Carbon quality regulates the temperature dependence of aquatic ecosystem respiration
Carbon quality regulates the temperature dependence of aquatic ecosystem respiration
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DOI：
10.1111/fwb.13168
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发表时间：
2018-11-01
影响因子：
2.7
通讯作者：
Rose, Kevin C.
中科院分区：
文献类型：
--
作者：
Jane, Stephen F.;Rose, Kevin C.
1.生态系统正在以复杂的方式应对气候和其他因素的大规模变化。许多内陆水体发生的两个关键变化是温度升高和陆地溶解有机物（tDOM）输入增加。部分由于tDOM输入，内陆沃茨在全球碳循环中发挥着重要作用，这些生态系统释放的CO2占陆地生态系统和海洋总碳汇的很大一部分。生态系统呼吸（ER）是水生生态系统调节CO2的重要机制，ER速率具有温度依赖性。然而，目前尚不清楚ER率将如何变化，因为ER对温度以外的因素敏感，如有机物的浓度和来源。理论假设，难熔碳化合物支持的ER速率应该比不稳定碳化合物支持的ER速率表现出更大的温度依赖性，但该理论的经验测试并不确定。3.我们实验操纵温度和碳质量的围隔，同时监测溶解氧（DO）与原位高频DO传感器。我们使用了两个高度不同的，自然DOM源和稀释的更难处理的源，使溶解的有机碳浓度在所有的围隔中是相似的。我们计算了27天内每个mesocosm的每日ER率。我们发现，ER增加更多的温度时，tDOM占主导地位的有机碳库。鉴于温度和tDOM输入到水生生态系统的广泛增加，这些结果突出了重要的相互作用，决定生态系统如何应对同时发生的环境变化，并改变其对全球碳循环的贡献。
1. Ecosystems are responding to broad-scale changes in climate and other factors in complex ways. Two key changes occurring in many inland waterbodies are increasing temperatures and increasing terrestrial dissolved organic matter (tDOM) inputs. Due in part to tDOM inputs, inland waters play an important role in the global carbon cycle, with release of CO2 from these ecosystems a substantial portion of the combined carbon sinks of terrestrial ecosystems and the oceans.2. Ecosystem respiration (ER) is an important mechanism regulating CO2 in aquatic systems, and ER rates are temperature-dependent. However, it is unknown how ER rates will change in the future because ER is sensitive to factors other than temperature, such as the concentration and source of organic matter. Theory posits that ER rates supported by refractory carbon compounds should exhibit a greater temperature dependence than ER rates supported by labile carbon compounds, but empirical tests of this theory are inconclusive.3. We experimentally manipulated temperature and carbon quality in mesocosms while monitoring dissolved oxygen (DO) with in situ high frequency DO sensors. We used two highly divergent, natural DOM sources and diluted the more refractory source so that dissolved organic carbon concentrations were similar in all mesocosms. We calculated daily ER rates over 27 days in each mesocosm.4. We found that ER increased more with temperature when tDOM dominated the organic carbon pool. Given widespread increases in temperature and tDOM inputs to aquatic ecosystems, these results highlight important interactions governing how ecosystems may respond to concurrent environmental changes and alter their contributions to the global carbon cycle.