Nothing so bad that can't get worse
If even today a large portion of the population does not know about the smallest part of the environmental problems that the oceans suffer, there are new problems every day.
One of the problems that few people know about and that can be considered new is the mining of the oceans in search of metals and other valuable elements. When we say mining, think about it, a mine of gold, silver, copper, niobium and so on. Imagine an old movie, with a mine being dug in a mountain, a big hole with a rail of carts going in, potholed walls and people all dirty with pickaxes digging deeper and deeper into the mine in search of ore.