Enhanced carbon overconsumption in response to increasing temperatures during a mesocosm experiment
Enhanced carbon overconsumption in response to increasing temperatures during a mesocosm experiment
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DOI：
10.5194/bg-9-3531-2012
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发表时间：
2012-09
期刊：
影响因子：
4.9
通讯作者：
J. Taucher;K. Schulz;T. Dittmar;U. Sommer;A. Oschlies;U. Riebesell
中科院分区：
文献类型：
--
作者：
J. Taucher;K. Schulz;T. Dittmar;U. Sommer;A. Oschlies;U. Riebesell
抽象的。预计大气中二氧化碳浓度的增加将导致海洋表面温度升高，可能影响海洋生态系统和海洋地球化学循环。在这里，我们进行了一个室内围隔实验与天然浮游生物群落采取从波罗的海在夏季。我们通过添加营养物诱导浮游生物水华，并在9.5 °C至17.5 °C的温度范围内（相对于环境温度为±4 °C）跟踪不同碳和氮库的动态一个月。溶解无机碳（DIC）的吸收以及颗粒物（POC）和溶解有机碳（DOC）的净积累都在较高温度下增强，并且在8 °C的温度梯度下几乎翻了一番。此外，颗粒物和溶解有机物中碳和氮的元素比（C：N）随着温度的升高而增加，在+4 °C时两者都达到非常高的C：N比，> 30。总而言之，这些观察结果表明，响应于升高的温度，过量的碳固定显著增加。大多数这些发现是相反的结果与浮游生物种群在春季采样进行了类似的实验，揭示了很大的不确定性，我们的知识的温度敏感性的关键过程在海洋碳循环。由于一个主要的区别，以前的围隔实验是占主导地位的浮游植物物种，我们假设，物种组成可能发挥重要作用，在响应地球化学循环温度升高。
Abstract. Increasing concentrations of atmospheric carbon dioxide are projected to lead to an increase in sea surface temperatures, potentially impacting marine ecosystems and biogeochemical cycling. Here we conducted an indoor mesocosm experiment with a natural plankton community taken from the Baltic Sea in summer. We induced a plankton bloom via nutrient addition and followed the dynamics of the different carbon and nitrogen pools for a period of one month at temperatures ranging from 9.5 °C to 17.5 °C, representing a range of ±4 °C relative to ambient temperature. The uptake of dissolved inorganic carbon (DIC) and the net build-up of both particulate (POC) and dissolved organic carbon (DOC) were all enhanced at higher temperatures and almost doubled over a temperature gradient of 8 °C. Furthermore, elemental ratios of carbon and nitrogen (C : N) in both particulate and dissolved organic matter increased in response to higher temperatures, both reaching very high C : N ratios of > 30 at +4 °C. Altogether, these observations suggest a pronounced increase in excess carbon fixation in response to elevated temperatures. Most of these findings are contrary to results from similar experiments conducted with plankton populations sampled in spring, revealing large uncertainties in our knowledge of temperature sensitivities of key processes in marine carbon cycling. Since a major difference to previous mesocosm experiments was the dominant phytoplankton species, we hypothesize that species composition might play an important role in the response of biogeochemical cycling to increasing temperatures.