SDA Winter Cruise SD050, a pre-cursor(ish) to POLOMINTS

By Mike Meredith

The Scenery in which we’re working. Photo 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.

CDT Deployment. Photo by Mike Meredith

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 !

Mike Meredith
Hugh Venables & Rhiannon Jones
Sean McLoughlin
Grainne Keogh
Rob at the winch controls. Photo by Mike Meredith

SDA Winter Cruise 2025

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!

BIOPOLE Rothera Campaign 2024/25

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.

Alanna and the Dash 7 airplane at Punta Arenas airport (credit: K Hendry)

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.

Alanna in front of the RRS Sir David Attenborough in Ryder Bay (credit: K Hendry)

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.

Sunny day off Adelaide Island (credit: K Hendry)

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

Can glaciers feed the ocean?

Originally posted on the BAS website

29 July, 2024 Arctic

You might imagine glaciers as vast, cold, and lifeless rivers of ice, but they’re far more dynamic and alive than we once thought. Kate Hendry, polar oceanographer at British Antarctic Survey is currently working in the Arctic. Below, she shares some insights from her recent research on these frozen rivers, and their impact on our oceans.

A group of people wearing sunglasses
The team are in the Arctic studying glaciers and their impact on our oceans. Kate Hendry.

Glaciers – vast rivers of ice that flow from ice caps and ice sheets – were once thought to be inert environments, too cold for biology or for chemical reactions to occur. In the past two decades, scientists have discovered that glaciers are teeming with diverse microorganisms and are hotspots for biogeochemical weathering—chemical processes that release essential elements into the environment. As glaciers flow, they grind the underlying rock into a fine “flour,” and the unique chemistry of the waters beneath these ice sheets leads to the formation of new, highly reactive materials. This glacial flour can release nutrients into the environment, acting as a significant source of precious elements for coastal marine ecosystems. While glacial flour has the potential to fertilize crops, it can also harbour toxic metals. We are just beginning to unravel the intricate web of interactions among these elements as they travel downstream.

People crouched down looking at rock
As glaciers flown they grind the underlying rock into a fine “flour” which releases nutrients into the environment. Kate Hendry.

Unveiling the role of silicon

One key nutrient we’re focusing on in our new project, Silicon Cycling in Glaciated Environments (SiCLING), is silicon. Every living organism needs silicon in small amounts, but some, like plants and diatoms (a type of algae), need larger quantities to build their silica-based structures. Glacial flour is rich in reactive detritus that dissolves, releasing biologically available silicon. This means it could be a vital nutrient source for crops and coastal marine systems deficient in silicon.

Through SiCLING, we’re investigating how silicon in glacial flour and fjord sediments is released, interacts with other elements like iron, and changes with global warming and accelerated ice melting.

Our journey begins in Ny-Ålesund, northern Svalbard, in the land of the polar bear. Here, we’re sampling water, flour, and sediments from Kongsfjorden near the UK Arctic Research Station. Using small boats, we collect samples and process them in the station’s labs. Many analyses will be done back in the UK, where we’ll use cutting-edge imaging and geochemical fingerprinting to understand silicon’s interactions with other elements. With all the data we gather, we’ll use new modeling methods to calculate how much silicon glaciers in Svalbard release.

Later this year, we will continue our fieldwork adventure by comparing our Arctic findings to coastal environments off the West Antarctic Peninsula.

A brown river flowing between rocks
Through the SiCLING project, researchers are looking at how silicon in glacial flour is released. Kate Hendry.

Meet the team

I am proud to lead the SiCLING project as the Deputy Science Leader of the Polar Oceans Team at the British Antarctic Survey. Joining me in Ny-Ålesund are Nathan Callaghan from the UK Centre for Ecology and Hydrology and Katie Howe from Dauphin Island Sea Lab, USA. Nathan is working on river chemistry and fluxes, and Katie is joining us as an expert in isotope uptake experiments. Our team also includes Rhiannon Jones and Siobhán Foden from BAS, and Helen Williams, and Helena Pryer from the University of Cambridge.

We’re thrilled to share our progress with you as we delve deeper into the fascinating world of glacial biogeochemistry. If you’re curious to learn more about our findings on silicon and glaciers, check out our latest paper: Detrital input sustains diatom production off a glaciated Arctic coast.

A body of water with a mountain in the background
Glaciers are teeming with diverse microorganisms and are hotspots for biogeochemical weathering. Kate Hendry.

Underwater tsunamis focus of new study

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.

A view of a snow covered mountain.
Sheldon Glacier near Rothera Research Station on Adelaide Island, Antarctica, will be one area of study for the POLOMINTS team

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.

Some observations will be taken from the RRS Sir David Attenborough’s science work boat Erebus

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)