An iceberg in Robertson Bay. The horizon is filled with peaks and glaciers on one side and bergs, sea ice and sky on the other. Photo: Craig Stevens
Ross Sea Voyage Update #11: Robertson Bay
We’ve departed the Antarctic continental shelf heading north, and the weather is okay…for now.
After much talk over the last week about the possibility, we managed to get into Robertson Bay. This wedge-shaped bay sits in the lee of Cape Adare, at the corner of the Ross Sea. As the surface flows in the region blast past the knife edge of the Cape, there’s exchange with Robertson Bay, and so sediment cores provide a record of past conditions.
This is also the location of one of the largest Adélie penguin colonies on Earth – the colony at Ridley Beach, just south of the cape. In addition, Borchgrevink's Hut, the first structures erected in Antarctica, are located just to the south of the colony.
Icebergs everywhere in Robertson Bay. Cape Adare is to the right and the scene is strewn with giant ice slabs silently drifting by. Photo: Craig Stevens
I’d seen quite a bit of data from Robertson Bay, as we maintained a couple of moorings in the bay a few years back – data that ended up in Olivia Truax’s (University of Canterbury) PhD thesis and research. But this was my first visit and there’s nothing quite like this remarkable place. It looks to be very protected from southerly storms, but there’s a pass to the south that is quite low, so the place can get scoured by extreme winds. But these weren’t the conditions on the day we came through. We had flat seas and little wind as we slowly worked our way into the bay through sea ice and many icebergs.
This was a great illustration of the complexity of sea ice and how rapidly it can change. These scales and processes are being examined as part of ASP Project Four: Sea Ice and Carbon Cycle Feedbacks.
Once we were well inside the bay, the University of Otago sedimentary team of Meghan Duffy and Luisa Fontanot undertook two sediment multi-corer deployments in rapid succession. This was very pleasing, as the gear has been challenging to deploy in rough weather; the perfect conditions enabled quality samples to be taken. A long, but satisfying day of sub-sampling ensued and the results were clearly rich in life, with all sorts of species captured in the near-surface mud.
Otago University multicore team in action. Photos: Lana Young
We took advantage of the improved internet and were able to have a conversation with Television New Zealand's Breakfast show. In addition, the MAC3 Impact Philanthropies NZ-Italy early career researcher team got to meet online with the donor and some great discussion took place.
From Robertson Bay we surveyed south along the coast, past the remarkable Possession Islands. This group of islands, around 10km off the coast of Cape Adare, include some amazing stack-like features. They’re home to Adélie penguins, skua and grounded icebergs.
6am CTD operations for seeps profiles. Photo: Craig Stevens
In yet another example of why you send scientists out into the wild, whilst driving past the island group, gas was seen bubbling to the surface. We checked in (thanks to great internet connectivity) with Dr Sarah Seabrook who has Antarctic Science Platform Opportunity Funding to examine seafloor gas seeps in the region. We then returned to the location and spent some time surveying the area with acoustics and undertaking CTD/water column sampling.
Our last tasks on the Antarctic continental shelf were some multibeam (mapping the seafloor) and CTD work towards the west from Cape Adare. This region, connecting the Ross sector and the East Antarctic, is the focus of international collaborations looking at ways to connect different datasets from different national programmes. This was led by Australia’s Dr. Petra Heil in a journal publication last year. We are looking to expand the description of how these datasets can combine, and now can include our Italian colleagues in the development of plans. This will be presented at the SCAR Open Science Conference in August 2024.
And now we head north for a week on the transit back to New Zealand.
This update was sent from the ship New Zealand voyage leader Prof Craig Stevens and revised by the New Zealand-based communications team.
One of the Possession Islands and the Heritage Expeditions vessel. Photo: Craig Stewart