Studies on the Inorganic Carbon Dioxide Component of Human Enamel. II. The Effect of Acid on Enamel CO2

1961 ◽  
Vol 40 (5) ◽  
pp. 903-914 ◽  
Author(s):  
Marguerite F. Little
Keyword(s):  
Carbon Dioxide ◽  
Inorganic Carbon ◽  
Human Enamel

A Study of the Inorganic Carbon Dioxide in Intact Human Enamel

1958 ◽  
Vol 37 (6) ◽  
pp. 991-1000 ◽  
Author(s):  
M.F. Little ◽  
Finn Brudevold
Keyword(s):  
Carbon Dioxide ◽  
Inorganic Carbon ◽  
Human Enamel

scholarly journals Combined effects of inorganic carbon and light on <i>Phaeocystis globosa</i> Scherffel (Prymnesiophyceae)

2012 ◽  
Vol 9 (5) ◽  
pp. 1885-1896 ◽  
Author(s):  
A. Hoogstraten ◽  
M. Peters ◽  
K. R. Timmermans ◽  
H. J. W. de Baar
Keyword(s):  
Carbon Dioxide ◽  
Photosynthetic Efficiency ◽  
Inorganic Carbon ◽  
Harmful Algal Bloom ◽  
High Light ◽  
Combined Effects ◽  
Low Light ◽  
Phaeocystis Globosa ◽  
High Co2 ◽  
Dissolved Carbon

Abstract. Phaeocystis globosa (Prymnesiophyceae) is an ecologically dominating phytoplankton species in many areas around the world. It plays an important role in both the global sulfur and carbon cycles, by the production of dimethylsulfide (DMS) and the drawdown of inorganic carbon. Phaeocystis globosa has a polymorphic life cycle and is considered to be a harmful algal bloom (HAB) forming species. All these aspects make this an interesting species to study the effects of increasing carbon dioxide (CO2) concentrations, due to anthropogenic carbon emissions. Here, the combined effects of three different dissolved carbon dioxide concentrations (CO2(aq)) (low: 4 μmol kg−1, intermediate: 6–10 μmol kg−1 and high CO2(aq): 21–24 μmol kg−1) and two different light intensities (low light, suboptimal: 80 μmol photons m−2 s−1 and high light, light saturated: 240 μmol photons m−2 s−1) are reported. The experiments demonstrated that the specific growth rate of P. globosa in the high light cultures decreased with increasing CO2(aq) from 1.4 to 1.1 d−1 in the low and high CO2 cultures, respectively. Concurrently, the photosynthetic efficiency (FV/FM) increased with increasing CO2(aq) from 0.56 to 0.66. The different light conditions affected photosynthetic efficiency and cellular chlorophyll a concentrations, both of which were lower in the high light cultures as compared to the low light cultures. These results suggest that in future inorganic carbon enriched oceans, P. globosa will become less competitive and feedback mechanisms to global change may decrease in strength.

scholarly journals Impact of seawater <i>p</i>CO<sub>2</sub> on calcification and Mg/Ca and Sr/Ca ratios in benthic foraminifera calcite: results from culturing experiments with <i>Ammonia tepida</i>

2010 ◽  
Vol 7 (1) ◽  
pp. 81-93 ◽  
Author(s):  
D. Dissard ◽  
G. Nehrke ◽  
G. J. Reichart ◽  
J. Bijma
Keyword(s):  
Carbon Dioxide ◽  
Calcium Carbonate ◽  
Benthic Foraminifera ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Planktonic Foraminifera ◽  
Ambient Conditions ◽  
Precipitated Calcium Carbonate ◽  
Shell Weight ◽  
Dissolved Carbon

