 |
JULY
16:
|
Phronima - the original 'Alien'?
|
Dr. Tammy Frank (HBOI) in the JOHNSON-SEA-LINK I preparing to dive, She's looking for layers of organisms in the water corresponding to various light intensities.
|
Steve Haddock (MBARI) is tending the trapeze on our blue-water dive.
|
Sonke Johnsen (WHOI) collects a Pegea in a sample jar.
|
Tammy Frank (HBOI) and Sonke Johnson (WHOI) blue-water diving in Oceanographer Canyon.
|
 |
|
Click below to learn a bit more about this advanced and versatile deep-sea research tool...
|
|
 |
|
|
 |
|
Tammy Frank leads an expedition that will explore a wide range of interesting marine science questions. Click below to read what it took for Dr. Frank to become a successful marine scientist...
|
|
|
|
|
 |
|
Accomplished videographer Brian Cousin is doing double duty on the Gulf of Maine cruise. He's gathering footage for a video about bioluminescence, and he's bringing the Gulf of Maine to your desktop as our @Sea correspondent. Click below to learn more about Brian...
|
|
|
|
Is there a question you'd like to ask our intrepid correspondent? Send us an email at
AskAtSea@hboi.edu.
Selected questions will be forwarded to Brian, and we'll post the answers online.
|
|
|
DISPATCH 9: Alien Encounters
@Sea correspondent/photographer, Brian Cousin
Harbor Branch's 168' Research Vessel EDWIN LINK, on station in the Gulf of Maine.
July 16 --
Today is about as good as it gets. Ideal weather and calm seas made possible the first full day of scheduled scientific activities. The JOHNSON-SEA-LINK I submersible made two uninterrupted dives. A blue-water scuba dive - the second of the mission was successfully completed. And Dr. Tammy Frank's Tucker trawl is in the water right now.
Tammy made the first submersible dive of the day, with her graduate student, Trevor Myslinski making his first-ever sub dive in the aft chamber. Dr. Edie Widder was in the sphere for the second dive, with Uli Siebeck from the University of Queensland aft.
Even though there's only a small porthole to look through (if you scrunch up your body enough), the experience of a dive in the aft chamber is unforgettable.
"It was great - absolutely fantastic", reported Uli. "We didn't see many animals in the water column until about 1,800 feet. And then they were everywhere. A squid got annoyed with our light just outside the window and attacked it twice, inking the sub."
Years ago, the aft compartment was used as a dive chamber. Specially trained divers could get out into the water to work, then get back in the compartment and decompress safely. Decompression is the process of slowly eliminating gasses, like nitrogen, that have been stored under pressure in the diver's blood stream and body tissue. Most people have heard the term "the bends" to describe what happens when nitrogen is released too quickly, causing bubbles to form.
Despite an excellent diving safety record, Harbor Branch scientists and engineers needed more capabilities. They needed to go deeper and stay longer. And so today, there is an array of tools on the front end of the JSL that can do more than a diver could, and to depths of 3,000 feet beneath the surface of the ocean. "Lock-out diving" as it is known, has long been abandoned.
Most of the science crew has lots to work with today. Both submersible dives returned with samples in each collection bucket and computer drives filled with data.
Trevor, unfortunately, needs animals that have never been exposed to light to continue observing the behavioral effects of short light bursts on these deep-sea dwellers. He is waiting for another Tucker trawl to provide him the krill he is looking for.
Tammy and Edie are poring over the data and samples they have collected in the sub so far.
Tammy is continuing a light sensitivity study on a krill, Meganyctiphanes norvegica, set up in the electrophysiological prep. Behind the tent of black plastic, the krill is being exposed to short flashes of light precisely regulated through a monochromator and graduated neutral density disk. A sensor on one of the krill's eyes is responding with micro-volt electrical charges that Tammy can plot against irradiance to determine what frequencies of light the animal can see.
Edie is taking startling high-resolution, high-magnification images of some of the most bizarre looking creatures the wildest science-fiction moviemakers could imagine. The camera exports the images directly to a computer for immediate display.
"That's a Phronima without its shell. Watch". Edie mouse-clicks on the display until only the upper body and head of the inch-long organism fill the entire screen. "We're pretty sure this is the animal they modeled the creature in the movie 'Alien' from".
Hollywood wouldn't have to do much with this design except make it a lot bigger and give it a nasty disposition.
Outer space and the open ocean. In an abstract way they have so much in common - vast, little known and largely unexplored. But one thing separates them undeniably. The oceans on our planet are teeming with living things; real "aliens" to maintain the analogy. Every cubic foot has something living in it. Maybe hundreds or thousands of things, any number of which could be totally new to science.
Imagine a space-walking astronaut encountering scores of aliens right outside the space shuttle. That's what a blue-water dive in the open ocean is like, except in the ocean, you really get to see the aliens up close and personal. At 3:30 this afternoon Steve Haddock, the diver in charge (MBARI), Sonke Johnsen (WHOI), Tammy Frank and I (HBOI) took a small boat a short distance from the Research Vessel EDWIN LINK, to make this unusual kind of scuba dive. There is no reef below or anywhere around for miles. In fact, the water we are in is 2,940-feet deep.
The purpose of our dive is to observe and collect organisms in the thin skin of water at the oceans' surface, to a depth of fifty feet.
"Most diving is coastal, or associated with the bottom", says Steve. "That's only a small fraction of the environment."
To explore the surface layer of deep water requires some special equipment and techniques. In addition to basic scuba gear, a down-line and a system of tether lines is used to keep the divers together and to keep them from going too deep. In the referenceless environment of the open ocean, it's easy to lose a sense of your depth, or how close or far things are away. Especially when all of your attention is focused on small gelatinous animals scarcely inches from your face.
All the divers' tethers run through a frame or "trapeze", which is connected to the down line. The trapeze keeps the tethers organized, allowing them to pay in and out as each diver ascends or descends. If the trapeze is positioned at the 40-foot depth marker on the down line and each diver has a 30-foot tether; the maximum depth they can achieve is 70 feet. The down line is connected through a buoy at the surface directly to the small boat.
Armed with nylon mesh bags full of collection jars, the divers are able to drift among the plankton or explore a vertical column of water. They can collect samples, and see how the delicate animals of the planktonic layer live as they drift along with the current.
Steve says, "A lot of animals can't be sampled well in other ways. Trawl nets would destroy so many of them. For example, years ago scientists found what was left of some jellies and amphipods in a net. When blue-water divers actually got in the water, they realized the amphipods were on the jellies - not just mixed in."
On our dive today the scientists were intrigued by Niobia dendrotentaculata, a species of medusa, which seems to be living an almost parasitic lifestyle on salps. These animals would probably have been separated and reduced to small gooey blobs if caught in a net.
Each diver in the team takes a turn as safety diver. It's the safety diver's job to remain on the down line at the trapeze, watching over the divers at work, keeping tether lines uncrossed and
keeping an eye out for larger animals like sharks, that might be attracted by the action in the water. Communications are maintained through a series of tugs on the tether lines.
Blue water diving has been Steve's primary sampling method for the last ten years. The samples he collects on this cruise will be fixed for transit back to the lab where he works at cloning photoproteins from bioluminescent animals.
"Blue-water diving requires patience. At first it seems like the water is just blue. Suddenly you focus and see the multitude of small animals around you."
All you have to do is look.
| |
|
