Estimating the large-scale biological pump: Do eddies matter?

Posted by mmaheigan 
· Wednesday, December 4th, 2019 

One factor that limits our capacity to quantify the ocean biological carbon pump is uncertainty associated with the physical injection of particulate (POC) and dissolved (DOC) organic carbon to the ocean interior. It is challenging to integrate the effects of these pumps, which operate at small spatial (<100 km) and temporal (<1 month) scales. Previous observational and fine-scale modeling studies have thus far been unable to quantify these small-scale effects. In a recent study published in Global Biogeochemical Cycles, authors explored the influence of these physical carbon pumps relative to sinking (gravity-driven) particles on annual and regional scales using a high-resolution (2 km) biophysical model of the North Atlantic that simulates intense eddy-driven subduction hotspots that are consistent with observations.

Figure 1: North Atlantic idealized double gyre ocean biophysical model. Top: Sea surface temperature, surface chlorophyll and mixed-layer depth during the spring bloom (March 21). Bottom: total export of organic carbon (POC+DOC) at 100 and individual contributions from the gravitational (particle sinking) and subduction (mixing, eddy advection and Ekman pumping) pumps for one day during the spring bloom (March 21) and averaged annually. Physical subduction hotspots visible on the daily export contribute little to the annual export due to strong compensation of upward and downward motions.

The authors showed that eddy dynamics can transport carbon below the mixed-layer (500-1000 m depth), but this mechanism contributes little (<5%) to annual export at the basin scale due to strong compensation between upward and downward fluxes (Figure 1). Additionally, the authors evidenced that small-scale mixing events intermittently export large amounts of suspended DOC and POC.

These results underscore the need to expand the traditional view of the mixed-layer carbon pump (wintertime export of DOC) to include downward mixing of POC associated with short-lived springtime mixing events, as well as eddy-driven subduction, which can contribute to longer-term ocean carbon storage. High-resolution measurements are needed to validate these model results and constrain the magnitude of the compensation between upward and downward carbon transport by small-scale physical processes.

 

Authors:
Laure Resplandy (Princeton University)
Marina Lévy (Sorbonne Université)
Dennis J. McGillicuddy Jr. (WHOI)

