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The article highlights a study which provides a contrast in that the grassland and tall herb communities, on the Carboniferous Limestone of Derbyshire, examined all occur on soils containing free calcium carbonate. It mentions that the changes in the nutrient status of the plant-soil system after fire have been studied by estimating losses in the smoke, deposition in the ash, retention of soluble nutrients in the soil and by monitoring the nutrient content of vegetation at intervals after a fire. It concludes that the effects of fire in respect of plant nutrition are unimportant in the ecology of these communities relative to damage caused to the plants and alterations in the physical environment.

The article presents a study on the soil development of the Carboniferous Limestone of Derbyshire, England. It discusses a previous study on the deposits of loam, clay and chert-gravel and their importance in the study of the soil in the area. The study aims to profile the different types of soil in the plateau and their relationship with the vegetation. Three sites were chosen for the soil samples which do not have calcium carbonate. They include podsols, brown earth, and mixed soils. The study argues that the soils could have come from the same material and describes the possibility of podsolization due to D. flexuosa.

The article discusses a study on the growth and distribution of Molinia caerulea in Great Britain. It determines the reason why Molinia is found in peat and mineral soils but not found in calcareous soils. It also determines the influence of calcium-carbonate present in the chemical properties of calcareous soil to availability of plant nutrients. The authors conclude that Molinia caerulea do not have the ability to obtain sufficient phosphorus that made it unsuitable to grow in calcareous soil of average nutrient status.

The article focuses on the study about the effects of calcium carbonate on the growth of several seedlings under controlled solutions. The study used calcicole and calcifuge seedling species such as Scabiosa columbaria L., Asperula cynanchica L., Holcus mollis L., and Galium saxatile L. to measure their interactions that happen in the presence or absence of calcium carbonate. Among the sample seedlings, only Scabiosa developed well under laboratory conditions. The effects of iron and calcium in the seedlings under alkaline conditions are also reported.

The article reports on the sand dunes on the east side of the Camel estuary in Cornwall. Sand dunes in Cornwall extends from south of Brea Hill to the village of Rock. They are consisted of open Ammophiletum or Ammophila plants on the bay of south Brea Hill. They are rich in calcium carbonate due to the presence of snail population on the area. They are made up of foreshore plants like Salsola kali, Agropyretum, and Polygonum raii. Its vegetation is also consisted of calcifuge plants which were developed in sandy heathland.

The article presents a study which examines the vegetation of the sand dunes of the Camel estuary in north Cornwall, England. The study found that samples taken over the dune area showed over 50% of calcium carbonate and while specimens from an older range of dunes in the golf-links area, nearly 1 kilometer from the shore were found to contain nearly 70 %. According to the study, the prevalence of Rosa spinosissima in the north-west areas and the occurrence of Iris foetidissima on both sides of the Bristol Channel are characteristic of dunes in widely separated localities in the same general area.

The sand size carbonate fractions of beach and dune sands from the southeastern U.S. Atlantic coast were investigated from the standpoint of mineralogy, roundness and size distribution. The carbonate fractions of beach-dune sands used in this study range in abundance from less than 1% to over 40% and average about 10%. Calcium carbonate is least abundant in Georgia beaches and increases slightly to the north and greatly to the south. The size distribution of the carbonate fraction is similar to that of the non-carbonate fraction since both have been distributed by the same processes. The variable flat shape of calcareous fragments causes the carbonate fraction to be usually coarser and more poorly sorted than the acid insoluble residues of the samples. No regional relationship between roundness and wave energies was found in sand size materials although field observations indicate high energies strikingly round gravel sized calcareous fragments. There is some tendency for angularity to increase with decreasing grain size in the sand sizes as with quartz grains. The mineralogy of beach sand carbonate fractions is characterized by the almost total absence of high Mg calcite. Aragonite is the dominant mineral. [ABSTRACT FROM AUTHOR]

Describes the distribution of carbonate in the surface sediments in the Atlantic continental margin between Nova Scotia and Hudson Canyon. Low value of calcium carbonate in surface sediments; Low production of aquatic organisms; Low average water temperatures; Increase in the concentration of calcium carbonate seaward of the shelf.

Solutions of calcium bicarbonate were allowed to lose carbon dioxide and evaporate to dryness under controlled temperature conditions. With filtered solutions prepared from spar calcite, precipitates were 100 % calcite in the 2° to 100°C temperature range. When, in analogous experiments, coralline aragonite was the starting material, the precipitates were 100% calcite. Essentially the same was true when carbonate rocks from karst areas were used to prepare the experimental solutions. An artificially prepared mixture (maximum crystal size of about 7 μ) of 70 % aragonite and 30 % calcite was also used in the study. The precipitates from this starting material were apparently affected by seed nuclei which passed through the filter. The stability of calcium carbonate seed nuclei appears to vary with temperature. Natural calcium bicarbonate solutions from caves yielded only calcite at 25°C. Calcite should be the dominant or only polymorph of CaCO[SUB3] formed by the loss of carbon dioxide and evaporation of natural calcium bicarbonate solutions if temperature is the controlling factor. Since appreciable amounts of aragonite are found in many cave deposits, factors other than temperature must influence the polymorphs formed. POBEGUIN (1955) proposed that rapid evaporation and slow diffusion of solutions favor aragonite. If so, layers of aragonite and calcite in speleothems may represent alternate wet and dry paleoclimates. During these periods, rate of introduction of solution and rate of evaporation would change markedly. [ABSTRACT FROM AUTHOR]

