Cold effect on corals & fish

[Subsea]

Several threads today focused on cold effects to fish during power failure and corals during shipping.

A few minutes ago, in a conversation with Dan Sanchez, diver/owner of Gulf Live Rock, he said that during winter cold fronts “the water temperature on bottom in 30’ of water gets into the upper 40’s with no harm”. I know that cold water holds more oxygen and slows down metabolism thus reducing stress and oxygen consumption.

Note: If you have a power failure with a battery backup system, limit your power consumption to life support. Water temperature in the 70’s is not a necessity.

 

[JTP424]

Makes sense. Do you think there's something to be said for the speed at which the temperature changes though? Larger water volumes take longer for temperature changes to occur no? So more of an "acclimation" period. Rather than an overnight swing do you think temps in open water change at a less rapid pace? I could be completely wrong though!

 

[BryanM]

My limited experience showed during my tank swap that my corals did fine in fairly cold water compared to the tank.

I kept heaters with the fish though, so can't talk to that.

 

[Subsea]

Makes sense. Do you think there's something to be said for the speed at which the temperature changes though? Larger water volumes take longer for temperature changes to occur no? So more of an "acclimation" period. Rather than an overnight swing do you think temps in open water change at a less rapid pace? I could be completely wrong though!

With respect to temperature changes in open water, it depends on the location as to how fast temperatures change. Deepwater uprisings change temperatures dramatically on reefs with no harm to inhabitants, in fact, these cold waters feed the reef with micro fauna & fana.

However, I will address the captive reef aquarium mantra that “stability of parameters is critical”. I disagree. The first technical elective I took as a Marine Engineer from Texas Maritime Academy was Oceeneering 101 titled Dynamic Equilibrium.

Consider that pH fluctuates between 8.2 to 7.8 on a healthy IndoPacific reef. In our reef tanks the real danger during lights out is low oxygen in the water, not low pH.

Also, I find the misinformation about carbon dioxide as a source of pollutant to be appalling. Earth is a carbon based planet and carbon dioxide fuels photosynthesis which combines the inorganic world with the organic world and this produces glucose which moves carbon up the food chain.

PS: I inject co2 into a calcium reactor which dissolves trace minerals and feeds calcium to bulk water.