期刊论文详细信息
Marine Ecology Progress Series
Evidence for light-environment control of carbon isotope fractionation by benthic microalgal communities
Elon M. Malkin1  David J. Hollander1  Kara R. Radabaugh1  Ernst B. Peebles1 
关键词: Photosynthetic fractionation;    Benthic algae;    Basal resource;    Light attenuation;    Estuary;   
DOI  :  10.3354/meps10559
学科分类:海洋学与技术
来源: Inter-Research
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【 摘 要 】

ABSTRACT: Assemblages of filamentous algae and diatoms were grown on glass plates suspended in the water column in Tampa Bay, Florida (USA). Carbon isotope ratios (δ13C) of the accumulated OM (OM) were analyzed to compare the effects of aqueous CO2 concentration, OM accumulation rate, algal type, and photosynthetically active radiation (PAR) on community-level carbon isotope fractionation between aqueous CO2 and organic carbon. Concentrations of nutrients, PAR, and colored dissolved OM exhibited spatiotemporal variation during 6 experiments conducted over 2 mo of variable rainfall and terrestrial runoff. Fractionation ranged from 6.8 to 13.7‰ and was positively correlated with PAR, resulting in higher δ13C values for OM in low-light conditions. Fractionation was lower and OM accumulation rates were higher during the 3 early experiments, which had high nutrient concentrations as a result of terrestrial runoff. OM accumulation rates and CO2 concentrations did not independently correlate with fractionation. The dominant factors influencing fractionation were PAR and spatial coverage by pennate diatoms, which together explained 56% of variability in fractionation. These results indicate that PAR significantly influences microalgal fractionation in estuaries, supporting the concept that the light environment may contribute to the widely observed phenomenon of higher δ13C values in benthic algae relative to phytoplankton.

【 授权许可】

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