Recently in Antarctica Category
Another update from austral graduate student Karen:
The rockin' zooplankton team working their magic aboard the LMG, LTER 2012.
Our two meter "metro" net is deployed off the stern of the ship. We typically tow this net down to 120 meters. For every regular sampling station, we take a tow with this net, and another with a smaller (one meter) net down to 300 meters.
Kate and Miram take a gander at what we have caught in our latest tow.
A mélange of zooplankton swim around in a large beaker after being brought inside the lab; here you can see different ages and species of krill, chaetognaths and more.
The head and dorsal fin of a humpback whale feeding near one of our sampling stations.
Humpback whale flukes- the patterns on the underside of humpback whale flukes are used to identify individual animals. The longest animal migration on record was recorded after a humpback known to frequent American Samoa was sighted in Antarctica.
Warning: this is a somewhat gratuitous entry with way too many animal pictures As the ship approaches Palmer Station, you get a beautiful view of mountains and glaciers sliding down into the Gerlache Strait.
Upon arrival at Palmer Station, we were given the opportunity to ride in small inflatable boats to Torgerson Island, a small island only a few minutes from the station. There an experiment is under weigh, looking at the impacts of human visitation on nesting behavior of adelie penguins. The entire island is inhabited by the penguins, and visitors other than scientists are excluded from half of the island.
Adelie penguins on Torgerson Island, with Palmer station (left) and the LMG (right) in the background.
Adelies on Torgerson Island with a sailboat in the background; yes, that boat and its passengers crossed the Drake Passage- I feel like a whimp.
A mother and her chick.
A male adelie brings his mate and chick a pebble for the nest.
However, after about one hour on this island, I realized that the penguins are a main course in the Antarctic food web, and that a whole community of predators surrounds the penguin rookery.
Here, a skua (the big brown bird in the foreground) devours a penguin chick which was still flapping its flippers when I grabbed my camera to take this picture- BRUTAL.
Penguins are such an important source of food for skuas that they have made their own nest only meters from the penguin nests. They are so well camouflaged that I nearly stepped on top of this mother skua, making her shriek, calling in the male to fly around my head making threatening sounds. Skuas are known for dive-bombing people and causing injury, so I backed away as fast as I could.
While poking around the island, I also found a leopard seal lying lazily on an ice flow, just abutting Torgerson Island. It appeared to have just feasted, likely on penguins.
This leopard seal sports the bloody grin of a predator with a full belly, as it floats on an ice flow next to the penguin rookery on Torgerson Island.
This harsh relationship between penguins and their predators represents an important link in the Antarctic food web. Penguins eat krill, which feed on phytoplankton- tiny marine plants which turn the sun's energy into sugars. Therefore, penguins are a link from the primary and secondary producers of the sea to top predators such as skuas and leopard seals. The relatively small number of links in this food web represents a fairly efficient system.
Stay tuned...more animal pictures to come. And some science too!
The Drake Passage is infamous for its trying conditions. It has been a formidable foe to voyagers from all periods of human history because the entire Southern Ocean, which circumvents the Antarctic continent, is squeezed dramatically between the southern extent of South America and the tip of the Antarctic Peninsula. You can think of it as taking a bunch of marbles rolling them around in a donut-shaped track. In some places the track gets wider, and the marbles are spread out, but in some places, the track is very narrow, so the marbles have to pile on top of one another to get through. Likewise, when the Southern Ocean squeezes into the Drake Passage, some water has to go up and some down, making the gigantic waves for which the Drake is known. We had a relatively smooth crossing this time: only about 15-18 foot seas- no big deal (haha).
Here, a wave breaks over the lower deck. I am taking this picture from two decks above the one being covered by the wave.
While traveling through the Drake, which takes 3 to 4 days depending upon conditions, we cannot conduct much science. We do collect information about temperature and salinity in the upper 900 or so meters of the water column. We call these collections XBTs and XCTDs, for the instruments used. Both are small torpedo-like units that are dumped over the side of the boat from a "gun"; as they descend into the water, a very thin copper wire trails behind relaying information about the conditions the probe meets through a cable in the gun, to the computer. The XBT only reads temperature, while the XCTD reads temperature and conductivity, a proxy for salinity.
