I’ve run across an excellent website for gaining a “big-picture” understanding of the current state of the world’s oceans. 
Oceans inc is a multi-media platform dedicated to transmitting
news about the ocean. It is concerned solely with what affects the ocean
and the measures necessary to preserve it for humankind.

Ocean inc covers key ocean
events around the world, issuing TV and written news as well as live
coverage via social media. Follow Ocean inc for major ocean
events throughout the year and on Twitter
via @oceans_inc