%0 Journal Article
%T Microbial Respiration of Organic Carbon in Freshwater Microcosms: The Potential for Improved Estimation of Microbial CO2 Emission from Organically Enriched Freshwater Ecosystems
%A Anderson, O. Roger
%J Acta Protozoologica
%V 2016
%R 10.4467/16890027AP.16.018.5750
%N Volume 55, Issue 3
%P 189-196
%K Aquatic microbial CO2 emissions, atmospheric CO2, climate change, environmental change, organic aquatic pollution, protists
%@ 0065-1583
%D 2016
%U https://ejournals.eu/en/journal/acta-protozoologica/article/microbial-respiration-of-organic-carbon-in-freshwater-microcosms-the-potential-for-improved-estimation-of-microbial-co2-emission-from-organically-enriched-freshwater-ecosystems
%X Respiratory CO2 emissions from laboratory freshwater microcosms enriched with organic C (glucose and amino acids) and kept in the dark at 24°C were compared to control microcosms without C enrichment for two different freshwater pond sources. The purpose was to estimate experimentally the rate of respiratory CO2 emission from organically polluted freshwater ecosystems compared to non-enriched water. Experiment One, used pond water collected at the Lamont-Doherty Earth Observatory campus; and Experiment Two used pond water, inoculated with natural detritus, obtained from North Carolina. At peak respiration, the net efflux of CO2 (enriched minus control) to the atmosphere was ~ 90 nmol min–1 L–1 (Day 7, Experiment One) and ~ 240 nmol min–1 L–1 (Day 3, Experiment Two). The corresponding net efflux of C to the atmosphere was 25 nmol C min–1 L–1 (Day 7, Experiment One) and 65 nmol C min–1 L–1 (Day 3, Experiment Two). Peak CO2 emissions from the organic-enriched microcosms expressed as μmol m–2 s–1 (as more typically reported for natural bodies of water) were 0.20 for Experiment One, and 0.42 for Experiment Two, at a surface layer depth of approx. 20 cm, i.e. the microcosm depth. There was a relatively large correlation between respiratory CO2 emission and bacterial densities in the organic-C enriched microcosms (r = 0.76), but a smaller correlation (r = 0.32) in the non-enriched, control microcosm. Further broad scale research, robustly sampling natural bodies of organically polluted water, is needed to confirm and better establish the results of the research reported here using microcosms.