- Written by julie schram
I refer to these mesocosms as "universes" because as we were putting the experiment together I was reminded of an early experimental population ecology paper I read last year in one of my ecology seminar classes. This paper (Huffaker 1958 in Hilgardia for those interested) described a system where Dr. Huffaker created what he called "universes" on of oranges with mite communities. It sounds strange but it was an early, simplified version of our mesocosms. As you can tell, the long cold hours spent in the aquarium building allow me lots of time to contemplate.
The term universe is no longer used to describe this type of set-up anymore. It has been abandoned for the terms mesocosm or microcosm (depending on the size of the experiment). A mesocosm can be defined as an "experimentally controlled" natural environment, allowing for interactions between varieties of members of a naturally occurring community assemblage.
Mesocosm experiments are being utilized to study the effects of ocean acidification in a variety of environments, such as the Arctic (http://www.bioacid.de) or in more tropical regions (http://www.ouramazingplanet.com/637-coral-reef-research-station-australia-101208.html) to name a few examples. Use of mesocosms in experiments is an increasingly popular and extremely informative way to study the effects of climate change and ocean acidification. It gives us information about individual species as well as how interactions between species and their environment may be alter by a changing environment.
To set up our mesocosms we used the Desmarestia menziesii that were collected on our dives (previously described by Chuck and Maggie from a diver's and tender's perspective, resp.). Chuck and I collected a medium sized D. menziesii, and all amphipods hiding among the branched fronds of the seaweed, from each of three dive sites as Maggie detailed. We chose to collect algae and amphipods from more than one site to ensure we get a balanced representation of the amphipod populations that live on D. menziesii around Palmer Station.
Once we got all of our samples collected and back to the Palmer aquarium we began setting up the mesocosms. Since our mesocosms (buckets) holds 5 gallons of seawater we used a pre-calculated small part of algae collected for each mesocosm. An entire individual wouldn't fit very well, way too crowded for happy algae and amphipods.
To equally distribute our collected amphipod populations, we first had to dislodge all of the amphipods from the Desmarestia by repeatedly rinsing it in seawater. After each algal rinse, the seawater and dislodged amphipods were carefully poured back into one of our large fine-mesh amphipod collecting bags and following the last, amphipod-free rinse, transferred to one common bucket. This was repeated for each of the three site specific Desmarestia collected.
At last, we had a bucket with all of the amphipods removed from all the Desmarestia. We then needed to equally distribute these amphipods among all of our mesocosms. First, we determined the total mass of the algae collected. Then we referred to previously acquired published data of amphipod numbers per mass of alga to guide us. Following some fun with math, we determined how to portion the collected amphipods up equally among the 18 mesocosms without counting every single one. A plankton splitter was key to this process.
The plankton splitter is ideal for dividing up a group of small swimming individuals, like amphipods, because it allows a sample of seawater with associated critters to be added, allowed to become evenly mixed, and then volumetrically split in half without too much jostling or handling (which amphipods don't tend to like very much).
After using the plankton splitter we added the amphipods from each of the rectangular trays to a separate bucket of seawater, to further dilute the population. We kept splitting and diluting the amphipods until we had enough buckets of amphipods, to ensure an equal and representative "sub-population" of amphipods for each mesocosm.
Once we finally had all of our dilutions completed, the amphipods were strained from the water in the bucket by gently rinsed into one of our mesh collecting bags. We next gently transferred all of the amphipods to one of the eighteen randomly selected mesocosm containers (Chuck and I pulled numbers out of a hat to determine the order of buckets getting populated !- science is crazy strict that way!)
For this experiment, each mesocosm consists of one of three pH treatments. We will be maintaining these amphipod-algal mesocosm assemblages to see if pH will alter or significantly influence the dynamics of this community. It was a long and tiring day of playing in chilly seawater (either when diving or in the aquarium building) but it was worth it. The mesocosms are now filled with algae and amphipods, 18 little assemblages for me to observe and care for over the next several weeks. I will keep you posted on the state of the "universe".
