Why does the increased level of nutrients in the water affect the survival of aquatic organisms

Increased level of nutrients in the water affect the survival of aquatic organisms as these act as nutrients for algae to flourish and once these algae die, they serve as food for decomposers like bacteria and a huge amount of oxygen in water body gets used up. This results in decrease in the oxygen level, which may kill aquatic organisms.

Survival of aquatic organisms: • Because algae and many species of plants take on dissolved oxygen, rising nutrient levels in water have an impact on aquatic animal life. • Chemicals are carried away from fields and end up in bodies of water including ponds, rivers, and the sea. • These provide nutrients for algae to grow. • When these algae die, they become food for bacteria and other decomposers. During this process, a significant amount of oxygen in the water is consumed. • The oxygen level in the aquatic creatures decreases as a result of this. As a result, aquatic species' chances of survival are reduced. • This might have an impact on aquatic species that consume dissolved oxygen.

Dead zones are low- oxygen, or hypoxic, areas in the world’s oceans and lakes. Because most organisms need oxygen to live, few organisms can survive in hypoxic conditions. That is why these areas are called dead zones. Dead zones occur because of a process called eutrophication, which happens when a body of water gets too many nutrients, such as phosphorus and nitrogen. At normal levels, these nutrients feed the growth of an organism called cyanobacteria, or blue-green algae. With too many nutrients, however, cyano bacteria grows out of control, which can be harmful. Human activities are the main cause of these excess nutrients being washed into the ocean. For this reason, dead zones are often located near inhabited coastlines. Understanding the eutrophication process provides the clearest picture of how and why dead zones develop. Causes of Eutrophication Eutrophic events have increased because of the rapid rise in intensive agricultural practices, industrial activities, and population growth. These three processes emit large amounts of nitrogen and phosphorous. These nutrients enter our air, soil, and water. Human activities have emitted nearly twice as much nitrogen and three times as much phosphorus as natural emissions. Different regions of the world emit different levels of these nutrients. In developed countries, such as the United States and nations in the European Union, heavy use of animal manure and commercial fertilizers in agriculture are the main contributors...

By:Michael F. Chislock( Department of Fisheries and Allied Aquacultures, Auburn University),Enrique Doster( Department of Animal Sciences, Auburn University),Rachel A. Zitomer( Department of Biological Sciences, Humboldt University)&Alan E. Wilson( Department of Fisheries and Allied Aquacultures, Auburn University)©2013Nature Education Eutrophication is characterized by excessive plant and algal growth due to the increased availability of one or more limiting growth factors needed for photosynthesis (Schindler 2006), such as sunlight, carbon dioxide, and nutrient fertilizers. Eutrophication occurs naturally over centuries as lakes age and are filled in with sediments (Carpenter 1981). However, human activities have accelerated the rate and extent of eutrophication through both point-source discharges and non-point loadings of limiting nutrients, such as nitrogen and phosphorus, into aquatic ecosystems (i.e., cultural eutrophication), with dramatic consequences for drinking water sources, fisheries, and recreational water bodies (Carpenter et al. 1998). For example, aquaculture scientists and pond managers often intentionally eutrophy water bodies by adding fertilizers to enhance primary productivity and increase the density and biomass of recreationally and economically important fishes (Figure 1) via bottom-up effects on higher trophic levels (Boyd & Tucker 1998). However, during the 1960s and 1970s, scientists linked algal blooms to nutrient enrichment resulting from ant...

Excessive quantities of chemicals (fertilizers, weedicides, pesticides etc.) washed from the fields enter into ponds. These act as nutrients for algae to flourish. Once these algae die, they serve as food for decomposers like bacteria. In this process a lot of oxygen in these ponds gets used up. This results in a decrease in the oxygen level, which kills aquatic organisms. • The increased level of nutrient in water helps the algae to grow rapidly and when the algae die, they serve as food for decomposers like bacteria. A lot of oxygen in water gets used up. This results in a decrease in the oxygen level in water and in that way the survival of aquatic organisms are affected. 👍 Good luck for exam👍 Excessive quantities of chemicals (fertilizers, weedicides, pesticides etc.) washed from the fields enter into ponds. These act as nutrients for algae to flourish. Once these algae die, they serve as food for decomposers like bacteria. In this process a lot of oxygen in these ponds gets used up. This results in a decrease in the oxygen level, which kills aquatic organisms.This process is caled electrophication