@stever60
⚒️ 🧪Earth scientist / geologist reconstructing past environmental change mainly from lake sediments from Antarctica, Arctic, S. America, Nepal, UK and other places 🏡Cambridge, UK 🏳️🌈 he/him Instagram @antarctic_diary
First step: produce reliable concentrations of key mineral elements in peat by comparing and calibrating high-res XRF-CS data to quantitative ICP-MS subsample data from islands around the Southern Ocean
… eventually allow us to quantify mineral flux through time and spatially across the Southern Ocean - and investigate key mechanisms driving changing SWW & Southern Ocean CO2 absorption/outgassing dynamics
Improving our ability to more-rapidly measure and quantify mineral input and concentrations in peat records from different latitudes at higher centennial-decadal resolutions by applying modern XRF core scanning (XRF-CS) techniques to peat will …
Changes in the mineral content of peat records we’ve collected from the sub-Antarctic islands over the last decade provide a proxy for increased wind intensity and storminess, reflecting local to regional shifts in wind patterns around the Southern Ocean over ~10,000 years
… which is ultimately thought to be reducing the capacity of surface waters in the Southern Ocean to absorb atmospheric CO2
The Southern Hemisphere Westerly winds (SWW) regulate the capacity of the Southern Ocean to absorb or release CO2. Recent warming is thought to have led to an intensification and/or poleward shift in the mean annual position of the core SWW wind belt …
This paper provides a new way to rapidly measure and quantify past changes in the mineral content of peat records from western coasts of several sub-Antarctic islands located in the core Southern Hemisphere Westerly wind belt of the Southern Ocean
View of site HER42PB on the western cliff edge of Isla Hermite, near Cape Horn
A four part figure for Figure 1 from our new paper showing (a) the locations of the four islands we samples peat from in the Southern Ocean, (b) an example surface Core Image and downcore XRF core scanning Ti counts per second downcore from site HER42PB, (c-f) location maps showing sample site on Bird Island, Isla Hermite, Kerguelen Island, and Marion Island
Photo of some peat cores collected from a peat coring site on Crozet Island (credit FDV)
A complicated figure for Figure 4 from our new paper showing a several downcore proxy records from the sampling sites - illustrating the good downcore coherence between high resolution XRF core scan data and ICP-MS subsample data and the conversion of XRF core scan data into quantitative concentrations
Early view of our new high-resolution sub-Antarctic islands peat geochemistry calibration paper in press @Nature Scientific Reports …
www.nature.com/articles/s41...
Spectacular ending to the annual Cambridge Bonfire Night fireworks display tonight …
Collage showing a map of the Shetland Islands in the top left, a map of Loch Flugarth and core sites and sampling locations top right, a sediment core from the centre of the loch bottom left, coring in a small boat on the loch middle bottom, and GPS surveying and measuring retaining sill altitudes bottom right
Short Article for the BAS IceSheet Newsletter Oct/Nov 2025 …
Ancient tsunamis and storms in the Shetlands Islands
See link for article: www.linkedin.com/posts/stephe...
British Antarctic Survey supervisors are involved in 20 Iapetus DTP PhD projects this year - 6 based at BAS, 14 at one of the Iapetus DTP univeristy partners. Full list and how to apply are in this link :
www.linkedin.com/posts/stephe...
Applications are now open for this years’ @iapetusdtp.bsky.social PhD projects … including this one investigating ice sheet and glacier history of the Sør Rondane Mountains in East Antarctica by developing in-situ 14C cosmogenic exposure dating methods - more here:
iapetus.ac.uk/studentships...
A person standing on a moraine which is in front of a mountain. The mountain is in East Antarctica, with a small glacier between the mountain and moraine. The person is using a saw to collect a rock sample from the surface of a boulder on top of the moraine.
A photo taken from a mountain in East Antarctica, with moraines and blue ice in the foreground, and the vast East Antarctic Ice Sheet extending to the horizon. Some small mountains (nunataks) are poking out above the surface of the ice sheet at varying distances.
Applications are now open for a Glasgow-based Iapetus DTP project centred on using in situ 14C to study glacier histories in East Antarctica! tinyurl.com/3ddvynn2 @stever60.bsky.social @uofglasgow.bsky.social @iapetusdtp.bsky.social @bas.ac.uk
Photo of Lake Tilicio in Nepal with an inset core showing our team collecting sediment cores from the lake
Applications are now open for this years’ BAS Iapetus PhD projects … including one working on our Big Thaw project investigating extreme precipitation in Nepal from sediment core and climate data - more details in this link @iapetusdtp.bsky.social @bas.ac.uk
iapetus.ac.uk/studentships...
Collab of @stever60.bsky.social @bas.ac.uk @uniheidelberg.bsky.social #geography
Gravel layer in humic coastal dune.
