Oxygen in Ponds | Fish and Algae Compete for Oxygen in Water
My friend William Kelly gave me permission to publish his article on oxygen. Now that Summer is in full swing water temperatures are at their highest and pond activity is also peaking ... this includes the rate of growth of algae and algae consume oxygen in large quantities during the nightime hours.
Oxygen that is available in water to fish can only be accessed once it is dissolved in the water in which the fish live. Whilst water is a remarkable solvent, being able to dissolve almost anything, water can only contain about 9% dissolved oxygen. Compare this to the air that we breathe which comprises our external environment and in which the oxygen content is 21%.
Add this to the fact that water is 800 times denser than air and that oxygen dissolves into it very slowly and you can appreciate the efforts that fish have to go to in order to just get a decent breath! In the same way that we do, fish produce carbon dioxide as the by product of the respiration/metabolic processes.
Koi are no different to any other fish. Their food needs are similar to other animals in that they require fats, proteins, carbohydrates, minerals, vitamins etc. They have limited access to oxygen which means that they must use it as efficiently as possible.
Because they are in constant contact with water they also need to deal with the constant diffusion and osmotic processes that take place. Osmosis, the movement of water from a location of higher concentration to lower, requires energy. Energy requires oxygen. Imagine if a fish had to not only control this process, but also generate its own body heat. It simply could not get enough oxygen from its watery environment to make this feasible.
Water fortunately has a high resistance to temperature changes. It takes a lot of energy to heat water and relatively speaking water can hold its temperature in colder conditions for a lot longer than other substances of similar chemical composition.
What does happen as water temperature drops is that the metabolic processes in our Koi slow down. Conversely as the temperature rises, the metabolic processes speed up and in the case of Koi, feeding rates can get to impressive levels.
The gills of a fish are highly efficient oxygen extractors and the membrane separating the water from the blood supply is often only one cell thick. This is tiny and represents precious little protection for the fish in the event that things in the pond water turn nasty. In turn, anything that affects the gills of a fish can have devastating consequences.
The rule of diffusion is a critical one to understand properly when it comes to understanding the processes that happen in a Koi pond.
Simply put
Substances will diffuse from one area of greater concentration to an area of lesser concentration in an ongoing process until equilibrium is reached.
I suggest if this article maybe gave you cause for some concern then read more about what happens during a pond containing algae during the day and night ... click this link below