This diver at the National Aquarium in Baltimore is a celebrity and she knows it
Which is a pity, because diving is a phenomenal opportunity to explore a part of the world that, until a few decades ago, was completely off limits to humans. Being unable to see beneath the surface of the water is like being in a library and being unable to open three-quarters of the books there. Divers get to explore a world of underwater ecosystems, from coral reefs to kelp forests, that I'll only get to know from documentaries and aquarium displays.
You see some diving going on in zoos - mostly for maintaining the largest aquatic exhibits - but not too much, and many zoos have no use for it. It's mostly used in enclosures that have fish sharing a habitat with other aquatic animals, such as hippos (many zoos with underwater viewing of hippos fill the tanks with cichlids and other fish to help keep the water clean). Obviously the pool can't be completely drained because of the fish, so staff have to dive to clean the pool. Again, SCUBA diving in zoos is pretty rare, limited mostly to the bigger institutions.
In aquariums, however, diving is an essential part of animal care. Staff are SCUBA certified and enter the larger tanks frequently for feeding, cleaning, or to monitor the health and well-being of the inhabitants. Some even allow special visitors the chance to join the staff on dive sessions; Georgia Aquarium, for example, has a program to let visitors dive with their whale sharks in a 6.3 million gallon tank. In many ways, divers are some of the biggest attractions at the aquariums. Watch a diver appear in a tank, one at which no visitors were gathered previously, and then watch the crowds materialize.
Even those of us who can't dive can still get a chance to interactive with divers. Among the most impressive educational additions at many aquariums are special communication systems that let aquarium divers talk with their audience outside. It's a great way to stir up interest about the aquatic world and help visitors make a personal connection with the institution, the staff, and the animals.
I volunteered briefly with an aquarium, taking care of a small section of marine creatures - moray eels, chambered nautilus, leopard sharks. Moving along the catwalk behind the tanks, tossing in food and siphoning off waste, I never really felt a connection with the animals, nothing like the first time I went behind-the-scenes at a zoo with a giraffe or a tiger. Instead, I felt like I did when I was in the public area, like there was a barrier between me and the animals still... and there was - the surface of the water. The only animals in the section that I really did feel like I related to were the loggerhead turtles, who would put their heads above the surface for me to feed.
If I had been able to dive like the aquarists were able to - to put on a mask and flippers and tank and splash through the surface, it would have been much different. I would have been able to enter a different world, where animals float overhead or drift around you, seemingly free from gravity. As it was, I was just a spectator - but a spectator to something incredible.