{"id":453,"date":"2015-12-28T02:09:27","date_gmt":"2015-12-28T02:09:27","guid":{"rendered":"http:\/\/192.168.99.100:8080\/award\/identifying-the-mechanisms-and-limits-of-the-microbial-enhancement-of-olivine-dissolution\/"},"modified":"2019-08-12T10:22:48","modified_gmt":"2019-08-12T17:22:48","slug":"identifying-the-mechanisms-and-limits-of-the-microbial-enhancement-of-olivine-dissolution","status":"publish","type":"award","link":"https:\/\/www.darkenergybiosphere.org\/award\/identifying-the-mechanisms-and-limits-of-the-microbial-enhancement-of-olivine-dissolution\/","title":{"rendered":"Identifying the mechanisms and limits of the microbial enhancement of olivine dissolution"},"content":{"rendered":"<p class=\"p1\">The project\u00a0focused on the efficacy by which microorganisms can obtain\u00a0nutrient Fe from silicate minerals. Silicate minerals are a particularly abundant mineral phase in\u00a0the oceanic crust and thus the bio-availability of silicate-bound nutrients has important implications\u00a0for microbial activity in the deep subseafloor (C-DEBI theme 1) and the limits to microbial\u00a0life (C-DEBI theme 3). The specific goal of this project was to quantitatively determine how metal-binding organic compounds (siderophores) produced by microorganisms under Fe-limited\u00a0conditions affect the rate of Fe-silicate mineral dissolution using laboratory experiments. The\u00a0exact effect of microbial activity on Fe-silicate mineral dissolution has previously been hard to\u00a0discern due to the complicating effects of feedbacks associated with microbial growth, siderophore\u00a0production, and mineral dissolution rates. To limit the effects of these feedbacks, my experimental\u00a0design used purified microbial siderophores and a silicate mineral (olivine) that dissolves\u00a0at a rate that is relatively insensitive to the accumulation of its constituent ions in solution.\u00a0My results showed that sub-millimolar siderophore concentrations lead to an order of magnitude\u00a0increase in olivine dissolution rates. The accelerating effect of siderophores was linked to the\u00a0removal of an inhibiting surface Fe-oxide coating that forms during the reaction of olivine at\u00a0circum-neutral pH in the presence of O<sub>2<\/sub>. By combining the experimental results with a numerical\u00a0model of the relevant biological feedbacks, this work further constrained the maximum\u00a0extent to which microbial activity may affect silicate mineral dissolution rates under conditions\u00a0of Fe-limitation. The results of this study are presently under review for publication in <em>Geobiology<\/em>.<\/p>\n","protected":false},"template":"","meta":[],"award_type":[9],"_links":{"self":[{"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/awards\/453"}],"collection":[{"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/awards"}],"about":[{"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/types\/award"}],"wp:attachment":[{"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/media?parent=453"}],"wp:term":[{"taxonomy":"award_type","embeddable":true,"href":"https:\/\/www.darkenergybiosphere.org\/wp-json\/wp\/v2\/award_type?post=453"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}