toxicity of contaminated sediments.
Kingdom:Animalia
Phyllum:Arthropoda
Class:Malacostraca
Order1:Amphipoda
Family:Photidae
Genus:Leptocheirus
Photo or Illustration:Illustration of brackish common burrower Amphipod,  Joann Wheeler 1999
Photo Desc:Illustration of brackish common burrower Amphipod, Joann Wheeler 1999
Photo/Illustration Credit:Artwork by: Joann Wheeler 1999
Size:Generally one half inch in length or less.
Habitat:
The common burrower amphipod is found in the subtidal zones of estuaries throughout the U.S. Atlantic coast from Cape Cod, Massachusetts to northern Florida. They live in permanent tubes constructed from sand grains and debris. Their tubes can be deeper than two inches in some areas of the Bay. Common burrower amphipods live in both shallow and deep water as long as there is good water flow. They prefer the oligohaline and mesohaline regions of the Chesapeake Bay.
Reproduction:
The common burrower amphipod breeds from March through November in the Chesapeake Bay. Fertilization is internal and females brood their young in the marsupium located on the ventral surface of the abdomen. The number of eggs a female produces depends on her size, meaning a larger female will produce more eggs than a smaller female. On average, females can carry 10-40 eggs at a time. Females breed five times in a year; however, this rate is greatly influenced by food availability and temperature.
Feeding:
The common burrower amphipod lies inside its tube with its head near the opening to filter plankton from the water.
Predators:
The common burrower amphipod is a favorite food item for fishes, such as spot (Leiostomus xanthurus) and croaker (Micropogonias undulatus), and crabs, such as the blue crab (Callinectes sapidus).
Description:
Amphipods have a segmented and laterally flattened body that contains the head, the thorax, and the abdomen.
Other Facts:
This species of amphipod is often a dominant species with densities sometimes reaching ³ 40,000 per square meter in the upper and mid-Bay regions. Therefore, they are an ecologically important component of the Chesapeake Bay benthic community.