- Written by Kevin Scriber
Since my last entry, the UAB Antarctic research group has done much. Though lately there has been less diving and more work in the laboratory. The typical day involves about twelve hours from start to finish, sometimes more. We wake up and have our daily meeting at 8 AM. We speak about what we plan to do that day, and we’re off. The other graduate students and I have been working diligently to keep up with Chuck and Maggie.
In the laboratory, fellow graduate students Julie, Kate and I have been using a flourometer, a device used in florescence spectroscopy, to measure and record the pH of water samples. We also have been conducting titrations to measure and record the total alkalinity of water samples. I collect saltwater samples from the pump house next to the Bio building, every morning and evening. I keep a record of the variable pH and daily fluctuations in total alkalinity. I catalogue the measurements into a database to be used in the ongoing ocean acidification research. Sometimes, I encounter wildlife such as elephant seals and fur seals while making my two daily collections, they usually don’t mind. They just give you a funny look or strange sound to let you know they’re there.
In the aquarium, Maggie has gotten me well acquainted with the different species of amphipods, as well other invertebrates, the group has been collecting. We sort through mounds if algae searching out and enumerating amphipods for use in the experiment. Maggie will later personally introduce you to the two amphipods in particualr we will use.
The divers collected many long, skinny armed brittle stars, relative of the more common sea star for a colleague. See my photograph of them to the left. I helped Chuck take tissue samples from several hundred brittles. Brittle stars are able to regrow that lost tissue 'donated' to science. All were happy to be returned to their home in the harbor. Their experience at Palmer may not have been too happy.
Yesterday Julie and I photographed some large brown algae the divers retrieved from the depths. There is always something to do. I suppose one could say the group has gotten into a routine; if there is anything routine living and working in Antarctica.
The weather had us off the water for several days in a row due to high winds. When I do get the chance to be out on the water, while dive tending, I have encountered some fantastic wildlife. Great humpback whales breach within view, thrusting their humungous body from and crashing back into the cold Antarctic water. Fur and crabeater seals lay asleep on a chunk of ice as we ride by. They move gracefully, manipulating their immense frame to cruise the waterways and inlets. The crabeater in the photo here is stretching and yawning awake.
The leopard seal is the sight to see. Literally, I am always looking for them for the diver’s sake. When the ice packs in, you can see several leopard seals asleep on the ice. In the water they seem both a dream and nightmare. They are a magnificent sight up close. They seem intelligent and have an inquisitive nature, but they are known to be aggressive at times. Setting eyes upon such uncanny creatures is a gift and excellent opportunity to learn.
These encounters elucidate the frailty of people in this savage landscape of ice, water, and stone. That epiphany, for me, breeds profound respect. Knowing one is out-matched by these animals, and never intended for this arena or element, is a strange realization. Studying here is an adventure every day, filled with wonderful surprises around every corner.
- Written by Kate Schoenrock
Many of the creatures down here, not just us humans, have circadian rhythms (daily patterns) and annual cycles. As biologists we like to describe these as life history characteristics, and these encompass a variety of traits that any species may express including growth, reproduction, death, and many metabolic processes like digestion and photosynthesis. Many of these are correlated with light especially in Antarctic algae (I consider seaweed a derogatory term). In fact many polar algae species reproduce, grow and die in time with the light level. So rad.
As Julie mentioned in her first blog I was able to attend a photosynthesis course in Mexico for a few weeks prior to leaving for Palmer Station. We learned a lot about light and photosynthesis on coral reefs, so now I am trying to use that information to carry out some studies on the algae that grow and are very abundant down here. Like the red algae in my underwater image below.
In order to look at light and how it affects photosynthetic organisms, you need a way to measure photosynthesis. People have developed a variety of methods which measure production of oxygen or carbon compounds (both products of photosynthesis), but we will use a fluorometer. It is specifically a pulse amplitude modulated fluorometer (PAM for short) and it measures the fluorescence which is like the algae having a mirror, bouncing energy right back at a source of energy. You can use this to measure how much energy is then moving through photosynthesis to create energy for the algae. It’s like shooting ray guns at algae for science. Also rad.
