Southbound (again) for science

A (warm) welcome back

Greetings, all!

It has been roughly a year and a half since my last posting in this space. After completing a successful field season at Palmer Station and aboard the ARSV Laurence M. Gould in the austral summer of 2013-2014, I’ve spent the past 19 months back in Woods Hole, Massachusetts, in my home laboratory at Woods Hole Oceanographic Institution. (You can check out some posts from the 2013-2014 field season using the “Archives” link on the main page of the blog…)

Right now, I am aboard the ARSV Gould in Punta Arenas, Chile, awaiting the roughly 9-day trip that will take me back down to Palmer Station until the end of December. The ship’s crew and scientific support staff are working feverishly right now to prepare the Gould for the transit: Food stores and equipment are being onloaded, navigation instruments and the ship’s engines are receiving necessary maintenance, and scientists and staff are moving into their temporary homes aboard the vessel.

No (reliable) word yet on what the weather will be like when we depart and cross the Drake Passage — the notoriously stormy body of water that separates the southern tip of South America from Antarctica.

I’ll be posting on the blog again over the course of my stay at Palmer, and I hope you’ll join me on the adventure. The subjects of my posts varied widely when I was on station two years ago, and I hope to maintain the same breadth of theme this time around. If you have a specific question about science or life on station, please e-mail me, and I’ll do my best to answer in my next post.

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What I’ve been up to, scientifically

During my time back home, I was working primarily to refine and develop the methods and techniques I will need to complete my dissertation project sometime next year. I am investigating a group of chemicals that marine algae — the ocean’s single-celled plants — use as signals to “talk” to each other about the various sources of stress in their environment. (“Investigating” is a word we use in science for “researching.”) My scientific collaborators and I are specifically interested in oxidative stress — an inescapable and nearly ubiquitous feature of life in a universe composed of atoms and electrons.

In algae, it turns out, lots of things can induce oxidative stress:

  • Photosynthesis, the fundamental means by which plants convert solar energy, water, and carbon dioxide into organic matter and oxygen
  • Predation (i.e., getting eaten, or even the threat of getting eaten, by microscopic grazing animals such as zooplankton)
  • The basic process of respiration, the means by which nearly all organisms break down stored organic matter (“food”) for energy
  • Nutrient stress
  • And, a host of other processes

Another source of oxidative stress that comes from outside the cell itself is ultraviolet radiation. This is what brought me (and is bringing me back) to Antarctica. As a result of anthropogenic (human-caused) thinning of the stratospheric ozone layer, Antarctica receives very high doses of UV radiation in the Southern Hemisphere spring. You can check out the current UV conditions at Palmer and the other U.S. stations in the Antarctic at http://www.esrl.noaa.gov/gmd/grad/antuv/

I am interested in whether we can see the effect of this source of stress on the structural molecules (lipids) that make up the cell membranes of the algae that inhabit the ocean in and around Palmer Station. (Previous research has shown in a somewhat nonspecific way that UV radiation can induce high levels of oxidative stress in diatoms, a type of algae.) Cell membranes can break down as a result of this stress, producing small molecules which algae (and terrestrial plants) use as signals. These smaller molecules can be use as “biomarkers,” a term used in human biomedicine and in geochemistry for molecules that serve as indicators of a certain environmental process.

I’ll be posting later in the season withe some specific examples of how these small “infochemical” molecules function in the environment. And I’ll be explaining in much more detail about what my collaborators and I are doing to identify potential biomarkers of oxidative stress in the ocean.

That’s all for now — looking forward to having you along this season for the ride.

Jamie

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