Pulse of dissolved organic matter alters reciprocal carbon subsidies between autotrophs and bacteria in stream food webs
Pulse of dissolved organic matter alters reciprocal carbon subsidies between autotrophs and bacteria in stream food webs
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溶解有机物的脉冲改变了河流食物网中自养生物和细菌之间的相互碳补贴
DOI：
10.1002/ecm.1399
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发表时间：
2020
影响因子：
6.1
通讯作者：
B. Thornton
中科院分区：
文献类型：
--
作者：
B. Demars;N. Friberg;B. Thornton
由于气候和土地利用变化或酸化恢复，目前土壤中溶解有机物 (DOM) 的浸出速度越来越快。对河流生物地球化学和食物网的影响在很大程度上仍然未知，特别是自养生物和细菌之间的代谢平衡（生物二氧化碳排放）和碳循环。我们在三周内将溪流中 DOM 的通量增加了 12%，以模拟富含有机质的土壤中天然 DOM 供应的脉冲。通过使用前后控制影响实验设计以及添加具有独特 dC 特征的 DOM，我们能够追踪其在食物网中的命运。我们使用全流代谢来量化碳通量。添加 C 后，光合作用和异养呼吸都迅速增加，但这种情况持续时间很短，可能是由于营养限制。在稳定水流条件下，控制流中自养生物和细菌之间的碳交换约占细菌产量的 49% 和净初级产量的 37%。净初级生产力部分依赖于天然异地溶解的有机碳（对照组为 19%），通过细菌呼吸产生的二氧化碳，将绿色和棕色的网混合在一起。细菌优先吸收不稳定碳以及相对于自养生物的营养物（N、P）过量的细菌CO2，将细菌和自养生物之间的相互碳交换转变为主要是从细菌到自养生物的单向碳流，增加了自养生物的C:N:P摩尔比，后者可能变得不太容易被消费者接受。细菌对蔗糖添加的反应将代谢平衡转向异养，增加了生物二氧化碳排放量（+125%），缩短了有机物分子的平均移动距离（40%），从而为下游生态系统提供了更少的低质量有机物。即使由于气候和土地利用变化而导致不稳定溶解有机物供应的小幅增加，也可能显着改变河流内的碳循环，对河流食物网和小溪流的生物地球化学产生重大影响，这些小溪流的排水流域土壤富含有机碳。
Soils are currently leaching out dissolved organic matter (DOM) at an increasing pace due to climate and land use change or recovery from acidification. The implications for stream biogeochemistry and food webs remain largely unknown, notably the metabolic balance (biotic CO2 emissions) and carbon cycling between autotrophs and bacteria. We increased by 12% the flux of DOM in a stream for three weeks to mimic a pulse of natural DOM supply from soils rich in organic matter. We were able to track its fate into the food web through the use of a before and after control impact experimental design and the addition of DOM with a distinctive dC signature. We used whole-stream metabolism to quantify carbon fluxes. Both photosynthesis and heterotrophic respiration increased rapidly following C addition, but this was short lived, likely due to nutrient limitations. Carbon exchange between autotrophs and bacteria in the control stream accounted for about 49% of bacterial production and 37% of net primary production, under stable flow conditions. Net primary production relied partly (19% in the control) on natural allochthonous dissolved organic carbon via the CO2 produced by bacterial respiration, intermingling the green and brown webs. The preferential uptake of labile carbon by bacteria and excess bacterial CO2 relative to nutrients (N, P) for autotrophs shifted the reciprocal carbon exchange between bacteria and autotrophs to a predominantly one-way carbon flow from bacteria to autotrophs, increasing the C:N:P molar ratios of autotrophs, the latter likely to become less palatable to consumers. The bacterial response to sucrose addition shifted the metabolic balance toward heterotrophy increasing biotic CO2 emissions (+125%), shortened the average distance travelled by a molecule of organic matter ( 40%), and thus provided less organic matter of lower quality for downstream ecosystems. Even a small increase in labile dissolved organic matter supply due to climate and land use change could significantly alter in-stream carbon cycling, with large effects on stream food web and biogeochemistry in small streams draining catchments with soils rich in organic carbon.
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影响因子：
18.3
作者：
Evans, Chris D.;Futter, Martyn N.;Kothawala, Dolly N.
通讯作者：
Kothawala, Dolly N.
湖泊食物网的陆地支持：综合揭示了对跨生态系统资源利用的控制
DOI：
10.17863/cam.9282
发表时间：
2017
期刊：
--
影响因子：
--
作者：
Tanentzap A
通讯作者：
Tanentzap A
ERSEM 15.06：海洋生物地球化学和低营养级生态系统动态的通用模型
DOI：
10.5194/gmdd-8-7063-2015
发表时间：
2015
期刊：
--
影响因子：
--
作者：
Butenschön M
通讯作者：
Butenschön M
影响因子：
2.7
作者：
Demars, Benoit O. L.;Thompson, Joshua;Manson, J. Russell
通讯作者：
Manson, J. Russell