Methane emissions in the coastal Balearic Sea between October 2019 – October 2021

• Main Authors: Hendriks, Iris E., Flecha, Susana, Paz, M. de la, Pérez, Fiz F., Morell Lujan-Williams, Alejandro, Tintoré, Joaquín, Barbà, Núria
• Other Authors: Agencia Estatal de Investigación (España), Fundación BBVA, Govern de les Illes Balears, Consejo Superior de Investigaciones Científicas (España), Hendriks, Iris E. [e-mail]
• Format: Dataset
• Language: English
• Published: DIGITAL.CSIC 2023
• Subjects: Greenhouse gases; Methane flux; Mediterranean Sea; Balearic Sea; Climate change; Coastal monitoring; Posi; Ocean acidification
• Online Access: http://hdl.handle.net/10261/332738; https://doi.org/10.20350/digitalCSIC/15491

[Description of methods used for collection/generation of data] Periodically water sampling for dissolved oxygen (DO) and total alkalinity (TA) was done during the sensor maintenance campaigns of BOATS. In two sites, monthly samples were collected from the same depth as the sensors of the BOATS stations, at 1m at the oceanographic buoy, and 4m in PN Cabrera. Samples were taken for dissolved methane (CH4), dissolved oxygen (DO), total alkalinity (TA), dissolved organic carbon (DOC), Chlorophyll a (Chl a), In both stations monthly discrete samples were collected, at 1 m in the Bay of Palma, Surface for Cap ses Salines and at 4 m depth in Cabrera. Samples were collected by submerging a hose connected to a pump at the sensor height of the BOATS stations in Cabrera and the Bay of Palma. At the third site, the lighthouse of Cap ses Salines, a bucket was used to obtain surface water samples. readme provides background information for xlsx datafiles. Methane (CH4) gas is the most important greenhouse gas (GHG) after carbon dioxide, with open ocean areas acting as discreet CH4 sources and coastal regions as intense but variable CH4 sources to the atmosphere. In this database we report measured CH4 concentrations and calculated air-sea fluxes in three sites of the coastal area of the Balearic Islands Archipelago (Western Mediterranean Basin). CH4 levels and related biogeochemical variables were measured in three coastal sampling sites between 2019 and 2021. CH4 concentrations in seawater ranged from 2.7 to 10.9 nM, without significant differences between the sampling sites. Averaged estimated CH4 fluxes during the sampling period for the three stations oscillated between 0.2 and 9.7 μmol m−2 d−1 following a seasonal pattern and in general all sites behaved as weak CH4 sources throughout the sampling period. Funding for this work was provided by the projects RTI2018-095441-B-C21 (SuMaEco) and, the BBVA Foundation project Posi-COIN and the Balearic Islands Government project SEPPO (PRD2018/18). This work is a ...