Antarctic Blog 2013

Penguin.rock

photograph © 2013 Lorena Lagos Pailla and Leticia Barrientos

Day 2 : Sampling for extremophiles begins (20.2.2013)

This day's samples: A0—B8: Dee Island, Arturo Pratt Base, Robert Island

My second day in Antarctica began early; it was my first sampling day: up at 4:30am, a "super breakfast" at 5:30 am of coffee with milk and a breaded roll with a slice of beef. The expedition scientists were divided into expedition sampling group depending on their area of focus: water, microbial samples, scuba diving (no kidding), etc. While the number of individuals who leave the ship for island sample varies daily, typically I saw four boats leave with about 9 scientists and two sailors per boat. Many researchers stay on the Aquiles and process samples all through the day or leave on alternate days depending on the sites available for sampling.

We're collecting soil, sediment, and water samples in search of bacteria that are metalloid resistant (examples of metalloids: selenium and tellurium) and so our sampling container of choice is a 50-mL falcon tube. In the left image below, tube B1 is empty and tube B0 has a sample of the soil under the Antarctic grass species called Deschampsia one of only two flowering plants that are Antarctic natives (Deschampsia antarctica):

 

Falcon Tube
Falcon sampling tubes, from JP's lab
grass sample
Sampling bacteria underneath
a dried-out Deschampsia antarctica
Sampling Antarctic grass
A healthier Deschampsia antarctica

We were into the zodiacs by 6:30 on Day 2 (sunrise was 5:35am and sunset at 8:40 in the late Antarctic summer) and our zodiac motored about 2 km to Dee Island where we pulled our first samples (Latitude: south 62° 25' Longitude: west 59° 46'; Gary Todd and Max, this is the format for easy entry in the search line in Google Earth: ,-62 25 34, -59 46 22). One of our hypothesis is that growing grass mounds might harbor fewer interesting microbes than decaying mounds even a few centimeters away. One indicator appear to be the temperature with green mounds of the native grass we examined always cooler than the decomposing mound even with comparable size, depth, and water content. Temperature difference between the decaying mound in the image above and adjacent vegetation-free soil was 2°C. This, of course, could be either microbial activity or merely differential solar heating but the temperature probe was 5 or 6 cm deep in the mound, so darker, decayed grass that might be preferentially heated by the sun shouldn't have affected the inner temperature of the mound that much. And besides, the cooler grass-free soil nearby was darker in color, so it should have absorbed more solar energy anyway, and yet it was 2° cooler.

A spring feed this stream that exited snow pack 100 m from the beach; the water temperature was about 0.8°C. The rocks on the right show the beautiful structure of frost fracturing. The air temperature was just above freezing most of the first day.

Spring sampling
Sampling a spring on Dee Island
Frost fractured rock
Frost riving
by temperature extremes in Antarctica
  1. At mid-morning we loaded up the zodiac and moved a few kilometers to the nearby Chilean base on Greenwich Island on Guesalaga penisula called Arturo Pratt (-62 28 44, -59 39 40) before we returned to Aquiles for lunch. We took samples of soil along different ridge profiles assuming we were sampling different minibiomes which will reveal different extremophiles in Dr. José Perez-Donoso's lab ("Jota's lab") at the University Andrés Bello in Santiago when we get the samples back. The microbiologist I'm partnered with in Antarctica is Juan Pablo Monrás ("JP"), a doctoral student at the University of Chile working in Jota's lab at Andrés Bello. His smile, wit, and short beard are his signature and his microbiological scientific skills are wonderful. We bunk together on the Aquiles and we will also room together in the Chilean base back on King George Island after 5 days of sample collecting.
Juan Pablo Monras
Juan Pablo Monrás
Rock outcrop sampling
Sampling among fractured rocks
Ridge sampling
JP and Arturo Pratt officer

Robert Island (-62 26 36, -59 23 28) was the designated sampling site that afternoon. We were "welcomed" upon arrival by seals, a very few penguins (see Punta Hanna below) and the bone of a much larger animal too.

Seal
Seals on Dee Island
Primordial ooze
Primordial ooze
Seals
Seals

Whale1
Probably a whale skeleton
Whale2
Closer
Whale3
Now you know the relative size

Again, we discovered a surprising temperature profile in a a biomass-rich pool that contained, what appeared to be, decaying marine algae blown in from the beach or from a particularly high tide.

Here's the scenario: the air temperature at Robert Island at this sampling was 8° and the water (snow melt with ice nearby) in a shallow pool was measured as 1.2°, but 1 cm down into what we called primordial ooze--sediment covered with 1 cm of the snow melt water of the pool--the temperature had heated up to 2.2°, and 3 cm down in the primordial ooze, it was 4°C. Again we posit that this is microbially-powered warming. Note that solar warming could have made the top of the sediment warmer that the associated snow melt because it was dark and poorly reflective of the afternoon sunlight, sunlight that would have heated it more that the water above, but the temperature profile in the sediment increased with depth down into the sediment. This strongly suggests something besides solar heating.

We sampled these two levels in the pond's sediment, of course, Robert Island Samples B6 and B7, samples of primordial ooze.

 

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