Ecology of the burrowing amphipod, Pontoporeia affinis, in Lake Michigan / by Wayne Paul Alley.

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and does not show any specific temperature preference.
Substrate Relationship: Marzolf (1963), in a laboratory study,
found that Pontoporeia selected sediment particle sizes smaller than
0. 50 mm in diameter but did not discriminate between smaller sizeso
Sand is composed of particles ranging from 1. 0 mm to 0. 062 mm in diameter, silt from 0. 062 to 0. 0039 mm, and clay less than 0. 0039 mm.
Examination of the percent organic carbon content of the sediment
in the present study revealed that Lake Michigan sand has an average
carbon percentage of 0. 14 with a range of 0. 04 to 0. 22, sandy silt an
average of 0.47 with a range of 0. 26 to 0. 71, silt an average value of
2. 82 with a range of 1. 70 to 4. 02, and the upper stratum of layered sediment an average value of 1, 08 with a range of 0. 68 to lo 69. These
ranges of percent organic carbon indicate that the largest values of sandy
silt overlap with the lowest values of layered sediment, and the largest
values of layered sediment overlap with the lowest values of silt.
Marzolf (1963) concluded from laboratory experiments that the
selection of a substrate by Pontoporeia was significant only when organic
matter was present as a surface film on the sediments. He also found a
significant association between the density of this amphipod and sedimentary bacterial numbers and the amount of organic matter in the sediments.
Zobell and Feltham (1942) showed that certain species of bacteria are
capable of degrading cellulose, chitin, and lignin which most animals
find difficult, if not impossible, to digest. They earlier (Zobell and