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Tom Chalk

@chalkyoceans

Dr Chalk, destined to be a researcher of carbonates. CO2, & ocean-climate links, resident isotope geochemist @exoceanlab.bsky.social, @cerege.bsky.social, France. Equalist, technologist, environmentalist. #climatevegan 🌱. πŸ‡¬πŸ‡§πŸ€πŸ‡²πŸ‡«. πŸ³οΈβ€πŸŒˆ but always with the πŸ³οΈβ€βš§οΈ.

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05.10.2023
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Latest posts by Tom Chalk @chalkyoceans

Part of the #legolab team, lego Jaime and lego Tom start looking at some new lego sediment core. They are surrounded by the tools of their trade; a giant 3D printed foram and lego mass spectrometer.

Part of the #legolab team, lego Jaime and lego Tom start looking at some new lego sediment core. They are surrounded by the tools of their trade; a giant 3D printed foram and lego mass spectrometer.

Watch this space for more #foraminifera, #CO2, and of course... more lego scientists @exoceanlab.bsky.social.

02.03.2026 14:07 πŸ‘ 5 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

Really proud of @jysuarezibarra.bsky.social for his upcoming #MSCA research position with us @climatecerege.bsky.social. Not only a really exciting project to help us find out more about the climate system, but also an excellent career step for a superb young researcher.

02.03.2026 14:07 πŸ‘ 10 πŸ” 4 πŸ’¬ 1 πŸ“Œ 0
Preview
β€˜Don’t go to the US – not with Trump in charge’: the UK tourist with a valid visa detained by ICE for six weeks Karen Newton was in America on the trip of a lifetime when she was shackled, transported and held for weeks on end. With tourism to the US under increasing strain, she says, β€˜If it can happen to me, i...

This story is at once unbelievable and very believable. Come to the US at your own peril under this regime.

21.02.2026 17:32 πŸ‘ 106 πŸ” 38 πŸ’¬ 4 πŸ“Œ 1

Four days later, I think I can finally process this:

I’ve been awarded a Marie SkΕ‚odowska-Curie Postdoctoral Fellowship (#MSCA -PF 2025).

17,066 applications this year. ~9.6% funded.

Still feels slightly unreal.

12.02.2026 20:32 πŸ‘ 14 πŸ” 2 πŸ’¬ 1 πŸ“Œ 1
Preview
Scooping out oceanic COβ‚‚ to make room for more

#CNRSNews πŸ“° Scientists have set up standards for marine CO2 removal, which could enable extra oceanic storage of carbon dioxide and its recovery as carbonate or biomass. Yet further research is needed prior to large-scale implementation

12.01.2026 19:37 πŸ‘ 12 πŸ” 2 πŸ’¬ 0 πŸ“Œ 0
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#exocean advent calendar day 24!
Today we thought it was a good fit to show an image/talk about β€œconception”…
One of the thing we (try to) do best at ExoCean is planktonic foraminifera reproduction. Here two immaculate mummies… 😏

We would like to wish you all a beautiful Christmas Eve!

24.12.2025 13:34 πŸ‘ 11 πŸ” 6 πŸ’¬ 0 πŸ“Œ 1
HMS Challenger

HMS Challenger

#exoCeanadvent Day 23: at exoCean we also look at some old questions: in the late 1800s, during the HMS Challenger expedition, they discovered that you can have a constant rain of shells from above, and still end up with a seafloor that looks like the carbonate budget never existed. Why? Pressure. 🌊

23.12.2025 18:21 πŸ‘ 8 πŸ” 7 πŸ’¬ 1 πŸ“Œ 0

More politicians, policymakers, and companies should be on Bluesky.

22.12.2025 18:15 πŸ‘ 132 πŸ” 14 πŸ’¬ 5 πŸ“Œ 0
Postdoc Matthieu Buisson loads samples into the rack ready for elemental analysis.

Postdoc Matthieu Buisson loads samples into the rack ready for elemental analysis.

#exoCeanadvent Day 22: Winding down for the holidays often means one thing... more mass spectrometry time is available! With our friends in @cerege.bsky.social's #ENVITOP facility, we're making use! Thanks to their equipment we're working on measuring elemental compositions down to the nano-gramme!

22.12.2025 16:28 πŸ‘ 9 πŸ” 5 πŸ’¬ 1 πŸ“Œ 0
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#exocean advent calendar Day 21! The strongest link between all of us is our love for the ocean. Leaving Marseille with a magnificent sunrise reminds us each time we go out how lucky we are to do what we love for a living!
We already have our ship time for the first 6 months of 2026 - exciting!

