Heat-Wave Effects on Oxygen, Nutrients, and Phytoplankton Can Alter Global Warming Potential of Gases Emitted from a Small Shallow Lake
Heat-Wave Effects on Oxygen, Nutrients, and Phytoplankton Can Alter Global Warming Potential of Gases Emitted from a Small Shallow Lake
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DOI：
10.1021/acs.est.5b06312
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发表时间：
2016-06-21
影响因子：
11.4
通讯作者：
Maranger, Roxane
中科院分区：
文献类型：
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作者：
Bartosiewicz, Maciej;Laurion, Isabelle;Maranger, Roxane
升高的气温可能导致更强的湖泊分层，潜在地改变营养物和生物气循环。我们通过比较分层对氧、营养物质和温室气体（CO2当量中CH4、CO2和N2O的总和）的全球变暖潜能值（GWP）的影响，评估了气候强迫的影响。在热浪期间，强烈的分层伴随着藻华和化学上增强的碳吸收。被困在地表的太阳能产生了一个更冷的、孤立的低阴离子，在比平均温度高的年份里，导致了更低的沸腾和总体更低的全球升温潜能值。此外，主要的CH4排放途径从沸腾转变为扩散，沉积物产生CH4的速率惊人地高(1.2-4.1 mmol m（-2) d(-1)）。在热浪期间，积聚的气体被困在低海拔地区，导致在秋季翻转期间向大气流出的气体达到峰值，释放了总排放量的70%，沿海地区成为热点。气候变暖对浅湖GWP的影响是浮游植物动态、排放途径、热结构和化学条件以及季节和空间变异的复杂相互作用。
Increasing air temperatures may result in stronger lake stratification, potentially altering nutrient and biogenic gas cycling. We assessed the impact of climate forcing by comparing the influence of stratification on oxygen, nutrients, and global warming potential (GWP) of greenhouse gases (the sum of CH4, CO2, and N2O in CO2 equivalents) emitted from a shallow productive lake during an average versus a heat-wave year. Strong stratification during the heat wave was accompanied by an algal bloom and chemically enhanced carbon uptake. Solar energy trapped at the surface created a colder, isolated hypolimnion, resulting in lower ebullition and overall lower GWP during the hotter-than-average year. Furthermore, the dominant CH4 emission pathway shifted from ebullition to diffusion, with CH4 being produced at surprisingly high rates from sediments (1.2-4.1 mmol m(-2) d(-1)). Accumulated gases trapped in the hypolimnion during the heat wave resulted in a peak efflux to the atmosphere during fall overturn when 70% of total emissions were released, with littoral zones acting as a hot spot. The impact of climate warming on the GWP of shallow lakes is a more complex interplay of phytoplankton dynamics, emission pathways, thermal structure, and chemical conditions, as well as seasonal and spatial variability, than previously reported.