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...