Carbon cycling and burial in New Zealand's fjords
Abstract Understanding carbon cycling in continental margin settings is critical for constraining the global carbon cycle. Here we apply a multiproxy geochemical approach to evaluate regional carbon cycle dynamics in six New Zealand fjords. Using carbon and nitrogen concentrations and isotopes, lipi...
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| Format: | Article |
| Language: | English |
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Wiley
2014-10-01
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| Series: | Geochemistry, Geophysics, Geosystems |
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| Online Access: | https://doi.org/10.1002/2014GC005433 |
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| author | Jessica L. Hinojosa Christopher M. Moy Claudine H. Stirling Gary S. Wilson Timothy I. Eglinton |
| author_facet | Jessica L. Hinojosa Christopher M. Moy Claudine H. Stirling Gary S. Wilson Timothy I. Eglinton |
| author_sort | Jessica L. Hinojosa |
| collection | DOAJ |
| description | Abstract Understanding carbon cycling in continental margin settings is critical for constraining the global carbon cycle. Here we apply a multiproxy geochemical approach to evaluate regional carbon cycle dynamics in six New Zealand fjords. Using carbon and nitrogen concentrations and isotopes, lipid biomarkers, and redox‐sensitive element concentrations, we show that the New Zealand fjords have carbon‐rich surface sediments in basins that promote long‐term storage (i.e., semirestricted basins with sediment accumulation rates of up to 4 mm yr−1). Using δ13C distributions to develop a mixing model, we find that organic carbon in fjord sediments is well‐mixed from marine and terrestrial sources in down‐fjord gradients. This is driven by high regional precipitation rates of >6 m yr−1, which promote carbon accumulation in fjord basins through terrestrial runoff. In addition, we have identified at least two euxinic subbasins, based on uranium, molybdenum, iron, and cadmium enrichment, that contain >7% organic carbon. Because the strength and position of the Southern Hemisphere westerly winds control precipitation and fjord circulation, carbon delivery and storage in the region are intimately linked to westerly wind variability. We estimate that the fjord region (759 km2) may be exporting up to 1.4 × 107 kgC yr−1, outpacing other types of continental margins in rates of carbon burial by up to 3 orders of magnitude. |
| format | Article |
| id | doaj-art-d0825cdb0d444d3a9a5f581a19dcc128 |
| institution | DOAJ |
| issn | 1525-2027 |
| language | English |
| publishDate | 2014-10-01 |
| publisher | Wiley |
| record_format | Article |
| series | Geochemistry, Geophysics, Geosystems |
| spelling | doaj-art-d0825cdb0d444d3a9a5f581a19dcc1282025-08-20T02:46:35ZengWileyGeochemistry, Geophysics, Geosystems1525-20272014-10-0115104047406310.1002/2014GC005433Carbon cycling and burial in New Zealand's fjordsJessica L. Hinojosa0Christopher M. Moy1Claudine H. Stirling2Gary S. Wilson3Timothy I. Eglinton4Department of GeologyUniversity of OtagoDunedin New ZealandDepartment of GeologyUniversity of OtagoDunedin New ZealandCentre for Trace Element Analysis, Department of ChemistryUniversity of OtagoDunedin New ZealandDepartment of Marine ScienceUniversity of OtagoDunedin New ZealandDepartment of Earth SciencesGeological InstituteETH Zürich Zürich SwitzerlandAbstract Understanding carbon cycling in continental margin settings is critical for constraining the global carbon cycle. Here we apply a multiproxy geochemical approach to evaluate regional carbon cycle dynamics in six New Zealand fjords. Using carbon and nitrogen concentrations and isotopes, lipid biomarkers, and redox‐sensitive element concentrations, we show that the New Zealand fjords have carbon‐rich surface sediments in basins that promote long‐term storage (i.e., semirestricted basins with sediment accumulation rates of up to 4 mm yr−1). Using δ13C distributions to develop a mixing model, we find that organic carbon in fjord sediments is well‐mixed from marine and terrestrial sources in down‐fjord gradients. This is driven by high regional precipitation rates of >6 m yr−1, which promote carbon accumulation in fjord basins through terrestrial runoff. In addition, we have identified at least two euxinic subbasins, based on uranium, molybdenum, iron, and cadmium enrichment, that contain >7% organic carbon. Because the strength and position of the Southern Hemisphere westerly winds control precipitation and fjord circulation, carbon delivery and storage in the region are intimately linked to westerly wind variability. We estimate that the fjord region (759 km2) may be exporting up to 1.4 × 107 kgC yr−1, outpacing other types of continental margins in rates of carbon burial by up to 3 orders of magnitude.https://doi.org/10.1002/2014GC005433fjordsNew ZealandSouthern Hemisphere westerly windscarbon cycling |
| spellingShingle | Jessica L. Hinojosa Christopher M. Moy Claudine H. Stirling Gary S. Wilson Timothy I. Eglinton Carbon cycling and burial in New Zealand's fjords Geochemistry, Geophysics, Geosystems fjords New Zealand Southern Hemisphere westerly winds carbon cycling |
| title | Carbon cycling and burial in New Zealand's fjords |
| title_full | Carbon cycling and burial in New Zealand's fjords |
| title_fullStr | Carbon cycling and burial in New Zealand's fjords |
| title_full_unstemmed | Carbon cycling and burial in New Zealand's fjords |
| title_short | Carbon cycling and burial in New Zealand's fjords |
| title_sort | carbon cycling and burial in new zealand s fjords |
| topic | fjords New Zealand Southern Hemisphere westerly winds carbon cycling |
| url | https://doi.org/10.1002/2014GC005433 |
| work_keys_str_mv | AT jessicalhinojosa carboncyclingandburialinnewzealandsfjords AT christophermmoy carboncyclingandburialinnewzealandsfjords AT claudinehstirling carboncyclingandburialinnewzealandsfjords AT garyswilson carboncyclingandburialinnewzealandsfjords AT timothyieglinton carboncyclingandburialinnewzealandsfjords |