Scripps scientists return from year-long polar drift experiment

Polarstern as seen from the Russian icebreaker Akademic Federov during the search for a suitable ice floe for the MOSAiC observatory in October, 2019. Photo: Jessie Creamean

Searching for a suitable floe is no easy task and often requires a closer look at the ice. The “Mummy-Chair” is used to transport scientists and gear onto the ice when a gangway is not feasible. Pictured here is an ice station from Aug 2020. Photo: Emelia Chamberlain

The Russian icebreaker Kapitain Dranitsyn in Tromso, Norway in late January, preparing to transport the Leg 3 personnel to Polarstern. Photo: Jeff Bowman

The Kapitain Dranitsyn transporting Leg 3 personnel to the Polarstern in February, 2020. The trip was supposed to take 2 weeks, but due to challenging ice conditions the trip took nearly 4 weeks. Photo: Jeff Bowman

A piston bulley prepares a road between the Dranitsyn and Polarstern to enable the exchange of Leg 3 and Leg 4 personnel in early March. Photo: Jeff Bowman

Normally simple science tasks become exceedingly difficult in the polar winter.  Launching the CTD rosette system (an instrument package equipped with sample bottles) required a coordinated effort between crew and science party to prevent instruments and samples from freezing. Photo: Jeff Bowman

Even in summer months, when freezing was not an issue, launching the CTD rosette could be a challenge. A combination of chainsaws, ice corers, the ship’s winch, and a garden hose were used to remove enough ice for a maintainable hole. On Leg 5, the CTD hole had to be rebuilt three times due to ice deformation - resulting in a rather spectacular ice formation near the gangway of the ship.
Photo (left): AWI/Creditless  Photo (right): Emelia Chamberlain.

Once the CTD was back on board, a flurry of activity commenced. Water column work was integral to many of the MOSAiC science teams from physical oceanographers and biogeochemists to ecologists and biologists. This resulted in a very busy rosette. Here, Leg 5 participants sample water collected from 4000 meters to two meters for properties ranging from dissolved gases to microbial community structure. Video: Emelia Chamberlain 

A major goal of the MOSAiC effort was to quantify the exchange of gases between the ocean and atmosphere.  Here a science team prepares to deploy a custom-built apparatus for measuring the concentration of gases in a known volume over the sea ice, critical for determining gas exchange rates. Photo: Jeff Bowman

Science installations were scattered around Polarstern to provide additional opportunities to collect water, make atmospheric measurements, and run experiments. Space was always at a premium at these sites. Photo: Jeff Bowman

A view of Polarstern and distributed ice camp installations from weather balloons to autonomous instruments in Sept. 2020. Photo: Emelia Chamberlain

Science parties working on the ice had to be vigilant at all times for polar bears; a real threat but also a special experience for those fortunate enough to see them.  Here Scripps Oceanography scientist Jeff Bowman stands watch for a team preparing their on-ice science installation. Photo: John Cassano.

During the summer legs, the need for these precautions became exceedingly clear with a multitude of bear visits. Such sightings often forestalled any planned work for the day and necessitated an evacuation from the ice. From the safety of the ship we could watch as they investigated the camp before eventually moving on to better hunting grounds. Here, a young male explores our ice floe in Sep 2020. Photo: Emelia Chamberlain

Another threat to ice work was fog, common in the Arctic summer. In July, there were several days where science parties were called back from the ice due to low visibility. Here is the view from relatively close to the ship on one such day (08/27). Photo: Emelia Chamberlain

The ice was in constant motion, even in the depth of the polar winter.  During Leg 3, cracks through the center of the MOSAiC observatory necessitated a fast response by the science party and logistics personnel to save equipment and data. Photo: Jeff Bowman. 

At times the movement of the ice created large expanses of open water even as temperatures plunged far below 0. During polar winter, these regions of open water quickly refroze, often producing fields of frost flowers (right) that were quickly consumed as the ice pack reconsolidated. Photo (left): Jeff Bowman. Photo (right): Lianna Nixon

During the summer, these expanses of open water remained liquid as fresh meltwater poured in, capping the seawater below with a layer of freshwater. This stratification created a unique sampling opportunity for studying the upper 100 cm of the water column. The greenish tint to the water comes from an abundance of phytoplankton just below the surface during this bloom season. Photo: Emelia Chamberlain

As fall approached and the weather shifted, new ice began to form again. Here (left), Scripps scientist Emelia Chamberlain and AWI Scientist Dr. Allison Fong collect surface ice and water from one of these refrozen leads. Note the delicate skeletal layer (right) of new ice formation. Given enough time, this ice could form part of next year’s first year ice pack - however the lead where this particular ice came from was consumed by a ridge a few days after this September sampling event took place. Photo (left): Lianna Nixon. Photo (right): Emelia Chamberlain

The shifting sea ice created challenges for the ship’s crew, who were responsible for maintaining power to science installations on the ice, and the position of the ship relative to the ice floe. Moorings were frequently broken, and power cables often damaged as the ship and ice shifted around each other. Photo: Jeff Bowman

Sectioning sea ice cores during the winter months required careful attention to detail during long hours kneeling in an open tent.  Scripps scientist Jeff Bowman and AWI scientist Laura Wischnewski section ice cores in early April. Photo: Eric Brossier.

During the summer months, it may have been warm enough to allow Emelia to work outside the tent (left) but heavy ponding around the ice coring site yielded another challenge to collecting ice core samples from the time series site (right). Bridges often had to be built on the fly to get personnel and gear to the site.  Photo (left): Lianna Nixon. Photo (right): Emelia Chamberlain

Beneath the ice, the ice-corer plunges through, pulling up what will be a perfect cylinder of ice sample for processing. Sometimes it’s easy to forget that the only thing between you and 4000 meters of open ocean is a 1-2 m matrix of frozen water. Photo: Lianna Nixon.

Due to unforeseen travel complications with the outbreak of the COVID-19 pandemic, R/V Polarstern ended up spending quite a bit of time near Svalbard, Norway. Including for mid-expedition re-fueling (right) and the transfer of personnel which brought Scripps scientist Emelia Chamberlain onboard in May 2020 (left). This transfer necessitated crew operated small boat operations - a stark contrast to the dark, on-ice transition which Jeff experienced in February (photo above). Photo (left): Lianna Nixon. Photo (right): Emelia Chamberlain

R/V Polarstern also ended her journey in Svalbard, when she paused on the way back to home port of Bremerhaven to drop off supplies and facilitate early re-packing of the ship. Here, a couple of ecologists pause to admire the view in the midst of hectic cargo operations. Photo: Emelia Chamberlain

Upon the return to Bremerhaven, a socially distant,  boat led welcome home celebration (including Scripps scientist Jeff Bowman)  followed the RV Polarstern (and Scripps scientist Emelia Chamberlain) into harbor. A wonderful conclusion to a successful field campaign. Photos: Emelia Chamberlain