Temperature 's impoact of growth, nutrients, and gas exchange

Tom Barr

Staff member
Jan 23, 2005
Temperature is very often overlooked when discussion take place concerning algae, plant growth and health. Some discussion takes place about several groups, namely mosses, ferns and the Aponogeton genus. In California, those aquarist without air conditioning can experience large changes in tempratures. Often going from 75F to 95F for their aquariums.

Metabolism and Biology:
As the temperature increases say from 10-20C, the metabolism of most organisms increased by a factor of 2x. 20-30C, another 2x faster. Much above 40C, many plant's enzymes start to loss efficiency/denature. So this concept has it's limits.
This change of temperature is often cited as "Q10" in biology.

Growth and Development:
As organisms develop and growth, the rates are driven by the metabolism. This clearly relates to aquatic plants and tropical fishes. Cold water species have enzymes that are better adapted for lower temperatures. Most species are able to adapt to some temperatur evariation over time.
If the temperature varies greatly with respect to time, these enzymes can only respond and adapt so fast.
As most of the species that interest aquatic gardens tend to be warm water species, the temperatures between 20C and 30C are often used.
This is 68F to 86F. So about 18F for the Q10.

Even if the temperature variation is less than 10C, say only 5 C, that's still a 50% increase in metabolism.

So as the tempratures rise, many aquarists see the decline in their tanks, some species fade out.

Gas exchange:
Cold water holds more O2 and CO2(actually any dissolved gas).

Adding each topics about temperature together, a clear picture can show how and why some tanks respond poorly to warmer temperatures while other tend to respond better.

1. Faster growth, more mineralization, more bacterial consumption of O2 breaking down waste, higher uptake rates by plants, bacteria, and fish, algae etc will occur with higher temperatures.

2. Adding more CO2, nutrients, doing more frequent water changes can help.

3. Watch how the tank and plants respond to higher temperatures, rather than focusing on nutrients heavily for every single problem you may have.

4. Experiment with the heater and see if you test these ideas out yourself.
Most every aquarist can do this that owns a heater!!!

5. Careful not to assume too much.

Tom Barr

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