Deep-sea ultramafic-hosted vent systems have the potential to provide large amounts of metabolic\u00a0energy to both autotrophic and heterotrophic microorganisms in their dispersing hydrothermal plumes.\u00a0Such vent-systems release large quantities of hydrogen and methane to the water column, both of\u00a0which can be exploited by autotrophic microorganisms. Carbon cycling in these hydrothermal plumes\u00a0may, therefore, have an important influence on open-ocean biogeochemistry. In this study, we investigated an ultramafic-hosted system on the Mid-Cayman Rise, emitting metal-poor and hydrogen sulfide-,\u00a0methane-, and hydrogen-rich hydrothermal fluids. Total organic carbon concentrations in the plume\u00a0ranged between 42.1 and 51.1 mM (background = 43.2 \u00c6 0.7 mM (n = 5)) and near-field plume samples\u00a0with elevated methane concentrations imply the presence of chemoautotrophic primary production\u00a0and in particular methanotrophy. In parts of the plume characterized by persistent potential temperature\u00a0anomalies but lacking elevated methane concentrations, we found elevated organic carbon concentrations\u00a0of up to 51.1 mM, most likely resulting from the presence of heterotrophic communities, their extracellular\u00a0products and vent larvae. Elevated carbon concentrations up to 47.4 mM were detected even in far-field\u00a0plume samples. Within the Von Damm hydrothermal plume, we have used our data to hypothesize a microbial food web in which chemoautotrophy supports a heterotrophic community of microorganisms. Such\u00a0an active microbial food web would provide a source of labile organic carbon to the deep ocean that\u00a0should be considered in any future studies evaluating sources and sinks of carbon from hydrothermal venting to the deep ocean.<\/p>\n","protected":false},"excerpt":{"rendered":"
Trophic regions of a hydrothermal plume dispersing away from an ultramafic-hosted vent-system: Von Damm vent-site, Mid-Cayman Rise S.A. Bennett, M. Coleman, J. Huber, E. Reddington, J.C Kinsey, C. McIntyre, J. Seewald and C. R. German. Geochemistry, Geophysics, Geosystems. 14(2):317-327, 2013. Deep-sea ultramafic-hosted vent systems have the potential to provide large amounts of metabolic\u00a0energy to both…<\/p>\n","protected":false},"author":2,"featured_media":0,"parent":659,"menu_order":4,"comment_status":"closed","ping_status":"closed","template":"","meta":[],"_links":{"self":[{"href":"https:\/\/www2.whoi.edu\/site\/jameskinsey\/wp-json\/wp\/v2\/pages\/715"}],"collection":[{"href":"https:\/\/www2.whoi.edu\/site\/jameskinsey\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/www2.whoi.edu\/site\/jameskinsey\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/www2.whoi.edu\/site\/jameskinsey\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www2.whoi.edu\/site\/jameskinsey\/wp-json\/wp\/v2\/comments?post=715"}],"version-history":[{"count":3,"href":"https:\/\/www2.whoi.edu\/site\/jameskinsey\/wp-json\/wp\/v2\/pages\/715\/revisions"}],"predecessor-version":[{"id":721,"href":"https:\/\/www2.whoi.edu\/site\/jameskinsey\/wp-json\/wp\/v2\/pages\/715\/revisions\/721"}],"up":[{"embeddable":true,"href":"https:\/\/www2.whoi.edu\/site\/jameskinsey\/wp-json\/wp\/v2\/pages\/659"}],"wp:attachment":[{"href":"https:\/\/www2.whoi.edu\/site\/jameskinsey\/wp-json\/wp\/v2\/media?parent=715"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}