Water pH affects the fertility waters because it affects the lives of microorganisms. Acidic waters will be less productive, can even kill domestic animals. At low pH dissolved oxygen content is reduced, as a result of decreased oxygen consumption, decreased respiratory activity, respiratory activity rose and appetite will decrease, the opposite occurs in alkaline conditions. On this basis, the aquaculture would work well in water with a pH of 6.5 to 9.0 with the optimum range of 7.5 to 8.7.
Table 4. The relationship between the pH of the water and the lives of farmed fish
a) Dissolved oxygen (DO)
Oxygen is very important because it is needed by aquatic organisms. The need dissolved oxygen to the type and stage (phase) of different fish life. Similarly, in the same environment, the need for oxygen varies depending on the type of fish. In general, the need for oxygen at an early stage is higher than an advanced stage. Critical boundaries for fish is highly dependent on acclimatization and other environmental factors.
Dissolved oxygen required by almost all forms of aquatic life for tubuh.Beberapa combustion process in bacteria and animals can live without O2 (anaerobic) at all; others can live in anaerobic conditions only briefly, but requires abundant penyediaanO2 any time. Most can live in a state of low O2 content once, but could not live without O2 altogether.
The state of the oxygen in the water greatly affect the life of the organism, either directly or indirectly. While the state of oxygen in water is influenced by several factors, among others, is the temperature.
b) Sources of dissolved oxygen
Dissolved oxygen in the water is obtained from:
1. Directly from the air.
The absorption of oxygen from the air can be in two ways:
With direct diffusion from the atmosphere (air),
Through regular water movement like the movement of waves, waterfalls and rotation (rotation) of water.
2. Results of plant chlorophyll photosynthesis.
Activity chlorophyll plants release oxygen into the water directly through the assimilation of carbon dioxide (photosynthesis) as follows:
The amount of oxygen obtained from the photosynthesis of plants depends on two factors, namely:
The amount of water in an aquatic plants (phytoplankton concentration in water).
the effective length of the light received by aquatic plants.
Figure 16. The windmill that serves for agitation, as an effort to increase oxygen levels in the water
Waters in general, incorporation of oxygen into the water was brought also by the flow of incoming water. The water flow will be churning water, thus encouraging the diffusion process that has been discussed above. Running water, although small debit, bringing new oxygen that has been dissolved water coming from elsewhere. The rain that fell, too, adds to the incorporation of oxygen into the water.
Typically, the fall rains that caused a decline in the temperature as well. This will lead to improved ability to bind water more oxygen. In addition, the rain will increase the volume of water that it also adds oxygen dissolved in the water.