Lake secondary production fueled by rapid transfer of low molecular weight organic carbon from terrestrial sources to aquatic consumers
Lake secondary production fueled by rapid transfer of low molecular weight organic carbon from terrestrial sources to aquatic consumers
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DOI：
10.1111/j.1461-0248.2010.01483.x
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发表时间：
2010-07-01
期刊：
影响因子：
8.8
通讯作者：
Jansson, M.
中科院分区：
文献类型：
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作者：
Berggren, M.;Strom, L.;Jansson, M.
在生产力低下的湖泊生态系统中，陆地来源的碳通常占消耗生物量的很大一部分。然而，陆地支持湖泊二次生产的机制在很大程度上尚不清楚。通过使用建模方法，我们表明，在 7 平方公里的北方湖泊中，溶解的不稳定低分子量碳 (LMWC) 化合物的陆地输出分别支持了细菌、原生动物和后生动物二次生产的 80% (34-95%)、54% (19-90%) 和 23% (7-45%)（括号中为保守估计和自由估计）。 LMWC 上的细菌生长程度与初级生产 (PP) 相似，并且对细菌的放牧有效地将 LMWC 碳引导至更高的营养水平。我们认为，森林 LMWC 池的快速周转使得新鲜光合产物和其他不稳定代谢物能够持续输出到水生系统，并且 LMWC 从陆地来源大量转移到湖泊消费者可以在几天内发生。因此，陆地来源的 LMWC 的封存有助于解释湖泊生物中陆地碳的高比例，并意味着湖泊食物网可能密切依赖于近期的陆地 PP。
P>Carbon of terrestrial origin often makes up a significant share of consumer biomass in unproductive lake ecosystems. However, the mechanisms for terrestrial support of lake secondary production are largely unclear. By using a modelling approach, we show that terrestrial export of dissolved labile low molecular weight carbon (LMWC) compounds supported 80% (34-95%), 54% (19-90%) and 23% (7-45%) of the secondary production by bacteria, protozoa and metazoa, respectively, in a 7-km2 boreal lake (conservative to liberal estimates in brackets). Bacterial growth on LMWC was of similar magnitude as that of primary production (PP), and grazing on bacteria effectively channelled the LMWC carbon to higher trophic levels. We suggest that rapid turnover of forest LMWC pools enables continuous export of fresh photosynthates and other labile metabolites to aquatic systems, and that substantial transfer of LMWC from terrestrial sources to lake consumers can occur within a few days. Sequestration of LMWC of terrestrial origin, thus, helps explain high shares of terrestrial carbon in lake organisms and implies that lake food webs can be closely dependent on recent terrestrial PP.