Nitrogen Cycle occurs in the aquarium.
Fish produce ammonia which is toxic. In a well established aquarium, Some beneficial bacteria will break down the ammonia into nitrite, and a second species of bacteria will break down nitrite into less harmful nitrate. The whole process of converting ammonia into nitrite and then into nitrate is called nitrogen cycle.
Although, only well established fish tanks have this nitrogen cycle going normally.
For new aquariums, fish keepers must do fishless nitrogen cycle before they add any fish at all, or the fish will risk dying to ammonia poisoning due to insufficient amount of good bacteria. The whole fishless nitrogen cycle process can take 6~8 weeks.
An established aquarium is an aquarium that has gone through the nitrogen cycle. This is not "established" it is a "cycled" aquarium. The stage after cycling where the plants are reproducing and fish are growing successfully is an "established" aquarium. See related question on the nitrogen cycle.
A Balanced Aquarium is one wherein the Oxygen/Nitrogen cycle is self sustaining.
the Krebs cycle, aka citric acid cycle, occurs in the mitochondrial matrix
The Krebs cycle occurs in the mitochondrial matrix, which is the innermost compartment of the mitochondrion.
The Krebs cycle occurs in the mitochondrial matrix of the cell.The kreb cycle takes place in the matrix of the mitochondria.
The cycle of sunspot activity.
The Kreb's Cycle occurs in the mitochondria or mitochondrion
The Kreb's cycle occurs in the mitochondrial matrix of eukaryotic cells. In prokaryotic cells, which have no mitochondria, the Kreb's cycle occurs in the cytoplasm.
The Calvin Cycle in Photosynthesis and The Krebs Cycle in Cellular Respiration. The Calvin Cycle occurs in chloroplasts and The Krebs Cycle occurs in the Mitochondria.
In an aquarium, fish waste and uneaten food release ammonia. The beneficial bacteria then convert the ammonia into nitrites, which are further converted into nitrates. Plants in the aquarium can utilize these nitrates for growth, completing the nitrogen cycle.
search very well
The cycle of sunspot activity.