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Free-drifting icebergs as proliferating dispersion sites of iron
enrichment, organic carbon production and export in
the Southern Ocean

Reports from the field
Written by Alison Kelley

March 02-08 | March 09-15 | March 16-22 | March 23-31 | Early April | Mid-April

Week of 02-08 March 2009

Nearly two days after departing Reno, NV, and Homer, AK, the Murray Field Team converged upon its favorite extreme southern Chilean city, Punta Arenas, or as the locals say, "Puntarena." After "shopping" for our extreme cold weather gear at the AGUNSA Warehouse. Fully geared up, it was time to face the inevitable chore of boarding the ship to assemble our lab. Preparing for Antarctic field work requires months of preparation, and once we leave Chile, there will be no trips to Home Depot, so it’s all about getting it right on the front-end. By September, Dr. Murray and Vivian had prepared our order for chemicals, sample tubes, instruments, plumbing parts, tubing, all of the miscellaneous items that we need to do our work and, yes, more sample tubes that Raytheon Polar Services Company (RPSC) orders and ships from Port Hueneme, CA to Punta Arenas, Chile. With a tiny bit of dread, we go through the unwieldy pillars of boxes that span floor to ceiling throughout the working level of the ship, checking packing lists against box contents, and box contents against our original order, to ensure we have everything we need. See photo 1.

Photo 1: The R/V Nathaniel B. Palmer wakes at dawn, ready to cast off for Antarctic waters.

Though veterans of the Antarctic, Dr. Alison Murray and her field technician, Alison Kelley, are rookies on the iceberg cruise. A veteran of the 2008 Iceberg Cruise, DRI Staff Scientist, Vivian Peng, is now an old salt and made the initial lab set-up – always a harrowing experience – run relatively smoothly, by taking much of the guesswork out of equipment placement, gear storage, and perfectly timing exactly when to place items into "deep" storage, the nether land deep in the ship's belly – just in case you need to retrieve them once we're underway. On March 4th, we began the task of creating our home for the next 40 days, which continued until we were well underway. See photos 2, 3 and 4. 

Chaotic bio lab

Photo 2: The Bio Lab is utter chaos as unpacking begins.

Cold room set-up

Photo 3: With the equipment accounted for, plumbed, and battened to the ship,
the Cold Room is ready for sample processing and assays.
 

Filter rack set-up

Photo 4: We can size-fractionate plankton using filters varying in pore-size
to select for specific members of the community.

While still on terra firma, however, we needed to measure out reagents to prepare media plates. It's impossible to measure them at sea because you can not level a balance at sea, which is critical to accurately prepare 18-milligram aliquots of amino acids, sugars, peptides – all of the treats that microbes need to thrive. Dr. Marcello Gonzalez and Carla Gimpel, the kind folks at the Chilean Antarctic Institute (CAI), allowed us to use their spiffy new lab, which just opened in October 2008. At no small price, it turns out... Our Chilean colleagues speak nearly perfect English, but via a subtle twist of dialect, Dr. Murray has agreed to present a talk for CAI and their local science colleagues when she returns from the cruise!

At 10 AM sharp, Friday, 06 March, 2009, the crew of the R/V Nathaniel B. Palmer cast off its lines and a full ship was committed to 40 days at sea, including the infamous "crossing of the Drake Passage," known to make queasy the toughest of stomachs. Sebastian, our Chief Mate, announced during our fire drill on 07 March, that a severe low was making its way into the Drake, that the barometer was forecast to hit 938 (that's low), to prepare for 25-foot seas, and to tie everything down - and then tie it down some more. Soon many aboard sported the tell-tale tattoo of scopalamine patches. By mid afternoon, the barometer was dropping, and fast. Tentative looks passed between first-timers, as they strung line and re-doubled their knots on meters, pumps, aspirator traps, funnel racks, laptops, and the endless array of equipment throughout the labs.

What came of that storm they spoke of that turned so many of us green before the first breath of foam spat across the rails and on to the aft deck?? Just past the dinner hour, the barometer had crept back up to 1000….and by midnight, to 1008. After a mild night's cruise, we awoke to calm waters, clear skies, and the pressure holding steady at 1008. The low pressure system had dissipated, or perhaps grown bored of harassing the orange and yellow ship that has crossed these waters countless times since it first set sail to Antarctica in 1992.  As we sailed down the Tierra del Fuego coastline, wandering albatross were cruising with the ship, see photo 5. 

Albatross flying overhead

Photo 5: Wandering albatross at sunset off the starboard side of the ship.

We continued to steam toward Clarence Island where we’ll conduct a series of tests on our sampling equipment – ETA 13:30, 09 March 2009. We’ll also stop at a second deep station to sample seawater to establish reference seawater – completely absent the potential effects of the icebergs, to obtain accurate reference samples as the Iceberg Zone of Influence (IZI) is challenging to define.

B-014 signing off…. Stay tuned for more. 

Week of 09-15 March 2009

All photos by Vivian Peng and Alison Murray

"The only constant is change..."

C18a

After several days' steam across the Drake Passage,
the magnificent C18a is a welcome change of view.

Sun and storm over Clarence Island

Sun and storm over Clarence Island.