- Written by Maggie Amsler
Standard procedure before leaving the station proper (either on foot or by zodiac) is to sign out on a big black chalk in the main hallway. Required information is names of folks, destination, departure and estimated return time and name of group. Chuck tended to that duty scribbling in white chalk: "Julie, Harry, Maggie, Chuck"; "Litchfield Is, DeLaca Is, Bonaparte Pt"; 9:30 am; 12:30 pm; Divers". Hmmm, a three hour island tour sounds oddly familiar.....
Since Harry was at the tiller and though also carrying a required radio his hands were busy so I radioed in to station that the "Divers" were departing for Litchfield. Yuki, the comms tech responded, acknowledging our departure time. He would continue monitoring our radio updates to acknowledge and track our whereabouts. As you can see in the image of tender/captain Harry and diver Julie, there was some brash ice on the harbor waters that slowed our transit but slowly bumping and dodging ice allows some social time and photography opportunities before throttling up the engine once in ice free water. It is also a good time to get a better sense of the winds being away from sheltering structures of station buildings. Wow- after days of high winds, barely a breath of breeze puffed at us. In fact when we reached Litchfield about 10 minutes later the dive site was windless and waters flat calm. My kind of tending!
Harry remained at the tiller as we floated, the gear shift in neutral, at the dive site and I tended to helping Julie and Chuck get into their shoulder-harnessed weight belt followed by tank for each. I spared Harry the joy of gloving the divers – stretching the heavy rubber lineman's glove up and over the hard wrist cuff of the diver's drysuit and securing it with a taut fat o-ring. The combination ensured the 5-fingered wool mitt encasing fingers would stay dry and somewhat warm/dexterous. Harry snapped an image of Chuck being gloved at left.
I took over on the tiller to put the divers in the water. Splash, splash went Julie and Chuck. A radio call to station updated "two divers in the water". Harry and I then watched bubbles indicating the location of the submerged pair. See the bubbles in image right, by Harry's elbow? In the meantime Harry took a quick photo and I noticed the wind had freshened – hmm. I remained at the tiller and picked up the divers a short ten minutes later. Another call to station "two divers out of the water" was followed by filling a bucket with seawater to keep the diver collected sampled critters happy. Harry took over at the tiller as I radioed our departure to station. Next stop DeLaca Island. As we cleared the high reaching spans of Litchfield it was evident the wind had picked up. Hmm... a three hour tour, the weather started getting rough....Harry pressed on through a deepening swell.
"Palmer Station Divers have arrived at DeLaca" I announced as Harry completed the survey of the area and we determined where next to take a quick plunge for the second island sample. Second dives are always more challenging for divers and tenders. When doing multiple dives, divers only remove tank and weight belt in order to get back into the zodiac. Gloves, mask and fins stay on. So getting divers back into shoulder-harnessed weight belt and tank while standing in fins three times the length of normal shoe size and wearing mask which severely limits peripheral and down-facing vision is a challenge for all. I spared Harry that fun too and danced about Julie and Chuck one at a time to get them re-geared. And then "Palmer Station two divers in the water at DeLaca".
Again, at the tiller, the zodiac was harder to keep in place. The wind had freshened yet again. Shortly thereafter the radio calls "Divers, Divers, this is Palmer Station - be advised the winds are gusting 24 knots". It is not legal/safe to be out in the zodiac when the sustained wind speed is over 25 knots. "Divers about to surface" was our reply and once they surfaced I aimed the bow between their hooded heads for a more difficult than usual pickup given the increased wind. "Palmer Station, two divers out of the water". While we dealt with getting the collection into a bucket of water we rechecked the weather. Wind was not quite over the limit yet so we decided "Palmer Station departing DeLaca for an alternate location of Hero Inlet" closer to station and should be wind protected from the direction of the wind. Hmmm.... A three hour tour, the weather started getting rough, the tiny ship was tossed....
