What are the main effect of water pollution on aquatic plants and animals?

Answer 1

Well, I'd say there are three types of pollutants we should look at here; toxic substances, artificial fertilisers and warm water. Although warm water is not a pollutant as such, I think it will be useful as a concious raiser that environmental damage is not only caused by harmful substances. If you do not wish to read about the impact of warm water on the environment, you should finish reading at the beginning of that section (I will put it last).

First, the common pollutants; toxic chemicals; harmful, decaying biological matter; and other substances. These substances release chemicals into water which will eventually make their way into the food chain. Now, we must not be hasty and say 'I saw someone throwing a barrel/drum full of dirty water into the canal the other day. I think this will cause the death of many local fish' because it is not necessarily so. In reality, when the dirty water is poured into the canal, it is already around, say, 20% pollutant, 80% water. As the chemicals diffuse, the impact will be that the concentration of pollutants in the canal will only rise by a fraction of a single percent. Any fish will be relatively unaffected by the selfish actions of this one person. Over time, the concentration will further reduce as the pollutants make their way downstream to the sea. However, damage will be done. Say if we were to measure the quantity of pollutant taken up by the algae is 1mg per plant, and a fish eats many of these in its lifetime, it may itself be consumed by a larger fish, with a higher dose of the pollutant than the algae, say 50mg, then the big fish may have a dose of 300mg. Note that the dose is not large enough to kill it, but with each step in the food chain, there will be more pollutant. Eventually the dose will be high enough to eat it, and that may be the point at which the human eats it. Pollutants may not have a particularly large effect on the aquatic world because the volume of water diffuses the pollutant to lower the concentration so that there is little effect except far up the food chain. However, the more pollution there is, the further down the food chain the animals will be dying off.

Many fertilisers are based on ammonium because it has a high nitrogen content. This means that any animals which come into contact with it will die with small doses (ammonia is very poisonous). But not all fertilisers are. In case you're wondering how the fertilisers got there in the first place, fertilisers are used on farmers' fields, which are often located near to rivers and streams as this land is more fertile. When it rains, the fertilisers in the soil are washed into the river. Fertilisers encourage the growth of algae. Algae form often on the surface of the water, and not all fish eat algae. Because less sunlight gets through, other plants are not able to photosynthesise as well, so they don't grow as fast, which may mean that there isn't enough for the fish. At night, the algae respire more than they photosynthesise, which decreases the concentration of oxygen in the water, which causes animals to die.

The final pollutant is warm water. The solubility of oxygen (the amount which dissolves in water) decreases as temperature increases. Cold water is more oxygen rich (usually). Therefore, although the water is usually clean, factories dumping warm water into waterways are causing a lot of damage as there may not be enough oxygen for the fish to respire, and they would die. Therefore, warm water is as dangerous as toxic chemicals to our aquatic ecosystems.

Answer 2

Water pollution have lots of negative effects on aquatic life and animals.

It may cause deaths to animals consuming polluted water directly or indirectly. It is also dangerous for animals and plant and animals that dwell in water. Spillage of oil on water surfaces acts as a blanket that prevents air penetration, therefore there's no air circulation thus organisms in the water ends up dying. Farm and industrial chemicals dumped in water source untreated affect the life through killing or affecting normal function of their hormones bringing about stuntered growth or reduced population.

Answer 3

Basicly the main problem to fish is their gills stop taking in oxygen and they sufforcate and die :(

Answer 4

Well, the animals can choke on plastic bags and cannot eat and they die.

Answer 5

the main cause of water pollution is that blue-green algae make a layer in water and restrict air penetration that create suffocation for aquatic plants and eventually causing death

Answer 6

I don't know it