After a solid week of lake coring and sampling for #storm and #tsunami deposits on the #Shetland Islands, we found this yet undocumented gem 💎 on northern Mainland - a distinct gravel layer inside the coastal dunes. Hoping for good OSL results 🤞🏽
Indeed, Loch Flugarth #ShetlandIslands is a beauty on the inside AND the outside! @stever60.bsky.social @uniheidelberg.bsky.social
Lake coring in the Shetland Islands last week, looking for ancient tsunamis with @drmaex.bsky.social @uniheidelberg.bsky.social @bas.ac.uk
This is Fan Lake on Annenkov Island nr South Georgia - sediments from the top of the lake record were analysed with sediments from >400 lakes around the world to construct a new global temperature calibration model which can be used to reconstruct past changes in temperature over thousands of years
See this link for more details
www.sciencedirect.com/science/arti...
Map showing the location of over 400 lake sediment samples used in this new study
Surface sediments from 400 lakes were analysed for biomarker compounds called branched glycerol dialkyl glycerol tetraethers (brGDGTs), a group of temperature-sensitive bacteria membrane lipids used in past temperature reconstructions - we expand calibration datasets, and evaluate calibration models
A map of the world showing the locations of over 400 lakes whose surface sediments were analysed for biomarker compounds called branched glycerol dialkyl glycerol tetraethers (brGDGTs) are a group of temperature-sensitive membrane lipids found in bacteria that have been widely used in palaeo-temperature reconstruction. The paper expands existing calibration datasets, and evaluates calibration models constructed using a range of statistical modelling approaches
A slide showing Fan Lake on Annenkov Island near South Georgia - sediments from the surface of a core taken from the bottom of the lake were analysed along with sediments from over 400 lakes around the world the construct a new global calibration model which can be used to reconstruct past changes in lake sediments over thousands of years
New exciting new global lake sediment temperature calibration paper and dataset by @geochemem.bsky.social, including the first 5- and 6-methyl brGDGTs measured in lake sediments from Antarctica - eg Fan Lake. See link for details:
doi.org/10.1016/j.qu...
@bas.ac.uk @iapetusdtp.bsky.social
Coring on Loch Flugarth north mainland Shetland - photo taken by Susie who lives in the house on the far right of this view of the loch looking at hills in the distance with a white houses
3 people in a small red boat on Loch Flugarth
View of Loch Flugarth from a large boulder with a rope tied to it towards some hills in the distance
A picture of the farm cat who lives near to Loch Flugarth
Second Scottish lake coring adventure of the summer … this time up to the Shetland Islands looking for ancient storms and tsunamis in lake sediments with @drmaex.bsky.social
the underside of a humpback whale chin sticking out of the ocean. It is covered in barnacles
My whale photo got shortlisted in the Royal Society of Biology @rsb.org.uk Photographer of the Year competition. It is of a whale's chin! Do me a favour and give it a vote here and check out the other amazing photos: www.surveymonkey.com/r/T23CPZC
@bas.ac.uk
Tom Bradwell helping out on the boat
Morning tea at SCENE with Colin Adams, Iain Geldard, Jodie Geldard, Eileen Tisdall, and Tom Bradwell sat around a table in the common area
Colin Adams and Tom Bradwell inflating the raft on the beach at SCENE
Ellen Tisdall carrying a core back to shore along the boat jetty at the end of days’ coring
And a big thanks to our ‘special guest stars’ Tom Bradwell and Eileen Tisdall from University of Stirling and Nicola Dakin from @bgs.ac.uk for all their help
SCENE University of Glasgow research centre where we were based - photo shows the road leading up to the wooden building through the forest
Collection of sediment cores taken from Loch Lomond over the last 2 weeks strapped into the van for transport to BAS and Southampton for analysis as part of Jodie Geldard’s Iapetus DTP PhD with University of Stirling
Final day lunch at the oldest pub in Scotland, the Clachan with Colin Adams, Iain Geldard, Tom Bradwell, and Jodie Geldard (not in photo)
Selfie With Tom Bradwell outside the sign for the Clachan in Drymen, the oldest pub in Scotland (apparently)
A huge thanks to everyone at @sceneuog.bsky.social for hosting us - in particular Prof. Colin Adams for his phenomenal support, & Iain Geldard - we couldn’t have done it without both of you! Jodie Geldard did an amazing job organising the whole trip as part of her @iapetusdtp.bsky.social PhD
Not everyday was like this but we had a couple of flat calm hot and sunny days out on the lake with stunning views across to Ben Lomond and surrounding mountains … which was very nice @iapetusdtp.bsky.social @bas.ac.uk
Loch Lomond at sunset with coring rig moored in sheltered bay at SCENE university of Glasgow research centre
Loch Lomond view from the southern basin across to Ben Lomond
Collecting cores in the middle of Loch Lomond - 4 people capping a surface core retrieved for potential fish eDNA analysis
Early morning calm on Loch Lomond
Some pictures from the last couple of weeks lake sediment coring on Loch Lomond with @iapetusdtp.bsky.social