Filter by Keyword

234Th disequilibrium abundance acidification africa air-sea flux air-sea interactions air-sea interface algae alkalinity allometry ammonium AMOC anoxia anoxic Antarctic anthro impacts anthropogenic carbon aquaculture aragonite saturation arctic Argo argon arsenic artificial seawater Atlantic Atlantic modeling atmospheric carbon atmospheric CO2 atmospheric nitrogen deposition authigenic carbonates autonomous platforms bacteria bathypelagic BATS BCG Argo benthic bgc argo bio-go-ship bio-optical bioavailability biogeochemical cycles biogeochemical cycling biogeochemical models biogeochemistry Biological Essential Ocean Variables biological pump biological uptake biophysics bloom blooms blue carbon bottom water boundary layer buffer capacity C14 CaCO3 calcification calcite calcium carbonate carbon carbon-climate feedback carbon-sulfur coupling carbon budget carbon cycle carbon dioxide carbon export carbon sequestration carbon storage Caribbean CCA CCS changi changing marine ecosystems changing marine environments changing ocean chemistry chemical oceanographic data chemical speciation chemoautotroph chesapeake bay chl a chlorophyll circulation climate change climate variability CO2 CO2YS coastal darkening coastal ocean cobalt Coccolithophores community composition conservation cooling effect copepod coral reefs CTD currents cyclone data data access data assimilation data management data product Data standards DCM dead zone decadal trends decomposers decomposition deep convection deep ocean deep sea deep sea coral deoxygenation depth diagenesis diatoms DIC diel migration diffusion dimethylsulfide dinoflagellate discrete measurements dissolved inorganic carbon dissolved organic carbon DOC DOM domoic acid dust DVM earth system models ecology ecosystems ecosystem state eddy Education Ekman transport emissions ENSO enzyme equatorial regions error ESM estuarine and coastal carbon estuarine and coastal carbon fluxes estuary euphotic zone eutrophication evolution export export fluxes export production EXPORTS extreme events extreme weather events faecal pellets filter feeders filtration rates fire fish Fish carbon fisheries floats fluid dynamics fluorescence food webs forage fish forams freshening freshwater frontal zone fronts functional role future oceans geochemistry geoengineering geologic time GEOTRACES glaciers gliders global carbon budget global ocean global warming go-ship grazing greenhouse gas Greenland groundwater Gulf of Maine Gulf of Mexico Gulf Stream gyre harmful algal bloom high latitude human food human impact hurricane hydrogen hydrothermal hypoxia ice age ice cores ice cover industrial onset inverse circulation ions iron iron fertilization isotopes jellies katabatic winds kelvin waves krill kuroshio laboratory vs field land-ocean continuum larvaceans lateral transport LGM lidar ligands light light attenuation lipids mangroves marine carbon cycle marine heatwave marine particles marine snowfall marshes Mediterranean meltwater mesopelagic mesoscale metagenome metals methane methods microbes microlayer microorganisms microscale microzooplankton midwater mixed layer mixed layers mixing mixotrophy modeling models model validation mode water molecular diffusion MPT multi-decade n2o NAAMES NASA NCP net community production net primary productivity new ocean state new technology Niskin bottle nitrate nitrogen nitrogen cycle nitrogen fixation nitrous oxide north atlantic north pacific nuclear war nutricline nutrient budget nutrient cycling nutrient limitation nutrients OA ocean-atmosphere ocean acidification ocean acidification data ocean carbon uptake & storage ocean carbon uptake and storage ocean color ocean modeling ocean observatories ocean warming ODZ oligotrophic omics OMZ open ocean optics organic particles oscillation overturning circulation oxygen pacific paleoceanography parameter optimization particle flux particles pCO2 PDO peat pelagic PETM pH phenology phosphorus photosynthesis physical processes physiology phytoplankton PIC piezophilic piezotolerant plankton POC polar regions policy pollutants precipitation predation prediction pressure primary production primary productivity Prochlorococcus prokaryotes proteins pteropods pycnocline radioisotopes remineralization remote sensing repeat hydrography residence time resource management respiration resuspension rivers rocky shore Rossby waves Ross Sea ROV salinity salt marsh satell satellite scale seafloor seagrass sea ice sea level rise seasonal patterns seasonal trends sea spray seaweed sediments sensors shelf system shells ship-based observations shorelines silicate silicon cycle sinking particles size SOCCOM soil carbon southern ocean south pacific spatial covariations speciation SST state estimation stoichiometry subduction submesoscale subpolar subtropical sulfate surf surface surface ocean Synechococcus teleconnections temperate temperature temporal covariations thermocline thermodynamics thermohaline thorium tidal time-series time of emergence top predators total alkalinity trace elements trace metals trait-based transfer efficiency transient features Tris trophic transfer tropical turbulence twilight zone upper ocean upper water column upwelling US CLIVAR validation velocity gradient ventilation vertical flux vertical migration vertical transport volcano warming water clarity water quality waves western boundary currents wetlands winter mixing world ocean compilation zooplankton

Copyright © 2023 - OCB Project Office, Woods Hole Oceanographic Institution, 266 Woods Hole Rd, MS #25, Woods Hole, MA 02543 USA Phone: 508-289-2838  •  Fax: 508-457-2193  •  Email: ocb_news@us-ocb.org

link to nsflink to noaalink to WHOI

Funding for the Ocean Carbon & Biogeochemistry Project Office is provided by the National Science Foundation (NSF) and the National Aeronautics and Space Administration (NASA). The OCB Project Office is housed at the Woods Hole Oceanographic Institution.