It doesn't look like they are growing under the water, am I mistaken? You may have better luck identifying these terrestrial mushrooms by posting in your local subforum or the mushroom subforum (if there is one) as it's some type of native mushroom that you brought in with the driftwood and it's growing/feeding on the rotting wood.

The only aquatic mushrooms are animals (not fungus at all) that live in saltwater.