I've been on the dive team for 2.5 years. I'll throw some info out there that I hope covers most everything that's being asked.
You'll get this info when you contact the aquarium about your interest in joining the team, but I'll post it here for everyone's benefit, including the curious.
You must be at least 18 years old and have completed at least 10 open water dives to be on the team. You will have to become and maintain certification in adult CPR and first aid to be an active diver. There is not a minimum number of divers the team is looking for at the tryout. The more, the better. October 3 will be at the aquarium theater in the south building, starting at noon, for paperwork processing, explaining participation requirements, etc. Bring a copy of your last 5 dive logs and your original c-card. After that, everyone moves to the main building for a behind-the-scenes walk-thru. October 4 is in-water skills. Starts at 0830 at the Princess Anne Rec Center. Bring all of your dive gear, including a full tank and weights. After the skills demonstration, you will become backboard trained. The backboard is used to remove an injured diver from the water, like EMTs use. Tryouts involve demonstrating the basic skills you learned when you became certified - mask recovery, reg recovery, and buoyancy control. You have to use your own gear when you dive at the aquarium. This includes at least a full 3mm suit, gloves, and hood. NO shorties allowed in the tanks. The only items the aquarium provides is tank and weights. If your BCD is weight integrated, it may be best to bring your own weights when you dive the tanks. I bring my own every dive.
Generally, the very minimum participation requirement is 1 dive per MONTH. If you can do more, that's great. If you want to do a dive and a spot, ok. If you want to do 2 or more dives per month, thats fine too. You must attend at least 50% of the monthly meetings. The January meeting is mandatory for everyone. Meetings are held at 7pm the first Monday of each month, unless that is a holiday, at the main aquarium building classroom. Meetings normally last up to an hour or so. The aquarium is looking for a minimum of 50 hours participation from you per year.
Your residency does not have to be Va Beach in order to join. I live in Isle of Wight county. I know other members who live in Smithfield, Hampton, Mechanicsville, Yorktown, Williamsburg.
Diving the Chesapeake Bay Aquarium (CBA) is cool. The visitors, and especially the young kids, get a kick out of watching you. I enjoy interacting with the audience. A docent is with the audience explaining what you are doing. Many people like to take pictures of you. The other tanks are very cool, too. But as mentioned, you have to dive the CBA for a while first. Maintaining neutral buoyancy and swimming about is tricky in the tanks. It's best to master the skill in the CBA before you move into swimming with turtles, sharks, or seals. The new Red Sea tank will be trickier than any, because it will be filled with many fish, spotted eagle rays, and the walls are covered with life-like (fake) corals which can be damaged (and cost a fortune). Word is that divers will use an auger mask in the Red Sea tank so they can talk to visitors standing in the large, clear acrylic tube beneath them.
I hope this answers most of the questions. Contact the aquarium if you have more questions or want to participate. All your questions will be answered during the October 3 session. The website's volunteer page has an application you can complete, and has contact information so you can request the official details on the October 3/4 tryout.
Official Virginia Aquarium Web Site Tryouts are given in April and October each year.