{"id":{"repo_id":"cape-town","oai_identifier":"oai:open.uct.ac.za:11427/6452"},"canonical_url":"https://search.dev.ndltd.org/etd/cape-town/oai:open.uct.ac.za:11427/6452","repository":{"repo_id":"cape-town","name":"University of Cape Town","base_url":"https://open.uct.ac.za/oai/request"},"display":{"title":"Particulate organic carbon and mineral export from the North and South Atlantic gyres : the 234Th/238U disequilibrium approach.","abstract":"Subtropical ocean gyres are typically characterised by low carbon export into the deep ocean. However, due to their large area, even relatively small average carbon export may be globally significant. Strong correlations observed between deep-sea organic carbon, calcite and opal suggest that mineral phases may enhance the export and survival of organic matter as it sinks (the 'ballast effect'). However, the processes underlying these correlations are not well understood and remain key uncertainties in models that predict global carbon cycling. To better constrain carbon and mineral export from the surface ocean of subtropical gyres, radioactive disequilibria between 234Th and 238U were used to estimate fluxes of particulate organic carbon (POe), calcite and opal in the North and South Atlantic subtropical gyres.","abstract_html":"Subtropical ocean gyres are typically characterised by low carbon export into the deep ocean. However, due to their large area, even relatively small average carbon export may be globally significant. Strong correlations observed between deep-sea organic carbon, calcite and opal suggest that mineral phases may enhance the export and survival of organic matter as it sinks (the 'ballast effect'). However, the processes underlying these correlations are not well understood and remain key uncertainties in models that predict global carbon cycling. To better constrain carbon and mineral export from the surface ocean of subtropical gyres, radioactive disequilibria between 234Th and 238U were used to estimate fluxes of particulate organic carbon (POe), calcite and opal in the North and South Atlantic subtropical gyres.","abstract_has_math":false,"creators":["Thomalla, S J"],"institution":"Department of Oceanography","degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":["Lucas, Mike","Turnewitsch, Robert"],"committee_chairs":[],"committee_members":[],"year":2007,"date_issued":"2007","date_published":"2007","updated_at":"2026-07-22T22:23:14Z","subjects":[],"languages":["eng"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"http://hdl.handle.net/11427/6452","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.advisor","label":"Advisor","values":["Lucas, Mike","Turnewitsch, Robert"]},{"key":"dc:creator","label":"Author","values":["Thomalla, S J"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-08-13T19:44:48Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-08-13T19:44:48Z"]},{"key":"dc:date.issued","label":"Date","values":["2007"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Department of Oceanography"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Cape Town"]},{"key":"dc:type","label":"Dc Type","values":["Doctoral Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["Doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["PhD"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language.iso","label":"Language (ISO)","values":["eng"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/11427/6452"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description","label":"Description","values":["Includes bibliographical references (leaves 228-270)."]},{"key":"dc:description.abstract","label":"Abstract","values":["Subtropical ocean gyres are typically characterised by low carbon export into the deep ocean. However, due to their large area, even relatively small average carbon export may be globally significant. Strong correlations observed between deep-sea organic carbon, calcite and opal suggest that mineral phases may enhance the export and survival of organic matter as it sinks (the 'ballast effect'). However, the processes underlying these correlations are not well understood and remain key uncertainties in models that predict global carbon cycling. To better constrain carbon and mineral export from the surface ocean of subtropical gyres, radioactive disequilibria between 234Th and 238U were used to estimate fluxes of particulate organic carbon (POe), calcite and opal in the North and South Atlantic subtropical gyres."]},{"key":"dc:title","label":"Title","values":["Particulate organic carbon and mineral export from the North and South Atlantic gyres : the 234Th/238U disequilibrium approach."]}]}],"canonical_facts":{"dc:contributor.advisor":["Lucas, Mike","Turnewitsch, Robert"],"dc:creator":["Thomalla, S J"],"dc:date.accessioned":["2014-08-13T19:44:48Z"],"dc:date.available":["2014-08-13T19:44:48Z"],"dc:date.issued":["2007"],"dc:description":["Includes bibliographical references (leaves 228-270)."],"dc:description.abstract":["Subtropical ocean gyres are typically characterised by low carbon export into the deep ocean. However, due to their large area, even relatively small average carbon export may be globally significant. Strong correlations observed between deep-sea organic carbon, calcite and opal suggest that mineral phases may enhance the export and survival of organic matter as it sinks (the 'ballast effect'). However, the processes underlying these correlations are not well understood and remain key uncertainties in models that predict global carbon cycling. To better constrain carbon and mineral export from the surface ocean of subtropical gyres, radioactive disequilibria between 234Th and 238U were used to estimate fluxes of particulate organic carbon (POe), calcite and opal in the North and South Atlantic subtropical gyres."],"dc:identifier.uri":["http://hdl.handle.net/11427/6452"],"dc:language.iso":["eng"],"dc:publisher.department":["Department of Oceanography"],"dc:publisher.institution":["University of Cape Town"],"dc:title":["Particulate organic carbon and mineral export from the North and South Atlantic gyres : the 234Th/238U disequilibrium approach."],"dc:type":["Doctoral Thesis"],"dc:type.qualificationlevel":["Doctoral"],"dc:type.qualificationname":["PhD"]},"updated_at":"2026-07-22T22:23:14Z"}