Algal communities grow and sometimes dominate the shallow marine areas (<90 feet deep) around the western Antarctic Peninsula like in this picture here. This is amazing to me mostly because of the extreme light conditions. There are times when light levels are very high which can be bad for photosynthetic organisms (think of a bad sunburn from too much UV exposure), but also times when light is non-existent because of the time of year and sea ice and snow. So not only are algae using light levels to adjust their life histories, but they have been able to adapt to these great light extremes.
Recently we brought a few long stipe Ascoseira mirabilis back to Palmer Station from the Lemaire Channel, which Chuck mentioned in his blog. With these individuals I was able to do look at how efficient the species or ecotypes are at using low levels of light to produce their own energy stores. Soon I’ll begin looking at the same processes in two species of other canopy brown algae, Desmarestia menziesii and D. anceps, which I will use in our climate change experiment.
PAM is definitely a useful tool for studying algae, especially because it can give you an idea about how healthy the algae are once you have a baseline ). For this reason, we are also planning to describe some basic photosynthetic parameters of common algae like Cystosphaera jacquinoti and D. anceps (shown right in another of my underwater pics) with PAM. She’s a good girl.
PAM and Science Girl on Ice Island (this one’s for you James).
- Written by Jim McClintock
Soft corals don't do this. Nowhere on the planet had anyone ever before witnessed a soft coral lie down, roll around on the seafloor, then stand back up and crawl off to another foraging site. This would be akin to gazing out your window one morning into your front yard and watching your oak tree move across the street to a sunnier location in your neighbors' yard. You gotta be kidding!
So what is it about Antarctica that might have nudged the evolution of such a novel mode of feeding? Normally soft corals stand firm, providing themselves with nutrition by catching plankton or suspended organic particles floating in the water. The answer I believe lies in what has puzzled Antarctic marine ecologists for decades. There is not much plankton to catch and eat. Near McMurdo Station on the Ross Sea, where Marc made this remarkable discovery, the water is so clear of plankton most of the year that you literally can see five-hundred feet. Indeed, with the notable exception of a short soup-like summer plankton bloom (an explosion of tiny plants and animals in the water), there is not much in the way of plankton. I suspect that this giant soft coral figured out a way to raid the refrigerator, supplementing its normal mode of feeding to make up the difference.
The first time I got a close view of the huge (up to two-and-a-half feet wide) multi-armed Antarctic sea star Labidiaster annulatus I could not believe my eyes. It was stunning. Its golden serpent-like arms, over twenty in number, wiggled, some lifting themselves up in to the water, others secured tightly against the bottom of the aquarium with tiny tube-feet. The sea star looked similar to the much-feared predatory Pycnopodia helianthoides, a species I had come to know well in the subtidal coastal communities of my home state of California. When Pycnopodia calls everyone listens (actually smells). I have seen snails, abalone, and sea urchins flee from this roving beast. Some to escape twirl their shells violently back and forth as they run. If caught up in the arms and tube feet of this "lion of the Serengeti" they are quickly slain.
After reading about and watching Labidiaster closely in the laboratory it is clearly not a lion of the seafloor. While it may prowl about a bit now and again, rather, it seems quite content to sit still. Nonetheless, its display of several unique feeding behaviors may make it just as effective a predator as a lion. One unusual habit is for this large sea star to lay flat but lift a number of its many arms - tube-feet extended - up into the water column. It's fishing! Not for fish per se (but see below), but more likely small crustaceans that are snagged by the tube feet and carried to the mouth. There are even documented observations of krill –the abundant shrimp-like animals that are the focal point of Antarctic food webs - being captured using this novel foraging technique.
Another unique feeding habit must have thrilled scientists when first observed. Labidiaster raises it central disc up, forming an inviting cave under its body. Marine invertebrates and fish love caves. Attracted to this seeming refuge they crawl right in, ironically, to meet a gustatory fate as the sea star collapses upon them. That a sea star can catch a fish is novel indeed. That one has learned to catch krill and fish to supplement its diet of clams, snails, and sea urchins, is remarkable. Once again, Antarctica surprises.