Ballasting by cryogenic gypsum enhances carbon export in a Phaeocystis under-ice bloom
Abstract
Mineral ballasting enhances carbon export from the surface to the deep ocean; however, little is known about the role of this process in the ice-covered Arctic Ocean. Here, we propose gypsum ballasting as a new mechanism that likely facilitated enhanced vertical carbon export from an under-ice phytoplankton bloom dominated by the haptophyte Phaeocystis. In the spring 2015 abundant gypsum crystals embedded in Phaeocystis aggregates were collected throughout the water column and on the sea floor at a depth below 2 km. Model predictions supported by isotopic signatures indicate that 2.7 g m-2 gypsum crystals were formed in sea ice at temperatures below -6.5 °C and released into the water column during sea ice melting. Our finding indicates that sea ice derived (cryogenic) gypsum is stable enough to survive export to the deep ocean and serves as an effective ballast mineral. Our findings also suggest a potentially important and previously unknown role of Phaeocystis in deep carbon export due to cryogenic gypsum ballasting. The rapidly changing Arctic sea ice regime might favour this gypsum gravity chute with potential consequences for carbon export and food partitioning between pelagic and benthic ecosystems.
Citation
Wollenburg , J E , Katlein , C , Nehrke , G , Nöthig , E M , Matthiessen , J , Wolf-Gladrow , D A , Nikolopoulos , A , Gázquez-Sanchez , F , Rossmann , L , Assmy , P , Babin , M , Bruyant , F , Beaulieu , M , Dybwad , C & Peeken , I 2018 , ' Ballasting by cryogenic gypsum enhances carbon export in a Phaeocystis under-ice bloom ' , Scientific Reports , vol. 8 , 7703 . https://doi.org/10.1038/s41598-018-26016-0
Publication
Scientific Reports
Status
Peer reviewed
ISSN
2045-2322Type
Journal article
Rights
© The Author(s) 2018. Open Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
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