iiinova — where your digital self keeps evolving

Camille Thomas @camthomas.bsky.social · 08/05/2026

Ending #EGU26 with a meeting with all @namcodigest.bsky.social and @icdpdrilling.bsky.social NamCore colleagues, to summarize all the new results and plan future collaborations. Great science, great people and great organization! See you next year!

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Camille Thomas @camthomas.bsky.social · 04/05/2026

It is #EGU26 kick off and we have a poster up today with @sedimentologika.bsky.social Come say hello and chat about what is best for scientific publishing in X1.149 🔓

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Camille Thomas @camthomas.bsky.social · 06/10/2025

We are at the #IPA-IAL meeting in Aix les Bains, to hear about the latest on lake research. The room is already crowded at the #sedaDNA session @ialipa2025.bsky.social

View from back of a congress room with all seats taken by people listening to science presentation

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Camille Thomas @camthomas.bsky.social · 27/02/2025

Also lake Bourget is truly beautiful !

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Camille Thomas @camthomas.bsky.social · 21/11/2024

@sedimentologika.bsky.social is now part of the Free Journal Network, and we are super proud of it! 🔥 sedimentologika.org freejournals.org

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Camille Thomas @camthomas.bsky.social · 30/05/2024

time to take off for our scientific drilling in Tibet! DNA sampling in lake Nam Co sediments coming up

pile of consumbales (syringes, tubes and tips) to sample DNA on the field

3 pieces of luggae piled up and ready to be taken to the airport

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Camille Thomas @camthomas.bsky.social · 06/03/2024

As a conclusion, while we do not question here the interpretations of fossil stromatolites, our Dead Sea example presents an extreme case where intense arsenic concentrations can be potentially recorded in a fossil record as a result of arsenic detoxification, and not arsenotrophy. 29/n

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Camille Thomas @camthomas.bsky.social · 06/03/2024

Such organic-matter and arsenic-rich lamina were found in Archean stromatolites, like the 2.7Ga Tumbiana Formation, Australia. They were interpreted to bear some of the first occurrences of anaerobic methane oxidation, nitrification, denitrification & arsenotrophy (Sforna et al., 2014) 28/n

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Camille Thomas @camthomas.bsky.social · 06/03/2024

This was likely a rare event, that could not be measured in the water when we sampled it, but which can be recorded in microbial mats. If time and conditions allow, it can then be potentially preserved in an organic lamina when the microbes build up a stromatolite. 27/

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Camille Thomas @camthomas.bsky.social · 06/03/2024

so here we suspect that at some point, a large pulse of arsenic was naturally (?) released in our sinkhole, triggering a protection and detoxification reaction by the microbial mat, that worked hardly to store arsenic into non-toxic organoarsenics, away from the cells, in their EPS. 26/n

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Camille Thomas @camthomas.bsky.social · 06/03/2024

We are not so sure about this. For the 1st time, arsenic is detected to this levels around the Dead Sea, but pulses arsenic are not uncommon in groundwater systems, especially dynamic ones. The Dead Sea sinkholes migration patterns by Abelson et al. (2017) shows how dynamic it can get. 25/n

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Camille Thomas @camthomas.bsky.social · 06/03/2024

This is a quite common phenomenon. Most living cells can perform this operation. So this is not a very sexy result. But it suggests that this mechanism can permit to accumulate arsenic to very high levels in microbial mats of the environment. But why? 24/n

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Camille Thomas @camthomas.bsky.social · 06/03/2024

These results show that microbes living in the mat can get rid of poisonous material by transforming arsenic contaminants into less mobile and toxic organoarsenic molecules we found today accumulated in the Dead Sea mat. 23/n

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Camille Thomas @camthomas.bsky.social · 06/03/2024

By looking at this mat under epifluorescent microscope, we indeed noticed that where arsenic could be mapped, organic matter was prevailing, under the form of exopolymeric substance produced by diverse communities, including filamentous cyanobacteria.