21.12.2025 19:12 πŸ‘ 7 πŸ” 5 πŸ’¬ 1 πŸ“Œ 0

Here's to #2026! Please don't hold us to any of these...

20.12.2025 17:37 πŸ‘ 6 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0

12 scientific papers πŸ’», 11 months of good weather 🌞, 10⁴ foram babies 🐚, 9 visiting scientists πŸ‘©πŸΌβ€πŸ”¬πŸ‘¨πŸΎβ€πŸ”¬, 8 successful boat missions πŸ›₯️, 7 website visits πŸ™πŸΌ, 6 new hypotheses πŸ’‘...*5 gold rings*...4 defended masters πŸ“œ, 3 #ForCry mass spec methods πŸ”, 2 #Deep-C reactors 🧿...

20.12.2025 17:35 πŸ‘ 7 πŸ” 2 πŸ’¬ 1 πŸ“Œ 1
glorious peacock seducing CEREGE people

glorious peacock seducing CEREGE people

please feed me

please feed me

we love peacocks so much they follow us in our offices

we love peacocks so much they follow us in our offices

#exoCeanadvent Day 19: Friday edition: today’s post is about the peacocks at CEREGE, because it’s Friday and our brains are in weekend mode. They wander around like they own the campus, scream for no reason, and block paths with absolute confidence. Honestly, goals. 🦚

19.12.2025 17:59 πŸ‘ 6 πŸ” 5 πŸ’¬ 1 πŸ“Œ 0

Essential reading for those interested in going carbon negative πŸ‘€. See what @sulpis.bsky.social does for a living and how it connects to @exoceanlab.bsky.social here!

18.12.2025 13:52 πŸ‘ 3 πŸ” 2 πŸ’¬ 0 πŸ“Œ 0
Monitoring, Reporting and Verification for marine Carbon Dioxide Removal Marine Carbon Dioxide Removal (mCDR) methods are being proposed and piloted in Europe. Monitoring, Reporting and Verification (MRV) is a structured process to collect, disclose and independently verif...

Read the European Marine Board report here: πŸ“˜πŸ‘€
www.marineboard.eu/publications...

18.12.2025 12:08 πŸ‘ 3 πŸ” 3 πŸ’¬ 0 πŸ“Œ 1

Net accident you say? Ooops, this net came back looking like it had been mauled by a shark, and I think... Maybe it had. A good, but expensive(!) sample. Sorry @tdegaridel.bsky.social!

17.12.2025 19:51 πŸ‘ 7 πŸ” 2 πŸ’¬ 0 πŸ“Œ 0
Jaime introduces his project and ForCry at a team seminar in Mainz. πŸ“· S. Chaabane

Jaime introduces his project and ForCry at a team seminar in Mainz. πŸ“· S. Chaabane

#exoCeanadvent Day 16: We're getting closer to the holidays, but we don't stop yet. @erc.europa.eu postdoc @jysuarezibarra.bsky.social was out today presenting his work @maxplanck.de in Mainz. @soniachaabane.bsky.social is also visiting to chat with colleagues.

16.12.2025 17:22 πŸ‘ 5 πŸ” 4 πŸ’¬ 1 πŸ“Œ 0
A rack of tiny samples, about 0.5mm in diameter... Here we've custom made some really clean rings to hold them in place... next step, freeze!

A rack of tiny samples, about 0.5mm in diameter... Here we've custom made some really clean rings to hold them in place... next step, freeze!

#exoCeanadvent Day 15: Some plankton are tiny [citation needed?], and for those we need ways to measure tiny (this is a theme you'll hear us talking about a lot). Sometimes just holding samples in place can be hard.... enter the #Cryostage! ❄️

15.12.2025 18:10 πŸ‘ 5 πŸ” 4 πŸ’¬ 1 πŸ“Œ 0
Sometimes you can replace a boat trip with a car trip, ever wondered how much ocean you can get into a Golf?

Sometimes you can replace a boat trip with a car trip, ever wondered how much ocean you can get into a Golf?

#exoCeanadvent Day 14 Footprint reduction: we do lab-based ocean science because we genuinely love it, but also because lab experiments can replace lots of field trips. More control, more insight, and in part, fewer emissions. Bonus: dissolving old sediment cores neutralizes a bit of CO2. πŸ˜‡

14.12.2025 18:04 πŸ‘ 6 πŸ” 5 πŸ’¬ 1 πŸ“Œ 0

#exoCeanadvent Day 13: Time Machine. Travel back in time with us 6 million years. Part of the reason for our work @exoceanlab.bsky.social is to better understand the past through observing the modern, but sometimes you just need some ancient mud..@chalkyoceans.bsky.social recently went to get some!

