(2.) P Ziveri, B De Bernardi, K Baumann, H Stoll and P Mortyn, "Sinking of Coccolith
Carbonate and Potential Contribution to Organic Carbon Ballasting in the Deep Ocean," Deep-Sea Res.
Chalk is a fine-grained carbonate rock constituted mostly of coccolith
tests and characterized by a wide range of porosities and low permeabilities.
Distribution of coccoliths
in surface sediments of the south-eastern South Atlantic Ocean: ecology, preservation and carbonate contribution.
A comparison of water samples and sediments across a variety of locations has shown that the weight of individual coccoliths
(mainly those of Emiliania huxleyi, the most common coccolithophore species, and Gephyrocapsa) increases as seawater [C[O.sub.3.sup.2-]] increases (Beaufort et al., 2011).
are formed almost exclusively of calcium carbonate, as most magnesium is expelled by metabolic processes within the cells, whereas foraminiferal shells contain a much higher concentration of magnesium.
(1980): Supplementary modification and introduction of code numbers to the low-latitude coccolith
biostratigraphic zonation (Bukry, 1973;1975).
Nicholls (1979), using X-ray emission spectra, has shown that the scales are composed of silica, but not calcified, and hence do not represent coccoliths
Nannoplankton fruto the Galapagos Islands: Michaelsarsia elegans Gran and Haloppapus adriaticus Schiller (coccolithophorids) with special reference to coccoliths
and their unmineralized comoponents.
The most important group of autotrophic and planktonic haptophytes, important primary producers, is without doubt the coccolithophorids, whose cells are covered with scales of calcium carbonate called coccoliths
. Most of these cells do not possess functional flagella.
The sedimentary origin of the calcareous components is proved by the presence of coccoliths
, fossils of marine algae that lived in past geological eras but not at present (Danin et al., 1989).
Diatoms fix carbon dioxide, but produce little DMS, whereas coccoliths
produce DMS, but also release carbon dioxide.