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Vertical distribution of the zoobenthos in southeastern Lake Michigan with evidence of seasonal variation *
Author(s) -
NALEPA THOMAS F.,
ROBERTSON ANDREW
Publication year - 1981
Publication title -
freshwater biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 156
eISSN - 1365-2427
pISSN - 0046-5070
DOI - 10.1111/j.1365-2427.1981.tb01244.x
Subject(s) - spring (device) , seasonality , ecology , substrate (aquarium) , population , invertebrate , biology , oceanography , environmental science , geology , mechanical engineering , demography , sociology , engineering
SUMMARY. The vertical distribution of the zoobenthos in southeastern Lake Michigan was investigated monthly from May to November 1976. The organisms could be divided into two categories: one in which the majority of the population occurred in the upper 1 cm of substrate ( Pontoporeia , naidids, chironomids, cyclopoids, harpacticoids, cladocerans, turbellarians, ostracods, rotifers, sphaeriids and gastropods) and one in which the majority of the population occurred deeper (immature tubificids without hair setae, Stylodrilus heringianus , enchytraeids, nematodes, and tardigrades). The vertical distribution of these infaunal forms showed a marked seasonal variation. They were found in the superficial sediments in the spring, but deeper in the sediments in the autumn. This trend coincided with the seasonal occurrence of a detrital layer that overlay the sandy substrate in the spring but was absent in the autumn.