13.12.2025 16:53 πŸ‘ 4 πŸ” 4 πŸ’¬ 1 πŸ“Œ 0
The exoCean team and friends actively brainstorming on hot topics

The exoCean team and friends actively brainstorming on hot topics

Tiny raclette pan, big ambitions

Tiny raclette pan, big ambitions

#exoCeanadvent Day 12: End-of-year celebration - raclette edition. On the agenda for this team meeting: cheese, cheese, cheese, goals for next year: even more cheese. We’ve officially reached our melting point. πŸ§€

12.12.2025 14:25 πŸ‘ 10 πŸ” 5 πŸ’¬ 0 πŸ“Œ 0
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#exoCeanadvent Day 11: Science makes you do strange things. Meet @astridhylen.bsky.social, a postdoc working with carbonate dissolution in coastal sediments. She recently found herself in the middle of a salt marsh, stirring one of the ponds with a (clean) toilet brush taped to a curtain rod.

11.12.2025 18:26 πŸ‘ 8 πŸ” 5 πŸ’¬ 1 πŸ“Œ 0

Correct! That will come later. I thought I added alt text, but that seems to have disappeared.

10.12.2025 22:53 πŸ‘ 2 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0

There's still much more to come from our trip to Bermuda with @juliemeilland.bsky.social, @thefosterlab.bsky.social and @case4climate.bsky.social. Whilst there, we were all tortured with video interviews... Here's a taster!

10.12.2025 18:14 πŸ‘ 7 πŸ” 2 πŸ’¬ 1 πŸ“Œ 0

100% recommend for fieldwork. See @maxime-felix.bsky.social for details on availability.

09.12.2025 16:57 πŸ‘ 6 πŸ” 0 πŸ’¬ 0 πŸ“Œ 0
Don't eat that! A large foraminifera trying to eat grains of olivine. It soon realised that they weren't food, but had no problems afterwards, so... not poison!

Don't eat that! A large foraminifera trying to eat grains of olivine. It soon realised that they weren't food, but had no problems afterwards, so... not poison!

#exoCeanadvent Day 9: Meet Maxime (again). At @exoceanlab.bsky.social and @climatecerege.bsky.social Maxime has been conducting several experiments focusing on the culture of marine organisms. One project involved culturing foraminifera in the presence of olivine (Mg,Fe)2SiO4, an igneous mineral.

09.12.2025 16:25 πŸ‘ 12 πŸ” 7 πŸ’¬ 1 πŸ“Œ 0

One of many super cool projects started or starting in @exoceanlab.bsky.social. Keep it up Katoo!

08.12.2025 15:25 πŸ‘ 3 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0
Schematic of the Deep-C high-pressure reactor and in situ sensors.

Schematic of the Deep-C high-pressure reactor and in situ sensors.

#exoCeanadvent Day 6: To study the deepest ocean trenches, we’re building reactors that make our lab behave like the deep ocean. Funded by @erc.europa.eu #Deep-C, they will hold cold seawater at ~1000 bar (10km water) so we* watch pressure shape chemistry and biology πŸ”¬πŸŒŠ

*mostly @sulpis.bsky.social

06.12.2025 15:23 πŸ‘ 11 πŸ” 5 πŸ’¬ 1 πŸ“Œ 0
A schematic graph showing global temperature, plotted against CO2. We know CO2 increases temperature, but the how far and how fast are still not totally constrained. Tipping points, or sensitivity changes could impact this relationship in the future, and may have done in the past.

A schematic graph showing global temperature, plotted against CO2. We know CO2 increases temperature, but the how far and how fast are still not totally constrained. Tipping points, or sensitivity changes could impact this relationship in the future, and may have done in the past.

#exoCeanadvent Day 4: Why did we set up this lab? Part I. What is going to happen to climate as CO2 levels go up? @chalkyoceans.bsky.social and @erc.europa.eu project #ForCry look at CO2 in the past to better understand climate sensitivity. Part of this is making better past CO2 reconstructions.

05.12.2025 18:10 πŸ‘ 5 πŸ” 3 πŸ’¬ 1 πŸ“Œ 1

Find this data, and more - in the fantastic paper by Elwyn de la Vega. Boron isotope CO2 reconstructions in the Pleistocene have come a long way... but we still have more to come. Watch this space with @mudwaterclimate.bsky.social and many others!

cp.copernicus.org/articles/19/...

05.12.2025 18:17 πŸ‘ 4 πŸ” 1 πŸ’¬ 0 πŸ“Œ 0