The Amoeba Lab

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FYI, Academia.edu has changed its terms of service to give an irrevocable worldwide license for anything uploaded to its site to be used for generative AI. I do not consent to this and have pulled all my papers.

Ice sheets big and small - Nature Geoscience Ice sheets can be extremely sensitive, or remarkably resilient, to environmental perturbations. Reconstructions of past ice sheet variability help identify what controls their stability and how they m...

Ice sheets big and small
www.nature.com/articles/s41...

Scientists Solve a 66-Million-Year-Old Climate Mystery That Changed Earth Forever Scientists have uncovered a surprising mechanism that may explain how Earth cooled dramatically after the age of dinosaurs. Scientists have solved a 66 million-year-old mystery, explaining how Earth s...

"the drop in calcium closely matched the slowing down of seafloor spreading – the volcanic process that continuously creates new ocean floors" ⚒️
scitechdaily.com/scientists-s...

Thank you - will do! And I hope to catch up in person at Goldschmidt if you'll be there

I of course very much appreciate your fascinating paper, and am really excited that we seem to be converging on a mechanistic understanding of the drivers of CO2 on long timescales. We have our own Mg isotope paper in the works in which your work will certainly get a mention!

precisely constraining the [Ca]-CO2 correlation over the Cenozoic, and exploring what needs to be true for [Ca] to be a CO2 driver; if the SiW-climate slope is steep, no change in [Ca] can drive CO2. What we crucially argue for, I think for the first time, is that this may not be the case.

Thank you, much appreciated! I'd only add that an association between SW chemistry & climate goes back at least to GEOCARB, & we cite several of those papers.
The key difference cf. previous work, aside from a new method of reconstructing SW chemistry at a resolution required assess causality is..

Paleoclimate pattern effects help constrain climate sensitivity and 21st-century warming | PNAS Paleoclimates provide examples of past climate change that inform estimates of modern warming from greenhouse-gas emissions, known as Earth’s clima...

Really excited to see this paper out!! Led by @vtcoop.bsky.social we show that if you use cold and warm paleoclimates together, you can reduce uncertainty in Earth's climate sensitivity by quantifying the pattern effect and more precisely constrain future climate change www.pnas.org/doi/10.1073/...

Earth with a greenish tint, showing North and South America against a dark background.

A person in a hard hat and orange safety vest examines a rocky hillside, using a tool to inspect or collect samples. The terrain is rugged and the sky above is clear.

Rows of tiny, translucent, spiral-shaped shells scattered on a black background.

Our scientists have unravelled a 66 million-year-old mystery behind how our planet transformed from a tropical greenhouse to the ice-capped world of today.

Read more: tr.ee/dPOe9u

@amoeba-lab.bsky.social | @sotonoceanearth.bsky.social | @russellgroup.bsky.social

And suggests that SFS changes may be responsible for the majority of the Cenozoic CO2 decline, not only via the direct effect on degassing, but also via the changes that the associated calcium change has on ocean-atmosphere carbon partitioning.

A graph showing that changes in the rate of sea floor spreading and the concentration of calcium in seawater are qualitatively similar over the Cenozoic.

Causally, comparing our composite seawater calcium curve to recent estimates of changes in sea floor spreading qualitatively indicates that this process may have been the key driver of seawater chemistry change over the Cenozoic:

A multi-panel figure presenting a carbon cycle box model driven by changes in the silicate weathering rate and the concentration of calcium in seawater. Both processes may result in large CO2 changes, depending on how silicate weathering is parameterised in the model.

While we cannot unambiguously determine whether this relationship is causal, we use a carbon cycle box model to show that calcium may - in and of itself - have been an important, or even the key, driver of CO2, via the effect it has on CaCO3 export and preservation:

A graph showing that the concentration of calcium in seawater and the concentration of CO2 in the atmosphere were closely correlated over the Cenozoic

We show that the concentration of calcium in seawater is tightly correlated with atmospheric CO2 over the last 56 million years:

We're delighted to announce our latest paper, which argues that seawater chemistry changes may have played a key role in driving the long-term carbon cycle:
www.pnas.org/doi/10.1073/...

Paleolatitude.org 3.0 is online!

At what latitude was your backyard in the time of the dinosaurs? The answer is a simple mouse click away, and now also if your backyard lies one of the world's big mountain ranges!

Paper Alert❗️We present the first Oligocene record of orbital variability in abyssal ocean temperature based on benthic foraminiferal clumped isotopes. Temperature changes up to 4 degrees C with a 110 kyr pacing, indicating Antarctic ice-volume at this time was less dynamic than previously thought.

Thermal and Non‐Thermal Controls on Benthic Foraminiferal Mg/Ca, Sr/Ca, B/Ca, and Mg/Li: Global Core‐Top Compilation, Revised Calibrations, and Application to the Geologic Record We compile ∼1,500 core-top benthic foraminiferal Mg-Sr-B-Li/Ca measurements from five species and one genus to produce new calibrations Many benthic foraminiferal elemental systems require multiv...

new paper led by Andressa Nauter-Alves assessing controls on trace elements (Mg, Sr, B, Li /Ca) in multiple species of benthic foraminifera using a large compilation of coretop samples (>1500 sites).

dx.doi.org/10.1029/2025...

