Originally posted on the BAS website

By Mike Meredith

Professor Mike Meredith is an oceanographer at British Antarctic Survey. He concludes a first of its kind science cruise on the RRS Sir David Attenborough conducting research in the polar winter. 

Winter in Antarctica is typically the preserve of the few hardy souls who “winter over” at the research stations scattered across the icy continent. But this year, I’ve had the extraordinary privilege of spending time in the Southern Ocean aboard the RRS Sir David Attenborough during the Antarctic winter – a rare opportunity that has yielded some fascinating scientific insights.

Antarctica may seem remote, but its influence stretches across our entire planet. The melt from its vast ice sheet contributes to rising sea levels globally. Changes in ocean circulation and sea ice affect climate patterns worldwide. Even shifts in the Southern Ocean’s chemistry and biology ripple through ecosystems thousands of miles away. While we’ve established these connections scientifically, we still need to understand the detailed mechanisms controlling these processes and how they might change in future. This knowledge is crucial if we’re to take meaningful action now to minimise negative impacts and prepare for inevitable changes.

Most Antarctic expeditions happen during the austral summer when conditions are relatively forgiving – warmer temperatures, minimal sea ice, and those famous endless daylight hours. But some critical processes function very differently during winter months. Glacier melting patterns change, nutrient delivery to the ocean shifts, and the growth of plankton – the foundation of the marine food web – follows different rhythms. Gathering winter data is challenging when you’re facing hostile weather, extensive sea ice, and perpetual darkness, which makes our expedition particularly valuable.

Even in these early stages of analysis, our winter expedition has revealed some intriguing findings. We’ve mapped the seabed near important glacial systems with greater precision, improved our understanding of how ocean processes drive wintertime glacier melting, and begun exploring how these glacial systems might actually help fuel marine life. There’s still extensive work ahead to fully analyse everything we’ve collected, but the value of conducting these rare winter expeditions is already crystal clear.

Beyond the science, being here has been an extraordinary personal experience. The brief winter days create extended twilight periods where sunrise and sunset blend together, painting the ice and ocean in spectacular colours. On clear nights, the dark skies reveal stunning views of stars and the Milky Way, unimpeded by light pollution. We’ve witnessed glaciers calving icebergs right before our eyes – a powerful reminder of the dynamic nature of this seemingly frozen landscape.

I was surprised by how much wildlife we encountered, possibly due to this winter’s unusually light sea ice cover. During just one day of our southbound journey, we spotted over a hundred humpback whales. We’ve also had frequent visits from inquisitive seals, coming to investigate our scientific equipment in the water. Their company was particularly welcome during the long, dark winter nights!

This winter research expedition to Antarctica has been both scientifically valuable and personally transformative. We’re returning home not just with new scientific knowledge, but with a deeper appreciation for this remarkable place – a frozen wilderness that, despite its remoteness, connects to all our lives through its profound influence on our shared planet.

By Mike Meredith

Science on the British Antarctic Survey’s research vessel RRS Sir David Attenborough cruise SD050 has now entered full swing, with sequences of oceanographic measurements close to the Sheldon Glacier near Rothera, near Blaiklock Island, and adjacent to the Horton and Hurley Glaciers. This cruise is a rare wintertime expedition with the ship, and affords us an excellent opportunity to further our understanding of how glaciers impact the ocean, and vice versa. It contributes to a number of scientific projects, including serving as a precursor the main POLOMINTS fieldwork that starts next season.

During our transit south to Rothera, we took the opportunity to make measurements in some important field sites along the way, including Börgen Bay on Anvers Island. This was the location where we witnessed a major glacier calving event some years ago, with bursts of rapid and intense ocean mixing as a result – the occurrence that led to the POLOMINTS project. We were surprised to again witness a calving event in Börgen Bay, albeit a smaller one, since such calvings are much more frequent in summer. We’ll be examining the data we collected there closely to look for the impacts on the ocean, and to better understand the seasonal differences in such effects.

One of the main instruments we are using on this cruise is a Conductivity-Temperature-Depth (CTD) system, which is lowered from the ship to near the seabed, and which provides us with vertical profiles of key ocean variables that we’re interested in: temperature, salinity, chlorophyll concentration, and so on. We’re also collecting water samples for analysis in the ship’s laboratories, with some being saved for analysis back in the UK, and additionally will be collecting sediment samples. Taken together, these data and samples will help progress our understanding of how glacier melt and calving affects the ocean, and how nutrients fuel the growth of life in the sea. Ultimately, the science will contribute to our understanding of how the ocean around Antarctica impacts climate and the ecosystem, with the wintertime nature of these data will making them especially valuable.

We are most grateful to the outstanding work of the officers and crew of RRS Sir David Attenborough for supporting this science !

Cruise SD050 includes some pre-cursor science to the major POLOMINTS field programme that starts in January 2026. ITV News are reporting from SD050, including with POLOMINTS scientists.

The article can be found here.

By Mike Meredith

RRS Sir David Attenborough winter cruise SD050 is currently on transit south toward Rothera and Ryder Bay, which will be our main POLOMINTS field site next summer season. During our transit, we called into Börgen Bay on Anvers Island, to take advantage of the opportunity to collect some water samples and underway ocean measurements. This is an especially interesting location for us, being where we witnessed the major glacier calving event some years ago that led to our discovery of calving-induced internal tsunamis, and the POLOMINTS project overall.

