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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Journal ArticleDOI
Optimum growth conditions as opposed to calcite saturation as a control on the calcification rate and shell-weight of marine foraminifera
TL;DR: It is shown that on a global basis planktonic foraminiferal calcification rates are not related to calcite saturation state, as has been inferred from culture experiments and across a short latitudinal core-top transect.
Journal ArticleDOI
Impacts of storms on Recent planktic foraminiferal test production and CaCO3 flux in the North Atlantic at 47 °N, 20 °W (JGOFS)
TL;DR: Foraminiferal assemblages are well known to vary in accordance with seasonal fluctuations in ocean properties, periodic reproduction cycles, and variations between water masses as discussed by the authors, and it has been shown that storms also can significantly influence foraminiferal assemblage.
Journal ArticleDOI
Ca isotope stratigraphy across the Cenomanian–Turonian OAE 2: Links between volcanism, seawater geochemistry, and the carbonate fractionation factor
Alice D.C. Du Vivier,Andrew D. Jacobson,G. O. Lehn,David Selby,Matthew T. Hurtgen,Bradley B. Sageman +5 more
TL;DR: In this paper, high-precision Ca isotope records were reported for three sections spanning a major perturbation to the Cretaceous ocean-climate system known as Ocean Anoxic Event 2 (OAE 2): central Colorado, USA (Portland #1 core), southeastern France (Pont d'Issole), and Hokkaido, Japan (Oyubari, Yezo Group).
Journal ArticleDOI
Evaluating the Ca isotope proxy
TL;DR: The use of Ca isotopes as a proxy for mass flux imbalances in the Ca cycle is evaluated critically in this article, where a compiled Ca isotope record for the last 45 Ma, derived from bulk nannofossil ooze and with a temporal resolution of ~0.5 Ma, and an interpretation of the record are presented in the context of the global Ca cycle.
Journal ArticleDOI
Phenological characteristics of global coccolithophore blooms
Jason Hopkins,Jason Hopkins,Stephanie A. Henson,Stuart C. Painter,Toby Tyrrell,Alex J. Poulton +5 more
TL;DR: In this paper, the seasonal dynamics of coccolithophores relative to a mixed phytoplankton community were investigated using remotely sensed PIC and chlorophyll data.
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
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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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