Journal ArticleDOI
Production and accumulation of calcium carbonate in the ocean: Budget of a nonsteady state
TLDR
In this article, it was shown that the oceans are not presently in a steady state, suggesting that outputs have been overestimated or inputs underestimated, that one or more other inputs have not been identified, and/or that one of the missing calcium sources might be groundwater, although its presentday input is probably much smaller than that of rivers.Abstract:
Present-day production of CaCO3 in tne world ocean is calculated to be about 5 billion tons (bt) per year, of which about 3 bt accumulate in sediments; the other 40% is dissolved. Nearly half of the carbonate sediment accumulates on reefs, banks, and tropical shelves, and consists largely of metastable aragonite and magnesian calcite. Deep-sea carbonates, predominantly calcitic coccoliths and planktonic foraminifera, have orders of magnitude lower productivity and accumulation rates than shallow-water carbonates, but they cover orders of magnitude larger basin area. Twice as much calcium is removed from the oceans by present-day carbonate accumulation as is estimated to be brought in by rivers and hydrothermal activity (1.6 bt), suggesting that outputs have been overestimated or inputs underestimated, that one or more other inputs have not been identified, and/or that the oceans are not presently in steady state. One “missing” calcium source might be groundwater, although its present-day input is probably much smaller than that of rivers. If, as seems likely, CaCO3 accumulation presently exceeds terrestial and hydrothermal input, this imbalance presumably is offset by decreased accumulation and increased input during lowered sea level: shallow-water accumulation decreases by an order of magnitude with a 100 m drop in sea level, while groundwater influx increases because of heightened piezometric head and the diagenesis of metastable aragonite and magnesian calcite from subaerially exposed shallow-water carbonates.read more
Citations
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Book ChapterDOI
Marine Carbonates: Their Formation and Destruction
TL;DR: For marine carbonates, an overwhelming amount of information exists in a variety of specialized journals addressing marine geochemistry and carbon cycling, as well as in many books summarizing the state of knowledge on this topic as mentioned in this paper.
Journal ArticleDOI
Modeling of subsurface calcite dissolution - including the respiration and reoxidation processes of marine sediments in the region of equatorial upwelling off Gabon
TL;DR: In this paper, the degradation of organic matter and subsequent dissolution of calcite were simulated for surface sediments of the upper continental slope off Gabon by using microsensors to measure O2, pH, pCO2 and Ca2+ (in situ), pore-water concentration profiles of NO3−, NH4+, Fe2+, and Mn2+ and SO42− (ex situ), as well as sulfate reduction rates derived from incubation experiments.
Book ChapterDOI
Global Ocean Carbon Cycle Modeling
TL;DR: In this article, the authors outline the role of modeling in ocean carbon cycle research, review the status of basin to global-scale modeling, and highlight major problems, challenges, and future directions.
Journal ArticleDOI
Calcification in the planktonic foraminifera Globigerina bulloides linked to phosphate concentrations in surface waters of the North Atlantic Ocean
TL;DR: In this paper, size-normalised weights (SNWs) of Globigerina bulloides, collected from the surface waters of the North Atlantic Ocean, are compared with in situ carbonate ion concentrations ([CO32−]), sea-surface temperature, optimum growth conditions and nutrient concentrations.
Journal ArticleDOI
The possible roles of algae in restricting the increase in atmospheric CO2 and global temperature
TL;DR: It is clear that algae are important, via the biological pump, in decreasing the steady state atmospheric and ocean surface CO2, and thus decreasing radiative forcing, a reduction enhanced by algal increases in albedo.
References
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Journal ArticleDOI
A 17,000-year glacio-eustatic sea level record: influence of glacial melting rates on the Younger Dryas event and deep-ocean circulation
TL;DR: In this paper, a global oxygen isotope record for ocean water has been calculated from the Barbados sea level curve, allowing separation of the ice volume component common to all isotope records measured in deep-sea cores.
Journal ArticleDOI
The carbonate-silicate geochemical cycle and its effect on atmospheric carbon dioxide over the past 100 million years
TL;DR: In this article, a computer model has been constructed that considers the effects on the CO/sub 2/ level of the atmosphere, and the Ca, Mg, and HCO/sub 3/ levels of the ocean, of the following processes: weathering on the continents of calcite, dolomite, and calcium-and-magnesium-containing silicates; biogenic precipitation and removal of CaCO 3/from the ocean; removal of Mg from the ocean via volcanic-seawater reaction; and the metamorphic-magmatic decarbon
Journal ArticleDOI
Vostok ice core provides 160,000-year record of atmospheric CO2
TL;DR: In this article, direct evidence of past atmospheric CO2 changes has been extended to the past 160,000 years from the Vostok ice core, showing an inherent phenomenon of change between glacial and interglacial periods.
Journal ArticleDOI
Biological communities at the Florida escarpment resemble hydrothermal vent taxa.
Charles K. Paull,Barbara Hecker,R.F. Commeau,R. P. Freeman-Lynde,C. Neumann,W.P. Corso,Stjepko Golubic,J.E. Hook,Elisabeth L. Sikes,Joseph R. Curray +9 more
TL;DR: Dense biological communities of large epifaunal taxa similar to those found along ridge crest vents at the East Pacific Rise were discovered in the abyssal Gulf of Mexico.
Journal ArticleDOI
A biogeochemical study of the coccolithophore, Emiliania huxleyi, in the North Atlantic
Patrick M. Holligan,Emilio Fernández,James Aiken,William M. Balch,Philip W. Boyd,Peter H. Burkill,Miles S. Finch,Stephen B. Groom,Gillian Malin,Kerstin Muller,Duncan A. Purdie,Carol V. Robinson,Charles C. Trees,Suzanne M. Turner,Paul van der Wal +14 more
TL;DR: The biogeochemical properties of an extensive bloom (∼250,000 km2) of the coccolithophore, Emiliania huxleyi, in the north east Atlantic Ocean were investigated in June 1991.
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