The carbon dioxide system in the Arabian Sea

Millero, Frank J.; Degler, Elizabeth A.; O’Sullivan, Daniel W.; Goyet, Catherine; Eischeid, Greg

doi:10.1016/s0967-0645(98)00069-1

Cited by 64 publications

(40 citation statements)

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“…4d), in accordance with previous studies (e.g. Millero et al, 1998;Milliman et al, 1999;Sabine et al, 2002). Hence, core MD042876 (X % 0.9) is above the lysocline, while waters overlying core MD042873 (X % 0.7) are undersaturated with respect to aragonite.…”

Section: Modern Water Column Properties Of the Indian Oceansupporting

confidence: 91%

Millennial/centennial-scale thermocline ventilation changes in the Indian Ocean as reflected by aragonite preservation and geochemical variations in Arabian Sea sediments

Böning

Bard

2009

Geochimica et Cosmochimica Acta

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Section: Modern Water Column Properties Of the Indian Oceansupporting

confidence: 91%

Millennial/centennial-scale thermocline ventilation changes in the Indian Ocean as reflected by aragonite preservation and geochemical variations in Arabian Sea sediments

Böning

Bard

2009

Geochimica et Cosmochimica Acta

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“…Depending on the species and on environmental conditions the C/P ratio of marine organisms varies between 40 and >200 (Goldman et al, 1979;Burkhardt et al, 1999;Geider and La Roche, 2002;Klausmeier et al, 2004). Nevertheless, despite such variations, a global analysis suggests a mean Redfield ratio of 117±14/16±1/1 (Anderson and Sarmiento, 1994), which is close to the constant Redfield ratio derived by a "General Circulation Model" (GCM, 122/16/1, Maier-Reimer, 1996), and to those found by a basin-wide analysis in the Arabian Sea (125:14:1, Millero et al, 1998).…”

Section: Introductionsupporting

confidence: 74%

“…In this study these calculated rain ratios ranging between 2 and 3.5 will be compared with rain ratios derived form total dissolved inorganic carbon concentrations (DIC), total alkalinity (TA), and CO 2 partial pressure differences ( pCO 2 ) between the atmosphere and surface water (Goyet et al, 1998b(Goyet et al, , 1999Millero et al, 1998). Furthermore plankton counts (Garrison et al, 2000;Schiebel et al, 2004) will be evaluated in conjunction with nutrient (Morrison et al, 1998) and iron concentrations (Measures and Vink, 1999) in order to study factors influencing shifts in the planktonic community structure and associated changes of the composition of sinking particles.…”

Section: Introductionmentioning

confidence: 99%

Diatoms and their influence on the biologically mediated uptake of atmospheric CO<sub>2</sub> in the Arabian Sea upwelling system

2006

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Abstract. Sediment trap experiments have been carried out in order to study processes controlling shifts from diatom to non-diatom dominated systems in the western Arabian Sea. One of our major problems was to link sediment trap records to surface ocean processes. Satellite-derived observations on upper ocean parameters were helpful to reduce this problem in the past and gain a new quality by combining it with results obtained during the Joint Global Ocean Flux Study (JGOFS) in the Arabian Sea. The new results imply that intense grazing can decline or impede the development of large diatom blooms in a silicon-enriched near shore upwelling system off Oman. In the open western Arabian Sea diatom blooms recover within the offshore advecting upwelled water and lead to peak organic fluxes into the deep sea but only during the later phase of the upwelling season. During onset of the upwelling season grazing favoured by eolian iron inputs causing the formation of thinner diatom shells seems to prevent the development of a large diatom bloom within the silicon-enriched offshore advecting upwelled water. An increased relevance of diatoms and diatom-grazing copepods in the planktonic community as well as oligotrophic conditions seem to raise the ratio between organic carbon formation and calcium carbonate carbon precipitation (rain ratio) in the surface water. The decomposition of organic matter in the water column reduces the rain ratio within in the sinking matter especially in the oligotrophic region dominated by cyanobacteria and reduces also the variation of the carbon to nutrient uptake ratios seen in the surface water.

