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This research examines the vulnerability of the ocean biological pump, which plays a critical role in regulating atmospheric CO2 levels. It explores the factors controlling the export of organic carbon and the response of key organisms to various environmental conditions. The study also evaluates the impact of climate change on the CO2 sink in the ocean.
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Vulnerability of the ocean biological pumpCorinne Le QuéréUniversity of East Anglia and British Antarctic Survey
biological activity CO2 + H2O + CO2-3 2HCO-3 33 11 11 physical transport oceanic carbon cycle numbers in PgC/yr atmosphere 90 CO2 chemical reactions 45 34 ocean
biological activity atmosphere surface 100 m mixed layer depth
biological activity atmosphere 100 m real surface
Respiration 34 PgC/y bacteria pico-heterotrophs pico-autotrophs Primary Production 45 PgC/y N2-fixers phyto-plankton calcifiers DMS-producers mixed silicifiers Export 11 PgC/y proto zoo-plankton meso macro Ecosystem composition
Primary Production 45 PgC/y what they do pico-autotrophs N2-fixers phyto-plankton calcifiers DMS-producers mixed silicifiers
what they do pico-autotrophs N2-fixers these bloom phyto-plankton calcifiers DMS-producers mixed silicifiers
what they do pico-autotrophs N2-fixers these form shells phyto-plankton calcifiers DMS-producers mixed silicifiers
what they do pico-autotrophs N2-fixers these respond to pH phyto-plankton calcifiers DMS-producers mixed silicifiers
what they do pico-autotrophs N2-fixers these float phyto-plankton calcifiers DMS-producers mixed silicifiers
what they need pico-autotrophs N2-fixers phyto-plankton calcifiers DMS-producers mixed silicifiers
Respiration 34 PgC/y bacteria pico-heterotrophs proto zoo-plankton meso macro what they do
what they do bacteria pico-heterotrophs these control blooms proto zoo-plankton meso macro
what they do bacteria pico-heterotrophs these produce big feacal pellets proto zoo-plankton meso macro
what they need bacteria pico-heterotrophs proto zoo-plankton meso macro
time scale phytoplankton turnover time: 1 week bacterial respiration: 1 day zooplankton turnover time: 1-many weeks sinking rate: 50 m/day
a few days a few +1 days time scale
TEMPERATURE RESPONSE Q10=3.0 Primary Production 45 PgC/y Q10=1.9 Q10=2.2 Export 11 PgC/y HOT SPOTS: Respiration 34 PgC/y bacteria pico-heterotrophs pico-autotrophs N2-fixers phyto-plankton calcifiers DMS-producers mixed silicifiers proto zoo-plankton meso macro
Primary Production 45 PgC/y Export 11 PgC/y HOT SPOTS: pH RESPONSE Respiration 34 PgC/y bacteria pico-heterotrophs pico-autotrophs N2-fixers phyto-plankton reduced ballast DMS-producers mixed silicifiers proto zoo-plankton meso macro
Primary Production 45 PgC/y Export 11 PgC/y HOT SPOTS: RESPONSE TO STRATIFICATION Respiration 34 PgC/y bacteria pico-heterotrophs pico-autotrophs N2-fixers phyto-plankton calcifiers DMS-producers mixed silicifiers ? proto zoo-plankton meso macro
biological activity CO2 + H2O + CO2-3 2HCO-3 33 11 11 physical transport oceanic carbon cycle numbers in PgC/yr atmosphere 90 CO2 chemical reactions 45 34 ocean
CO2 sink (PgC/y) 0 4 10 Export (PgC/y) 14 in one decade
what controls export? the ecosystem composition and the physical transport
what controls export in models? the ecosystem composition = the physical transport
models air-sea fluxes PO4 Phyto DOC Zoo POC export
C L I M A T E R E S P O NS E O F OCE A N I C U PT A KE S a r mi e nto M ate a r a n d J o os e t a l. et a l. (1 9 9 8 ) H i r s t (1 9 9 9 ) ( 19 9 9 ) T i me S p a n 19 9 0 - 20 6 5 18 5 0 - 210 0 17 6 5 - 210 0 W a rm i n g E f f e ct -11 % -1 2 % -1 3 % Anthropogenic Effect - 2 2% -1 0 % - 3 % B iolo gi cal Pump + 2 4 % + 8 % + 6 % T O TA L - 9 % -1 4 % -1 0 % (slide adapted from J. Sarmiento)
Global changes in Atmospheric Potential Oxygen models only
Global changes in Atmospheric Potential Oxygen Slide not available because the data is not published. APO data shows at least 2x more variability than the models.
Interannual chla variability (mgChl/m3) PO4 Fe PO4 Calcifiers DOC Zoo POC export Observations (SeaWiFS) NPZD PISCES-T DGOM
Interannual chla variability (percent) Observations (SeaWiFS) NPZD PISCES-T DGOM
model projection of climate change in 2060 temperature mixed layer depth ice cover
Fe PO4 Calcifiers Impact of climate change on the CO2 sink in 2060 (mol/m2/y) (Preliminary result from E. T. Buitenhuis)
evolution of model results truth (what is the vulnerability of the marine biological pump?) illusion time
evolution of model results truth (what is the vulnerability of the marine biological pump?) illusion chaos time
ocean biogeochemistry models evolution of model results truth (what is the vulnerability of the marine biological pump?) relief illusion chaos time
thanks to Erik T. Buitenhuis and Olivier Aumont for providing model codes and results