After nearly a week in transit to our objective, we arrived at C18a, a tabular iceberg whose name is derived from its source, the Ross Ice Shelf, on the Antarctic continent. It's alpha-numeric designation tells us where it originated (nearly across the continent from us!), in what sequence the ice broke free from its parent ice shelf, and whether it is a smaller berg cleaved from the parent. Dr. John Helly is on board to provide iceberg history and mapping data. He's working closely with Dr. David Long, of the Brigham Young University Center for Remote Sensing, to obtain current and historical images from tools such as the NASA Scatterometer Climate Record Pathfinder (SCP). Using satellite-based scatterometer imagery and other tools, Dr. Helly guided us to C18's current location in the open sea (Lat 62° 13.336’ S, Lon 51° 41.330’W), and prepared maps showing the path C18a has carved since it was liberated from the Ross Ice Shelf in approximately 2003. Who knew that the tiny, wandering specks of light we spy in our night sky might plot the family trees of icebergs, deep into the southern hemisphere? To learn more about how we map and track the icebergs, visit the MBARI Daily Log.

People gathered on the bridge of the ship

Everyone gathers on the bridge as C18a comes into view.

An important and exciting element of this project is the degree of collaboration between the various fields of science. Just take a look at the individual bios for the science team. Critical to integrating this amalgamation of science minds is a plethora of specialized instrumentation on board, all of which requires testing to ensure its operation before we all begin sampling. The weather and the seas have been immensely forgiving until recently, though the extensive suite of equipment tests have set our schedule back a bit. Of course, taking the time now assures quality data and, we hope, fewer problems once we get down to the business of sampling and generating data.

MBARI scientists put finishing touches on ROV

MBARI Scientists Craig Dawe and Alana Sherman put the finishing touches on the ROV.

13 March: With most testing complete and science ready to move forward, we encountered another more unfortunate delay. Immediate orders to cease science and steam directly to King George Island came from the captain, to support the medivac of one of our shipmates, who fell ill enough that another 5 weeks at sea could have led to a more serious condition. We were all saddened at losing one of our emerging 'tribe,' as people bond quickly in the close communities at sea and in field camps. Those who only a week ago were mere seat assignments aboard American Airlines Flight 945 have become faces we look forward to at meal times, in the lab, on the deck, and viewing scenery and wildlife up on the bridge. Science temporarily relegated to the back burner, everyone focused instead on the rare opportunity to glimpse the ghostly beauty of King George Island and the first green we've seen – though mostly lichens and only one or two species of grass! – since sailing out of Punta Arenas. Just as special was the brief but festive rendezvous across the water with our sister ship, the Lawrence M. Gould, all aboard both ships clustering at the rails and on the bow deck to wave, shout greetings, and snap shots of friends we'd made on prior deployments.

A tiny patch of green

A brief detour takes us past a tiny patch of green in this sea of grey, blue, white, and black.

Zodiac in the water

Sadly but successfully, R/V Nathaniel B. Palmer transfers our ill crewmate to sister ship R/V Lawrence M. Gould.

Another two days and we arrived back at C18a. Planning began, yet again, to move the project forward. First on the list for the Murray Field Team, the Iron Men, and Dr. Vernet's Phyto Phanatics was collecting water for a series of Seawater Enrichment Experiments (SEE). In the spirit of collaboration that defines Iceberg III, we're combining the trace metal chemistry skills of Dr. Ben Twining (aided by grad student, Hai Lin), the phytoplankton knowledge of Dr. Maria Vernet (aided by Karie Sines, Diane "PD" Chakos, and Aregentine grad student Adrian Cefarelli), with Dr. Alison Murray's world of marine microbes and molecular biology (assisted by Vivan Peng and Alison Kelley). We'll need lots of water to run all of our treatments, duplicates, and controls, so we'll be harvesting water with the shallow TOWFish.

The question we ask for the enrichment experiment is basic, but big: Are plankton iron-limited– and if so, is this limitation relieved in iceberg-impacted waters?

Learn more about the specifics of the seawater enrichment experiments...

The plan for Saturday was to prepare bottles, bottles, and more bottles, for our SEE. We need to ensure that the bottles are meticulously cleaned to trace-metal standard. Vivan Peng, and Alison Kelley followed Iron Man Ben Twining's lead in the bottle brigade – rinsing, soaping, rinsing again, filling with acid, storing with acid, emptying the acid, and rinsing again once sample water became available. Once we have water, the Iron Men, with help from us as needed, will fill the trace-metal clean sample bottles in the Clean Bubble, to further ensure against metals contamination.

Sample bottles

Sample bottles for trace metals analyses must be ultra-clean.
Once they've been acid rinsed, storage on or near metals (as in this picture) will not happen.

Our efforts to plan and stick to a schedule have been foiled at least three times since Saturday. Mother Nature doing as she does best, the winds mischievously kicked up whenever we attempted to sample for the SEE. As we move well into our 2nd week at sea, and our 3rd since we left home, the Murray Field Team is eager to dip our hands deep into the water, where we hope to reveal some of the mystery of life in the wake of our iceberg, C18a. At this point, the SEE will have to wait for another day. Instead, we hope today (March 16) to engage in a little "synchronized swimming," a sampling bonanza to coordinate data from all the water fairies (the collective group of chemistry (led by Tim Shaw, Ben Twining) and biology groups (led by Maria Vernet and Alison Murray)). But in the realm of remote field work, the only constant is change.

No challenge comes without its rewards, and they were plentiful this past week, with a moon-rise over C18a, numerous whale sightings (both humpbacks and fin whales), a few small colonies of penguins floating by on bergs or porpoising through our wake, the beauty of King George Island, and our sweet, brief encounter with R/V Lawrence M. Gould.

R/V LM Gould approaching King George Island

R/V Lawrence M. Gould provides the only spectra outside blue, black, and white,
as she approaches King George Island