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“…In the oxycline, we have | DIC| max /| O 2 | max varying from 0.6 to 1.5, and | DIC| max /| NO In OMZs, anomalous low N/P (<10 instead of 16) have been classically reported as, for example, off Peru (Codispoti and Christensen, 1985). Abnormally high C/O of ∼1.1 (Millero et al, 1998) and C/N of 7-8 (Graco, 2002) have already been observed as well, but in iron fertilization experiment (IRONEX II, Indian Ocean) and anoxic sediments (on the shelf off Chile), respectively. The OMZ specific remineralization associated with the coexistence of different bacterial processes should be a key-element to understand why | DIC| max /| O 2 | max ratio in the carboncline-oxycline is abnormally variable.…”

Section: Local Remineralization and Biogeochemical C/o Variations At mentioning

confidence: 84%

CO<sub>2</sub> maximum in the oxygen minimum zone (OMZ)

2011

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Abstract. Oxygen minimum zones (OMZs), known as suboxic layers which are mainly localized in the Eastern Boundary Upwelling Systems, have been expanding since the 20th "high CO 2 " century, probably due to global warming. OMZs are also known to significantly contribute to the oceanic production of N 2 O, a greenhouse gas (GHG) more efficient than CO 2 . However, the contribution of the OMZs on the oceanic sources and sinks budget of CO 2 , the main GHG, still remains to be established.We present here the dissolved inorganic carbon (DIC) structure, associated locally with the Chilean OMZ and globally with the main most intense OMZs (O 2 <20 µmol kg −1 ) in the open ocean. To achieve this, we examine simultaneous DIC and O 2 data collected off Chile during 4 cruises (2000)(2001)(2002) and a monthly monitoring (2000)(2001) in one of the shallowest OMZs, along with international DIC and O 2 databases and climatology for other OMZs.High DIC concentrations (>2225 µmol kg −1 , up to 2350 µmol kg −1 ) have been reported over the whole OMZ thickness, allowing the definition for all studied OMZs a Carbon Maximum Zone (CMZ). Locally off Chile, the shallow cores of the OMZ and CMZ are spatially and temporally collocated at 21 • S, 30 • S and 36 • S despite different cross-shore, long-shore and seasonal configurations. Globally, the mean state of the main OMZs also corresponds to the largest carbon reserves of the ocean in subsurface waters. The CMZs-OMZs could then induce a positive feedback for the atmosphere during upwelling activity, as potential direct local sources of CO 2 . The CMZ paradoxically presents a slight "carbon deficit" in its core (∼10%), meaning a DIC increase from the oxygenated ocean to the OMZ lower than the corresponding O 2 decrease (assuming classical C/O molar ratios). This "carbon deficit" would be related to regionalCorrespondence to: A. Paulmier (aurelien.paulmier@legos.obs-mip.fr) thermal mechanisms affecting faster O 2 than DIC (due to the carbonate buffer effect) and occurring upstream in warm waters (e.g., in the Equatorial Divergence), where the CMZ-OMZ core originates. The "carbon deficit" in the CMZ core would be mainly compensated locally at the oxycline, by a "carbon excess" induced by a specific remineralization. Indeed, a possible co-existence of bacterial heterotrophic and autotrophic processes usually occurring at different depths could stimulate an intense aerobic-anaerobic remineralization, inducing the deviation of C/O molar ratios from the canonical Redfield ratios. Further studies to confirm these results for all OMZs are required to understand the OMZ effects on both climatic feedback mechanisms and marine ecosystem perturbations.

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The carbon dioxide system in the Arabian Sea

Cited by 64 publications

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Millennial/centennial-scale thermocline ventilation changes in the Indian Ocean as reflected by aragonite preservation and geochemical variations in Arabian Sea sediments

Millennial/centennial-scale thermocline ventilation changes in the Indian Ocean as reflected by aragonite preservation and geochemical variations in Arabian Sea sediments

Diatoms and their influence on the biologically mediated uptake of atmospheric CO<sub>2</sub> in the Arabian Sea upwelling system

CO<sub>2</sub> maximum in the oxygen minimum zone (OMZ)

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The carbon dioxide system in the Arabian Sea

Cited by 64 publications

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Millennial/centennial-scale thermocline ventilation changes in the Indian Ocean as reflected by aragonite preservation and geochemical variations in Arabian Sea sediments

Millennial/centennial-scale thermocline ventilation changes in the Indian Ocean as reflected by aragonite preservation and geochemical variations in Arabian Sea sediments

Diatoms and their influence on the biologically mediated uptake of atmospheric CO&lt;sub&gt;2&lt;/sub&gt; in the Arabian Sea upwelling system

CO&lt;sub&gt;2&lt;/sub&gt; maximum in the oxygen minimum zone (OMZ)

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Diatoms and their influence on the biologically mediated uptake of atmospheric CO<sub>2</sub> in the Arabian Sea upwelling system

CO<sub>2</sub> maximum in the oxygen minimum zone (OMZ)