The IVARS project (for Interannual Variability in the Ross Sea) involves two cruises per year through the Southern Ocean: one in December during the spring phytoplankton bloom, and one at the end of the growing season in February. Cruises are scheduled to visit the same sampling sites during each of the project's five years. Cruises deploy from the U.S. McMurdo Research Station.

The 2005-2006 IVARS cruise will take place aboard the R.V. Nathaniel B. Palmer, and is proceeding in cooperation with the multi-institution CORSACS project.

By comparing data from each cruise to that of "pre-bloom" water, IVARS researchers can calculate seasonal phytoplankton productivity and compare it to that of previous years, thereby revealing year-to-year changes.

During the December cruise, IVARS researchers deploy two moorings. Each has an elaborate suite of instruments designed to continuously sample the surface layer to reveal short-term variations within each growing season. The instruments are a fast repetition rate fluorometer (FRRF), a nitrate analyzer, a silicic acid analyzer, a whole-water sampler, two additional fluorometers, a sediment trap, thermistors, a CTD, and current meters. The moorings are retrieved during the second cruise.

IVARS scientists typically travel from the U.S. to Antarctica by flying to either Christchurch, New Zealand or Hobart, Tasmania, and then either flying aboard a LC-130 or C-141 cargo plane to McMurdo Station, or sailing across the Southern Ocean. The NZ-McMurdo flight takes 5-8 hours. The Southern Ocean transit typically takes about 8 days. Once the ship arrives at the ice edge, scientists are often ferried to McMurdo via helicopter.

The Trip South

December 20

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The VIMS IVARS team continues south on the Nathaniel B. Palmer, the flagship research icebreaker of the National Science Foundation. We presently are at 55°S and have traveled 600 nautical miles through open water. Luckily, our weather has been good, with relatively calm winds, little swell, and cloudy skies. But we all realize that weather conditions in these regions can change dramatically, so we remain aware of the possibility of bad weather.

This year's IVARS cruise is being conducted in conjunction with another research effort, CORSACS. CORSACS will investigate the controls of algal composition, and in particular look at the interactive effects of iron, light and carbon dioxide. To do this, a group was assembled that includes Jack DiTullio (Charleston University), Rob Dunbar (Stanford), Dave Hutchins (Delaware), Pete Sedwick (Bermuda Biological Station), Philippe Tortell (British Columbia) and Mac Saito (Woods Hole), as well as Walker Smith of VIMS. They will use not only observations of in situ conditions (that is, seeing what algal species occur under various iron concentrations), they will experimentally manipulate natural waters (by adding iron and altering light and CO2) and establish algal cultures to see what species grow faster under the manipulated environments. It has been found in the equatorial Pacific that carbon dioxide had a tremendous impact on algal composition, with diatoms (common, large forms that have a characteristic shell made of silica) growing under low CO2, and another group dominated by a species called Phaeocystis dominating at high CO2. It was further speculated that this was due to the mechanism by which these groups acquire CO2 and their photosynthetic enzymes. Because these groups are important in the Ross Sea, and because carbon dioxide concentrations are changing rapidly in the ocean due to human releases into the atmosphere, controls by CO2 potentially could be critical throughout the entire ocean and influence food webs and elemental cycles.

IVARS will sample within this project, and occupy the same set of 12 stations in a transect roughly parallel to the Ross Ice Sheet that were sampled in previous years. We will also deploy two moorings to collect continuous data on nitrate and fluorescence, a measure of the numbers of algae in the water. The Ross Sea experiences substantial "blooms," or large accumulations of algae, during its short austral summer, and by knowing the rates of accumulation we can begin to understand the short-term variations and controls of algal growth. IVARS will recover the moorings in a separate, short cruise at the end of January and early February.

And the march south continues...

