Can you think of 3 types of marine pollution?
There are lots of types of pollution that can make it's way into the sea, recent studies have shown that over 80% of the pollution found at sea comes from the land, either running into drains and waterways (rivers) which make their way to the sea or purposely dumped there. Of course there can be pollution on land but it is usually easier to clean up and more contained.
Oil spills - the type of pollution many people are most familiar with, their can be hugely harmful to seabirdsand other marine life. But did you know oil is much more likely to leak from old wells or run off from drains than enter the sea from a spill. Spills reach the news becuase it is a lot of oil all at once rather than the 'steady trickle' from land based run-off.
Chemical spills - Fertilizer is the biggest problem with chemical spills and high volumes run off into the sea, especially during rainy periods. Fertilizers cause algae to grow which chokes marine life by removing oxygen from the water. Other chemicals (chemicals from factories and even radioactive waste) build up in the food chain once they are eaten, causing illness or even death in larger animals like whales.
Similarly lots of sewage used to run straight into the sea, this can also cause algal bloomsin addition to human illness.
The sea used to be the place where people sent things to get dumped - can you think why people might have thought this was acceptable to do in the sea? Think about how much of the sea you can see and how many people live in the sea. There are now laws against this but it is hard to police the sea and some of the chemicals are still there from when this was allowed.
You have to wonder if all of these things are in the sea how are they affeccting humans and our food chains?
Tomorrow we will look at another form of pollution - plastics. Perhaps the biggest challenge the marine environment will ever face.