Here, Nathalie holds the XBT gun before launching the probe. Sidenote: Nathalie is a first grade teacher going to Palmer Station to help study flies that freeze solid in the Antarctic winter, can lose up to 30% of their body moisture, and survive the whole ordeal eating moss. She will be doing education and outreach.
The temperature profiles tell us about how deep the water is mixed, indicated by a constant temperature. Maxima and minima following the mixed layer indicate different bodies of ocean water of different origins.
In this picture, besides half of my face, you can see that there is a lot of noise caused by the rough seas at the surface, then a mixed layer down to about 50 meters, a temperature minimum, and finally a constant temperature to the bottom of the profile. This cold subsurface layer is thought to be caused by the formation of dense, cold, salty water off of the Antarctic continent, which then sinks below the surface water of the Antarctic Circumpolar Current (ACC). The water is particularly cold due to the conditions in which it forms. It is relatively salty because as ice forms, fresh water is taken up and frozen, and salt is excluded, leaving saltier water behind. The saltier and colder water is, the more dense, or heavy is it; fresher, warmer water is less dense, or lighter. These principals of water density related to temperature and salinity in large part govern ocean water circulation world-wide.
Other activities that are popular during the Drake crossing include: sleeping, movie-watching, email checking, looking for whales and other critters, and of course, celebrating NEW YEARS!
Happy 2012 to everyone- may it be a year of adventure and new discoveries!
Science is all about acronyms. The better an acronym for a proposed project is, the more likely it will get funded. While I say that somewhat in jest, it is true that anything with an acronym is more likely to be remembered and is almost always used in place of the full name. Throughout science blogs everywhere, acronyms abound- be warned and get used to it.
Punta Arenas is the most austral port and town in the world. It is one endpoint between which the research vessel the Lawrence M. Gould (LMG) bounces, the other of which is the Antarctic Peninsula and Palmer Research Station. When I think of Punta Arenas, a feeling of decadent decay is invoked; eating and sleeping in PA, as it's affectionately called by those working on the LMG, is like going back to a time when care was taken in every detail of construction; dark wooden moulding is the norm, glass atrium greenhouses serve as dining rooms, and brass-adorned underground bars are filled nightly with cigarette smoke and patrons.
One theory is that PA was a booming port town when the Straits of Magellan were the safest route from one coast of the American continent to the other. It is the largest town on the Straits, which serve as a safer passage compared with rounding the fearsome Cape Horn. It is thought that PA saw the end of its glory days with the construction of the Panama Canal, which eliminated the need for ships to sail the full perimeter of the continent to get from, for example, New York to San Francisco. The town now waxes and wanes with the Southern Ocean fishing fleet that calls PA home, as well as the Antarctic and Patagonian tourism industry.
A view of Punta Arenas from the research vessel Lawrence M. Gould as we depart from port.
The Straits of Magellan, under an interesting sky.
ON OUR WAY- the crossing
We departed from PA on December 29th. Filling ones time while making the crossing can be a challenge. While still in the Straits, it is possible to set up equipment, use the machines in the ship's gym, and generally go about life at a normal pace. I spent a lot of time looking for wildlife. There are always interesting birds following the ship, including different types of albatross and shearwaters.
A black-browed albatross.
A greater shearwater.
As we left the Straits and headed for the Drake Passage, we were visited by several groups of dolphins, some Commerson's dolphins, and some Peel's dolphins. Peel's dolphins are endemic to the area, and are therefore seen nowhere else in the world.
Some Peel's dolphins making their way toward the boat to ride its bow and stern waves; in the background you can nearly see the end of the American continent.