Abstract. Evidence of increasing concentrations of dissolved carbon dioxide, especially in the surface ocean and its associated impacts on calcifying organisms, is accumulating. Among these organisms, benthic and planktonic foraminifera are responsible for a large amount of the globally precipitated calcium carbonate. Hence, their response to an acidifying ocean may have important consequences for future inorganic carbon cycling. To assess the sensitivity of benthic foraminifera to changing carbon dioxide levels and subsequent alteration in seawater carbonate chemistry, we cultured specimens of the shallow water species Ammonia tepida at two concentrations of atmospheric CO2 (230 and 1900 ppmv) and two temperatures (10 °C and 15 °C). Shell weights and elemental compositions were determined. Impact of high and low pCO2 on elemental composition are compared with results of a previous experiment were specimens were grown under ambient conditions (380 ppvm, no shell weight measurements of specimen grown under ambient conditions are, however, available). Results indicate that shell weights decrease with decreasing [CO32−], although calcification was observed even in the presence of calcium carbonate under-saturation, and also decrease with increasing temperature. Thus both warming and ocean acidification may act to decrease shell weights in the future. Changes in [CO32−] or total dissolved inorganic carbon do not affect the Mg distribution coefficient. On the contrary, Sr incorporation is enhanced under increasing [CO32−]. Implications of these results for the paleoceanographic application of foraminifera are discussed.

scholarly journals Temporal changes in surface partial pressure of carbon dioxide and carbonate saturation state in the eastern equatorial Indian Ocean during the 1962–2012 period

2014 ◽  
Vol 11 (22) ◽  
pp. 6293-6305 ◽  
Author(s):  
L. Xue ◽  
W. Yu ◽  
H. Wang ◽  
L.-Q. Jiang ◽  
L. Feng ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Indian Ocean ◽  
Partial Pressure ◽  
Ocean Acidification ◽  
Inorganic Carbon ◽  
Equatorial Indian Ocean ◽  
Co2 Concentration ◽  
Atmospheric Co2 ◽  
Saturation State ◽  
Eastern Equatorial Indian Ocean

Abstract. Information on changes in the oceanic carbon dioxide (CO2) concentration and air–sea CO2 flux as well as on ocean acidification in the Indian Ocean is very limited. In this study, temporal changes of the inorganic carbon system in the eastern equatorial Indian Ocean (EIO, 5° N–5° S, 90–95° E) are examined using partial pressure of carbon dioxide (pCO2) data collected in May 2012, historical pCO2 data since 1962, and total alkalinity (TA) data calculated from salinity. Results show that sea surface pCO2 in the equatorial belt (2° N–2° S, 90–95° E) increased from ∼307 μatm in April 1963 to ∼373 μatm in May 1999, ∼381 μatm in April 2007, and ∼385 μatm in May 2012. The mean rate of pCO2 increase in this area (∼1.56 μatm yr−1) was close to that in the atmosphere (∼1.46 μatm yr−1). Despite the steady pCO2 increase in this region, no significant change in air–sea CO2 fluxes was detected during this period. Ocean acidification as indicated by pH and saturation states for carbonate minerals has indeed taken place in this region. Surface water pH (total hydrogen scale) and saturation state for aragonite (Ωarag), calculated from pCO2 and TA, decreased significantly at rates of −0.0016 ± 0.0001 and −0.0095 ± 0.0005 yr−1, respectively. The respective contributions of temperature, salinity, TA, and dissolved inorganic carbon (DIC) to the increase in surface pCO2 and the decreases in pH and Ωarag are quantified. We find that the increase in DIC dominated these changes, while contributions from temperature, salinity, and TA were insignificant. The increase in DIC was most likely associated with the increasing atmospheric CO2 concentration, and the transport of accumulated anthropogenic CO2 from a CO2 sink region via basin-scale ocean circulations. These two processes may combine to drive oceanic DIC to follow atmospheric CO2 increase.

Lased Enamel: Ultrastructural Observations of Pulsed Carbon Dioxide Laser Effects

1972 ◽  
Vol 51 (2) ◽  
pp. 455-460 ◽  
Author(s):  
Ralph H. Stern ◽  
Johanna Vahl ◽  
Reidar F. Sognnaes
Keyword(s):  
Carbon Dioxide ◽  
Carbon Dioxide Laser ◽  
Ruby Laser ◽  
Electron Microscopic ◽  
Human Enamel ◽  
Scanning Electron Microscopic ◽  
Laser Effect ◽  
Scanning Electron ◽  
Surface Changes

Scanning electron microscopic observations of the pulsed carbon dioxide laser effect on human enamel support microradiographic findings and indicate that this laser is significantly more efficient than the ruby laser within the limits of this investigation. Surface changes which were suggestive of fusion occurred between energy densities of 13 to 50 joules per square centimeter.

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