Synthesis & Modeling Project
Susumu Honjo
Roger Francois

Steven Manganini

Global export and recycling of biogenic material into the ocean interior; A synthesis

NSF OCE-9986766 04/00-04/03

PROJECT DESCRIPTION: A large number of moored, longer term, time-series deep-sea sediment traps have been deployed by our group and others in the world ocean over the past 2 decades, and more are being deployed every year. We are proposing a compilation of published and unpublished sediment trap flux data that will result in an integrated and consistent data set. Our goal is to refine our present estimates of global and regional fluxes and remineralization of biogenic material (organic C, calcite, aragonite, opal, N, and P) and lithogenic particle input in the ocean interior. More specifically, we are proposing a 3-year project to
  1. Build synoptic maps of organic carbon, nitrogen, phosphorus, carbonate (aragonite and calcite), opal, and lithogenic fluxes to the ocean interior;
  2. Document systematic regional variations in the seasonality of particle flux and composition;
  3. Evaluate the extent of organic matter remineralization and nutrients (N and P) regeneration within the upper 1 km by comparing fluxes at 1 km with synoptic estimates of export production;
  4. Estimate the recycling of organic C, N, P, opal, and carbonate (calcite vs. aragonite) in water below 1 km by comparing fluxes measured at different depths, after correction for trapping efficiency using a radiochemical method based on the scavenging of 230Th and 231Pa;
  5. Document the relative importance of coccolith vs. foraminifera vs. pteropod in establishing the fluxes of CaCO3, and diatoms vs. silicoflagellates vs. radiolarians in establishing the flux of biogenic SiO2;
  6. Estimate the extent of recycling in surface sediment by comparing sediment trap flux data with 230Th-normalized fluxes measured in sediment underlying each trap site;
  7. Compare fluxes of lithogenic particles with estimates of dust input into ocean basins to assess the link between aeolian input and the accumulation of terrigenous matter on the seafloor.

We will compare our results with synoptic data sets on primary production, plankton ecology, export flux, surface nutrient concentration, upper water column structure, aeolian dust input, and surface water pCO2 to distinguish environmental or ecological factors that may affect the export and degradation of biogenic material in the deep-sea (e.g. f-ratio, seasonality, food web structure, "ballast" effect from aeolian dust). This synthesis effort will provide an important basis for introducing a more accurate particle flux field and better constrained algorithms for the recycling of biogenic material in GCM models.

DATA: Table of global sediment trap results with links to online data
PUBLICATIONS: complete list of source publications
RELATED PROJECTS: - no related projects listed -

Susumu Honjo
Dept. Geology and Geophysics
Woods Hole Oceanographic Institution
Woods Hole, MA 02543
tel: 508-540-1162
fax: 508-540-9439
web site

Roger Francois (updated: 29 April 2005)
Department of Earth and Ocean Sciences
University of British Columbia
2329 West Mall
Vancouver, BC Canada V6T 1Z4
tel: 604-822-6355

Steven J. Manganini
Dept. Geology and Geophysics
Woods Hole Oceanographic Institution
Woods Hole, MA 02543
tel: 508-457-2000 x2778
web site