EGU22-10108, updated on 27 Jun 2024
https://doi.org/10.5194/egusphere-egu22-10108
EGU General Assembly 2022
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.

The influence of drought and salinity on Greenhouse Gas emissions in “Fuente de Piedra” endorheic lagoon

Ihab Alfadhel1,2, Isabel Reche1,2, Enrique P. Sánchez-Cañete3,4, Ignacio Peralta1,2, Sergio David Aguirre-García1,4, Jesús Abril-Gago3,4, Andrew S. Kowalski3,4, Francisco Domingo5, and Penélope Serrano-Ortiz1,4
Ihab Alfadhel et al.
  • 1Department of Ecology, University of Granada ,18010, Granada, Spain
  • 2Instituto del Agua, University of Granada ,18010, Granada, Spain
  • 3Department of Applied Physics, University of Granada ,18010, Granada, Spain
  • 4Instituto Interuniversitario de Investigación del Sistema Tierra en Andalucía, Centro Andaluz de Medio Ambiente (IISTA -CEAMA),18006, Granada, Spain
  • 5Estación Experimental de Zonas Áridas (EEZA), Consejo Superior de Investigaciones Científicas (CSIC), 04120, Almería, Spain

Wetlands represent 15% of global organic carbon storage and act as natural “blue carbon”, playing a significant role in the global carbon sink. However, due to climate change and anthropogenic activities (such as desiccation), they can become an important atmospheric CO2 source.  In many arid areas, lagoons may constitute the greatest part of the natural waters in temperate latitudes. They are usually very shallow or even temporary since evaporation exceeds precipitation. The most common lagoons are saline lakes in endorheic basins, which are strongly dependent on the hydrological budget. “Fuente de Piedra” lake (hereafter FdP) is a shallow and saline endorheic lagoon located in the province of Málaga, in the south of Spain. It is an important nature reserve because of its population of nesting flamingos in the Western Mediterranean, and is also the largest lagoon in Andalusia and is part of Ramsar since 1999. Based on previous studies, we hypothesize that FdP will be a net sink of CO2 but probably a yearly source of CH4 and N2O. However, its magnitude is still to be determined. Regarding the effect of drought, due to the contradictory results found in the literature, it is difficult to predict how GHG balances will behave during periods of drought and flooding. Therefore, the main objective of this study is to quantify CO2, CH4 and N2O fluxes in FdP and their seasonal variability. In this regard, the Picarro G2508 spectrometer, is being used every 15 days in four locations over a transect (dry sediments, wet sediments, shore and lagoon) to measure CO2/CH4/N2O fluxes since March 2021. At the same time, the eddy covariance technique is being used since August 2021 to quantify CO2, CH4 and H2O exchanges at the ecosystem level. Positive values of fluxes denote a net release to the atmosphere, while negative values indicate a net uptake. Preliminary results of Picarro measurements show that, during the drought period there is a significant effect of salinity for CO2 emissions with maximum value 0.3 µmol m-2 s-1 when sediments are covered by salt and 2.8 µmol m-2 s-1 when salt was removed. Regarding measurements of the transect, during the flooding period CO2 and CH4 fluxes ranged respectively from -3 µmol (CO2) m-2 s-1 and 0.008 µmol (CH4) m-2 s-1 in the lake to 1.7 µmol (CO2) m-2 s-1 and zero (CH4) µmol m-2 s-1 in the dry sediments. On the other hand, no N2O emissions where detected. Regarding the eddy covariance measurements at the ecosystem level, CO2 and CH4 flux values ranged from 10 µmol (CO2) m-2 s-1 and 0.01µmol (CH4) m-2 s-1 to zero µmol (CO2) m-2 s-1 to -0.05 (µmol CH4 m-2 s-1) during drought period (no measurements for the flooding period were taken yet). As a preliminary conclusion FdP seems to act as a source of CO2 during the drought period, while for CH4, FdP seems to act as a slight sink. However, more measurements are needed in order to provide stronger conclusions about the drought and the flooding period.

How to cite: Alfadhel, I., Reche, I., Sánchez-Cañete, E. P., Peralta, I., David Aguirre-García, S., Abril-Gago, J., Kowalski, A. S., Domingo, F., and Serrano-Ortiz, P.: The influence of drought and salinity on Greenhouse Gas emissions in “Fuente de Piedra” endorheic lagoon, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-10108, https://doi.org/10.5194/egusphere-egu22-10108, 2022.