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
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Journal ArticleDOI
Clams as CO2 generators: The Potamocorbula amurensis example in San Francisco Bay
TL;DR: In this article, the authors evaluated the role of the invasive Asian clam Potamocorbula amurensis as a source of CO2 in northern San Francisco Bay, and found that it releases CO2 at a mean rate of 37 (� 34) gCm �2 yr �1
Journal ArticleDOI
Optical backscattering by calcifying algae: Separating the contribution of particulate inorganic and organic carbon fractions
William M. Balch,David T. Drapeau,Terry L. Cucci,Robert D. Vaillancourt,K. A. Kilpatrick,Jennifer J. Fritz +5 more
TL;DR: Light scattering properties of biogenic CaCO3 particles [particulate inorganic carbon (PIC)] were determined on cultured calcifying algae and field-derived Ca CO3 particles as discussed by the authors.
Journal ArticleDOI
Global biogeochemical cycle of boron
TL;DR: The global Boron cycle is primarily driven by a large flux (1.44 Tg B/yr) through the atmosphere derived from seasalt aerosols, which adds 0.20 TgB/yr as an anthropogenic contribution.
Journal ArticleDOI
Shallow-water oceans: a source or sink of atmospheric CO2?
TL;DR: In this article, the effects of human activity on the CO2 exchange between the atmosphere and the surface water of shallow-water oceans were evaluated based on changes in net ecosystem metabolism, net ecosystem calcification and atmospheric CO2 concentrations, as seen in a process-driven biogeochemical box model.
Journal ArticleDOI
Monsoonal forcing of calcification in the Arabian Sea
TL;DR: In this article, the changes in pelagic calcification and the standing stock of calcium carbonate associated with the SW Monsoon and NE Monsoon (cruises TN049 and TN053 of the U.S. JGOFS study, respectively) in the northern portion of the Arabian Sea were summarized.
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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