Application of stable isotope technique in ecological studies

In recent years, with the development of nuclear science, the application of isotopic techniques (stable and radioactive) in biological and non-biological sciences has grown significantly, while in the field of biological sciences, stable isotopes play a more important role. In ecology, we also envisage various applications of isotopic techniques, especially sustainable ones. One of the most important applications is the study of the health of organisms in aquatic ecosystems. In this method, the existing general health and reproduction are examined and its relationship with the stable isotope values ​​of nitrogen in the muscle of the living body is measured, and finally the level of living health and its relationship with nutrients in the ecosystem is determined. Another application of these techniques is to determine the standard catch rate in ecosystems by determining the breed of fish in terms of wild or domesticated. In this method, the amount of stable carbon in the body of fish (purchased randomly from distribution centers) is compared with each other. Existential domestication (due to the use of higher carbon foods in domestic fish) and lower amounts indicate the wildness of the fish, and ultimately to determine the trophic conditions of aquatic ecosystems and identify the origin of existing materials using the stable isotope technique as a last resort. In this study, it is pointed out that the use of isotopes to identify different sources of nitrate is based on the principle that nitrate created from different sources has different isotopic compositions. Due to the very high importance of the application of these techniques for ease of study, high safety and great accuracy, it is necessary that the various methods in this field are well understood and implemented in the form of practical research. An attempt was made to describe the mentioned techniques in detail.

For the first time in 1983, Schroeder presented several papers focusing on a new way of evaluating food in aquaculture. In these articles, sustainable food isotopes, because they are considered as the best indicator of the usual diet of living organisms, as new and strong indicators to determine the amount and distribution of food in aquatic ecosystems and how it is distributed in networks. Food is named. Later, the applications of various stable isotopes in ecology were discussed and introduced, some of which include: finding relationships between different food levels in food networks (Hobson, (1999, determining the migration path of fish, finding fish species in the wild). Or farming (Trambazuki, (2011, study of the richness of aquatic ecosystems in terms of essential nutrients) (Foucault, (2008) and the effect of different amounts of nutrients in water on the health of various fish Blazer et al., 2014.

What is an isotope?

Isotopes of an element are atoms of that element that have different masses. The reason for the mass difference between the isotopes of an element is the difference in the number of neutrons in their nuclei. Natural isotopes of elements can be divided into two categories: stable and unstable. Stable natural isotopes have a very long half-life, so 55.5 billion years after the formation of the earth, these isotopes are still found in nature. In total, 256 known isotopes of 80 elements with one or more stable nuclei have been identified. Stable nuclei do not change over time and are highly resistant, and this is one of the main reasons for the importance of their application in various environmental and ecological studies.

Application of isotopic techniques in studying the health of organisms in aquatic ecosystems

The presence of any excess substances in aquatic ecosystems, including chemical, physical and biological, causes pollution in the aquatic environment, and all types of pollution in aquatic ecosystems for biofuels and biological flora living in these environments are considered as stressors. Excessive presence of food, especially rich in nitrogen and carbon, also has detrimental effects on biological communities in ecosystems. Accordingly, the study of fish (sedentary and sedentary) in different areas of rich aquatic ecosystems (eutrophs) and the study of physiological health And their reproduction can be used both as an indicator to compare the trophic contamination of different ecosystem areas and to determine the health of fish (in terms of management in fish feed), including the study of stable isotopes, especially nitrogen (one One of the most important nutrients in eutrophication ecosystems) has been presented as one of the newest and most powerful methods in this field due to its high accuracy results.