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Effects of oxytetracycline on populations and community metabolism of an aquatic microcosm
Author(s) -
Shibata Kenichi,
Amemiya Takashi,
Itoh Kiminori
Publication year - 2014
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1007/s11284-014-1128-3
Subject(s) - microcosm , biology , heterotroph , population , respiration , algae , scenedesmus , ecology , respiration rate , microbial population biology , aquatic ecosystem , botany , bacteria , demography , sociology , genetics
To investigate the ecological impacts of a widely‐used antibiotic agent oxytetracycline (OTC), we prepared an aquatic microcosm consisting of two green algae ( Chlorella sp. and Scenedesmus sp.), a blue‐green alga ( Tolypothrix sp.), a protozoan ( Cyclidium sp.), two rotifers ( Philodina sp. and Lecane sp.), an aquatic oligochaete ( Aeolosoma hemprichi ), and bacteria. We investigated the effects of OTC on population abundance of composite species, gross primary production (GPP), and community respiration (CR). We linked population abundance, GPP and CR to understand the relationship between these measures. First, ‘experimental respiration rate of heterotrophs’ (HR exp ) was obtained by CR minus algal respiration that is calculated by 0.35 × GPP. Next, the population respiration of each heterotroph was calculated from the direct measure of population abundance and the assumed constant of per‐capita respiration. We defined the sum of the population respirations across all heterotrophs as ‘theoretical respiration rate of heterotrophs’ (HR theo ). Finally, relative community metabolism (RCM) of the heterotrophic community was obtained by calculating the ratio of HR exp to HR theo that indicates changes in specific respiration rates as a whole in the community. The influence of OTC on RCM was larger than on CR, thus the effect of OCT on the metabolism of heterotrophs was far more severe than expected from CR. RCM can magnify the rate of change in the original data, and facilitate the detection of influences in ecotoxicological studies.