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Substantial Increase of Chironomus Abundance Obtained in Field Experiment
Author(s) -
Kajak Zdzisław,
Dusoge Krzysztof
Publication year - 1996
Publication title -
internationale revue der gesamten hydrobiologie und hydrographie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 52
eISSN - 1522-2632
pISSN - 0020-9309
DOI - 10.1002/iroh.19960810315
Subject(s) - chironomus , tray , larva , chironomidae , biology , zoology , population , population density , abundance (ecology) , ecology , botany , demography , sociology
Mud (with or without Chironomus ) taken from the bottom of a shallow (6 m) eutrophic reservoir, was maintained (about 3 weeks) in trays supported 30 cm and 70 cm above the bottom. At the end of the experiment it contained 7‐9 times more Chironomus plumosus individuals than did the mud at the bottom. Numbers of young (≤12 mm) larvae were up to 18 times higher, and youngest (≤6 mm) larvae (absent in the bottom at the end of the experiment) were abundant. Such patterns were more evident at the higher (70 cm) than the lower (30 cm) level. Numbers of the oldest (≥18 mm) larvae at the higher level were only 6 times higher (whilst more than 8 times at the lower level) than at the bottom, probably due to quicker development and emergence in higher trays. So the production of the population increased with the increasing distance from the bottom. In the tray at the bottom (which could protrude 1–2 cm above it) numbers were twice those outside it, and the youngest larvae occurred. There was a slight current at the research site. Nevertheless, short time oxygen deficits occurred periodically, and were probably the main cause of considerable reductions in Chironomus numbers at the bottom during the experiment.