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

[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.

[数据采集与生成方法说明] 依托BOATS传感器维护作业周期，定期采集水样以检测溶解氧（dissolved oxygen, DO）与总碱度（total alkalinity, TA）。在两个站点中，月度水样均采集自BOATS观测站传感器所在的同一深度：海洋观测浮标处取1米层水样，卡布雷拉国家公园（PN Cabrera）处取4米层水样。本次采集的水样检测指标涵盖溶解甲烷（dissolved methane, CH₄）、溶解氧（DO）、总碱度（TA）、溶解有机碳（dissolved organic carbon, DOC）与叶绿素a（chlorophyll a, Chl a）；在上述两个站点均同步采集离散月度水样：帕尔马湾（Bay of Palma）取1米层水样，卡普塞萨利内斯（Cap ses Salines）取表层水样，卡布雷拉取4米层水样。卡布雷拉与帕尔马湾的BOATS站点通过将连接泵体的软管浸没至传感器安装高度处完成水样采集。第三个站点为卡普塞萨利内斯灯塔，采用水桶采集表层水样。