There is no great stagnation in marine research
Thanks to technology:
Sea gliders are small unmanned vessels which are now cruising the briny by the hundred. They use a minuscule amount of power, so they can stay out for months. And, being submarines, they are rarely troubled by the vicissitudes of weather at the surface.
…gliders have been deployed on many previously unthinkable missions. In 2010 teams … used them to track the underwater effects of the Deepwater Horizon oil spill in the Gulf of Mexico. That same year a glider owned by Oregon State University watched an underwater volcano erupting … In 2011 a glider made by another firm … tracked seaborne radiation leaked from the tsunami-damaged reactors in Fukushima, Japan. And the University of Newfoundland is planning to use gliders equipped with sonar to inspect icebergs, to work out whether they are a threat to underwater cables and other seabed infrastructure.