What causes sea pollution?

Answer 1

Well - there are many things out there (if anyone wants to change this answer please just add on to it) that cause sea pollution, but to me the biggest one is dumping sewage/waste into lakes, rivers, ponds, oceans and, seas.

It gunks up at the top AND bottom of the water and blocks out light which kills off plankton and plants. Without those, some fish and whales will die.

The lack of small herbivorous fish will cause larger fish and some birds (seagulls, pelicans, etc) to become endangered or extinct, lack of any meat (fish) will cause sharks to die off causing a gap in the food chain which could affect everyone from sea creatures to humans.

We must stop dumping waste into the waters of our great planet.