GitHub - dbjevans/ElCaRBenthic Contribute to dbjevans/ElCaRBenthic development by creating an account on GitHub.

Data processing code available here:
github.com/dbjevans/ElC...
The database and all data analysis code here:
zenodo.org/records/1754...

Benthic foraminifera B/Ca and Sr/Ca-derived Omega/[CO32-] reconstructions over the last 150 kyr for site VM28-122 (Caribbean)

Perhaps most usefully, we also provide a data processing tool that can solve multiple trace element datasets to simultaneously reconstruct temperature and Omega/[CO32-], while fully propagating all sources of uncertainty. (VM28-122 B/Ca + Sr/Ca as an example)

The quality of multivariate benthic foraminifera temperature and saturation state calibrations assessed via inverse prediction intervals.

Including fully propagated uncertainties, and highlighting which combinations of species-elemental systems can produce palaeoceanographic reconstructions with the lowest uncertainty:

A compilation of benthic foraminifera trace element data plotted against temperature, saturation state, and DIC concentration.

Almost ~2000 Mg, B, Sr, and Li/Ca data points facilitating new global core-top Mg/Ca, B/Ca, Sr/Ca, and Mg/Li calibrations for six key species.

Thermal and Non‐Thermal Controls on Benthic Foraminiferal Mg/Ca, Sr/Ca, B/Ca, and Mg/Li: Global Core‐Top Compilation, Revised Calibrations, and Application to the Geologic Record We compile ∼1,500 core-top benthic foraminiferal Mg-Sr-B-Li/Ca measurements from five species and one genus to produce new calibrations Many benthic foraminiferal elemental systems require multiv...

Absolutely delighted to announce the publication of our benthic foraminifera trace element compilation + revised multivariate calibrations: Nauter-Alves et al. (2025):
agupubs.onlinelibrary.wiley.com/doi/10.1029/...

With @willerstorfi.bsky.social @mudwaterclimate.bsky.social and others

PhD Topics - Entry September 2026 — The Foster Lab This year we are involved in 3 fully funded PhD projects via IGNITE our NERC DLA. The deadline is Thursday Jan 8th 2026 .  1.      Is the world already 1.5 C warmer?...

Fully funded PhD projects available in my group (Please share with interested parties, details here: www.thefosterlab.org/blog/2025/11...):

Calcifying plankton: From biomineralization to global change The cycling of calcium carbonate (CaCO3) in the ocean is closely linked to seawater alkalinity and the regulation of atmospheric CO2. In the modern pelagic ocean, almost all CaCO3 is produced by three...

Hello! we have a new paper out today in @science.org reviewing Calcifying Plankton : from Biomineralization to Global change 🌊🧪🐚

www.science.org/doi/10.1126/...

Changes in host gene expression patterns underpin responses of the coral Stylophora pistillata to nutrient stress - Scientific Reports Scientific Reports - Changes in host gene expression patterns underpin responses of the coral Stylophora pistillata to nutrient stress

New Paper Alert!! Tessa Page and others show how corals deal with low or unbalanced nutrients www.nature.com/articles/s41...
The main issue is lack of P that causes them to upregulate P-transporter genes and likely consume their symbionts and bleach! 🪸🌊🧪

🎉Are you a mineralogist who also loves museums? 🎉
Come join the Natural History Museum Denmark! We are looking for an assistant professor and curator of mineralogy. Advert can be found below, but apply soon! Deadline is 11th August😱

candidate.hr-manager.net/ApplicationI...

Ten years of Tridacna sclerochemistry at up to daily resolution from a controlled aquarium environment – Records of habitat change, induced seasonality and growth variability Giant clams such as Tridacna sp., with their rapid shell accretion (mm-cm/year), decade-long lifespans and aragonitic shells, are invaluable (palaeo)e…

Fascinating study on a #giantclam that was kept in the Dutch @burgerszoo.bsky.social aquarium for a decade and recorded changes in it's (semi)controlled environment in its shell. These types of growth experiments allow us to use shells as archives of past change
www.sciencedirect.com/science/arti...

If you can't be with the forams you love, love the forams you're with #Ammonia

👇🏼extended #ICP15 deadlines to submit abstracts and complete registration -5th May!

Cover of the latest issue of Elements Magazine called Biomineral Geochemisty: Windows into Past Climates and Calcification. The cover shows a picture of small clusters of amorphous calcium carbonate

Great to finally hold this in my hand! Pleasure to work with @amoeba-lab.bsky.social and Ros Rickaby in editing this issue of Elements: Biomineral Geochemistry. Thanks also to all the authors who made such a great set of articles! www.elementsmagazine.org 🧪🌊⚒️