{"id":13503,"date":"2019-03-15T13:44:58","date_gmt":"2019-03-15T20:44:58","guid":{"rendered":"https:\/\/www.darkenergybiosphere.org\/?post_type=publication&#038;p=13503"},"modified":"2019-04-01T13:31:41","modified_gmt":"2019-04-01T20:31:41","slug":"dissolved-organic-carbon-in-basalt-hosted-deep-subseafloor-fluids-of-the-juan-de-fuca-ridge-flank","status":"publish","type":"publication","link":"https:\/\/www.darkenergybiosphere.org\/publication\/dissolved-organic-carbon-in-basalt-hosted-deep-subseafloor-fluids-of-the-juan-de-fuca-ridge-flank\/","title":{"rendered":"Dissolved organic carbon in basalt-hosted deep subseafloor fluids of the Juan de Fuca Ridge flank"},"content":{"rendered":"<p>Marine\u00a0dissolved organic carbon\u00a0(DOC) is highly depleted in radiocarbon and thus inferred to be largely\u00a0refractory\u00a0to removal processes that operate on less than millennial timescales. However, a growing number of reports have shown that a large fraction of marine DOC can be effectively removed during circulation through submarine\u00a0hydrothermal systems. What is not clear, however, is whether the DOC that remains in\u00a0hydrothermal fluids\u00a0is remnant non-reactive DOC from recharged seawater, or DOC that has been largely produced in the subsurface. We collected and characterized warm (\u223c65\u00a0\u00b0C) hydrothermal fluids from deep (18, 40, 73, 200 m) within the basalt-hosted basement of the Juan de Fuca Ridge flank in the Northeast\u00a0Pacific Ocean. DOC concentrations in hydrothermal fluids were 9 to 18 \u03bcM, much lower than measured in local deep seawater (37.5 \u03bcM). DOC\u0394<sup>14<\/sup>C\u00a0values of \u2212683\u2030 to \u2212856\u2030 were much lower than the\u00a0\u0394<sup>14<\/sup>C-dissolved\u00a0inorganic carbon\u00a0(DIC) values of \u2212880\u2030 to \u2212918\u2030, while DOC\u00a0\u03b4<sup>13<\/sup>C values of \u221223.6\u2030 to \u221227.0\u2030 were much heavier than that of the\u00a0particulate organic carbon\u00a0(POC) pool (\u223c\u221234\u2030), suggesting that\u00a0biological production\u00a0in the subsurface is not a primary source of DOC. Rather, our data suggest that isotopically enriched DOC are selectively removed from recharged seawater, leaving DOC that is very isotopically depleted in the basaltic basement fluids. Despite the removal of 50\u201375% of DOC in the subsurface, nuclear magnetic resonance (NMR) functional group analyses indicate that aromatic compounds were added to basaltic basement fluids during passage through the deep subseafloor and may partly contribute to the depleted\u00a0<sup>14<\/sup>C DOC in the ridge-flank basement fluids.<\/p>\n","protected":false},"template":"","tags":[],"publication_type":[19],"_links":{"self":[{"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/publication\/13503"}],"collection":[{"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/publication"}],"about":[{"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/types\/publication"}],"wp:attachment":[{"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/media?parent=13503"}],"wp:term":[{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/tags?post=13503"},{"taxonomy":"publication_type","embeddable":true,"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/publication_type?post=13503"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}