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  • 1
    Electronic Resource
    Electronic Resource
    Compartmentation and turnover of organic carbon in the Staghorn coral Acropora formosa (1980)
    Springer
    Marine biology 59 (1980), S. 181-187 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Four colonies of Acropora formosa were incubate with Na2 14CO3 for separate 2 h periods within a 24 h period, and then returned to the reef from which they were collected. Terminal branches were collected at intervals over the following 5 d and analysed for radioactivity associated with the skeleton and certain organic pools. Colonies incubated at night showed little or no loss of fixed radioactivity during the 5 d on the reef. However, 50–60% of photosynthetically-fixed 14C was lost from the terminal branches during the first 40 h on the reef. This loss of radioactivity probably resulted from release of mucus and dissolved organic carbon from the coral tissues. Most of the loss of photosynthetically-fixed 14C was due to decrease in the radioactivity of lipids (80% of the total 14C loss) and methanol-water soluble compounds. Determination of any sequencing in metabolic compartments was made difficult by the rapidity with which 14C dissappeared from most of the metabolic pools measured. 14C was incorporated into the skeleton throughout the 5 d on the reef, although the rate of incorporation was very low in colonies which had been incubated with Na2 14CO3 at night.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00396866
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  • 2
    Electronic Resource
    Electronic Resource
    Coral calcification: Sources of error in radioisotope techniques (1977)
    Springer
    Marine biology 42 (1977), S. 119-129 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Isotopic exchange occurs between coral skeleton and 45Ca++ and H14CO 3 - in seawater. Exchange of 14C onto skeletons is more rapid than exchange of 45Ca++. Exchange of 14C from skeletons to seawater takes place more slowly than exchange of 45Ca++ to seawater. When living coral is incubated in the dark with radioisotopes for 1 h, the tissues contain considerably more radioactivity than is associated with the skeleton. The tissue radioactivity reflects permeation of tissues and coelenteron by radioactive compounds from the incubation seawater. Addition of alkalis to cardioactive seawater results in a radioactive precipitate, part of which becomes associated with any coral skeleton present, and part of which forms on the wall of the containing vessel. Strong alkali removes biologically-deposited radioisotope from coral skeletons. Deposition, of 14C from H14CO 3 - in skeletons of living coral incubated in the dark is greater than in dead coral. The reverse situation occurs with 45Ca++.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00391562
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  • 3
    Electronic Resource
    Electronic Resource
    Gas-exchange studies with the staghorn coral Acropora acuminata and its zooxanthellae (1977)
    Springer
    Marine biology 40 (1977), S. 185-194 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Compensation point and light-saturation values were determined from oxygen-exchange experiments with branches and isolated zooxanthellae from the staghorn coral Acropora acuminata. Branches and dense suspensions of zooxanthellae showed similar lightresponse curves for oxygen exchange, with light saturation at about 23 Klux (300 W. m-2) and compensation point occurring between 4 and 6 Klux (60–80 W. m-2). Zooxanthellae appear to be mutually shaded in dense suspensions and coral tissues. The effects of metabolic inhibitors, including photosynthetic and respiratory inhibitiors, on oxygen exchange in coral branches and isolated zooxanthellae are presented. Bubbles formed on coral tissues and on several macroalgae under conditions of high illumination contained large amounts of oxygen, suggesting that a high oxygen tension may occur in coral tissues during the day. Photorespiration and dissolved organic carbon production by suspensions of zooxanthellae are discussed in relation to a high oxygen tension which probably occurs in coral tissues during daylight.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00396265
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  • 4
    Electronic Resource
    Electronic Resource
    Calcification in the staghorn coral Acropora acuminata: Variations in apparent skeletal incorporation of radioisotopes due to different methods of processing (1977)
    Springer
    Marine biology 43 (1977), S. 57-62 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Pieces of branch from the staghorn coral Acropora acuminata were incubated with 45CaCl2 and NaH14CO3 under identical conditions in the light or in the dark. Specimens were then processed in different ways. All specimens were placed in N KOH to digest tissues. Some were placed in KOH immediately after incubation; others were placed in KOH after 2 h washing, or after 2 h extraction with methanol-chloroformwater. Specimens were washed in running fresh water or running seawater; some were killed in liquid N2 before washing. Radioactivity associated with skeleton and tissues was determined. The method of processing profoundly affected the results. In dark incubations, there was up to a four-fold difference in apparent skeletal incorporation of 45Ca++ between average values obtained for the different treatments. For 14C incorporation, there was a difference of up to 2.5 times. In light incubations, skeletal incorporation of both radioisotopes showed a two-fold difference between high and low average values obtained for the different treatments.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00392571
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  • 5
    Electronic Resource
    Electronic Resource
    Diurnal lipid and mucus production in the staghorn coral Acropora acuminata (1980)
    Springer
    Marine biology 60 (1980), S. 81-90 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Net 14C-accumulation into lipids of Acropora acuminata was rapid and increased with light intensity. Dark 14C-incorporation was less than 1% noon maximum. Structural lipids were the first radioactively labelled lipid types showing linear 14C-uptake kinetics. Storage lipids showed non-linear, power-curve kinetics for 14C-uptake. The rate of 14C-incorporation into triglycerides and wax esters was maximal during early afternoon and at midday, respectively. Electron microscopic evidence is given for zooxanthellae being primary sites for synthesis of lipids which are exuded from chloroplasts and transferred to animal tissues. Free lipid droplets and crystalline inclusions (wax ester) were common in animal tissues, the inclusions being often associated with mucus-producing cells. The diurnal rate of mucus production was constant. However, 14C-mucus-lipid production showed a light-dependent diurnal pattern and accounted for 60 to 90% total 14C of mucus during periods of photosynthetically-saturating light. Here, 14C was primarily associated with wax esters which were always present in the mucus-lipid. 14C-triglycerides occur in mucus released only during the day. Lipid and mucus synthesis is discussed in relation to the carbon budget of A. acuminata, in which mucus represented a loss of 40% net C fixation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00389151
