Increased calcium=increased calcification

[boxfishpooalot]

http://archive.reefcentral.com/forums/showthread.php?s=&postid=8701242#post8701242

I posted this there, what do you think of it?

The relationship between calcification and photosynthesis in coral was investigated using standard sea water with enhanced calcium concentration. In standard sea water at 23°C with the calcium concentration increased by 2.5 mmol l-1, incorporation of calcium into the skeleton increased by 30-61 %, depending on the method of data normalisation, and photosynthesis, measured as 14C incorporation into the tissues, also increased by 87 %. At 29 °C, calcium incorporation into the skeleton increased by 54-84 % and 14C incorporation increased by 32 % when sea water calcium concentration was increased by 5 mmol l-1. However, photosynthesis measured as net photosynthetic oxygen production did not increase. Similarly there was no change in respiration rate when coral polyps were incubated in high-calcium sea water. It is conjectured that an increase in photorespiration may be responsible for the latter observations. Bisphosphonate has been considered to inhibit calcification but not photosynthesis in corals. We show that bisphosphonate may not inhibit formation of amorphous calcium carbonate and that the inhibition of calcification is possibly illusory. The data are consistent with the trans-calcification model, which suggests that calcification is a source of CO2 for photosynthesis in corals.

http://jeb.biologists.org/cgi/content/full/205/14/2107

Thought you might be interested to see this :)

[boxfishpooalot]

and this one too is interesting about bicarbonate

Abstract
The addition of 2 mM bicarbonate to aquaria containing tropical ocean water and branches of Porites porites caused a doubling of the skeletal growth rate of the coral. Nitrate or ammonium addition (20 $\mu$M) to oligotrophic sea-water caused a significant reduction in coral growth, but when seawater containing the extra bicarbonate was supplemented with combined nitrogen, no depression of the higher growth rate was evident. We infer that (1) the present dissolved inorganic carbon (DIC) content of the ocean limits coral growth, (2) this limitation is exacerbated by nitrate and ammonium, and (3) adding DIC increases coral calcification rates and confers protection against nutrient enrichment

[Randy Holmes-Farley]

Interesting.

If I am reading the first article correctly, the incubation times were extraordinarily short (a few hours max) and so may not reflect growth in the medium to long term (days, weeks, months, years). Corals may just absorb and deposit more calcium for a short period.

The second one is as expected based on other studies (or maybe this is one I've referenced :D ).

[boxfishpooalot]

This one is kind of the opposite.

Somthing to do with low calcium not effecting the rate of calcification. I dont know why all those money symbols are showing :lol: What do you make of it?

Abstract
The interaction between photosynthesis and calcification remains poorly known in zooxanthellate scleractinian corals. We tested whether calcification is a significant source of CO$_2$ for photosynthesis in Stylophora pistillata. Rates of net photosynthesis, respiration, and calcification were measured on colonies incubated in synthetic seawater (SSW) controlled with respect to the inorganic carbon system and containing standard (11.40 mmol kg$^{-1}$) and low (2.85 mmol kg$^{-1}$) calcium concentrations. Net photosynthesis and respiration are not significantly different in standard and low-Ca$^{2+}$ SSW despite a rate of calcification 2.0-2.4 times lower in Ca$^{2+}$-depleted SSW. Additional experiments carried out on the noncalcifying zooxanthellate Anthozoa Anemonia viridis demonstrate that a low calcium concentration has no direct effect on rates of photosynthesis and respiration. It is suggested that calcification is not a significant source of photosynthetic CO$_2$ and that photosynthesis stimulates calcification rather than the opposite.

I guess the first article shows higher calcium speeds calcification in coral larvae.?

[Randy Holmes-Farley]

yes, the articles that I reviewed for my calcification mechanism articles indicated that calcium is not limiting above about 350 ppm.