As Harry motored us in the direction of station and adjacent Hero Inlet it was obviously windier and seas lumpier than regular boating allowed. Another check of the weather verified sustained winds were now above the legal limit. (See the graph right that shows the abrupt change in wind speed during our morning out. The red horizontal line is the boating limit.) For an experiment Julie will write next about, a third collection was vital. The two sites alone would not tend to the needs of the experiment. A third collection had to be done. So – diving from shore is not wind limited like diving from the boat. "Palmer Station, divers are returning to station, will tie zodiac up to floating dock and divers will dive from boat". Technically, we were no longer boating so all was cricket. "Palmer Station two divers in the water". Ten minutes later "Palmer Station two divers out of the water".
Not quite a three island tour, but gratefully not more than a three hour tour much less a stranding on Gilligan's Isle polar style. Anything goes when tending but has always included a safe return to Palmer Station! For a less weather-impacted tender view check out this video made in a previous season :
- Written by Kevin Scriber
The view of the glacier, from a distance, was shamed by the view from atop. I felt on top of the world, rather than on the bottom of it. The mountains in the distance drew an embrace from the clouds in the sky. Waves crashed into the calving face of the glacier. Thunderous sounds emanated from the ice. Crevasse fields stretched far and wide, molding the uniform surface atop the glacier into an alien landscape of blue spires of ice. Never was someplace so barren so beautiful, then in those few hours I sat atop the glacier alone.
I will miss waking to fantastic views of ice and stone, the smell of cold crisp salt air, and the joy of exploration and science. I will forever cherish my time there, in the Antarctic, at Palmer Station. I had been anticipating going to Antarctica since June, 2012. I was surprised and elated to know my Dr.s McClintock and Amsler had that much faith in me, having been there student for just under a year.
Not many scientists ever work in Antarctica, let alone graduate students. I went through much. I wanted and waited, so long, to go there; now I'm leaving. The entire experience seems over too quickly, and the time spent preparing for it seemed so long.
As I recall the days at Palmer, I am bombarded with images; memories of people I've met and places I've seen stream across the screen in my mind. I take solace in the idea that I can take these, my memories, with me. I am happy to share these gifts with others. Sharing seems an inherent responsibility, considering the gravity and magnitude of where I've been.
I have learned much, about science, about people, and about life. Knowledge accrued is not just facts and figures. Rather, it is true understanding. Our world is changing, faster than you think. The severity, scale, and speed of that change is evident. One sees and hears the repeated calving of a mammoth glacier there day and night. The experience and reality of witnessing such drama, day after day, greatly changed my level of concern. Seeing is believing.
I thought I knew the state of my world. I thought that there's ample time to turn things around. Now I see the truth, instead of a indistinguishable silhouette of the future. All cannot see the truth of things, concerning our natural world, because most are disconnected from their nature. See the world as it should be, untouched and unbridled, instead of what has been made of its resources. We have become dependent on everyday luxuries, but abuse the necessities. A life sustaining world is a necessity.
Now, having left Palmer, I journey back to Birmingham, Alabama. I am saddened, leaving the Antarctic behind. The L.M. Gould carries us all forward, eventually into the dark-blue depths of the Drake. Antarctica slips past us with every lunge of the ship, as if the sea resists our departure.
Albert Einstein said once, "reality is merely an illusion, albeit a very persistent one". I like this quote. It embodies the lackadaisical indifferent opinion of many that there is nothing wrong with the world, especially if I turn the channel. How will your reality be reconciled with the truth? So, how's this for truth. We inhabit a rocky planet, orbiting a star, with an atmosphere that protects us from the ravages of space; we know none like it, and we're killing it. Change your reality; subscribe to another channel. Change the truth of our circumstances. So that we do not find ourselves wanting, wishing for and dreaming of yesterday's opportunity.