文章基本信息

标题：Daily and seasonal variability of CO2 saturation and evasion in a free flowing and in a dammed river reach
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作者：Monica Pinardi ; Marisa Rossetto ; Pierluigi Viaroli 等
期刊名称：Journal of limnology
印刷版ISSN：1129-5767
电子版ISSN：1723-8633
出版年度：2014
卷号：73
期号：3
DOI：10.4081/jlimnol.2014.947
出版社：Istituto italiano di idrobiologia
摘要：The daily and seasonal evolution of O 2 and CO 2 saturation, water-atmosphere fluxes and budgets were measured in two fluvial reaches of the Mincio River (Italy).The northern reach is free flowing and is dominated by macrophytes while the southern reach is dammed, hypertrophic and phytoplankton dominated.We hypothesized short term regulation of gas saturation and fluxes by primary producers and the reversal of CO 2 off-gassing in the southern reach.Results indicated that both reaches were always CO 2 supersaturated.Higher CO 2 evasion rates in the northern compared to the southern reach depended on reaeration coefficient, in turn depending on water velocity.In the northern reach dissolved inorganic carbon (DIC) production was one order of magnitude higher than oxygen consumption, likely due to a combination of anoxic heterotrophic activity in the hyporheic zone and carbonate dissolution.The activity of macrophytes influenced CO 2 saturation on short time scales.A net summer abatement of DIC occurred in the southern reach, probably due to fixation by phytoplankton, which attenuated supersaturation but not reversed CO 2 efflux.This study demonstrates how in small rivers CO 2 evasion can undergo rapid and significant changes due to eutrophication, altered hydrology and shift in primary producer communities.
关键词：carbon dioxide; fluxes; river metabolism; mass balances; macrophytes; phytoplankton.