I've been using Chris Jordan's amazing images of Midway (and other projects of his) for some years now.
They show the impact of activity on the oceans, and in particular the impact of ocean plastics.

Watch the trailer of the film, which is currently in production here.

Midway Atoll, one of the most remote islands on earth, is a kaleidoscope of geography, culture, human history, and natural wonder. It also serves as a lens into one of the most profound and symbolic environmental tragedies of our time: the deaths by starvation of thousands of albatrosses who mistake floating plastic trash for food.

With Seas and Oceans now specifically mentioned in the KS3 Programme of Study, now is the time to start looking for appropriate oceanic resources and stories...