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Camille Thomas @camthomas.bsky.social · 06/03/2024

This tells us that arsenic is not in its most dangerous form, and that most of the mat had a similar composition in terms of arsenic. Also, arsenic has been bond to organic matter by a specific process, yet to be evidenced. 19/n

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Camille Thomas @camthomas.bsky.social · 06/03/2024

In collaboration with Montserrat Filella from Univ. Geneva and Dario Ferreira Sanchez at the Paul Scherrer Institute, we interpreted most of the arsenic to be linked with organic elements, under the form of oxidized arsenic. 18/n

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Camille Thomas @camthomas.bsky.social · 06/03/2024

Arsenic is a Group 1 human carcinogen, contaminating food and ground water. So knowing how it has been mobilized and immobilized in nature is very important. So we tried to investigate under what form it was in the mat by going to the Swiss Light Source Synchrotron. 17/n

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Camille Thomas @camthomas.bsky.social · 05/03/2024

We mapped arsenic more closely in the mat, using XRF and particle-induced X-ray emissions, allowing quantification of numerous elements at high resolution. Arsenic was tied to other elements like Mg, Si, and Mn. This was in collaboration with AIFIRA member Stephanie Sorieul. 14/n

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Camille Thomas @camthomas.bsky.social · 05/03/2024

So we went a little bit further to try to understand what was the nature of this arsenic enrichment. I created a poster explaining the step by step process for a congress. I will detail it below. 13/n

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Camille Thomas @camthomas.bsky.social · 05/03/2024

Covid lock down started. Our microbial communities, although adapted to life in extreme environments could hardly be monitored & and we were missing many supplies. So abandoned part of the project, and redirected to analyses, easier to postpone or delay. Life found its way though 10/n

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Camille Thomas @camthomas.bsky.social · 05/03/2024

We eventually sampled many of them, for their DNA, chemistry, microscopic investigation and laboratory growth. Then went back to our lab in Switzerland at the University of Geneva, and prepared for the next steps. That was January 2020. 9/n

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Camille Thomas @camthomas.bsky.social · 05/03/2024

One pool caught our attention as it had a well laminated and mineralized microbial mat looking like some of the oldest stromatolites recovered from Australia for example. 8/n

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Camille Thomas @camthomas.bsky.social · 05/03/2024

As we visited these sinkholes in the Dead Sea, with D. Ariztegui, A. Agnon and N. Gedulter, we found some of these ecosystems with different t° or salinity, which lead to changes in how the microbes looked like. Some were purple, some green, some aggregated and formed minerals, others did not 7/

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Camille Thomas @camthomas.bsky.social · 05/03/2024

These sinkholes form along the Dead Sea shores and follow the lake retreat mainly caused by human activity pumping water for agriculture and to extract minerals in giant evaporative pans. 10 years ago, the Dead Sea Works company was the 4th largest potash production company in the world. 4/n

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Camille Thomas @camthomas.bsky.social · 05/03/2024

Varied colors are formed by microbial communities developing in pools/sinkholes thanks to the dilution of Dead Sea brine. Salinity is much lower there than in the lake, where no photosynthetic activity can be sustained. Mixed minerals also influence the color (Dead Sea kidney by Tzvika Stein). 3/n

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Camille Thomas @camthomas.bsky.social · 05/03/2024

It started with fieldwork by the Dead Sea shores, where sinkholes are being formed by the circulation of fresher water into the evaporitic subsurface. The lake retreats by ca. 1m per year, leaving halite and gypsum that can be readily dissolved. A lot of springs emerge in those systems 2/n

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Camille Thomas @camthomas.bsky.social · 13/02/2024

Paper acceptance day ! I generally cannot stand my papers anymore when they get to the point of acceptance. But for this one, i feel different! Very happy about it Stay tuned for some combined genomics and synchrotron data on the #DeadSea #arsenic

iéage of a poster summarizing the study discussed in a tweet, representing a rainbow colored road snaking from top to bottom the image though the different methods and approaches used for the study. This poster was presented at a geochemistry scientific congress

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Camille Thomas @camthomas.bsky.social · 31/01/2024

just saw this on @clasticdetritus.bsky.social page Gives a fun overview of your publishing record ! mine seems to be about DEAD stuff 🧟 scholargoggler.com

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Camille Thomas @camthomas.bsky.social · 11/12/2023

Authigenic minerals reflect microbial control on pore waters in a ferruginous analogue by a bunch of great minds working on the Towuti #ICDP project www.geochemicalperspectivesletters.org/article2339/

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Camille Thomas @camthomas.bsky.social · 07/11/2023

It is Swiss #drilling day 🇨🇭 today at the uni. Of Bern, with a suite of wonderful and diverse presentations about drilling-associated research, allowed by the swiss national science foundation, icdpDrilling and IODP

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