Are you based in a city? Perhaps you cannot get to the coast.
Arrange a school trip to your local aquarium – this can be a real time or even a virtual activity with lots of aquariums live streaming.
Monterey Bay Aquarium is a fantastic example… Here is a video clip of their kelp forest but they have multiple livestreams too.
Your class will learn a lot about marine wildlife of course, but they will gain so much more than that.
Did you know that watching aquarium exhibits directly impacts heart rate and blood pressure?
Aquariums have been proven to calm their visitors – not only impacting their self assessed mood, but actually impacting physiology.
Your class might arrive in one state and leave in another. Explore how the watery ecosystem is interconnected – perhaps your class might do a project on a particular species?
Highlight how we really have ONE OCEAN in that all water bodies are connected… This links well with the blue marble game.