Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Discussion papers
https://doi.org/10.5194/bg-2019-257
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-2019-257
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: research article 08 Jul 2019

Submitted as: research article | 08 Jul 2019

Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Biogeosciences (BG).

Decoupling of net community production and particulate organic carbon dynamics in near shore surface ocean waters

Sarah Z. Rosengard1, Robert W. Izett1, William J. Burt2, Nina Schuback3,4, and Philippe D. Tortell1,5 Sarah Z. Rosengard et al.
  • 1Department of Earth, Ocean and Atmospheric Sciences, University of British Columbia, Vancouver, V6T 1Z4, Canada
  • 2College of Fisheries and Ocean Sciences, University of Alaska Fairbanks, Fairbanks, 99775, USA
  • 3Swiss Polar Institute,Lausanne, CH-1015, Switzerland
  • 4École Polytechnique Fédéralede Lausanne,Lausanne, CH-1015, Switzerland
  • 5Department of Botany, University of British Columbia, Vancouver, V6T 1Z4, Canada

Abstract. We report results from two Lagrangian surveys off the coast of Oregon, using continuous ship-board sensors to estimate mixed layer net community production (NCP) from diel cycles in biological oxygen saturation (∆O2 / Ar) and optically-derived estimates of particulate organic carbon (POC) and phytoplankton carbon (Cph). The first drifter survey, conducted in a nearshore upwelling zone during the development of a microplankton bloom, exhibited significant differences in NCP derived from ∆O2 / Ar and POC diel cycles, suggesting the presence of large POC losses from the mixed layer. At this site, we utilized the discrepancy between NCPO2 / Ar and NCPPOC, along with additional constraints derived from mixed layer nutrient inventories and surface water excess nitrous oxide (N2O), to estimate particle export, vertical mixing fluxes and DOC production. We estimate that export, vertical mixing and DOC production account for 13–45 %, 24–38 % and 25–49 % of the daily NCP discrepancy, respectively. In contrast, the second drifter survey occurred in more oligotrophic offshore waters, where NCP derived from ∆O2 / Ar and POC measurements were more closely coupled, suggesting a tighter relationship between production and community respiration. These results support the use of diel POC measurements to accurately estimate NCP in lower productivity waters with limited vertical carbon export. Although diel POC measurements may underestimate NCP in higher productivity waters, our results highlight the potential utility of coupled O2 and optical measurements to estimate the fate of POC in such regions.

Sarah Z. Rosengard et al.
Interactive discussion
Status: final response (author comments only)
Status: final response (author comments only)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Sarah Z. Rosengard et al.
Data sets

rosengard-tortell-oc2017: Releasev1.0_03Jun19 S. Z. Rosengard, R. W. Izett, W. J. Burt, N. Schuback, and P. D. Tortell https://doi.org/10.5281/zenodo.3269887

Sarah Z. Rosengard et al.
Viewed  
Total article views: 227 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
173 53 1 227 15 2 1
  • HTML: 173
  • PDF: 53
  • XML: 1
  • Total: 227
  • Supplement: 15
  • BibTeX: 2
  • EndNote: 1
Views and downloads (calculated since 08 Jul 2019)
Cumulative views and downloads (calculated since 08 Jul 2019)
Viewed (geographical distribution)  
Total article views: 188 (including HTML, PDF, and XML) Thereof 188 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Cited  
Saved  
No saved metrics found.
Discussed  
No discussed metrics found.
Latest update: 22 Sep 2019
Publications Copernicus
Download
Short summary
Net community production sets the maximum quantity of phytoplankton carbon available for the marine food web and longer-term storage in the deep ocean. We compared two approaches to estimate this critical variable from autonomous measurements of mixed layer dissolved oxygen and particulate organic carbon, observing a significant discrepancy between estimates in an upwelling zone near the Oregon coast. We use this discrepancy to assess the fate of organic carbon produced in the mixed layer.
Net community production sets the maximum quantity of phytoplankton carbon available for the...
Citation