The action spectrum of coccolith formation in Coccolithus huxleyi was determined by measuring the uptake of carbon-14 in coccoliths in four-hour experiments as a function of light intensity at each of seven wavelengths. An action spectrum of photosynthetic carbon assimilation was obtained at the same time. The coccolith action spectrum had peaks at wavelengths of about 440 nm and 670 nm, probably corresponding to the regions of maximum cellular absorption and carbon assimilation. However, blue light appeared to he relatively more efficient in coccolith formation than in carbon assimilation. The results suggest that light-dependent coccolith formation may he catalyzed by two photochemical reactions, one mediated by chloroplast pigments and the other by some pigment absorbing specifically in the blue part of the spectrum. [ABSTRACT FROM AUTHOR]

Coccolith formation in Coccolithus huxleyi was investigated in a semiquantitative manner by microscopic enumeration of coccolith‐carrying cells appearing, after varying periods in normal growth medium, following an initial removal of all coccoliths by treatment with a decalcifying medium. Coccoliths were formed both in the light and in the dark, but the rate of coccolith formation was very much greater in the light. Time‐course experiments on the uptake of carbon‐14 in coccoliths demonstrated that after a period in darkness, the cells required half an hour of illumination in order to adjust to the light rate of coccolith formation. Coccoliths were produced at a maximum rate only as long as the illumination lasted, although about one hour in the dark was needed before the transition back to the original dark rate was complete. [ABSTRACT FROM AUTHOR]

The effect of 3-(p-chlorophenyl)-1,1-dimethylurea (CMU) on photosynthetic oxygen evolution, carbon assimilation, and uptake of calcium and inorganic carbon in light-dependent coccolith formation in Coccolithus huxleyi was investigated by means of Winkler titration (for oxygen) and isotope techniques (for calcium and carbon). Light-dependent coccolith formation was found to be less sensitive to CMU than was photosynthesis. Time course experiments al 10-6 M CMU suggested that coccolith formation proceeded at a linear, although somewhat reduced rate even when carbon assimilation was totally inhibited. Possible reasons for an initial lag in the lime course curves of coccolith formation were discussed. The data supported the hypothesis that some light-dependent process other than photosynthetic carbon assimilation, possibly a phosphorylation process, is involved in the precipitation of calcium carbonate in coccoliths. [ABSTRACT FROM AUTHOR]

The fine carbonate fraction (less than 63 μ in diameter) in 175 sediment samples collected from the Carolina continental margin has been studied. This fraction, generally under 5% of the total sample, averages 43% CaCO3. By comparison, the CaCO3 fraction of the total samples averages only 25%. On the inner shelf, the percentage CaCO3 in the fine fraction is twenty or more times greater than the percentage CaCO3 in the total sample. With increased distance offshore, the percentages of CaCO3 in the tine fraction and the total sample approach equality. Beyond the shelf break the percentage of CaCO3 in the total sample is greater than that in the fines. The CaCO3 faunal components are primarily foraminifera, fragments of foraminifera, molluscbarnacle fragments and echinoid material. Minor constituents include alcyonarian and tunicate spicules, Hulimeda and other calcified green algae. Many grains are bored and show solution effects. The coarse carbonate fraction shows distinct regional faunal assemblages, but the fines are essentially uniformly distributed. Two exceptions are a zone of mollusc fragments around Cape Hatteras and a foraminifera zone on a portion of the outer shelf. The average carbonate mineral assemblage consists of 44% low-Mg calcite, 38% aragonite and 18% high-Mg calcite. The principal modes of origin of calcareous fines on the Carolina continental margin are probably biological and physical destruction of coarser particles and primary formation in fine size fraction (as in the case of some foraminifera). [ABSTRACT FROM AUTHOR]

In the Roman snail, like in all other molluscs, the development of the shell proceeds gradually, as the formation of an organic membrane, matrix, and a subsequent mineralization of this membrane which results in the deposition of calcium carbonate crystals in it. Hitherto it is not fully understood, whether during the mineralization calcium carbonate is immediately deposited in the matrix. The article presents an investigation which analyzes in greater detail the early mineralization stage of the regenerating shell of Helix pomatia, with special regard to the morphology and chemistry of the calcifying elements. The damaged shell of the snail is quickly repaired, yet, slowly enough to afford a good opportunity for the observation of the different stages of the regeneration.

The article presents information on a study which investigated soil variation based on their calcium carbonate content. The author reveals that in the progressive disintegration of the rock by weathering, the soil becomes gradually depleted of its carbonate. The study also notes that as the percentage of carbonate changes, so does other soil constituents such as sand, clay, and substances which have a more direct significance in the life of the plant, particularly magnesium. The author also emphasizes the need to understand soil profile.