Describe the phases of the nitrogen cycle, in the marine environment, starting with the death of a fish.
Could someone help me with this? I just need it explained to me, I've watched and read many articles.. but still do not understand very well
Certainly! I can explain the phases of the nitrogen cycle in the marine environment starting with the death of a fish. The nitrogen cycle is the process by which nitrogen, an essential nutrient, circulates and transforms through various forms in ecosystems. It involves several key stages:
1. Ammonification: When a fish dies in the marine environment, bacteria and other decomposers quickly begin breaking down its organic matter. During this initial phase, called ammonification, proteins from the dead fish are converted into simpler organic compounds, including ammonia (NH3). Ammonia is a toxic compound but serves as an essential starting point in the nitrogen cycle.
2. Nitrification: Ammonia, being toxic, is converted into nitrite (NO2-) by a group of bacteria known as nitrifying bacteria. This process is called nitrification. Nitrite is still harmful to most marine organisms, so the conversion continues to the next stage.
3. Further nitrification: In this stage, nitrite (NO2-) is converted into nitrate (NO3-) by another group of nitrifying bacteria. Nitrate is much less toxic and serves as a crucial nutrient for marine plants and algae.
4. Assimilation: Marine plants and algae, as primary producers, take up the nitrate from the water and use it to build proteins and other essential compounds for growth. Through this process, called assimilation, the nitrogen in the nitrate becomes a part of the plant's tissues.
5. Consumption: Marine herbivores, such as small fish and invertebrates, feed on marine plants and algae, incorporating the nitrogen from the plants into their own bodies.
6. Excretion: Marine animals excrete nitrogenous waste, primarily in the form of ammonia, urea, or uric acid. These waste products are released back into the marine environment.
7. Denitrification: In the final step of the nitrogen cycle, denitrifying bacteria convert nitrate (NO3-) back into nitrogen gas (N2), which is released into the atmosphere. This process occurs in areas with low oxygen levels, such as deep ocean sediments or oxygen-depleted zones.
So, in summary, when a fish dies in the marine environment, it undergoes ammonification, followed by nitrification to convert ammonia to nitrite and then to nitrate. The nitrate is taken up by marine plants and algae through assimilation, which is then consumed by herbivores. Nitrogenous waste from marine animals is released back into the environment, which undergoes denitrification to convert nitrate back into nitrogen gas, completing the nitrogen cycle.