Question: What type dangers does human effect on freshwater ecosystems? I know about pollution and over harvesting of seafood, but are there any other major problems that are effecting freshwater ecosystems , lotic, lentic or wetland ecosystems?
Keywords: ecosystems, freshwater, outcome, overharvesting, pollution
byeat16
Hi byeat16,
Your right that pollution and over fishing is effecting freshwater systems. Some other effects can be:
High nutrient loading. This is runoff from fertilisers used in home gardens and farming, particularly phosphorus and nitrogen minerals. Also high nutrients can be released from sewage treatment plants or domestic sewage systems in our homes. There are lots of law which determine the amount of nutrients a treatment plant can release.
Vegetation clearing and development. Removing all the plants from the side of a creek can change the type of animals that live there. Also plant roots hold the soil in place, if the plants are removed then we see really bad erosion. where the water washes away all the soil.
These are concerns for all the freshwater ecosystems you mentioned.
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Hi byeat16,
I think Shona has covered this pretty well. The other dangers that come to my mind are:
1. The introduction of invasive species such as the common carp (Cyprinus carpio). This species negatively effects freshwater ecosystems in many ways: they compete with native species, contribute to erosion of river banks and reduce the water quality by uprooting vegetation and stirring up sediments during feeding. Other invasive species such as the brown trout, rainbow trout and mosquitofish also do damage to our natural freshwater ecosystems.
2. Something I know less about is the negative effects of dams and channelisation on freshwater ecosystems. I think when we disrupt the natural flow of river systems, we disrupt the nutrient cycling process.
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The points Shona and Blaire both made are the main ones but there is another problem with freshwater ecosystems at the moment which we don’t really know how to deal with because it is so new…
There is a certain amount of water on the planet, it doesn’t increase or decrease it stays the same but it just changes form, from ice, to sea water, to ground water to clouds to freshwater. Considering 70% of the earth is covered in water you would think there is a lot of it and that running out of water isn’t a worry but actually less than 1% of all water on the planet is in the form of accessible freshwater (rivers, lakes and streams).
One of the biggest threats to fresh water systems in the future is simply that we are using it all!
Rivers and wetlands are drying up because we are taking all the water out of the river to use ourselves.
As the human population increases we will need more and more of that water to drink, grow crops with, feed our domesticated animals with, wash with, use in industry, etc…
The human population is nearly doubling every second generation at the moment so we have to ask ourselves, when will the water run out?
We are already seeing rivers drying up in Australia because farmers are taking all the water out to grow their crops. But people need to eat? and you cant tell people that they are only allowed to have one child! what do we do?
…So freshwater management will be a very very important area of science and politics in the near future as we will have to be very careful with whet we are using it for.
For example, at the moment, even though Australia is one of the driest continents on the planet, the government still allows farmers to grow cotton on their land and cotton uses a ridiculous amount of water to grow! So water intensive farming practices should be discouraged.
There is also a process called fracking for gas which involves pumping millions of gallons of freshwater into the ground at really high pressures to release gas deposits below so we can use gas as a fuel. This traps the freshwater in the ground never to be seen again for potentially millions of years! So we are essentially throwing water away!
Further to that, we use a lot of water feeding our cattle and livestock just so we can eat meat. It takes a lot more water to grow a cow that it does to grow a whole field of vegetables. so maybe we should eat less meat.
These are all things that will need to be considered in the future if we want to ensure our rivers don’t run dry.
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