The bone lander after recovering it on the back deck of the ship. The attached whale bones will be removed and analyzed by Dr. Craig Smith and colleagues to see what animals, big and small, have made these bones their home.

While the deep sea below the euphotic zone (the top 100 or so meters, or 300 ft, where light penetrates and primary production from algae occurs) was long thought as a vast oceanic desert where few organisms (even microbes) could survive, research in the last century starting with the Challenger Expedition between 1872-1876 has shown a rich diversity of marine life specialized to face the harsh conditions of high pressure, cold temperature, and complete darkness. One of these, the annelid worm Osedax, has developed the ability to feed on complex hydrocarbons in whale bones, using bacterial endosymbionts (bacteria living inside the worms) to break down the compounds inside the bones into a usable form of energy.

Our ship, the Palmer, breaking through sea ice in the Weddell Sea.

As luck or fate would have it, the sea ice around Antarctica seems to be unusually persistent this year, reaching far beyond its usual summer extent, which makes moving forward a slow going process. For those of you living in cold regions of the United States and the world, you might be used to seeing your lakes and rivers freeze and thaw as the seasons progress. Sea ice around the Antarctic goes through much of the same cycle, building during the winter (between April and September in the Southern Hemisphere) and melting during the summer. The extent of ice any given year is related to weather as well as global climate, and has been shown to decrease around the Antarctic Peninsula over the past 60 years.

Sea ice extent in September (austral winter) of 2009 as measured by satellite. Black corresponds to land, blue to open water, and the other colors to sea ice. The approximate location of the Larsen B ice shelf, our target, is indicated by a white circle. Notice the band of purple surrounding that location, indicating persistent sea ice.

Sea ice extent in December (summer) of 2009 as measured by satellite.

Here’s another view of the same data. In this version, grey corresponds to land, blue to open water, and white to sea ice. The approximate location of the Larsen B ice shelf, our target, is indicated by a black circle.

Sea ice extent in December (summer) of 2009 as measured by satellite.

Because the Antarctic serves as home to a rich assemblage of species, including fish, seals, sea birds, whales, and penguins, you can imagine that life doesn’t simply stop in the cold polar winter… it adapts. Algae, which you may think as growing only in bodies of water such as lakes, oceans, and rivers, can also grow on the underside and inside of sea ice. If you look at the picture of our ship’s track you’ll notice a surprising brown color to the normally white or bluish ice. This color is due to ice algae, which due to their adaptation to low light conditions thrive both in the summer and winter. Ice algae may play an important role in starting the phytoplankton blooms that are common in the ocean as the ice retreats in the spring. Because it grows in such great abundance it also provides an important source of food to higher trophic levels, include the krill that whales love to eat. So in a way, what happens on the often hidden underside of ice can have a great impact on the bigger Antarctic animals we all know and love!

Cracks in the sea ice expose algae growing underneath and inside the ice.

ABOARD THE RVIB N. B. PALMER, ON THE SOUTHERN OCEAN– As most unicellular phytoplankton algae, diatoms usually reproduce by division. One cell becomes two after mitosis; the two new algae are called “daughter cells”. Once in a long while diatoms go through sexual reproduction. After meiosis the new daughter cells have a recombined genetic material. What brings this phenomenon? Some scientists think that the cell division (or asexual reproduction) produces silicon valves smaller and smaller until size can become a problem. Stress is another factor thought to affect reproductive strategy. Cells under unfavorable conditions for growth, when nutrients run out, undergo meiosis to increase their change of survival.

Corethron criophilum after cellular division through asexual reproduction.

The dominant diatom around the C18A iceberg is undergoing sexual reproduction. It is easy to see this process under the microscope as Corethron criophilum is large and the changes are striking. In cell division two smaller cells are seen at the extremes of the valve in cingular view, or along the cylinder. The auxospore is produced after fertilization of male and female gametes, leaving the mother cell.

Auxospore leaving a diatom frustule after sexual reproduction and fertilization.

Is the iceberg affecting phytoplankton in such a way to start sexual reproduction? Or does Corethron criophilum under stress due to diminishing light days as the fall season advances? These are questions we are asking ourselves. Detailed analysis of samples under the microscope once we are home will shed light on the first question. The importance of changing season on Corethron criophilum cannot be assessed during a 40-day cruise. Several months of study in the field would be needed. This is a question that might remain open and maybe can be answered in future cruises.

Canada Glacier with frozen Lake Hoare in the background.

Summer melting from the Canada Glacier feeds a stream that flows into Lake Hoare.

The Dry Valleys are dry because very little snow falls here, the average water content is less than a centimeter. Yet a fully functioning ecosystem exists here, in the ice-covered lakes and the soils of the valley floor. Even though the ecosystem is all but invisible to the naked eye, it still has a basic food web: primary producers (mats of moss and algae in the lakes, bacteria, yeast, fungi and other microbial life in the soils ), grazers (microscopic invertebrates called rotifers and tardigrades), with the top of the food chain consisting of tiny nematode worms. Curiously, there are no known predators in the Dry Valleys soils. These valleys constitute a Long-Range Ecological Research (LTER) study site and represent what scientists believe might be a model for life on Mars if it exists.

