A physiological evaluation of carbon sources for calcification in the octocoral Leptogorgia virgulata (Lamarck).

1997 ◽  
Vol 200 (20) ◽  
pp. 2653-2662
Author(s):  
J M Lucas ◽  
L W Knapp
Keyword(s):  
Calcium Carbonate ◽  
Carbonic Anhydrase ◽  
Inorganic Carbon ◽  
Sea Water ◽  
Dissolved Inorganic Carbon ◽  
Carbon Sources ◽  
Iodoacetic Acid ◽  
Transport Systems ◽  
Disulfonic Acid ◽  
Leptogorgia Virgulata

The union of calcium cations with carbonate anions to form calcium carbonate (CaCO3) is a fundamentally important physiological process of many marine invertebrates, in particular the corals. In an effort to understand the sources and processes of carbon uptake and subsequent deposition as calcium carbonate, a series of studies of the incorporation of 14C-labeled compounds into spicules was undertaken using the soft coral Leptogorgia virgulata. It has been surmised for some time that dissolved inorganic carbon in sea water is used in the biomineralization process. Furthermore, it was suspected that metabolically generated CO2 is also available for calcification. As a means of testing these possible sources of carbon in spicule calcification, key enzymes or transport systems in each pathway were inhibited. First, the enzyme carbonic anhydrase was specifically inhibited using acetazolamide. Second, the active transport of bicarbonate was inhibited using DIDS (4,4'-diisothiocyanato-stilbene-2,2'-disulfonic acid). Third, CO2 generation resulting from glycolysis and the citric acid cycle was arrested using iodoacetic acid, which interferes specifically with the enzyme glyceraldehyde-3-phosphate dehydrogenase. The results indicate that dissolved CO2 is the largest source of carbon used in the formation of calcitic sclerites, followed by HCO3- from dissolved inorganic carbon. In L. virgulata, the dissolved inorganic carbon is responsible for approximately 67% of the carbon in the sclerites. The other 33% comes from CO2 generated by glycolysis. Two important conclusions can be drawn from this work. First, carbon for spiculogenesis comes not only from dissolved inorganic carbon in the environment but also from metabolically produced carbon dioxide. While the latter has been theorized, it has never before been demonstrated in octocorals. Second, regardless of the carbon source, the enzyme carbonic anhydrase plays a pivotal role in the physiology of spicule formation in Leptogorgia virgulata.

MARINE BIOGENIC CARBONATES AND RADIOCARBON—A RETROSPECTIVE ON SHELLS AND CORALS WITH AN OUTLOOK ON CHALLENGES AND OPPORTUNITIES

Radiocarbon ◽  
2021 ◽  
pp. 1-16
Author(s):  
Susanne Lindauer ◽  
Carla S Hadden ◽  
Kita Macario ◽  
Thomas P Guilderson
Keyword(s):  
Calcium Carbonate ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Growth Patterns ◽  
Annual Growth ◽  
Environmental Research ◽  
Climate Research ◽  
Marine Carbonates ◽  
Challenges And Opportunities ◽  
Biogenic Carbonates

ABSTRACT Many organisms living in the ocean create tests, shells, or related physical structures of calcium carbonate (CaCO3). As this is most often from dissolved inorganic carbon, using organisms that create calcium carbonate structures for climate research and dating purposes requires knowledge of the origin of carbon that is incorporated. Here, we give a short overview of research on marine carbonates over the last 60 years, especially that based on shell and coral samples. Both shells and corals exhibit annual growth patterns, like trees, and therefore offer possibilities for yearly resolution of past radiocarbon (14C) variations. We concentrate on their evolution in 14C dating including difficulties in determining reservoir ages as well as the possibilities they offer for archaeological dating, oceanography, calibration purposes as well as environmental research in general.

Active HCO3− transport in cyanobacteria

1991 ◽  
Vol 69 (5) ◽  
pp. 936-944 ◽  
Author(s):  
George S. Espie ◽  
Anthony G. Miller ◽  
Ramani A. Kandasamy ◽  
David T. Canvin
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Reaction Medium ◽  
Transport Systems ◽  
Bicarbonate Transport ◽  
Key Words Cyanobacteria ◽  
Sodium Dependent ◽  
Rate Of Photosynthesis ◽  
Low Levels ◽  
In Cells

