(Supplementary Table 1) Proportions of methane (C1) to ethane (C2) and the stable isotope composition of methane (δ¹³CCH4) of gas and oil collected by gas bubble sampler during METEOR cruise M114/2 in the southern Gulf of Mexico

DOI

Hydrocarbon seepage is a widespread process at the continental margins of the Gulf of Mexico. We used a multidisciplinary approach, including multibeam mapping and visual seafloor observations with different underwater vehicles to study the extent and character of complex hydrocarbon seepage in the Bay of Campeche, southern Gulf of Mexico. Our observations showed that seafloor asphalt deposits previously only known from the Chapopote Knoll also occur at numerous other knolls and ridges in water depths from 1230 to 3150 m. In particular the deeper sites (Chapopopte and Mictlan knolls) were characterized by asphalt deposits accompanied by extrusion of liquid oil in form of whips or sheets, and in some places (Tsanyao Yang, Mictlan, and Chapopote knolls) by gas emission and the presence of gas hydrates in addition. Molecular and stable carbon isotopic compositions of gaseous hydrocarbons suggest their primarily thermogenic origin. Relatively fresh asphalt structures were settled by chemosynthetic communities including bacterial mats and vestimentiferan tube worms, whereas older flows appeared largely inert and devoid of corals and anemones at the deep sites. The gas hydrates at Tsanyao Yang and Mictlan Knolls were covered by a 5-to-10 cm-thick reaction zone composed of authigenic carbonates, detritus, and microbial mats, and were densely colonized by 1-2 m-long tube worms, bivalves, snails, and shrimps. This study increased knowledge on the occurrences and dimensions of asphalt fields and associated gas hydrates at the Campeche Knolls. The extent of all discovered seepage structure areas indicates that emission of complex hydrocarbons is a widespread, thus important feature of the southern Gulf of Mexico.

Supplement to: Sahling, Heiko; Borowski, Christian; Escobar-Briones, Elva; Gaytán-Caballero, Adriana; Hsu, Chieh-Wei; Loher, Markus; MacDonald, Ian R; Marcon, Yann; Pape, Thomas; Römer, Miriam; Rubin-Blum, Maxim; Schubotz, Florence; Smrzka, Daniel; Wegener, Gunter; Bohrmann, Gerhard (2016): Massive asphalt deposits, oil seepage, and gas venting support abundant chemosynthetic communities at the Campeche Knolls, southern Gulf of Mexico. Biogeosciences, 13(15), 4491-4512

Identifier
DOI https://doi.org/10.1594/PANGAEA.860373
Related Identifier https://doi.org/10.5194/bg-13-4491-2016
Related Identifier https://doi.org/10.1594/PANGAEA.863824
Related Identifier https://doi.org/10.1594/PANGAEA.864043
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.860373
Provenance
Creator Sahling, Heiko ORCID logo; Borowski, Christian ORCID logo; Escobar-Briones, Elva ORCID logo; Gaytán-Caballero, Adriana; Hsu, Chieh-Wei ORCID logo; Loher, Markus ORCID logo; MacDonald, Ian R ORCID logo; Marcon, Yann ORCID logo; Pape, Thomas ORCID logo; Römer, Miriam ORCID logo; Rubin-Blum, Maxim ORCID logo; Schubotz, Florence ORCID logo; Smrzka, Daniel ORCID logo; Wegener, Gunter (ORCID: 0000-0002-6819-373X); Bohrmann, Gerhard ORCID logo
Publisher PANGAEA
Publication Year 2016
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Language English
Resource Type Supplementary Dataset; Dataset
Format text/tab-separated-values
Size 48 data points
Discipline Earth System Research
Spatial Coverage (-94.343W, 19.931S, -93.246E, 22.393N); Gulf of Mexico
Temporal Coverage Begin 2015-03-05T19:32:00Z
Temporal Coverage End 2015-03-18T19:11:00Z