A Cold Blue Desert Full of Life

A Cold Blue Desert Full of Life

What words come to mind when you think of Antarctica? Do you think of Antarctica as a place covered in plants?  What is enticing to living organisms about this inhospitable continent? Why do we want to come study this area? Repeat after me:  Algae, carbon, and salty deep water. Algae, carbon and salty deep water. Algae and carbon and salty deep water.  

 Photo credit: C. Brooks

Before this trip, I was not well read up on Antarctica. I felt proud knowing that polar bears only exist at the North Pole, penguins only exist at the South Pole and they exist together only in Coca Cola ads. I wasn’t fooled.  Other than that, Antarctica is covered in ice, its flat, white, cold, lifeless and only scientists or tourists with money to burn visit…right? What on Earth would actually live on, in, or around this continent

Photo Credit: R. Dunbar

Did you even consider the water when you thought of Antarctica? The Ross Sea is one of the world’s largest pristine marine ecosystems. So, what is in this water that is so great? Algae! Phytoplankton! You better remember this organism, because it is responsible for producing ~50% of the oxygen that you breathe! Don’t give land plants and trees all of the credit.  Over 700 species of algae live in the Southern Ocean. On our trip in the Ross Sea, we have mostly seen a majority of two algae types: “diatoms” and “Phaeocystis”. These brown cells make up the base of the food web and support great populations of krill, whales, penguins, fishes, seals, and birds, oh my! But wait! Don’t rush me. I can’t talk about the algae YET. I have to set up the scene where they live.

Average sea ice extent in the Southern Ocean in the winter (left) and summer (right;

graphic by Hugo Ahlenius, UNEP/GRID-Arendal, red arrows by A.Lee).

Think of Antarctica as a castle with a moat surrounding it (but no drawbridge, no dragon, no fare maiden to rescue—except for me. Get me out of here!—kidding). It is a strong sturdy continent all by its lonesome and around it whirls ocean currents and hurricane speed winds.

As winter approaches, temperatures drop and pack ice starts to form. With ice formation, salt remains behind concentrating the water below. This saltier cold water is more dense and sinks to the bottom of the sea. The winds blow the formed ice away leaving open water which again freezes back up, thus continuing the cycle of ice/salty water formation. The Ross Sea is an area where this salty “Antarctic Bottom Water” is formed and this water ends up being circled around the entire world! Great, OK, sinking salt water, you got it, and you’re dying to read more…

If you go running and screaming at the point where the graph shows up, then I’m gonna slap you! It’s JUST a colorful picture with a lot of arrows. Get a grip and keep reading! Image 1 shows the whole “ice forms, winds blow, salty water is left behind and sinks” business. Image 2 shows deep cold salty water (blue arrow) as it moves around the earth. Betcha didn’t know it traveled to your home beach!

                  

This whole deep water formation process is a way to transport stuff from the surface to the deep. That’s what we refer to as “export”. So what stuff is in the surface that we care about? Carbon!

(Again, just focus on the pointy arrows:)

Carbon exists everywhere in the world. It exists in two forms: organic and inorganic and its constantly changing from one form to the other. Every year there is a predictable large algal bloom that is seen from space in the Ross Sea. I know how personable little algae cells can be, but for a moment I need to objectify them and speak of them solely as “carbon”. They are no longer the cute fluffy organisms you know and love, so get over it. Because we are looking at an entire process we cannot stay glued at the hip to these phytoplankton.

The algae grow, they eat up all the nutrients, they snot out organic carbon, they become food for other organisms who poop out organic carbon, and they die. They create and become many forms of carbon. That carbon then sinks down the water column along with the sinking of the salty cold water. Bacteria will eat up this organic carbon and convert it back to inorganic carbon and then, voila, that is how we continue the great and grand and all important Carbon Cycle of the oceans.

Scientists on the TRACERS cruise are trying to understand every step of what happens to carbon after the algae blooms and the cells start to die. We want to TRace the fate of Algal Carbon Exported into the depths of the Ross Sea. I hope that acronym makes more sense now. By looking at this export process in the Ross Sea, we can apply that knowledge to other areas of the world.

Satellites in space capture images of the Algal Bloom in the Ross Sea. Photo courtesy of NASA

…..and much, much more!

I don’t know what everyone else’s preconceived notions of Antarctica are, but my whole vocabulary has expanded with adjectives to describe this place. Yes, it’s cold. Yes, it’s white, but flat and lifeless? It is not.

Photo credit: K. Goetz

-Allison