We studied the glacier in Börgen Bay for several hours while collecting measurements, during which we witnessed a significant calving event. This was surprising and fortuitous, since glacier calving is typically much more frequent in summer. We continue to learn and build up our understanding of these important dramatic events!

Originally posted on the BIOPOLE website

In the early morning of December 20th Kate Hendry (BAS) and Alanna Grant (CEH) boarded the British Antarctic Survey’s Dash 7 airplane at Punta Arenas airport to make the five-hour journey across the Drake Passage to the West Antarctic Peninsula. They were making their way to Rothera Research Station for the BIOPOLE project.

The overall aim of the BIOPOLE Rothera campaign was to assess the flux of organic and inorganic nutrients into Ryder Bay, the glaciated bay near Rothera Research Station. Kate and Alanna worked together in 2023 during the first BIOPOLE Svalbard fieldwork season, but faced very different conditions this time around off the West Antarctic Peninsula.

Whilst the northern fieldwork involved extensive river sampling, of glaciated and non-glacial river systems, the freshwater inputs into Ryder Bay are much harder to access. They’re hoping to be able to sample surface meltwater runoff later in the season, as the summer months progress, but in the meantime will be sampling seawater and using isotope geochemistry to unpick the meltwater contributions.

As well as characterising freshwater inputs, the team have been working with the Rothera Time Series (RaTS) project, together with Rothera Ocean Scientists Alice Clement and Sean McLoughlin, to sample marine waters within Ryder Bay. RaTS has been operating since 1997, and is an almost unique long-term observational dataset, especially important as data are collected year-round (not just in the Antarctic summer, when access is more straightforward).

The BIOPOLE fieldwork is being carried out in collaboration with NERC-funded project SiCLING. Kate will be joined by SiCLING team members later in January to carry out sampling of marine sediments and waters.

The BIOPOLE/SiCLING team would like to thank Allie and Sean (Rothera Ocean Scientists), and the rest of the marine team. Thanks also to everyone at Rothera Research Station for all their support.

The author of the article – Kate Hendry from British Antarctic Survey and Alanna Grant from UK Centre for Ecology & Hydrology

Originally posted on the BAS website

An international research team, led by British Antarctic Survey (BAS), has been awarded £3.7M to advance a ground-breaking study on how underwater tsunamis are triggered by glacier calving around Antarctica.

The scientists will analyse how these underwater tsunamis contribute to the mixing of ocean waters, a process that plays a critical role in shaping global climate systems, the Antarctic Ice Sheet, and marine ecosystems. This week, scientists from the project, called POLOMINTS, are meeting at the BAS headquarters in Cambridge to finalise plans for the project, which promises to shed light on this newly discovered phenomenon.

The research will build on recent findings that challenge traditional beliefs about the forces driving mixing in Antarctic waters. Historically, winds, tides, and heat loss were thought to be the primary drivers of oceanic mixing around the continent. However, the team recently identified that calving glaciers can initiate underwater tsunamis—multi-metre waves that travel rapidly from the ice, and generating powerful bursts of ocean mixing. Initial calculations suggest these tsunamis could rival the impact of wind-driven mixing and play a larger role than tides in redistributing ocean heat.

POLOMINTS is led by oceanographer Professor Mike Meredith from BAS. He says:

“We’re excited to explore this uncharted scientific territory. By learning more about underwater tsunamis and their influence on ocean mixing, we can refine ocean models, which in turn will help project future climate scenarios more accurately. This knowledge is crucial for the global community as we all grapple with the complex impacts of climate change.”

To investigate the extent and effects of these underwater tsunamis, the team will use advanced technology, including robotic underwater vehicles and remotely piloted aircraft, to gather data near calving glaciers, where humans cannot go. They will also employ deep-learning algorithms to analyse satellite data, and computer simulations to model the generation and spread of these tsunamis. These cutting-edge methods will allow the researchers to assess the impacts of intense mixing on factors such as ocean temperature, nutrients, and marine productivity – all of which are critical to our climate and ecosystems.

The Scottish Association for Marine Science (SAMS) is a key partner in the project. Professor Mark Inall from SAMS says:

“Whilst we have many images of icebergs calving from glaciers, and have studied internal waves within the ocean interior, we know next to nothing about how calving generates these large waves hidden from sight below ocean’s surface. POLOMINTS will break new ground in our knowledge of how crumbling ice sheets stir the coastal oceans of polar regions.”

Professor Kate Hendry from BAS co-leads the project and concludes:

“Our research as part of this project will be a key step toward filling critical gaps in our understanding of Antarctica’s influence on the global climate.”

POLOMINTS is a collaboration led by British Antarctic Survey, and includes the Scottish Association for Marine Science, the University of Southampton, the University of Leeds, the National Oceanography Centre, the University of Exeter, and Bangor University. International partners are from the Scripps Institution of Oceanography, the Institute of Geophysics of the Polish Academy of Sciences, the University of Delaware, and Rutgers University.

POLOMINTS is funded by the Natural Environment Research Council (nerc.ac.uk)