Cyanobacteria possess systems for the active transport of both CO2 and HCO3−. While the active CO2 transport system seems to be present in cells grown on all levels of CO2 or dissolved inorganic carbon, the bicarbonate transport systems are only present in cells grown on low levels of CO2 or dissolved inorganic carbon (air levels or lower). Active bicarbonate transport can be shown to occur when the rate of photosynthesis exceeds that which could be sustained by the production of CO2 from the dehydration of bicarbonate or when CO2 transport is inhibited with carbon oxysulfide or hydrogen sulfide. Two systems for active bicarbonate transport have been identified: one is dependent on the presence of millimolar concentrations of sodium, and the other is independent of the sodium requirement. Cells grown with air bubbling normally possess the first whereas cells grown in standing culture normally possess the second. The sodium-dependent bicarbonate transport can be inhibited by omitting sodium from the reaction medium or competitively with lithium when sodium is present. Monensin and amiloride also inhibit sodium-dependent bicarbonate transport. It does not appear to be inhibited by ethoxyzolamide. The inhibition of sodium-independent bicarbonate transport is not yet established. Bicarbonate transport appears to have no effect on CO2 transport and CO2 transport appears to have no effect on bicarbonate transport. Hence, the transport systems seems to be independent. Although a number of mechanisms have been proposed for bicarbonate transport, the experimental data are not sufficient to clearly distinguish between them. Key words: cyanobacteria, active CO2 transport, active HCO3− transport, photosynthesis, sodium.

Photosynthetic utilisation of inorganic carbon and its regulation in the marine diatom Skeletonema costatum

2004 ◽  
Vol 31 (10) ◽  
pp. 1027 ◽  
Author(s):  
Xiongwen Chen ◽  
Kunshan Gao
Keyword(s):  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Skeletonema Costatum ◽  
Co2 Concentration ◽  
Marine Diatom ◽  
Disulfonic Acid ◽  
High Co2 ◽  
Low Co2 ◽  
Diatom Skeletonema Costatum ◽  
Very High

Photosynthetic uptake of inorganic carbon and regulation of photosynthetic CO2 affinity were investigated in Skeletonema costatum (Grev.) Cleve. The pH independence of K1/2(CO2) values indicated that algae grown at either ambient (12 μmol L–1) or low (3 μmol L–1) CO2 predominantly took up CO2 from the medium. The lower pH compensation point (9.12) and insensitivity of photosynthetic rate to di-isothiocyanatostilbene disulfonic acid (DIDS) indicated that the alga had poor capacity for direct HCO3– utilisation. Photosynthetic CO2 affinity is regulated by the concentration of CO2 rather than HCO3–, CO32– or total dissolved inorganic carbon (DIC) in the medium. The response of photosynthetic CO2 affinity to changes in CO2 concentration was most sensitive within the range 3–48 μmol L–1 CO2. Light was required for the induction of photosynthetic CO2 affinity, but not for its repression, when cells were shifted between high (126 μmol L–1) and ambient (12 μmol L–1) CO2. The time needed for cells grown at high CO2 (126 μmol L–1) to fully develop photosynthetic CO2 affinity at ambient CO2 was approximately 2 h, but acclimation to low or very low CO2 levels (3 and 1.3 μmol L–1, respectively) took more than 10 h. Cells grown at low CO2 (3 μmol L–1) required approximately 10 h for repression of all photosynthetic CO2 affinity when transferred to ambient or high CO2 (12 or 126 μmol L–1, respectively), and more than 10 h at very high CO2 (392 μmol L–1).

scholarly journals Sources of Carbon to Deep-Sea Corals

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 533-543 ◽  
Author(s):  
Sheila Griffin ◽  
Ellen R M Druffel
Keyword(s):  
Growth Rate ◽  
Organic Matter ◽  
Deep Sea ◽  
Inorganic Carbon ◽  
Sea Water ◽  
Dissolved Inorganic Carbon ◽  
Growth Rings ◽  
Time Histories ◽  
Visible Growth ◽  
Deep Sea Corals

Radiocarbon measurements in deep-sea corals from the Little Bahama Bank were used to determine the source of carbon to the skeletal matrices. Specimens of Lophelia, Gerardia, Paragorgia johnsoni and Corallium noibe were sectioned according to visible growth rings and/or stem diameter. We determined that the source of carbon to the corals accreting organic matter was primarily from surface-derived sources. Those corals that accrete a calcerous skeleton were found to obtain their carbon solely from dissolved inorganic carbon (DIC) in sea water from the depth at which the corals grew. These results, in conjunction with growth-rate studies using short-lived radioisotopes, support the use of deep-sea corals to reconstruct time histories of transient and non-transient tracers at depth in the oceans.

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.