Lisa Strong on a hike with Canada Glacier behind her.

The origins of Seuss Glacier pouring through a mountain pass in the Dry Valleys.

Lisa and I went for a walk up the Taylor Valley to see whether we could uncover any evidence of life and saw little, except for a couple of long-dead seal mummies (why they traveled so far from the sea ice is anyone’s guess) and some algae-covered rocks and brown floating scum, looking for all the world like whipped chocolate mousse. We did see plenty of wind-scoured rocks and glaciers pouring through gaps in the surrounding mountains.

Bones and skin of a seal mummy that perished hundreds or thousands of years ago.

Biological scum on Lake Chad.

For easier walking, I tried to cross the moat between land and solid (white) lake ice. What I thought was thick ice wasn’t and I broke through up to my knees for my own version of the polar plunge. After changing into dry pants and socks, we continued on our walk but the only macroscopic life we saw was a lone skua winging up the valley.

Mary after breaking through lake ice.

I knew I needed to dig deeper, so I’ll turn to the LTER scientists studying the different parts of this ecosystem from the glaciers that feed life-giving water to the lakes and soils, to the ice-covered lake waters that support microbial life, to the soils that provide habitat to bacteria, yeast and fungi, and invertebrate creatures that make up “charasmatic megafauna” of the Dry Valleys. Look for upcoming video interviews with these LTER scientists.

Glaciologist Hassan Basagic of Portland State University explaining the dynamic of Canada Glacier to Lisa.

We’ve been doing modern limnological sampling to better understand why the haptophyte algae (the producers of biological thermometers) fare so well in our Greenlandic study lakes… it’s still a mystery.

We sit on a rubber boat (a Zodiac) making measurements and taking different kinds of samples. Have a look at this video to see us recover sediment samples from last season, and get introduced to some of the equipment we use to sample water, algae and sediment.

One natural thermometer comes in the form of alkenones: trans-fats produced by certain algae. The alkenone thermometer is already used to reconstruct sea surface temperatures from ocean sediments. My research aims to extend their use to lakes, so we can reconstruct continental temperatures as well.

Watch this video to see how this biological thermometer works.

Shrimplike marine invertebrates that grow no bigger than about two and one-half inches (6 cm), krill are nonetheless food for gigantic baleen whales, along with penguins, seals, fish, sea birds, and many other predators. It may seem unlikely that 80-ton whales can be sustained by these small crustaceans, but the whales consume them by the ton—which says a lot about the numbers and concentrations in which krill are found. Krill gather into dense swarms that can have from 1,000 to 100,000 individuals per cubic yard (1 cubic meter), and a swarm can extend from 30 feet (10 meters) to almost 4 miles (6 km) in length.

Krill play a critical role in a variety of marine food webs, especially those in the polar regions. Many krill species themselves feed primarily on phytoplankton, organisms that use sunlight to synthesize their own food. In the light-filled summers of the sub-Arctic and Antarctic, there are huge blooms of phytoplankton for the krill to feed on, so there are immense swarms of krill—just when hungry penguins and migrating baleen whales need them.

In terms of biomass, krill are one of the most successful species on the planet– with a total estimated mass of approximately 500 million tonnes.

Antarctic krill have a special relationship with sea ice, which is both shelter and dining hall for larval and juvenile krill in the winter. That’s because the ice serves as habitat for algae. These ice algae live on and inside the ice and can give the floating ice a brown or greenish hue.

This image, taken by a remote operated underwater vehicle (or ROV), shows how most krill feed by swimming upside-down directly under the ice, grazing as they go. A single krill can clear one square foot of ice algae in approximately 10 minutes.

But the sea ice is shrinking in both winter and summer. This is especially pronounced in the Southern Ocean adjacent to the western Antarctica Peninsula, where there’s been a considerable increase in atmospheric and sea surface temperature. The krill population in this region has decreased by about 80% since the mid-1970s, according to several experts. Experts also think that the warmer temperatures and the loss of sea ice are at least partly to blame.

Climate change is not the only thing impacting the health of the krill population, however. During the 1970s, commercial krill fishing in Antarctic waters began expanding rapidly. Initially, the krill were used mostly for pet food and fertilizer, but more recently they’re being used for nutritional products such as omega-3 fatty acid supplements, feed for the rapidly growing aquaculture industry, and even in some new cosmetics.

Deep-frozen plates of krill meat destined for animals and humans alike. While nearly 100% of Canadian-caught krill becomes fish food, about 43% of Japanese-caught krill is targeted for human consumption as meat, pastes, or additives.

Krill fishing is managed by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), which sets catch limits. At the CCAMLR 2007 annual meeting, the commission increased the yearly allowable catch in some areas, including the coastal area of Eastern Antarctica. But they also put into place some new requirements. Now, all krill fishing vessels in the region must participate in the CCAMLR vessel monitoring system, and vessels fishing in the Eastern Antarctica area need to have observers on board. In addition, once certain catch levels have been reached, CCAMLR will introduce other measures in order to protect the animals that feed on krill.