Not much.
It'll sit a little higher. Ideally, it'll need another anti-fouling paint to keep the weeds off.
== == water with out salt water with out salt
Thats not true. Salt water is more dense than fresh water so the boat wont sink as much
The boat will sink lower in fresh water. Try floating in the ocean versus your pool. You will see it is easier to stay afloat in salt water.
In fresh water it will swell in salty one it will shrink
Salt water is denser than unsalted (fresh) water.
They die
it dies
they will die
You get lesser salty water. The fresh water and salt watwr will diffuse together. In aquatic ecology sense, area where fresh water meet with sea water is brackish water.
They die because they can not live in saltwater, due to the salt.
yes An object, like a boat for example, will sink into the water until the weight of the water it displaces equals the gross weight of the object. Since salt water is denser than fresh water, a boat will sit slightly higher in salt water. (That's why the Mythbusters needed far fewer ping pong balls to raise a boat from the bottom of the bay than they originally calculated; they based their calculation on the fresh water boyancy of the ping pong balls.)
Fresh and salt water are very different for one key reason, fresh water doesn't contain salt and salt water obviously does. There are different flora and fauna in fresh and salt water for this reason.