Icebergs and snow in King Edward VII Land. Photo:Craig Stevens.
Ross Sea Voyage Update #7: Cape Colbeck & King Edward VII Land
We’ve just finished working in the Cape Colbeck Area, the northeast limit of the Ross Sea embayment. This is likely one of the critical gateways for the Ross Sea continental shelf area, as it is downstream from the hot glaciers of the Amundsen Sea. As if to prove the point, the region is strewn with very large icebergs, many likely spawned in the Amundsen Sea.
At the same time, the deeper layers of sea water in close by the coast are the wildcard in the pack – modified Circumpolar Deepwater (mCDW) reaches temperatures above zero. If this enters the Ross Cavity system in increased volumes, then the present rough equilibrium will change. As it stands, the mCDW flow rate onto the shelf and into the cavity are poorly quantified.
In science activities, we’ve conducted a sequence of CTD stations, some coring work, zooplankton sampling, acoustics, as well as three Italian Argo deployments.
Gliders
Jasmin McInerney deployed NIWA’s ocean glider, Manaia, for the second time. While our first attempt near the Ross Ice Shelf front ended prematurely, it did give us confidence in the glider ballast, so we were able to deploy direct from the ship. This, and the initial checks, went well, and we sent it off for several days survey work in the region. Meanwhile, we completed our CTD casts and then sat behind Cape Colbeck from incoming weather (30 knot winds to the west of us).
The glider has the standard conductivity and temperature sensors, and also some biological and particle size sensors. The initial results coming in via satellite are very exciting, with a number of layers and come correlations between the physical and biological parameters. These data provide a counter-point to two Italian gliders working on long south to north transects farther west from us.
Presently, we are remotely navigating Manaia around fast-moving patches of sea ice, with help from the Wellington-based glider pilots at NIWA (Eleanor Haigh and Cassandra Elmer). This again demonstrates the usefulness of the remote internet connectivity, with WhatsApp messages bouncing between shore and different places on the ship.
Craig Stewart and Jasmine McInerney preparing the glider for deployment. Photo: Lana Young.
The NIWA ocean glider, Manaia, being deployed in the Ross Sea. Photo: Lana Young.
Marine ecology
Dr Alina Madita Wieczorek is combining acoustic survey data and eDNA techniques to look at fish species and community structure. There’s a long history of using acoustics to detect fish and identify fish species. By combining this with eDNA sampling from the CTD rosette bottles deployed close(ish) to acoustic targets, Alina is trying to improve our understanding of higher tropic levels in the region.
Environmental DNA (eDNA) classifies the mix of genetic material sampled when a volume of water is collected. eDNA can be used to describe the community of species, or to target a particular species. It’s challenging getting the acoustics and CTD to match up on such a fast-moving voyage, so this trip has been an opportunity to develop ways to blend sampling approaches.
Alina filtering eDNA samples in the wet lab. Photo: Lana Young.
A short history of the Laura Bassi
The RV Laura Bassi icebreaker is named after Professor Laura Maria Caterina Bassi Veratti (1711–1778), the first woman to become a University Professor. The ship was designed as a base resupply vessel but has a long history of providing a platform for ocean research as the British Antarctic Survey ship, Ernest Shackleton.
The Italian Antarctic programme, Programma Nazionale di Ricerche in Antartide (PNRA), bought the vessel in 2019 and have invested significant funds in improvements. The ship has a new CTD “Baltic Room” and hydrolab, as well as paired wet and dry labs, along with several lounges each with a different flavour, function - and colour. It is a ship that, while clearly not new, feels comfortable to live and work in, with a variety of spaces connected by the inevitable maze of corridors.
It is a rather singular experience to be inside the ship as it forces its way through pack ice – the feeling is like a combination of Wellington-level aircraft turbulence and the loudest thunderstorm you’ve yet encountered.
Smashing through the ice on the RV Laura Bassi. Photo: Lana Young.
Workshops & collaboration
Our weather-enforced stay in the lee of Cape Colbeck lasted more than two days. We kept busy with data archiving, plus a number of impromptu workshops on topics ranging from python and GIS through to origami!
We also held a workshop with the ship-board Early Career Researchers (ECR) who are receiving support from MAC3 Impact Philanthropies. This generous contribution is enabling the MAC3 Antarctic Fellows (a mixture of post-doctoral researchers and PhD students from both New Zealand and Italy) to advance their Antarctic research careers. At this workshop, everyone’s work on the voyage was introduced and we discussed what the big-picture outcomes might be. We homed in on specifics that could be attempted during the voyage, how to collaborate, and what would be required after.
MAC3 Antarctic Fellows and senior researchers. Photo: Lana Young.
Heading westwards
We now start the return phase of the voyage, sampling as we head westward along the continental shelf edge, with upcoming stops at Iselin Bank and then the Victoria Land region. The weather is looking reasonable, at least for us to get across the Ross Sea. The next weather front will limit the time we can work in the open shelf region.
Our first task upon leaving Cape Colbeck is to recover the ocean glider Manaia. So, we are getting our shore team prepared, looking closely at sea ice trajectories and trying to weave a path with the vehicle. We need to rendezvous close by to the ice for protection from the swell, but not so close that the glider rises into pack ice, which would be less than ideal.
Stay tuned…
Origami penguin, from an impromptu workshop during bad weather. Photo: Craig Stevens.
This update was sent from the ship by New Zealand voyage leader Prof Craig Stevens and revised by the New Zealand-based communications team.