Homeward Bound

We’ve been transiting north towards Punta Arenas, Chile for several days now. After exchanging some personnel and gear at Palmer Station on Anvers Island we passed through the Gerlache Strait and into the Drake Passage. We were extremely fortunate to have favorable seas on both our transit south toward Antarctica and again heading north. (The Drake Passage can have some of the roughest seas in the world!)

A 180° view of the Gerlache Strait

We’ve noticed much warmer air temperatures and more sea birds since reaching the tip of South America. Soon we’ll turn into the Straits of Magellan and we are hoping to spend our last day at sea observing dolphins, penguins, and whales before the hectic off-load and long flights home begin.

As we near the Argentinian coastline we’ve spotted quite a few fishing and re-supply vessels like the one above

This afternoon we held a “science symposium” where the leader of each research group shared some of their team’s more interesting findings from the previous month. The photos and vast quantity of data were remarkable, but what struck me the most was how all of our research – physics, microbiology, macrobiology, and chemistry – fits so well together to tell a “big picture” story about the changes that are occurring on the Western Antarctic Peninsula as our climate changes. The LTER (Long Term Ecological Research) Program is one of the more unique scientific endeavors that the US supports; normally research studies are only 1 – 3 years in the field. Having 20+ years of interdisciplinary field data is rare; having it in one of the most rapidly changing climate systems on Earth is priceless. Let’s hope funding for this type of vital research that helps us understand food webs, sea level changes, ocean circulation, and climate change continues for many years to come.


~ This is the final post for the Southern Ocean 2015 blog - thanks for reading along! ~

February 3, 2015

Most groups on board study things that are visible to the naked eye – whales, penguins, plankton, etc. These creatures are all part of the marine food web, and at the base is phytoplankton – the very small algae that photosynthesize. In addition to light, these plankton need carbon, nitrogen, phosphorus and a bunch of other elements in very small quantities to grow. Among these essential elements is iron (Fe). Iron is such a scarce nutrient that it can actually limit the growth of phytoplankton in some marine areas – including the Western Antarctic Peninsula. Because iron and many other elements (mercury, lead, zinc, etc.) occur in such small quantities we call them “trace” elements.

Trace elements are interesting because they can help us figure out why phytoplankton grown in certain areas but not others. Some of them can also help us figure out where they are coming from – dust blown over from South America and Australia, the weathering (“decay”) of the Antarctic continent, the melting of glaciers, or ocean currents which move south from lower latitudes.

In order to study these trace elements from a ship made of metal (inside and out!) many precautions are required to avoid contaminating seawater samples. These include using special metal-free collection bottles and a make-shift cleanroom made from wooden framing and plastic sheeting.

Rob Sherrell (Rutgers U., foreground) leads a deployment of the surface water sampler

Jess Fitzsimmons (Rutgers U.) sampling surface water, plumbed from the sampler off the side of the ship into the make-shift clean room

The “trace elements” team prepares the water collection bottles for a cast into the ocean

Ice

One of the more dangerous hazards to Antarctic explorers/oceanographers is ice. Its behavior is highly dependent on the wind which can either hold it together loosely or pack it in very tightly so that when the temperature drops, the ice freezes together and ships get stuck. This happened to Ernest Shackleton in the earlier 1900s and continues to happen to vessels as recently as last year. Our science questions only bring us about 2 km beyond the ice edge, and the Captain keeps a watchful eye on the wind and temperature in case we need to get out quickly. No need to worry, Mom!

As we approached the Wilkins Ice Shelf we found a surreal amount of ice.

Loosely packed sea ice as far as the eye can see

Lots of wildlife on the ice – including a Crabeater seal in the foreground and some penguins in the background; the horizon is almost impossible to see with the snowy-white sky

Ice is extremely strong and destructive, so it must be kept away from the equipment. Here our Antartctic Support Crew memebers Lindsey Loughry (L) and Hannah Gray (R) use boat hooks to keep ice away from the CTD and its wire.

Some of the ice floes are larger and can support the seals, some are enormous icebergs (very far distance), and a lot of it reminds me of Slurpee from 7-11.

2 curious Crabeater seals watch our ship pass by – I wonder what they think of our giant orange ship??? Most seals watch us bump through the ice instead of scooting away or hiding below the ice.