Last time I mentioned that we collect water samples at multiple depths at a couple of spots when we do fieldwork. How exactly do you get water from 7 specific depths simultaneously? We use these nifty things called Niskin bottles! Essentially, they're tubes with tops and bottoms that are open until a pole on the side is hit- then the top and bottom simultaneously close. We attach these bottles to a cable, so they are spaced apart at certain intervals. We then lower them all down, so each bottle is at a depth we want to sample. We then put a weight at the top of the cable and let it go, to slide down the cable. It hits the pole on the top Niskin bottle, shutting that bottle and releasing another weight which slides down to the second bottle, shutting that bottle and releasing another weight which slides down to the third bottle, and so on... We then haul them all up (thankfully they're on a winch- it would be way too heavy to do by hand), take them off the cable and TA-DAH! We have water samples from particular depths! Didn't I say they were nifty?
Attaching a Niskin bottle to the cable. Hitting the white bar on the right releases the top and bottom to close the bottle.
The parking lot at Palmer- the 2nd boat from the right, Bruiser, is our trusty zodiac for fieldwork.
The L.M. Gould will be arriving again at Palmer tomorrow. This time when it arrives we'll be beginning a month long research cruise. There's 2 parts to the research going on here- what's happening at Palmer Station and the annual research cruise. At Palmer, the different lab groups sample the area right around Palmer intensively for the entire spring to fall season. However, everything we do is limited to be within a couple miles of Palmer (due to safety reasons). In January, there's a research cruise that samples a 600 km x 200 km grid along the Antarctic Peninsula. This allows us to study the changes occurring on a larger scale. The types of sampling and experiments on the ship will be very similar to what occurs at Palmer Station, just on a larger scale. As it's my first oceanographic cruise, it should be pretty interesting!
I've officially been a Palmer Station resident for 5 days now! The ship left on Monday evening to head north back to Punta Arenas. It was definitely a strange feeling standing on the pier and watching the ship leave. However, I didn't have very long to spend thinking about this as it's traditional to do a polar plunge when the ship leaves the station. Jumping in the Antarctic water definitely erased any thoughts of the ship from my mind.
There are currently 33 people at Palmer, about half scientists- half support staff (station manager, administrative, instrument tech, power plant, chefs, boating coordinator, cargo and supply, etc.) Notice that I did not mention maintenace in that list. Very similarly to GMRI, there is no maintenance staff at Palmer. Everyone is responsible for helping to clean.
While it is light all day, I have not actually seen the sun since last weekend. In true Antarctic form, our weather has been overcast, windy and rainy all week. The typical wind the last few days has been around 20-25 knots (~23-29 mph) with gusts around 35 knots (~28 mph). However, we have had sustained wind speeds of 45 mph and gusts of over 50mph several times already.
There are several science groups here, each working on something different. As I mentioned before I'm in the microbial group, then there is a phytoplankton group, a zooplankton group and the birders. (Other groups are here at other times of the year as well.) Together, we cover all of the trophic levels in the marine food web in this region. All of us depend on zodiacs to do our field work. For safety reasons we can only use zodiacs when winds are less than 20 knots and if winds reach 25 knots they call back any zodiacs that are already out. Essentially, this ends up meaning that planning is very difficult. Anytime someone talks about doing field work it seems to end with the phrase "weather cooperating".
For my lab group, most of our field sampling involves collecting water samples. Ideally we go to two different places twice a week and collect water at 7 depths at each place. We're interested in the microbial activity in the water. There's several analyses we do with the samples. One thing we're interested in is how much microbial activity is going on. We measure this using radioisotopes. Leucine is an amino acid that is normally limiting for microbes. By adding a radioactive form of leucine to a water sample we can measure how much has been taken up by the microbes and therefore, how much activity there is going on. We also measure the abundance of microbes using flow cytometry. Flow cytometers work by shooting light beams through the sample and then based on the amount of scattering it can determine abundance of particles and some other properties, such as size.
I am also enjoying getting to see the wildlife around here! There's lots of birds, seals and multiple penguin species. A couple of gentoo penguins were hanging out around our pier this morning and an Adelie penguin was playing around our boat yesterday.
A gentoo penguin next to the pier