Phytoplankton biomass, dissolved organic matter, and temperature drive respiration in whole lake nutrient additions
Phytoplankton biomass, dissolved organic matter, and temperature drive respiration in whole lake nutrient additions
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DOI：
10.1002/lno.11738
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发表时间：
2021-04
影响因子：
4.5
通讯作者：
M. Pace;C. Buelo;S. Carpenter
中科院分区：
文献类型：
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作者：
M. Pace;C. Buelo;S. Carpenter
湖泊呼吸支持的混合物的本地和外来资源，但这些来源的相对意义和相互作用是不确定的梯度的初级生产和有机质的投入。在三个夏季，我们通过向两个湖泊中添加无机氮和磷来操纵本地资源，并监测第三个参考湖泊。外来资源被测量为荧光溶解有机物（FDOM）。在参考和两个实验湖泊中，每天的呼吸量的估计是由连续部署的氧传感器。温度和FDOM的每日平均值是根据高频测量值以及叶绿素a（浮游植物生物量的指数）的每日测量值来确定的。沿着。我们分析了呼吸的时间序列，并测试了使用自变量叶绿素，FDOM和温度组合的模型。最好的模型包括所有三个自变量。在14.5-28.6°C的温度范围内，呼吸增加两倍。呼吸增加与营养物质增加引起的浮游植物水华有关，但由于每天的变化很大，因此没有密切跟踪水华。Respertium变化积极与FDOM主要是异地和不同的湖泊和年份。我们没有发现叶绿素和FDOM之间的相互作用，尽管大量的观测和范围的叶绿素和FDOM。水文、气候和土地利用的变化正在改变湖泊的温度和营养物质及有机物的输入。我们的研究结果表明，这些变化可能会导致在生态系统过程中的线性响应，如呼吸在这项研究中所代表的广泛的输入。
Lake respiration is supported by a mixture of autochthonous and allochthonous resources, but the relative significance and interaction of these sources are uncertain across gradients of primary production and organic matter inputs. We manipulated autochthonous resources by adding inorganic nitrogen and phosphorus to two lakes during three summers and monitored a third reference lake. Allochthonous resources were measured as fluorescent dissolved organic matter (FDOM). In the reference and two experimental lakes, daily estimates of respiration were made from continuously deployed oxygen sensors. Daily mean values of temperature and FDOM were determined from high‐frequency measurements along with daily measures of chlorophyll a, an index of phytoplankton biomass. We analyzed time series of respiration and tested models that used combinations of the independent variables chlorophyll, FDOM, and temperature. The best models included all three of the independent variables. Respiration increased twofold over the temperature range of 14.5–28.6°C. Respiration increased in association with phytoplankton blooms caused by the nutrient additions, but did not track blooms closely, because of large day‐to‐day variability. Respiration varied positively with FDOM that was primarily allochthonous and differed among lakes and years. We did not detect an interaction between chlorophyll and FDOM despite the large number of observations and range of chlorophyll and FDOM. Hydrologic, climatic, and land use changes are altering temperature and inputs of nutrients and organic matter to lakes. Our results indicate that these changes may lead to linear responses in ecosystem processes like respiration for the wide range of inputs represented in this study.