Is a relatively new reefer forgive my ignorance, but I'm pretty logical at my core. I'm assuming a larger consumption during the day might be relative to having corals that thrive in highlight? That's their growth and processing of the supplements takes place when the lights are hig is a relatively new reefer forgive my ignorance, but I'm pretty logical at my court. I'm assuming a larger consumption during the day might be relative to having corals that thrive in highlight? That's their growth and processing of the supplements takes place when the lights are on?
GS
A more complex question than it might seem.
It is likely that corals take up more alkalinity during the day (which is an empirical observation of some reefers) due to photosynthesis happening then. It might possibly just be that the tank pH is higher then.
However, the exact reason alkalinity is taken up then is not 100% clear. There have been papers that showed more skeletal extension at night, and skeletal growth is the primary place where the alkalinity ultimately ends up. That may have been an incorrect scientific paper, or perhaps it depends on the species of coral. Others papers, like the one below from 2014 show equal day and night growth:
http://www.ncbi.nlm.nih.gov/pubmed/24511631
from it:
"However, in our study, the average night-time extension rate (visualized in three successive 12 h pulses) was similar to the average daytime extension (visualized in the initial 12 h pulse), in all growth directions and skeletal structures."
Bicarbonate is taken up during photosynthesis, and bicarbonate is the largest component of alkalinity. But photosynthesis does not actually use the alkalinity, just the CO2 that is taken from the bicarbonate:
HCO3- --> CO2 + OH-
bicarboante --> carbon dioxide plus hydroxide
i doubt corals can store much hydroxide, but they perhaps can store it as carbonate, which they do use for skeletal growth:
OH- + HCO3---> CO3-- + H2O
I discuss some of these issues here:
Aquarium Chemistry: The Chemical and Biochemical Mechanisms of Calcification ? Advanced Aquarist | Aquarist Magazine and Blog
http://www.advancedaquarist.com/issues/apr2002/chem.htm
