Carbon export and transfer to depth across the Southern Ocean Great Calcite Belt
Name
Rosengard-2015-Carbon export and tr.pdf
Size
1.1 MB
Format
Adobe PDF
Checksum (MD5)
7048cb865cbd8c23c455e10d0a982fda
Author(s)
Lam, P. J.
Balch, W. M.
Auro, M. E.
Pike, S.
Drapeau, D.
Bowler, B.
Rosengard, Sarah Zhou
Date Issued
July 2015
Journal
Biogeosciences
Publisher
Copernicus GmbH
Citation
Rosengard, S. Z., P. J. Lam, W. M. Balch, M. E. Auro, S. Pike, D. Drapeau, and B. Bowler. “Carbon Export and Transfer to Depth Across the Southern Ocean Great Calcite Belt.” Biogeosciences 12, no. 13 (2015): 3953–3971.
Version
Final published version
Abstract
Sequestration of carbon by the marine biological pump depends on the processes that alter, remineralize, and preserve particulate organic carbon (POC) during transit to the deep ocean. Here, we present data collected from the Great Calcite Belt, a calcite-rich band across the Southern Ocean surface, to compare the transformation of POC in the euphotic and mesopelagic zones of the water column. The [superscript 234]Th-derived export fluxes and size-fractionated concentrations of POC, particulate inorganic carbon (PIC), and biogenic silica (BSi) were measured from the upper 1000 m of 27 stations across the Atlantic and Indian sectors of the Great Calcite Belt. POC export out of the euphotic zone was correlated with BSi export. PIC export was not, but did correlate positively with POC flux transfer efficiency. Moreover, regions of high BSi concentrations, which corresponded to regions with proportionally larger particles, exhibited higher attenuation of > 51 μm POC concentrations in the mesopelagic zone. The interplay among POC size partitioning, mineral composition, and POC attenuation suggests a more fundamental driver of POC transfer through both depth regimes in the Great Calcite Belt. In particular, we argue that diatom-rich communities produce large and labile POC aggregates, which not only generate high export fluxes but also drive more remineralization in the mesopelagic zone. We observe the opposite in communities with smaller calcifying phytoplankton, such as coccolithophores. We hypothesize that these differences are influenced by inherent differences in the lability of POC exported by different phytoplankton communities.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Woods Hole Oceanographic Institution
Terms of Use
Creative Commons Attribution
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.5194/bg-12-3953-2015
