The Google Maps Oceans Street View provides a nice way for students to dive below the surface to see marine life in its natural habitat. But if you want to go beyond just looking at things, then Marine Explore is good site to note.
Marine Explore is an open data community in which scientists and others share data sets about oceans. As a member (membership is free) you can search for data sets according to location and type of data (temperatures, sea ice extent, pollution, etc).
Applications for Education
Marine Explore could be a good resource for students in marine science courses. The data sets could be used to create visualizations and correlations on services like the Google Maps Engine. Marine Explore provides some good tutorials on how to analyze data sets. Marine Explore is currently running a challenge contest in which users are asked to develop data visualizations. Some of the suggestions include exploring the effects of salinity in ocean currents, the routes of mobile data platforms, or compare datasets measuring the same parameter in different time frames.