Christmas at Sea

December 25

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Christmas and the Holiday Season is a time most often spent with family and loved ones, so being at sea in the cold waters of the Antarctic make that impossible. Many different reactions occur among the various people on the ship, and each of the IVARS group has written with his/her personal reactions to having Christmas at sea:

Walker

This is my fifth Christmas in a row spent away from family and friends, but each one is different. You are with people that you enjoy, and we always pre-arrange a small gift exchange. Each person contributes something different to the festive spirit, such as an Advent Calendar, Santa Claus hat, or a mini-tree. For me it is truly a time for giving, as I honestly don't worry about what is given to me. It is a time to say "Thank you" to all in the group for making the commitment to the project that causes some personal loss. I also take time to think about others in my life that I am missing: children, parents, loved ones, and distant friends. The time to reflect on the importance of friends, my upbringing, and how I live my life is important to me on this day. We do have a massive meal, but it always strikes me at how much more I like my own Christmas cooking! It also is snowing hard outside now, and it reminds me of my youth in Buffalo, New York, where it was not uncommon to have a white Christmas (and January, February, and March). But reality intrudes as well; two fishing boats are following us in to the Ross Sea, one of the few (only?) areas in the ocean that has had no fishing pressure, and I find myself angry at the thoughtless disruption of such a pristine ecosystem for trivial economic gain. And because I understand how the food web works in the Ross Sea, I know that the loss of such large fishes is bound to generate a serious alteration in the region's ecology. I can only hope they have terrible luck in fishing.

So, Christmas at sea for me is a time for reflection, of being thankful for friends and family, and mentally preparing myself for the hard work ahead.

Sasha

Christmas at sea in Antarctica is definitely the whitest Christmas I've ever had. For the past three years on Christmas day I have been on ships breaking ice in the Southern Ocean, and it is always been very special. It is definitely different from the traditional Christmas celebration at home with family and friends, but special bonds and solidarity are quickly established between people on board, and I still consider spending this holiday working in such an extraordinary and extreme location an incredible opportunity.

Carol

This Christmas has been like no other I have ever experienced. I woke up to the bright shining light coming through the porthole. Wow, what a blinding brightness as the sun reflected off the ice, the snow and the water! It was bright white and bright blue. Our group gathered to start the day off right. We exchanged presents and laughter and holiday wishes. I was the lucky one. I got flashing reindeers antlers to be worn all day. More people came from their rooms dressed in Santa Claus hats, twinkling lights and smiling faces. Merry Christmas cheer was spread with each greeting and my reindeer antlers got a nod of approval. Lunch came soon and what a feast. Afterwards, just like home, a nap was due. But the best was yet to come. Later, I put on my wool socks, boots, wool scarf, leather insulated gloves, and bright orange parka and made my way to the bow of the boat. What a magnificent sight, the endless ice, crushed and melded into figures you could pick out, and the water so blue. It was snowing. To top off the day I saw my first seal in the wild as well as three frolicking penguins. They played and slid on their bellies on the ice. They were so silly and soon they were out of sight. Yes, this has been a joyful and magnificent day, one probably never to be repeated, filled with jolly good cheer and a satisfying peacefulness at sea.

Jenny

Christmas at sea is a unique experience that is full of festivities but also full of longing. All around the ship, there are decorations and blinking lights that let us know Christmas is near. As I look out on the horizon, all I can see is a vast ocean of ice and white. It is indeed a white Christmas and I have the feeling of being at home since I grew up in Alaska. We awake in the morning and like children with their eyes shining bright, we assemble near the Christmas tree (granted a miniature one) and survey the gifts before us. One by one they are opened and there is an assortment of games to entertain and chocolate to soothe. I am thankful for being here and thankful for the great friendships I find in the people around me but there is a hint of sadness as we are spending Christmas without our family and loved ones. We each try to call home from the satellite phone and some are successful and some are not. The voices break in and out but they are what keep us anchored and give us some peace since we are amazingly lucky to be able to call at all. Lunch is a warm welcome of turkey and all the trimmings and it is just like home (without a few small comforts). Most people head off for an afternoon nap and I head outside to breathe in the Antarctic air. As I look out at the ice and ocean before me I realize that these memories are one's that will not be forgotten. It is hard being away from those closest to us but there is also something to be said to being in the middle of one of the most remote places on earth.

Jill

Christmas this year on the NBP Palmer has been a mix of work and play as we continue to underway sample. This year we can actually talk with our loved ones on Christmas—it's amazing. The NSF has purchased an Iridium phone that will allow any of us to call home for a couple of quick minutes. What a nice change from shooting an email off at the stroke of midnight! In all reality, we do our best to keep in the holiday spirit; we hang lights, buy presents, and decorate the tiniest of plastic Christmas trees (that are well secured to our work surface) with the smallest of ornaments. We even adapted our non-denominational holiday countdown this year (like an advent calendar) to feature pictures of our loved ones. Although we all certainly miss our families, being on this ship has provided us with an opportunity to share stories of holiday tradition and spirit from not only around the country but also from around the world.

