Drought disrupts atmospheric carbon uptake in a Mediterranean saline lake

Saline inland lakes play a key role in the global carbon cycle, acting as dynamic zones for atmospheric carbon exchange and storage. Given the global decline of saline lakes and the expected increase of periods of drought in a climate change scenario, changes in their potential capacity to uptake or emit atmospheric carbon are expected. Here, we conducted continuous measurements of CO2 and CH4 fluxes at the ecosystem scale in a saline endorheic lake of the Mediterranean region over nearly 2 years. Our focus was on determining net CO2 and CH4 exchanges with the atmosphere under both dry and flooded conditions, using the eddy covariance (EC) method. We coupled greenhouse gas flux measurements with water storage and analyzed meteorological variables like air temperature and radiation, known to influence carbon fluxes in lakes. This extensive data integration enabled the projection of the net carbon flux over time, accounting for both dry and wet periods on an interannual scale. We found th..., We carried out continuous and interannual measurements of CO2 and CH4 fluxes at the ecosystem level in the saline lake Fuente de Piedra using the Eddy Covariance (EC) method. -Study site: Fuente de Piedra is a shallow, saline lake in an endorheic basin in Málaga, Andalusia, Spain, covering approximately 17 km² with a maximum depth of 1.5 meters. Designated as a Ramsar site in 1983, it benefits from extensive historical data on water storage and meteorological conditions. Salinity levels in the lake, influenced by the hydrological cycle, vary from oligosaline to hypersaline, with groundwater inflow, streams, and surface runoff contributing to its water, while sediment samples show homogeneity in organic carbon, nitrogen, and the C ratio. -Field measurements of greenhouse gas fluxes and meteorological drivers: We used the eddy covariance method to measure CO2, CH4, and energy exchanges every 30 minutes from August 2021 to May 2023, including two dry summer periods. In addition to gas meas..., , # Data from: Drought disrupts atmospheric carbon uptake in a Mediterranean saline lake [https://doi.org/10.5061/dryad.r4xgxd2nn](https://doi.org/10.5061/dryad.r4xgxd2nn) Inland saline lakes are crucial in the global carbon cycle, but increased droughts may alter their carbon exchange capacity. We measured CO2 and CH4 fluxes in a Mediterranean saline lake using the Eddy Covariance method under dry and wet conditions. We found the lake acts as a carbon sink during wet periods but not during droughts. These results highlight the importance of saline lakes in carbon sequestration and their vulnerability to climate change-induced droughts. ## Description of the data and file structure The attached files contain the data and R code to replicate the analyses and figures presented in the paper, including those from the Supplementary Material. Note that missing values in all data files have been filled as NA or they are kept as empty cells. **CODE (1 FILE)** * **code.R:** R script to repli...内陆咸水湖在全球碳循环中扮演关键角色，是大气碳交换与储存的动态区域。鉴于全球咸水湖持续衰减，且在气候变化背景下干旱期预计增加，其吸收或排放大气碳的潜在能力或将发生改变。本研究于近2年时间内，在地中海区域的一处咸水闭流湖中，开展了生态系统尺度的CO₂与CH₄通量连续观测。本研究采用涡度协方差法（eddy covariance, EC），旨在明确干旱与淹水两种状态下，该湖泊与大气间的净CO₂与CH₄交换过程。本研究将温室气体通量观测数据与水体储量数据相结合，同时分析了已知会影响湖泊碳通量的气象变量，如气温、辐射等。通过全面的数据整合，本研究得以在年际尺度上结合干湿期特征，实现净碳通量的时序推演。本研究发现……[原文截断]。本研究在富恩特皮德拉咸水湖（Fuente de Piedra）的生态系统尺度上，开展了连续的年际CO₂与CH₄通量观测，同样采用涡度协方差法。 - **研究站点**：富恩特皮德拉湖（Fuente de Piedra）是位于西班牙安达卢西亚自治区马拉加省的一处浅水性咸水闭流湖，流域面积约17 km²，最大水深1.5米。该湖于1983年被列入拉姆萨尔湿地公约（Ramsar site）名录，拥有丰富的水体储量与气象条件历史观测数据。受水文循环影响，该湖盐度范围从低盐到超咸不等，地下水径流、溪流与地表径流为其补充水源；沉积物样本显示其有机碳、氮元素及碳比值均较为均一。 - **温室气体通量与气象驱动因子野外观测**：本研究于2021年8月至2023年5月期间，采用涡度协方差法每30分钟开展一次CO₂、CH₄及能量交换观测，观测周期涵盖两段夏季干旱期。除气体通量观测外……[原文截断] # 数据集来源：《干旱干扰地中海咸水湖的大气碳吸收过程》（Drought disrupts atmospheric carbon uptake in a Mediterranean saline lake） [https://doi.org/10.5061/dryad.r4xgxd2nn](https://doi.org/10.5061/dryad.r4xgxd2nn) 内陆咸水湖在全球碳循环中具有重要价值，但日益频发的干旱或会改变其碳交换能力。本研究采用涡度协方差法，在干湿两种状态下对地中海咸水湖的CO₂与CH₄通量进行观测，结果发现该湖在淹水期为碳汇，但在干旱期则不具备碳汇功能。上述研究结果凸显了咸水湖在碳固持中的重要性，以及其对气候变化引发的干旱的脆弱性。 ## 数据与文件结构说明 附件包含可复现本文（含补充材料）中分析与图表的数据集与R语言代码。所有数据文件中的缺失值均以NA填充，或保留为空单元格。 **代码文件（共1个）** * **code.R**：用于复现分析的R脚本……[原文截断]