Physiological aspects of CO2 and HCO3− transport by cyanobacteria: a review

1990 ◽  
Vol 68 (6) ◽  
pp. 1291-1302 ◽  
Author(s):  
Anthony G. Miller ◽  
George S. Espie ◽  
David T. Canvin
Keyword(s):  
Active Transport ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Structural Analog ◽  
Transport Systems ◽  
Ribulose Bisphosphate Carboxylase ◽  
High Concentration ◽  
Bisphosphate Carboxylase ◽  
Ribulose Bisphosphate Carboxylase Oxygenase ◽  
Inorganic Carbon Transport

Cyanobacteria grown at air levels of CO2, or lower, have a very high photosynthetic affinity for CO2. For ceils grown in carbon-limited chemostats at pH 9.6, the K0.5 (CO2) for whole cell CO2 fixation is about 3 nM. This is in spite of a K0.5 (CO2) for cyanobacterial ribulose bisphosphate carboxylase/oxygenase of about 200 μM. It is now clear that cyanobacteria can photosynthesize at very low CO2 concentrations because they raise the CO2 concentration dramatically around the carboxylase. This rise in the intracellular CO2 concentration involves the active transport of HCO3− and CO2, perhaps by separate transport systems. The transport of HCO3− often requires millimolar levels of Na+, and this provides a ready means of initiating HCO3− transport. The active transport of CO2 requires only micromolar levels of Na+. In the rather dense cell suspensions used in transport studies the extent of CO2 uptake is often limited by the rate at which CO2 can be formed from the HCO3− in the medium. The addition of carbonic anhydrase relieves this kinetic limitation on CO2 transport. The active transport of CO2 can be selectively inhibited by the structural analog carbon oxysulfide (COS). When HCO3− transport is allowed in the presence of COS there is a substantial net leakage of CO2 from the cells. This leaked CO2 results from the intracellular dehydration of the accumulated HCO3−. This CO2 is normally scavenged by the active CO2 pump. If cells are allowed to transport H13C18O18O18O− for 5 s and if CO2 transport is suddenly quenched by the addition of COS, then a rapid leakage of 13C16O16O occurs. If the rapidly released CO2 was actually present in the cells before the addition of the COS, then the intracellular CO2 concentration would have been about 0.6 mM. Not only is this a high concentration, but since the leaked CO2 was completely depleted of the initial 18O, it must have been in rapid equilibrium with the total dissolved inorganic carbon within the cells. Cells grown on high levels of inorganic carbon, either as CO2 or HCO3−, lack the active HCO3− system but still retain a capacity, albeit reduced, for CO2 transport. Cyanobacteria seem to adjust their complement of inorganic carbon transport systems so that the K0.5 for transport is close to the inorganic carbon concentration of the growth medium.

Dissipation of Permethrin in Limnocorrals

1985 ◽  
Vol 42 (1) ◽  
pp. 70-76 ◽  
Author(s):  
K. R. Solomon ◽  
J. Y. Yoo ◽  
D. Lean ◽  
N. K. Kaushik ◽  
K. E. Day ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Water Chemistry ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Secchi Disk ◽  
Secchi Disk Depth ◽  
Southern Ontario ◽  
First Order ◽  
First Order Kinetics ◽  
Rate Of Dissipation

Permethrin (3-phenoxybenzyl(1RS)-cis,trans-3-(2,2-dimethy[-3-dichlorovinyl)-2,2-dimethylcyciopropanecarboxylate) applied to approximately 100-m3 enclosures (limnocorrals) in a small mesotrophic lake in Southern Ontario (47°51′25″N; 77°25′30″W) at concentrations of 500, 50, 5, and 0.5 μ∙L−1 dissipated from the water rapidly and approximated first-order kinetics in the first 8–12 d. Time taken for 50 and 90% dissipation ranged from 1.65 and 3.65 d, respectively, at 0.5 μ∙L−1 to 3.5 and 6.75 d, respectively, at 50 μ∙L−1. Inter- and intra-seasonal replication of dissipation patterns was good. Rate of dissipation varied slightly with depth, normally being slower at greater depth. Absorption of permethrin to sediments was rapid, penetration shallow, and disappearance slow. Permethrin had no effect on water chemistry but there was an increase in the Secchi disk depth in the treated limnocorrals. Dissolved inorganic carbon decreased in all limnocorrals, including controls after treatment, suggesting precipitation of calcium carbonate which may act as a scavenging agent for permethrin in the water. Limnocorrals are a useful tool for evaluating the behavior of pesticides in the aquatic system.

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