Best wishes for a Happy Holiday Season from us all!—The IVARS Filtering Fools

Deploying the Moorings

January 1

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For the fifth year in a row the IVARS group deployed two moorings in the Southern Ross Sea. Vernon L. Asper (University of Southern Mississippi) prepared all the hardware and most of the sensors in Lyttelton, NZ. The two moorings (Calinectes and Xiphias) have similar configurations, each bearing a surface float equipped with an Argos satellite transmitter that regularly sends us the mooring position via e-mail. In the top 50 meters we mounted three Wetlabs fluorometers, a Chelsea Fast Repetition Rate Fluorometer (FRRF), a MBARI-ISUS nitrate sensor (only on Calinectes), a Microcat temperature/salinity recorder, and a Benthos transponder. A 240-meter S-Tether connects the surface part of the mooring to the bottom portion. The bottom array consists of a 40" Syntactic float, a current meter positioned at 210 meters below the surface, followed by a sediment trap, which is used to measure settling rates of particulate matter in the lower water column (see picture). Each mooring also has 10 glass floats attached to a Dual Edgetech acoustic release and a 2,200 pound anchor made of train wheels.

We deployed the first mooring, Xiphias, most eastward, at 77° 39.98 S 179°59.94 W in a depth of 662 m. Exactly 30 hours later, we deployed Calinectes at (76°54.600S and 171°46.550 E) at a depth of 665 m. Thanks to calm seas and excellent support of the ship crew, both moorings were smoothly deployed in exactly two hours each. The back deck team had Annie Coward at the winch, Pete Delferro and Meghan King at the transom, and Skip Owen coordinating all the operations. Robert Dunbar and Dave Mucciarone (Stanford University) used their experience in mooring deployments to ensure the correct sequence of operation. Sasha Tozzi was responsible for the Chelsea Fast Repetition Rate Fluorometers (FRRF), and the MBARI-ISUS nitrate sensor and all other scientific equipment on the mooring. Isaiah Norton (ship Network Administrator) helped Sasha secure many of the sensors.

The moorings are scheduled to be recovered on February 1st, in conjunction with the last IVARS cruise. Until then, we hope for continued good weather and low ice conditions!

New Year's Day

January 1, 2006

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Happy New Year from the IVARS team! We completed our sampling transect and deployed our two moorings on the 30th of December. The transect took the better part of 36 hours and we more or less completed it with virtually no sleep. We've worked together so many times that we are like a well-oiled machine and from our end, it seems like things went off without a hitch. After finishing up and getting about 12 hours of well-earned sleep we spent New Year's Eve cleaning up and getting ready for CORSACS sampling. Just before dinner, the ship broke into some pretty thick ice near Beaufort Island in the western Ross Sea. We were all treated to penguin, whale, and seal sightings and the cameras came out in full force. After dinner, a team surveyed the ice and marked an area where we could go and play! We played Frisbee, stretched our legs, danced, and had a fantastic time while entertaining the local penguin population. All of this entertainment was fueled in part by beer and wine, which are not allowed on the ship but were provisioned ahead of time for this event. One penguin was particularly interested in our Frisbee and literally ran after it when it touched the ground—you have to really wonder what they are thinking! At the stroke of midnight, we set off flares, the ship sounded its horn, and we took our cruise photo. There is nothing quite as amazing as toasting the New Year in full sunlight with Mount Erebus as a backdrop. Some hearty (perhaps a better adjective is foolish) souls continued to brave the elements until 0600 when the ship departed for the next station location. At 0900 the science began anew, with the realization that spending New Year's Eve in such an incredible location was truly a unique way to begin the year.

