Love handles in aquatic ecosystems: The role of dissolved organic carbon drawdown, resuspended sediments, and terrigenous inputs in the carbon balance of Lake Michigan
Love handles in aquatic ecosystems: The role of dissolved organic carbon drawdown, resuspended sediments, and terrigenous inputs in the carbon balance of Lake Michigan
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DOI：
10.1007/s10021-002-0163-z
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发表时间：
2002-08-01
期刊：
影响因子：
3.7
通讯作者：
Cotner, JB
中科院分区：
文献类型：
--
作者：
Biddanda, BA;Cotner, JB
在1999年和2000年的非分层（冬季）和分层（夏季）期间，我们研究了密歇根湖南部的上层水体中的碳（C）动态。结果表明：（a）细菌呼吸（BR）和光合呼吸（PR）是C的主要汇;（B）在冬季，由于细菌产量（BP）的减少和细菌生长效率（BGE）的提高，通过细菌的C通量（CFTB）减少;溶解的有机碳（DOC），再悬浮的有机物从湖底，和河流有机物可能提供有机碳，以弥补这一时间的赤字。在冬季和夏季之间，水体中的DOC减少（29-91 mg C m（2）d（-1）），占CFTB的20%-53%和PR的11%-33%。沉积物再悬浮事件支持冬季异养的增加，它们发生的最大强度（1998年和2000年），可能是重要的年际变化在C动态。此外，河流排放，含有升高的DOC（5X）和溶解磷（10 X）相对于湖水，在冬春季节在密歇根湖南部达到高峰。总的来说，陆源输入（河流，溪流和地下水排放;雨水径流;和大气降水）可以支持大约10%-20%的年度湖泊异养以及自养。陆地补贴可能发挥关键作用，即使是非常大的湖泊的碳平衡，陆地和水生生态系统之间的关键联系。
During the unstratified (winter) and stratified (summer) periods of 1999 and 2000, we examined carbon (C) dynamics in the upper water column of southern Lake Michigan. We found that (a) bacterial respiration (BR) and planktonic respiration (PR) were major sinks for C, (b) C flux through bacteria (CFTB) was diminished in winter because of reduced bacterial production (BP) and increased bacterial growth efficiency (BGE) at colder temperatures, and (c) PR exceeded primary production (PP) during the spring-summer transition. Draw-down of dissolved organic C (DOC), resuspended organic matter from the lake floor, and riverine organic matter likely provided organic C to compensate for this temporal deficit. DOC in the water column decreased between winter and summer (29-91 mg C m(2) d(-1)) and accounted for 20%-53% of CFTB and 11%-33% of PR. Sediment resuspension events supported elevated winter heterotrophy in the years that they occurred with greatest intensities (1998 and 2000) and may be important to interannual variability in C dynamics. Further, riverine discharge, containing elevated DOC (5X) and dissolved P (10X) relative to lake water, peaked in the winter-spring season in southern Lake Michigan. Collectively, terrigenous inputs (river, stream, and groundwater discharges; storm water runoff; and atmospheric precipitation) may support approximately 10%-20% of annual in-lake heterotrophy as well as autotrophy. Terrestrial subsidies likely play a key role in the C balance of even very large lakes, representing a critical linkage between terrestrial and aquatic ecosystems.