Spatial distribution of (sub-)outcropping methane-derived authigenic carbonate structures at the outer Aquitaine Shelf

the present database is composed of a polygon shape file (.shp) dedicated to gis applications. this seafloor surface represents the area within which (sub-)outcropping methane derived authigenic carbonates were identified based on ship-borne multibeam bathymetry and seafloor backscatter data; as displayed in figs. 4 and s1a of dupré et al. 2020 (dupré s, loubrieu b, pierre c, scalabrin c, guérin c, ehrhold a, ogor a, gautier e, ruffine l, biville r, saout j, breton c, floodpage j, lescanne m (2020) the aquitaine shelf edge (bay of biscay): a primary outlet for microbial methane release. geophysical research letters 47 (7):e2019gl084561. doi:10.1029/2019gl084561). the presence of (sub-)outcropping methane-derived authigenic carbonates at the seafloor was confirmed by remotely-operated-vehicle dives during the gazcogne2 marine expedition.the acoustic data were acquired in 2013 on board the r/v le suroît during the gazcogne1 expedition with two ship-borne multibeam echosounders, the kongsberg em302 and em2040, with transmission frequency of 30 and 200 khz, respectively. details on multibeam data acquisition, processing and interpretation of sub-outcropping methane-derived authigenic carbonate structures are presented in dupré et al 2020 (including a supporting information section).cited from dupré et al 2020: “the carbonates are exclusively located along the shelf edge with the majority (98%) between 140 and 220 m water depths. the (sub-)outcropping carbonates are spread over a 375 km2 area that extends over a distance of 80 km between the cap ferret and capbreton canyons. the western spatial limit of the methane-derived authigenic carbonates coincides with the shelf break.”

本数据库由一个专用于地理信息系统应用的polygon形状文件（.shp）构成。该海底表面代表通过船舶搭载的多波束测深和海底回波数据识别的（亚）出露甲烷衍生自生碳酸盐所在区域；如Dupré等（2020年）在图4和S1a中所示（Dupré S, Loubrieu B, Pierre C, Scalabrin C, Guérin C, Ehrhold A, Ogor A, Gautier E, Ruffine L, Biville R, Saout J, Breton C, Floodpage J, Lescanne M (2020) 阿基坦大陆架边缘（比斯开湾）：微生物甲烷释放的主要出口。地球物理研究快报47(7):e2019gl084561. doi:10.1029/2019gl084561）。通过Gazcogne2海洋考察期间的遥控潜水确认了海底（亚）出露甲烷衍生自生碳酸盐的存在。2013年Gazcogne1考察期间，在R/V Le Suroît船上使用了两台搭载的多波束测深仪，Kongsberg EM302和EM2040，分别以30和200千赫兹的传输频率进行声学数据采集。Dupré等（2020年）详细介绍了多波束数据采集、处理以及对（亚）出露甲烷衍生自生碳酸盐结构的解释（包括辅助信息部分）。引用Dupré等（2020年）：‘碳酸盐仅位于大陆架边缘，其中98%分布在140至220米水深之间。（亚）出露的碳酸盐分布在375平方公里区域内，从Ferret角到Capbreton峡谷延伸80公里。甲烷衍生自生碳酸盐的西部空间极限与大陆架边缘相吻合。’