IVARS meets CORSACS

January 9, 2006

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This year the IVARS program (a five-year NSF-funded program, in which this is our last year) was "merged" with the CORSACS program (Controls of Ross Sea Algal Community Structure), a three-year program also supported by NSF. We occupied the IVARS transect early in the CORSACS cruise, and deployed the IVARS moorings within that transect. The data from the transect will be available to all CORSACS investigators, and the transect also served to "survey" the southern Ross Sea to help determine the site of experimental manipulations to be conducted during CORSACS. The major difference from previous years was that the number of IVARS personnel on the ship was greatly restricted, and we had to do the same amount of work with about half of the people. Luckily we had excellent weather and help from a few CORSACS workers and were able to complete the transect with no problem.

Now we are working on the CORSACS project, conducting experimental manipulations in the Ross Sea. Specifically, we are investigating how iron and carbon dioxide affect phytoplankton assemblage structure. The composition of phytoplankton communities is a major determinant of food web structure and biogeochemical cycles in marine systems, and hence an essential component of the carbon cycle. In experiments in the equatorial Pacific, co-Principal Investigators Jack DiTullio, Phillippe Tortell, and Dave Hutchins found that CO2 was a major factor in controlling phytoplankton composition, with high CO2 waters giving rise to Phaeocystis, while low-CO2 waters were dominated by diatoms. Based on these results, we hypothesized that this factor, as well as the interaction with light and iron, would exert a major control in the Ross Sea (where diatoms and Phaeocystis are commonly found). We are conducting "chemostats"—large cultures in which iron, CO2, and light are experimentally manipulated and in which nutrients are continually provided—that run for weeks on deck. These experiments are very difficult, in large part because of the difficulty of keeping all cultures and inflows free from iron contamination. After all, we are on an iron ship, burnables are incinerated and ash comes out of the ship stacks, and sea spray contains iron. We are presently nearing the completion of the first chemostat, and hope to initiate another one to be completed before the cruise ends.

We also are doing a variety of other measurements, in large part to see if the in-situ conditions of low CO2, low Fe concentrations, and low light generate a specific phytoplankton composition that can be mimicked in our chemostats. We have found a wide range of oceanographic conditions and phytoplankton assemblages, but at this time we can't see if there is a relationship between the various hypothesized controls. Each group also has a series of experiments that are being conducted to assess the various controls of phytoplankton growth and composition, with the VIMS group closely looking at the effects of light.

Today is "hump day," or the half-way point of the cruise. We will stop our science on January 24, in a little over two weeks, and begin packing our gear. The VIMS group will not pack, however, as we have our second cruise to complete after CORSACS. Our time will be used in data analysis, rest, and some "down time" to rejuvenate. We still have a good deal to finish during CORSACS, and look forward to its successful completion and our entry into McMurdo Sound. It is always nice to put our feet on solid ground again after six weeks of ocean motion.

"Hump" Day

January 10, 2006

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An oceanographic tradition is "celebrating" what is known as "Hump Day." Celebrating really means noting or acknowledging, as the work continues unabated. We departed from Lyttleton, New Zealand on December 17, and today is January 11. So we have been gone for nearly four weeks. As we are due at McMurdo Station on January 26, we have passed the half-way point of the cruise, or Hump Day (as in over the hump). This actually occurred during our last transect along 76°S, along which we encountered relatively low concentrations of phytoplankton and extremely dense fog, cloud cover, and snow squalls. We did not see the sun for five days, in fact. Because a few important supplies did not make it to the ship prior to departure, we chose this time to make a relatively short trip towards McMurdo into the ice, where a US Antarctic Program helicopter met us, and dropped essential goods to us. Our trip into the ice found us excellent, clear weather, no wind, and warm (for Antarctica) air temperatures—2°C or 35°F. We were treated to views of numerous grounded icebergs during the transit, as well as myriads of penguins and seals on the ice. Upon the delivery of the materials (including coffee beans from our VIMS colleagues in McMurdo Station; thanks, guys!), we exited the ice and are en route to a new transect along 77°S. We hope the great weather follows us! Only 13 more science days are left, and we are in the midst of some exciting experiments and observations, some of which will be described in reports of the following days.

Zooplankton

January 11, 2006

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Zooplankton are a critical part of all marine food webs, and the Antarctic food web is no different.

In the Southern Ocean much is known about krill, the dominant zooplankton organism that is the food supply for higher trophic levels like penguins, crabeater seals, and baleen whales. However, there is an amazing abundance of other small zooplankton that can be found when sampling the open ocean in Antarctica.

