Ammonotelism

Introduction 

Ammonotelism can be defined as the process of excreting ammonia and ammonium ions that are highly soluble in water from living organisms. The animals that excrete through ammonotelism are called ammonotelic animals, including marine creatures like fish, echinoderms, larvae, and others. Aquatic animals excrete nitrogenous wastes in the form of ammonia naturally. Since ammonia is a small molecule and highly soluble in water, it can naturally diffuse through marine animals’ gills. Ammonia is highly toxic, and marine animals cannot survive the slightest traces of it in their bodies. Hence ammonotelism is a crucial natural mechanism for aquatic animals to get rid of these wastes. 

Importance of Removing Ammonia Waste Products

Nitrogenous wastes are excreted from the body through the process of ammonotelism. These wastes from toxic ammonia can affect various body organs and can even be fatal. Ammonia raises the body’s pH levels and can cause severe damage to one’s body. For instance, the entry of ammonia fumes into the nasal or respiratory tract can cause a burning sensation, disrupted inhalation, and even death. Smaller amounts of ammonia deposition can cause slight breathing distress in humans but are eventually fatal. Thus, it is crucial to excrete toxic ammonia from living organisms. While, on the one hand, aquatic animals have a natural mechanism of releasing ammonia into the water, terrestrial animals have adapted to transform ammonia into urea through the urea cycle and thereby get rid of them through excretion in the form of urine and feces. 

Factors Affecting the Toxicity of Ammonia on Marine Animals 

Ammonia is highly fatal for fishes and other marine creatures. However, the impact of ammonia and its reactions depend on several external factors like the pH levels of water, the water temperature, the time period of exposure of the marine creature to the toxic ammonia, and many others. Studies reveal that the ammonia toxicity in water increases with its pH levels and decreases with the hardness of the water. This is because, with a greater temperature and Ph level of water, the concentration of unionized ammonia (NH3) increases in water. In general, ammonia might exist in two forms when dissolved in water- the unionized form (NH3) and the ionized form (NH4+). The concentration and toxicity of ammonia are also interrelated to water’s salinity and ionic strength. Thus, the toxicity of ammonia depends on the pH levels of water, its salinity, and temperature amongst various external factors. Furthermore, the impact of toxic ammonia in fishes and other marine animals may depend on their internal and bodily factors and external factors. These include the length of exposure of the fishes to toxic ammonia, the biological features of different marine animals, the age of the fish, and much more. 

Time of Exposure

The impact of toxic ammonia on fishes depends on their duration and frequency of exposure. For instance, if a fish or any marine creature is exposed to ammonium ions for a short duration, it might not be fatal for the fish. Such exposure can slightly impact their health, but it does not cause any serious consequences. An ammonia concentration of lower than 0.02 mg/l is considered to be safe for fishes and their reproduction. However, it is crucial to regulate the pH levels of water and its salinity to control the concentration of ammonia. Since most aquatic animals release nitrogenous wastes in the form of ammonia, the overall ammonia concentration in water may rise over time, thereby raising the permissible limits of ammonia concentration considered safe for marine animals. 

The Life Stage of Marine Animals

The life stage of marine animals also plays a decisive role in the impact of toxic ammonia on their bodies. Studies reveal that the susceptibility of marine animals to ammonia increases with their age. Thus, as a fish transforms from a juvenile to an adult fish, its ammonia susceptibility rises and peaks with further aging. The aging of fish also indicates they are exposed to the toxic ammonia for a longer time, thereby having more disastrous health impacts on them. 

Impact of Toxic Ammonia in Fishes

As a result of being highly water-soluble, ammonia can enter the fish gills through diffusion in the form of a gas solution in water. When fishes are exposed to high ammonia levels in the water, they might be susceptible to several fatal biological consequences. Furthermore, fishes might be exposed to ammonia due to their excretion process that releases nitrogenous wastes in the form of ammonia. 

Exposure to high levels of ammonia can cause a condition called the ‘acute ammonia intoxication in fishes that results in convulsions and death. Other consequences might include a faster heartbeat, coma, oxygen uptake, and severe convulsions in their body cavities. 

Exposure to lower levels of ammonia might not be fatal. However, it can affect their reproductive system, kidneys, gills, and liver. Though the impact of lower concentration ammonia is initially negligible, it can cause severe consequences if fishes are exposed to such water standards for a prolonged time. 

Conclusion 

Ammonotelism is a natural mechanism of marine animals of releasing nitrogenous wastes in the form of ammonia into the water. Since ammonia is highly water-soluble, such a mechanism helps in an easy diffusion of waste materials from the bodies of marine animals and helps them get rid of such toxic wastes. However, fishes and other marine creatures might be exposed to toxic ammonia because of the ammonia concentration in water. The ammonia concentration depends on the Ph levels of water, its temperature, and salinity. Thus, it is crucial to ensure marine animals are not exposed to such water standards for a prolonged time.