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Today's surface ocean is saturated with respect to calcium carbonate, but increasing atmospheric carbon dioxide concentrations are reducing ocean pH and carbonate ion concentrations, and thus the level of calcium carbonate saturation. Experimental evidence suggests that if these trends continue, key marine organisms--such as corals and some plankton--will(More)
Oceanic uptake of anthropogenic carbon dioxide (CO 2) is altering the seawater chemistry of the world's oceans with consequences for marine biota. Elevated partial pressure of CO 2 (pCO 2) is causing the calcium carbonate saturation horizon to shoal in many regions, particularly in high latitudes and regions that intersect with pronounced hypoxic zones. The(More)
Surface nutrient concentrations in the Southern Ocean are an important indicator of the atmosphere ocean chemical balance that played a key role in ice-age reduction of atmospheric pC0, and would play a role in any Fe fertilization scenario for increasing oceanic uptake of anthropogenic CO,. The response of the ocean and atmosphere to a scenario of extreme(More)
[1] A suite of standard ocean hydrographic and circulation metrics are applied to the equilibrium physical solutions from 13 global carbon models participating in phase 2 of the Ocean Carbon-cycle Model Intercomparison Project (OCMIP-2). Model-data comparisons are presented for sea surface temperature and salinity, seasonal mixed layer depth, meridional(More)
Ocean was much more vigorous in the period from ϳ1350 to 1880 A.D. than in the recent past. Our simulations reflect primarily late–20th century oceanographic conditions and support the conclusion of a subordinate role for deep convection in the Southern Ocean during this time period (21). Our conclusion that present-day Southern Ocean uptake of(More)
[1] New radiocarbon and chlorofluorocarbon-11 data from the World Ocean Circulation Experiment are used to assess a suite of 19 ocean carbon cycle models. We use the distributions and inventories of these tracers as quantitative metrics of model skill and find that only about a quarter of the suite is consistent with the new data-based metrics. This should(More)
  • J C Orr, J.-M Epitalon, J.-P Gattuso
  • 2014
Biogeosciences Discussions This discussion paper is/has been under review for the journal Biogeosciences (BG). Please refer to the corresponding final paper in BG if available. Abstract To study ocean acidification and the carbon cycle, marine scientists often use two measured or modeled carbonate system variables to compute others. These carbon-ate(More)
[1] Results are presented of export production, dissolved organic matter (DOM) and dissolved oxygen simulated by 12 global ocean models participating in the second phase of the Ocean Carbon-cycle Model Intercomparison Project. A common, simple biogeochemical model is utilized in different coarse-resolution ocean circulation models. The model mean (±1s)(More)
[1] An ocean model is used to test the idea that sea surface D 14 C behaves as a thermocline proxy in the eastern equatorial Pacific. The ORCA2 model, which includes D 14 C as a passive tracer, has been forced with reanalysis fluxes over 1948 – 1999, and the output is compared with a previously reported Galapagos D 14 C record. The model reproduces the(More)