This year during IVARS we have been conducting zooplankton tows to test if there is a reduced abundance of zooplankton associated with the dominance of certain phytoplankton groups. In recent zooplankton tows in the Ross Sea we have observed shelled pteropods (Limacina helicina antarctica), unshelled pteropods (Clione antarctica), numerous amphipod species, jellyfish, ctenophores, pelagic polychaetes, and fish larvae. The pteropods and amphipods are the most abundant animals found in our samples.

To collect zooplankton samples we drop a large weighted net with a closed cup at the end into the water. It descends to 200 meters and then it is brought back to the surface. A flowmeter records the actual volume of water that passes through the net. The animals are collected in the cup and emptied into a bucket. Most zooplankton samples are preserved at sea and brought back to the lab for analysis under a dissecting scope to quantify and identify species, although individual animals are available for analysis and experimentation at sea.

There are many important factors driving the diversity and abundance of zooplankton species we collect; some include temperature, sunlight, daily migration patterns, food availability and season. Overall, there is a rich zooplankton community present in the Ross Sea's cold waters. These organisms are not only interesting to study but also beautiful in form.

Some have hypothesized that pteropods may be the "missing link" in the food web of the Ross Sea. That is, Antarctic krill are largely absent on the continental shelf of the Ross Sea, but are replaced by another species called crystal krill. These are obligate ice species—their life cycle depends on the presence of ice. Because Phaeocystis commonly occurs in the Ross Sea, and because it is large with many compounds that may serve as anti-grazing devices, Phaeocystis is thought to be a dead-end in the food web. If pteropods could ingest and use Phaeocystis, it would provide a major food source to the entire food web.

Additionally, pteropods are major components of the biological pump here—the means by which organic matter, produced during photosynthesis, moves to depth and hence is eliminated from the carbon cycle for long time periods. Pteropods are often found in sediment traps, but the flux generally occurs in May or June, periods when no surface production occurs. Understanding the link between surface production, phytoplankton standing stocks, and pteropods may help improve our understanding of the cycling of carbon on the continental shelf. Our IVARS studies will hopefully provide a small piece of this big picture.

Phytoplankton Rx

January 13, 2006

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One of the aspects that interests us on CORSACS is called the "health index" of phytoplankton, which we call the quantum yield of photochemistry. We use a number of instruments to measure this, but one unusual one that VIMS has is the pulse amplitude modulated fluorometer. It measures fluorescence, the light that is absorbed by a chemical and re-emitted at a different wavelength (similar in many ways to fluorescent lights, in which a chemical such as neon is energized and gives off energy at a different wavelength; in neon's case, the energy is in the red region of the visible spectrum, so neon lights are always red). This fluorescence can be impacted by various environmental factors such as iron, light, and macronutrient concentrations. One of the advantages of measuring this fluorescence is that it allows us to ascertain the health of the phytoplankton assemblage in near real time. Nearly anything that stresses the algae will cause a decrease in fluorescence, but we handle the samples in a uniform manner to better understand the status of the phytoplankton, especially in assessing potential iron limitation. This is important to us since the phytoplankton bloom in the Ross Sea is believed to be seasonally limited by iron.

We also analyze fluorescence on a single-celled basis. This is an extremely laborious procedure that involves putting a sample under a microscope, illuminating a single cell with pulses of light, and measuring the fluorescence of only that cell. Because the phytoplankton are composed of many different kinds of species, this technique can determine the different types of responses to various oceanographic conditions. We are using this to better understand why Phaeocystis antarctica or diatoms dominate in certain areas of the Ross Sea. We also conduct experiments by collecting water, adding various materials (such as iron or inhibitors of the uptake of silicon, an essential component of diatoms) to test the response. Because all phytoplankton are not alike in their responses, and because each has a unique role in the food web and the regional biogeochemical cycle, this approach allows us to understand how efficiently each taxon is operating in a given set of environmental conditions.

