North Carolina Museum of Natural Sciences Life on the Edge: Exploring Deep Ocean Habitats - NC Museum of Natural Sciences Website
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2005 Questions & Answers

10/26/05

Crush, a seventh grader from Burke county, has several questions:

Have you seen any sea turtles? If so, how big are they?
So far there have been no sea turtle sightings on this trip. Hurricane Wilma has slowed things down a bit, but as we head back out to sea and head south, our chances to see turtles may increase.

Have you seen a sea cucumber?
Though deep-sea sea cucumbers do exist, none have been spotted so far. Past missions have resulted in some being collected, so possibilities still abound.

Has anyone found any unfamiliar species?
Yes! We've collected five crustaceans, about four echinoderms, and a couple of fish that we have never collected before and with which we are currently unfamiliar.

What is the pressure at the deepest depth the submersible can go?
The submersible has a 3,000 ft. maximum dive capacity. At that depth, the pressure is 1,336.4 psi (pounds per square inch). Fortunately, the pressure inside the submersible is kept at one atmosphere, which is comparable to pressure at sea level.

Additional information on the Johnson-Sea-Link can be found on the Harbor Branch Oceanographic Institution's website.

What is the most interesting creature you would like to research?
This is like asking a group of people what their favorite flavor of ice cream is! Depending on who you ask and where the ship is at the time the question is posed, answers differ and change accordingly. Galatheid crabs, sharks, Lophelia coral, and "anything we find" were some answers given.

Matthew, a third grader from Randolph county, wants to know how small the sub is.
The Johnson-Sea-Link is on the "large" size of submersibles. She stands at 26.5 feet long and can safely carry four people: two (a pilot and researcher) in the fore compartment and two (one pilot and one observer/researcher) in the aft compartment. The fore compartment is a five foot diameter sphere made of five inch thick Plexiglas and the aft compartment is a cylinder made of cast aluminium. Emergency equipment onboard will keep these four people alive for five days should the sub ever need to stay under that long.

Additional information on the Johnson-Sea-Link can be found on the Harbor Branch Oceanographic Institution's website.

Trace, a fifth grader from Alaska, wants to know how deep can a submersible like the Johnson-Sea-Link go and what it needs to go there.
Different submersibles are equipped to descend to different depths. The Johnson-Sea-Link is rated for 3,000 feet, although it has not been utilized much below 2,800 feet. The construction of the submersible itself, and its ability to withstand the intense pressure that descending to such depths puts upon it, determines how deep it can dive. Pneumatics allow the descent of the sub. Attached to the starboard and port exterior of the JSL are ballast tanks that are filled with air. The top is opened upon deployment, and the tanks fill up with water, giving the sub a higher density than the salt water, allowing it to sink. When under water, the pilots try to keep the JSL at or near neutral (density as close to that of surrounding water), so that the sub can actually hover right above the ocean floor and to increase its maneuverability. Tanks mounted on the sub can also shoot air back into these chambers as needed to increase buoyancy while moving about. Multiple thrusters aid in descent and allow for forward, backward, and lateral movement once under the water.

Additional information on the Johnson-Sea-Link can be found on the Harbor Branch Oceanographic Institution's website.

Mia, a third grader from Randolph county, wonders what it is like under the sea.
Wet! But seriously, the deeper you go in the ocean the darker it gets. When you reach the bottom of the ocean the only light available omes from the Xenon lights that are attached to the Johnson-Sea-Link submersible. These lights are so powerful that if turned on outside of the cooling waters of the ocean, they would explode from the heat they generate. Depending on the makeup of the ocean floor, many organisms might thrive within a coral community or the area can appear lifeless. Check previous questions to learn about temperature differences in the water column as you descend.

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