Bill and I dove yesterday at a new site for our project. Depth sounding information suggested a wall on the north west corner of Shortcut Island. It is a real thrill to dive a site that probably no one else ever has. The privilege of a new site aside, this spot was truly thrilling -biologically awesome!
The Shortcut wall at our deepest excursion (120 ft) was overwhelmingly lush with huge vase shaped-sponges, graceful arching branches of white coral draping over numerous overhangs, and a myriad of other beauties I simply could not take in all at once.
This was a reconnaissance- let's see what there is to see dive - so we did not stay long at depth before we started working our way back up. At 80 ft we collected large colonies of the palmerolide- producing tunicate Jim introduced in an earlier entry. We encountered many of the sponges I need for my studies. The algae in the shallower depths were stunning. Chuck is anxious to see the massive, must be anciently old brown algae - one specimen had a stipe (stem) the diameter of a small tree!
Everything about this new found site seemed untouched by time, much less specimen collecting divers. Isolation whether via lack of disturbance by man and especially isolation over geological time is one of the factors that make Antarctic waters and its inhabitants - whether they are sponges, algae, or even vertebrates - so unique.
Philip's recent "New Life on Station" entry introduced a science team now in residence that study some very unique Antarctic fish. Bruce Sidell, a long term Palmerite (we met here in 1987) has traveled from the University of Maine with graduate students Kim Borley and Jody Wujick. Co-Principal Investigator Kristin O'Brien and her graduate student Matt Urschel journeyed from the University of Alaska- Fairbanks.
Shortly after their arrival on station, these five fishy scientists were back at sea aboard the Laurence M. Gould. Their target specimens live much deeper than ours so in lieu of divers, Bruce and crew, relied on elaborate oceanographic sampling gear sent depths as great as 150 meters as collection tools.
Upon return to Palmer after several days of fishing, the station population would swell into the hundreds! Fish-wise that is! The aquaria on the Gould were brimming with fish - each at least a foot long. Getting that mass of fish off the Gould and settled into the Aquarium Building is just short of a Herculean task. Bruce has been at this awhile though and over the years has developed a great system.
The large, heavy duty plastic aquaria are gently craned off the ship and onto the Palmer pier. Each aquarium holds about 500 gallons and has a built in pallet on the base allowing it to be picked up by the forks on the station's four wheeled tractors. The fish-filled cargo is then driven over to the wooden deck walkway alongside the Biolab and gently set down. Bruce and crew then take over with a hand fork lift, wheeling the aquaria over to the big garage door entrance to the Aquarium Building. The fish are then transferred one by one to the station's large round aquaria both inside and outside the building. Phew!! My images at the right show some of these labor intensive and labor of love efforts to keep the precious fins happy and alive for planned experiments.
The majority of the fish captured are one of two relatively closely related species - Notothenia gibberifrons and Chaenocephalus aceratus. N. gibberifrons, gibbie, for short is a type of Antarctic rock cod. In a previous season I used a cousin of this fish in some of our experiments (see image of N. coriiceps).
Chaenocephalus aceratus is a member of a really cool family of fish known as ice fish. Ice fish are not only unique among fishes, but also among vertebrates in general worldwide in that they have no hemoglobin in their red blood cells. It is the hemoglobin molecule that gives our blood and that of a gibbie, the red color. Ice fish blood is colorless, actually sort of a translucent white.
Hemoglobin not only gives blood color, it gives any vertebrate animal energy in that it is the molecule that transports oxygen from lungs (or gills in the fish) to the cells and then carbon dioxide from the cells to the lungs for exhalation. At the heart of the complex hemoglobin molecule is iron. Iron sort of holds hemoglobin together so that it can taxi around our blood gases. If you have iron poor blood, your hemoglobin levels will be low; the cells in your body will be essentially gasping for oxygen to produce energy. Fatigue will lead to anemia. So how do the ice fish survive without hemoglobin???
Bruce and Kristin acknowledge that the isolation of Antarctic deep waters and constant low water temperature over long geologic time have contributed to the success of ice fish - organisms bearing an otherwise fatal mutation. Additionally, they are also not very active fish and do not lead an energy-demanding lifestyle. What an ice fish lack in hemoglobin it perhaps compensate by having an unusually high ratio of blood vessels in its scale-less skin compared to the hemoglobin bearing gibbie. Icefish also have a greater gill surface, more powerful heart muscle and higher blood volume compared to other Antarctic fish. Given the lack of hemoglobin, the ice fish is a cardio-vascular champion!
While the gibbies and the ice fish have gotten settled in their new, shallow depths here on station, the Maine-Alaska team has gotten settled in their new laboratory space at Palmer. Throughout the coming weeks, experiments will be conducted to help understand the mechanisms driving such amazing differences between a cold water Antarctic fish that has hemoglobin and one that does not.
As always, stay tuned to our website for an update on this cool and unique fish story.
And, to add another teaser, don't forget to check back for a follow up feature on the latest new dive site at Shortcut Island. Oh the joy of science and discovery in Antarctica seems endless.......