The Bay of Whales

January 16, 2006

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After completing another long transect (this one along 77°30'S), the RVIB N.B. Palmer headed south to the ice edge to complete a longitudinal survey of surface-iron concentrations. At the end of this surface transect, we entered the Bay of Whales. This embayment has a special place in the history of Antarctic exploration. It is formed by Roosevelt Island, a landmass under the Ross Ice Sheet, which deforms and slows the movement of ice in its lee (similar to wind in the lee of an island) and continually generates an indentation in the ice shelf. Robert Scott considered it as a depot location during his first voyage to the Ross Sea, although he ultimately decided to establish one on Ross Island, some 600 kilometers to the east. Because of a feud with Shackleton during the first attempt to reach the pole, Scott forbade Shackleton from using Ross Island when Shackleton led expeditions to the Ross Sea, and Shackleton then used the Bay of Whales. Even more dramatic was that Raold Amundsen used the bay as the starting location for his famous and successful trek to the South Pole.

Our trip was far less dramatic and of much shorter duration. We arrived in the Bay early in the morning, and began our observations by completing a zooplankton tow. This was followed by a CTD (conductivity-temperature-depth) cast to collect water for analysis. We then went as far as we could into the Bay. Our intent—to be the ship that has gone as far south as it is possible to do by sea. Last year a New Zealand tourist vessel reported setting that record, and we were determined to establish ourselves farther south. In the end we were successful, and now have the deepest oceanic penetration of any ship.

Two of the CORSACS Principle Investigators (Rob Dunbar of Stanford and Walker Smith of VIMS) visited the Bay of Whales in 1983 on the USCGC Glacier. We did not have the exact recorded position from that year, but will compare it to our recent visit. It will undoubtedly be different, because the ice shelf continually moves northward, driven by the gravitational flow of ice down from the Antarctic Plateau. Large icebergs calve off when the ice shelf thins due to melting at its base and the shelf becomes unstable (seawater is warmer than the ice, even though seawater is at -1.86°C! By melting the ice at the ice-shelf's base, it becomes super-cooled and is less than -2°C, a condition made possible by the depth of the melting, which is ca. 250 meters. Otherwise the water would freeze immediately. If you bring the super-cooled water to the surface, that is exactly what happens!). Therefore, the position of the Bay shifts with time.

The name of the Bay clearly indicates that the early explorers found large cetacean populations in the vicinity. We, unfortunately, saw only one whale, a Minke; we did, however, see many pelagic birds (Antarctic and snow petrels), along with some penguins and a good number of crabeater seals. Many of these higher trophic levels feed on krill species, but our zooplankton collection in the morning was one of the smallest we have seen. It is likely that the Bay serves as a protected location and nesting site, and that feeding occurs farther to the east nearer to shallow regions of high production.

The scenery was indeed dramatic, with steep drop-offs from the ice shelf, numerous icebergs, and dramatic tunnels and bridges in the ice. Although we were impressed by the ice and the location, we soon had to return to our science and began a transit to 75°S, where our last CORSACS transect will begin. We also have to refuel from the fuel tanker when it arrives in McMurdo Sound, but at present we do not know when this will be. Until we need to break off science for this operation, we will continue to sample along the transect.

CORSACS Comes to a Close

January 22, 2006

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The CORSACS cruise is coming to an end. We are busily conducting a final survey of the Terra Nova Bay region in the hope of encountering extremely low CO2 waters. We have seen some low carbon dioxide concentrations here (ca. 150 ppm, in contrast to saturation levels of 370 ppm, indicating very strong biological removal of carbon by phytoplankton and little replenishment from the atmosphere), and hope to find even lower levels. Tomorrow night (Jan. 23) will be our last day of sampling, and after that we will head south towards McMurdo Station.

Terra Nova Bay is the site of two national bases, the major one being manned by Italy (Baia Terra Nova). It is occupied seasonally, and a site for jump-offs into the continent's interior. It is helped greatly by its closeness to McMurdo and depends to some degree on US logistics. It is the site of the deepest spot on the continental shelf, and during winter has very high katabatic winds. These density-driven winds flow off the glacier and over the ocean, and make the bay a site of intensive ice and deep-water production. However, this year we have seen absolutely no evidence of high winds here (see pictures). Indeed, the weather has been spectacular, allowing the science party to enjoy the beauty and grandeur of Victoria Land. In the northern portion of the area is ,2733 meter (8,966 foot) Mt. Melbourne, the only active volcano on the mainland of Antarctica.

