Sediment and heat pollution, and invasive species

Sediment pollution (too much soil getting into the water) Thermal pollution (water that is too warm getting into a lake or river) Invasive species (species that don’t belong take over)

What is sediment? It is loose sand, clay and silt, and some organic matter (dead leaves, branches, etc.) that is washed or blown away.

 Where does this soil/sediment come from? Mostly from agriculture (erosion of soil from farm fields or animals drinking directly from water body) and some from clearcutting forests

 What is the problem with sediment pollution?  LOTS!  animals that live in the water can be affected (e.g. fish’ gills get clogged).  If soils carries nutrients, it could lead to algal blooms  Could block sunlight to aquatic life

 What can be done about it?  Plant tree/shrub ‘buffer’ strip between farms and a body of water  Plant grasses on bare soil fields

 What is it? A lowering of water quality due to the addition of hot or cold water that will change the temperature of the body of water.

Where does thermal pollution come from? Mostly from power plants that need water to cool equipment. After the water is used it can be released into lakes and rivers.

What’s the problem? When the returned water is hotter?  Decrease in oxygen  Increased hunger and activity in fish and other water (aquatic) animals – they will eat more  Reproduction problems  Bacteria and algae can grow fast

What’s the problem? When the returned water is COLDER? Could stop reproduction completely Could cause extinction of certain sensitive fish species

What can be done to prevent it? Require power plants to use very efficient cooling Encourage people to use less energy – that means less power for power plants to produce. Other ideas?

What is it? An invasive species is not from here and once it is here it is likely to hurt the ecosystem. Often they have nothing that eats them so they can multiply like crazy!

What is the problem? Invasive species can: Can make other native species go extinct (gone forever!) Can reduce biodiversity Can cost a lot of money to deal with (i.e. zebra mussels)

Some examples: Sea lampreys – now much less but caused the collapse of the Great Lake trout and whitefish fisheries in the 1950s. They suck bodily liquids out of other fish.

Another example – zebra mussels Came in with international ships, they spread rapidly and grow on docks, boats, fishing nets, pipes, etc. they also make the water cloudy…

What can be done? Depends on the species – fish can be fished, plants can be physically removed Difficult and usually expensive!