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  • 6
    Electronic Resource
    Electronic Resource
    The role of metabolic nitrogen in coral calcification (1974)
    Springer
    Marine biology 28 (1974), S. 325-332 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract When pieces of the staghorn coral Acropora acuminata are incubated with 14C-urea, the label is incorporated into skeletal carbonate. Incorporation of this label differs from that of H14CO 3 - , suggesting urea is not immediately hydrolysed to provide a further source of HCO 3 - . The effects of certain organic substrates upon calcification suggest the ornithine cycle is involved. Citrulline, an ornithine cycle intermediate, is found in high concentrations in the tissues of hermatypic corals. Urea, allantoins, NH3 and arginine are also present. These compounds are barely detectable in zooxanthellae or an ahermatypic coral. The allantoins may be present as calcium salts. It is suggested that allantoins are the medium by which Ca2+ and CO2 are transported to sites of calcification. Hydrolysis of urea, formed by breakdown of allantoins, yields CO2 and NH3. The NH3 may neutralise protons formed during precipitation of CaCO3 and bring about their removal from sites of calcification. As well as providing urea, the ornithine cycle may also be involved in the removal of NH3 from sites of calcification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00388501
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  • 7
    Electronic Resource
    Electronic Resource
    Role of coral reefs in global ocean production (1991)
    Springer
    Coral reefs 10 (1991), S. 55-64 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Coral reefs cover some 600 thousand square kilometres of the earth's surface (0.17% of the ocean surface). First order estimates show coral reefs to contribute about 0.05% of the estimated net CO2 fixation rate of the global oceans. Gross CO2 fixation is relatively high (of the order 700×1012 g C year-1), but most of this material is recycled within the reefs. Excess (net) production of organic material (E) is much smaller, of the order 20×1012 g C year-1. We estimate that 3×1012 g C year-1 (15% ofE) is buried in reef structure, 2×1012 g C year-1 (10% ofE) is available for sustained human harvest, and the remaining 75% ofE is available for export from coral reefs to adjacent areas. Comparison of estimates for net production by reefs and their surrounding oceans indicates that the excess production by coral reefs is similar to new production in the photic zone of oligotrophic oceans. Consequently, estimates for global ocean production should as a first approximation include reefal areas with the surrounding ocean when assigning average net production rates. While there are significant uncertainties in these numbers, it can be concluded that organic production by reefs plays a relatively minor role in the global scale of fluxes and storage of elements. In comparison, the companion process of biologically-mediated inorganic carbon precipitation represents a major role for reefs. While reef production does respond on local scales to variation in ocean climate, neither the absolute rates nor the amount accumulated into organic pools appear to be either sensitive indicators or accurate recorders of climatic change in most reef systems. Similarly, the productivity of most reefs should be little affected by currently predicted environmental changes resulting from the Greenhouse effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00571824
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  • 8
    Electronic Resource
    Electronic Resource
    In situ release of mucus and DOC-lipid from the corals Acropora variabilis and Stylophora pistillata in different light regimes (1987)
    Springer
    Coral reefs 6 (1987), S. 35-42 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Abstract Rates of mucus and DOC-lipid release were determined for colonies of Acropora variabilis and Stylophora pistillata at 5 m depth and for a colony of A. variabilis at 23 m depth. In addition, colonies at 5 m were shaded to simulate ambient irradiance at 6 m, 10 m and 16 m depth to evaluate the effect of light on the rates of release. A. variabilis released more mucus and DOC-lipid at 5 m than at 23 m depth. For both corals, the night rates were about 30% those of the day. A reduction in total integrated irradiance decreased mucus output from the corals. Similarly, DOC-lipid release showed a diurnal pattern and diminished with reduction in daily irradiance. For both coral species, DOC-lipid release rates were greater in the afternoon than in the morning. The night rates were less than 55% those of the day. The DOC-lipid comprised wax esters and a phospholipid fraction. The diurnal variation was due to changes in yield of wax esters which contributed 〉90% of the carbon released as DOC-lipid. In situ release of mucus and DOC-lipid was infuenced by light effects on phototrophic carbon metabolism. A daily budget for carbon released as mucus and DOC-lipid was estimated for each coral species at 5 m depth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00302210
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  • 9
    Electronic Resource
    Electronic Resource
    Variability in the calcification rate of Acropora acuminata measured with radioisotopes (1982)
    Springer
    Coral reefs 1 (1982), S. 53-57 
    Details
    ISSN: 1432-0975
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences
    Notes: Summary Under standard experimental conditions, sample groups of Acropora acuminata gave calcification results having a coefficient of variation approaching 50%. Because of this, the resolution of radioisotope measurements approaches the magnitude of the effect of light on calcification rate. Differences in calcification rate between samples appear to be caused by short-term variations in calcification rate of samples, rather than size differences between samples. The coefficient of variation associated with results can be decreased by relatively straightforward modifications to the standard technique.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00286540
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  • 10
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    In situ release of mucus and DOC-lipid from the corals Acropora variabilis and Stylophora pistillata in different light regimes (1987)
    Springer
    Details
    Publication Date: 1987-07-01
    Print ISSN: 0722-4028
    Electronic ISSN: 1432-0975
    Topics: Biology , Geosciences
    Published by Springer
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