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Sarah B. Das and Elizabeth B. Kujawinski. Bhatia, Maya Pilar, 1979- Woods Hole Oceanographic Institution. Joint Program in Oceanography/Applied Ocean Science and Engineering Woods Hole Oceanographic Institution Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences n-gl--- 2012-05-15T21:11:26Z 2012-05-15T21:11:26Z 2012 2012 http://hdl.handle.net/1721.1/70775 790610200 Thesis (Ph. D.)--Joint Program in Oceanography/Applied Ocean Science and Engineering (Massachusetts Institute of Technology, Dept. of Earth, Atmospheric, and Planetary Sciences; and the Woods Hole Oceanographic Institution), 2012. Cataloged from PDF version of thesis. Includes bibliographical references. Global warming has led to a significant increase in Greenland ice sheet (GrIS) melt and runoff since 1990, resulting in escalated export of fresh water and associated sediment to the surrounding North Atlantic and Arctic Oceans. Similar to alpine glacial systems, surface meltwater on ice sheet surface drains to the base (subglacial) where it joins a drainage system and can become chemically enriched from its origin as dilute snow- and ice-melt. In this thesis, I examine the interdependence of glacial hydrology and biogeochemical cycling in terms of export of carbon and iron from the Greenland ice sheet. I develop a new isotope mixing-model to quantify water source contributions to the bulk meltwater discharge draining a GrIS outlet glacier. Results illustrate (a) the new application of a naturally occurring radioisotope (radon-222) as a quantitative tracer for waters stored at the glacier bed, and (b) the seasonal evolution of the subglacial drainage network from a delayed-flow to a quick-flow system. Model results also provide the necessary hydrological context to interpret and quantify glacially-derived organic carbon and iron fluxes. I combine bulk- and molecular-level studies of subglacial organic carbon to show that GrIS discharge exports old (radiocarbon depleted), labile organic matter. Similar investigations of dissolved and particulate iron reveal that GrIS discharge may be a significant flux of labile iron to the North Atlantic Ocean during the summer meltseason. Both carbon and iron are subject to proglacial processing prior to export to the marine environment, and exhibit strong seasonal variability in correlation with the subglacial drainage evolution. Low, chemically concentrated fluxes characterize the spring discharge, whereas higher, chemically dilute fluxes typify the summer discharge. Collectively, this thesis provides some of the first descriptions and flux estimates of carbon and iron, key elements in ocean biogeochemical cycles, in GrIS meltwater runoff. by Maya Pilar Bhatia. Ph.D. 143 p. eng Massachusetts Institute of Technology M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission. http://dspace.mit.edu/handle/1721.1/7582 Joint Program in Oceanography/Applied Ocean Science and Engineering. Earth, Atmospheric, and Planetary Sciences. Woods Hole Oceanographic Institution. Hydrological and biogeochemical cycling along the Greenland ice sheet margin Thesis application/pdf false Publication unknown unknown <Publication xmlns="https://www.openaire.eu/cerif-profile/1.1/" id="144aea61-d3ad-445f-aee3-14ebdc1a0d67"> <Type xmlns="https://www.openaire.eu/cerif-profile/vocab/COAR_Publication_Types">http://purl.org/coar/resource_type/c_1843</Type> <Language>eng</Language> <Title>Hydrological and biogeochemical cycling along the Greenland ice sheet margin</Title> <PublishedIn> <Publication> </Publication> </PublishedIn> <PublicationDate>2012</PublicationDate> <Authors> <Author> <DisplayName>Bhatia, Maya Pilar, 1979-</DisplayName> <Affiliation> <OrgUnit> </OrgUnit> </Affiliation> </Author> </Authors> <Editors> </Editors> <Publishers> <Publisher> <DisplayName>Massachusetts Institute of Technology</DisplayName> <OrgUnit /> </Publisher> </Publishers> <License>http://dspace.mit.edu/handle/1721.1/7582</License> <Keyword>Joint Program in Oceanography/Applied Ocean Science and Engineering.</Keyword> <Keyword>Earth, Atmospheric, and Planetary Sciences.</Keyword> <Keyword>Woods Hole Oceanographic Institution.</Keyword> <Abstract>Global warming has led to a significant increase in Greenland ice sheet (GrIS) melt and runoff since 1990, resulting in escalated export of fresh water and associated sediment to the surrounding North Atlantic and Arctic Oceans. Similar to alpine glacial systems, surface meltwater on ice sheet surface drains to the base (subglacial) where it joins a drainage system and can become chemically enriched from its origin as dilute snow- and ice-melt. In this thesis, I examine the interdependence of glacial hydrology and biogeochemical cycling in terms of export of carbon and iron from the Greenland ice sheet. I develop a new isotope mixing-model to quantify water source contributions to the bulk meltwater discharge draining a GrIS outlet glacier. Results illustrate (a) the new application of a naturally occurring radioisotope (radon-222) as a quantitative tracer for waters stored at the glacier bed, and (b) the seasonal evolution of the subglacial drainage network from a delayed-flow to a quick-flow system. Model results also provide the necessary hydrological context to interpret and quantify glacially-derived organic carbon and iron fluxes. I combine bulk- and molecular-level studies of subglacial organic carbon to show that GrIS discharge exports old (radiocarbon depleted), labile organic matter. Similar investigations of dissolved and particulate iron reveal that GrIS discharge may be a significant flux of labile iron to the North Atlantic Ocean during the summer meltseason. Both carbon and iron are subject to proglacial processing prior to export to the marine environment, and exhibit strong seasonal variability in correlation with the subglacial drainage evolution. Low, chemically concentrated fluxes characterize the spring discharge, whereas higher, chemically dilute fluxes typify the summer discharge. Collectively, this thesis provides some of the first descriptions and flux estimates of carbon and iron, key elements in ocean biogeochemical cycles, in GrIS meltwater runoff.</Abstract> <Access xmlns="http://purl.org/coar/access_right" > </Access> </Publication>