 |
JULY
14:
|
This squid reflects UV light.
|
Brad Seibel, from the University of Miami calibrates equipment he will use to study respiration rates on midwater organisms.
|
Dr. Edie Widder takes high-resolution images of a bioluminescent species of squid.
|
Drs. Steve Haddock, Brad Seibel and Tammy Frank in the lab aboard the R/V EDWIN LINK.
|
 |
|
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...
|
|
|
|
|
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 7: Trawling for Deap-sea Animals
@Sea correspondent/photographer, Brian Cousin
This mission, funded by the National Science Foundation, allows Chief scientist Dr. Tammy Frank to study the distribution of planktonic animals within the water column.
July 14, 6:40 PM --
It's our third full day at sea. Right now, Dr. Edie Widder and Dr. Tammy Frank are making the first submersible dive of the day - their third of the mission - to collect data and samples as the subjects of their investigation begin their evening migration from depths, to feed in shallower water.
The pattern for work and down-time is beginning to establish itself. On a good day - when everything from equipment to weather and seas is behaving favorably - scientific work should start at about 10:00 AM and end at around 3:30 to 4:00 AM the next morning. Most of the work that goes on during the day is centered around three events: two submersible dives that Tammy and Edie make together, and Tammy's Tucker trawl. From these activites come the raw materials that keep most of the scientists on board busy throughout the day and most of the night.
While sea conditions were not as rough as those that forced the cancellation of both of yesterday's sub dives, this morning's launch plans still had to be aborted. Tammy and her crew made trawls instead, twice putting the net with its depth-metering apparatus and insulated cod end over the stern of the R/V EDWIN LINK. As one of the trawls was being recovered a school of pilot whales came in for a closer look.
Last nights' 1:00 AM trawl yielded a variety of subjects after a recovery in seas that washed up over the stern. Once in the cold room and under red light (which doesn't blind the animals), Tammy and her team opened the canister and removed the catch; primarily krill, Meganyctiphanes norvegica, from the the migrating animal layer. Computers, analyzers, respirometers, UV cameras, intensified cameras and more are brought to bear on these tiny animals to learn more about them and their environment.
Earlier today I asked Brad Seibel from the University of Miami what he was up to when he dipped one of the krill into liquid nitrogen, pressed it flat as a postage stamp and carefully placed it in a small glass vial.
Brad is studying the respiration rates of mid-water organisms. He is taking krill samples from the trawls and placing them in glass respirometry chambers containing seawater bubbled with air at the normal .03-percent carbon-dioxide content, as well as in chambers containing seawater bubbled with an elevated carbon-dioxide content of 3 percent.
After varying periods of time the krill are frozen in liquid nitrogen and the tissue ground up. The ground tissue will reveal measurements of intra-cellular Ph and CO2 from both samples. The water is analyzed for oxygen content during the process to ensure the data is based on aerobic and not anaerobic consumption.
Brad expects that small animals living in the open ocean with an abundance of oxygen will be less tolerant of increased carbon-dioxide levels than others, like inter-tidal animals, or animals in the oxygen minimum regions of the oceans. Many of those organisms can control their internal Ph to compensate for increases in CO2 - sort of like a scrubbing mechanism. Some species of mussels actually begin dissolving their own shells to change the bicarbonate levels in their blood and tissue when needed.
Brad wants to perform the same experiments he is doing here on animals living in the oxygen mimimum layer off the California coast to compare results.
"There is some talk of taking some of the CO2 that enters our atmosphere and storing it in the ocean as a way to reduce greenhouse gasses - bubbling it in, or sending it to the bottom in liquid form."
Animals that can't change their Ph to counter the effects of elevated CO2 could suffer under those conditions. And since small open-ocean organisms - including krill - form the base of the food chain, the ramifcations could be profound.
1,500 meters of cable are payed out to position the Tucker trawl at a depth of about 500 meters in the water column.
Dr. Tammy Frank plots voltage against log irradiance curves based on a Meganyctiphanes norvegica krill's response to light stimulation from a monochrometer.
|
|
|