Ice continues to plague McMurdo Station. The Russian icebreaker Krasnin was hired by the National Science Foundation to break the ice channel into the station, but under heavy ice conditions it sheared one of its three propellers; as a result, it cannot break ice efficiently. In addition, the channel that it has broken is being compacted laterally, and so the channel remains difficult to pass through. The fuel re-supply tanker is at the ice edge, but due to the conditions of the last 12 miles of the channel, cannot get to the pier in McMurdo. The re-supply ship American Tern is also due to McMurdo in four days, but it remains uncertain if it can reach the pier either. The Palmer, being an ice-breaker, should be able to get to the pier, although it may take much longer than originally intended. We are scheduled to arrive on January 26. Because the Krasnin has another contract and must leave February 2, NSF has asked the Coast Guard to send the Polar Star to McMurdo to assist if needed. Their transit from Seattle is expected to take 30 days, so it remains to be seen how helpful it will be.

The major problem with these delays is that fuel and food must get to the South Pole Station before air flights cease in early February. Right now they are likely going to keep the Pole's season open longer to allow more and later flights for re-supply. As of this moment the Palmer's schedule remains unchanged, and we expect to depart from McMurdo on January 30 to complete the final portion of IVARS.

IVARS: The End, and a Beginning

February 2, 2006

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During the past 48 hours, the IVARS team (Walker Smith, Jill Peloquin, Sasha Tozzi, Jenny Dreyer, and Scott Polk of VIMS; Vern Asper and Colleen Finnigen of Southern Mississippi; and Buzz Ballenger of Santa Cruz, CA) worked around the clock to complete the final IVARS transect. After five years, many disappointments, and numerous successes both large and small, we completed the last CTD station at 22:45 on February 1, 2006. No ground hogs were noticed. With the last filtration, the last data entry, and last nutrient sample, we took time to reflect on all of the effort (and yes, money) that has gone into this program in the past five years. The personnel changed repeatedly, but many of the VIMS community gave their time and energy to the program, and hopefully learned something about both the Ross Sea and the challenges and opportunities of working in the Antarctic. Large portions of 3 Ph.D. dissertations, one M.S. degree, and one Honors Thesis were based on IVARS cruise results and will form a lasting legacy to the efforts of all.

One immediate lesson we learned is that variations among years in the chemical and biological conditions of the Ross Sea are substantial. For example, nutrient removal varies not only in total uptake over the southern Ross Sea, but in the temporal progression of nutrient removal. Variations in nutrient uptake ratios were also observed. These affected, and were affected by, the composition of the phytoplankton assemblages in the surface layer. Understanding the controls of these changes will remain a major focus of the research team in the coming years. In short, what we knew for sure in the late 1990s is no longer a certainty.

We observed some amazing changes in the region. During our study period one of the most massive icebergs ever observed was grounded in our study area, and appears to have altered the physical circulation of the region, which in turn impacted the biological processes. How these changes in the phytoplankton in turn altered the food web and the regional biogeochemistry will be assessed in part in the coming months and years. We observed the "hundred year event" of ice cover in 2002, when ice was kept in the region by another massive iceberg (C-19), and which ultimately resulted in the loss of two moorings. We saw previously unreported secondary blooms in the region, and substantial spatial variations in oceanographic conditions that were poorly appreciated prior to the study. We fully expect many additional findings to result from the analysis of the data.

Our results have also pointed to other questions about the area. We have repeatedly observed large changes in space and time that occur over days and tens of kilometers (so-called mesoscale variations). We have observed that diatoms often rival haptophytes (a non-siliceous form of algae) in abundance and production, and we have seen large concentrations of pteropods, filter-feeding gastropods, that may be a poorly known but critical component of the food web.

So while the end of the fieldwork marks the end of a large effort, it also represents a beginning of data analysis and publication. Already one major publication has arisen from IVARS, with others submitted, and most likely another 10-15 publications will highlight the data collected. It is very unusual to have such repeated time-series data in such a southern location; indeed, it is a unique data set that has broad implications to the understanding of the most productive region in Antarctica.

So this final report is a thank you to all that had a part in the planning and execution—to those who ordered the supplies, arranged for travel, worked long hours, missed us when we were gone, and who paid the bills. It was great fun, hard work, and a challenge that none of us ever would have missed.

2005-2006
Cruise Journal

Click a title below to learn about that day's activities.

Click here for the 2004-05 cruise log.