#brGDGTs
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ninadavtian.bsky.social
Second, this #TeamBacteria study led by Sai Ke:
www.sciencedirect.com/science/arti...
Involving two bacterial membrane lipid groups—3-hydroxy fatty acids and branched tetraether lipids—and last authored by @arnaudhuguet.bsky.social.
#IDWGS
#WomenInScienceDay
#brGDGTs
🧪 ⚒️ 👩‍🔬
(2/2)
Evaluation of bacterial membrane lipids (3-hydroxy fatty acids and branched GDGTs) as environmental proxies in lakes of the French Alps and southern Chile
Revealing high-resolution paleoclimate records in lakes is essential for our understanding of the climate system. To date, the ubiquitous branched gly…
www.sciencedirect.com
February 11, 2026 at 7:08 PM
ninadavtian.bsky.social
Here is a paper led by a former PhD student and which further shows that indicators based on bacterial tetraether lipids in lakes consistently need refinement:
doi.org/10.1029/2025...
With @nemiahladd.bsky.social and @cindydejonge.bsky.social
#brGDGTs #TeamBacteria
🧪 ⚒️ 👩‍🔬
Implications for #PaleoSky
Controls on brGDGT Production in the Seasonally Anoxic Water Column and Sediments of Rotsee (Lake Rot)
MBT'5ME values in Rotsee are influenced by lake stratification while the isomer ratio (IR) more directly reflects epilimnion temperature MBT'5ME and IR are strongly correlated, providing a diagno...
doi.org
December 19, 2025 at 8:56 AM
ninadavtian.bsky.social
Once again, marine tetraether lipids also include bacterial #brGDGTs!
See, for instance, this new marine brGDGT paper by @drxiaowj.bsky.social et al., just published in Geochimica et Cosmochimica Acta:
www.sciencedirect.com/science/arti...
#GDGTs #TeamBacteria
🧪 ⚒️ 🌊
With implications for #PaleoSky
Global distribution of marine bacterial BrGDGTs in sediments: patterns and implications
Branched glycerol dialkyl glycerol tetraethers (brGDGTs), originally linked to terrestrial bacteria for paleoenvironmental reconstructions, are now al…
www.sciencedirect.com
December 10, 2025 at 2:28 PM
ninadavtian.bsky.social
Congrats to @aecpaleo.bsky.social on her new first authored paper, just published in @egubg.bsky.social!
doi.org/10.5194/bg-2...
With @cindydejonge.bsky.social and @sebjoannin.bsky.social.
Please also check out @sebjoannin.bsky.social’s post! 👇🏻
#brGDGTs #TeamBacteria
@egu.eu
🧪 ⚒️ 🦣 👩‍🔬
#PaleoSky
December 8, 2025 at 8:03 AM
ninadavtian.bsky.social
Yanwu Duan is the first author of two new papers which collectively support both #TeamBacteria and #TeamArchaea from the #GDGTs perspective.
Bacterial lipids #brGDGTs paper:
www.sciencedirect.com/science/arti...
Archaeal lipids #isoGDGTs paper:
www.sciencedirect.com/science/arti...
🧪 ⚒️
#PaleoSky
Divergent environmental controls on branched tetraethers along precipitation gradients in soils of the Tibetan Plateau
Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are widely used for terrestrial paleotemperature reconstructions, yet their environmental con…
www.sciencedirect.com
November 8, 2025 at 8:48 AM
ninadavtian.bsky.social
To all #TeamBacteria and team #brGDGTs members:
L. Dugerdil et al. (2025) PALO @agu.org have a new paper!
doi.org/10.1029/2025...
With @sebjoannin.bsky.social and @aecpaleo.bsky.social.
Also with my former PhD co-supervisor G. Ménot, who helped me to join team #GDGTs.
🧪 ⚒️ 🦣
#PaleoSky
Boosted Regression Trees Machine Learning Method Improves the brGDGT‐Based Climate Reconstruction in Drylands
Machine Learning methods reduce confounding effects and error in Branched glycerol dialkyl glycerol tetraether climate calibrations Boosted Regression Trees yields better results than Random Fore...
doi.org
October 26, 2025 at 12:02 PM
ninadavtian.bsky.social
How to use bacterial membrane lipids, named #brGDGTs, for reliable paleo-temperature reconstructions from Quaternary lake sediments?
The new paper quoted below further addresses this important question! 👇🏻
Congrats @geochemem.bsky.social and co-authors!
#GDGTs #TeamBacteria
🧪 ⚒️ 🦣 👩‍🔬
#PaleoSky
September 19, 2025 at 1:48 PM
geochemem.bsky.social
In our work we:

Construct and assess new global lake brGDGT temperature calibrations using different analytical methods, demonstrating the use of each for temperature reconstructions.

Construct the first global lake temperature calibration including 5- and 6-methyl brGDGTs from Antarctica.

and
September 19, 2025 at 11:59 AM
stever60.bsky.social
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
Map showing the location of over 400 lake sediment samples used in this new study
September 19, 2025 at 9:54 AM
stever60.bsky.social
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
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
September 19, 2025 at 9:50 AM
ninadavtian.bsky.social
On this #InternationalWomensDay, let me highlight two 👩‍🔬.
First, @aecpaleo.bsky.social, who leads the following @egu.eu preprint:
egusphere.copernicus.org/preprints/20...
With @cindydejonge.bsky.social among other 👩‍🔬 co-authors.
#GDGTs #brGDGTs #TeamBacteria
🧪 ⚒️ 🦣
#PaleoSky
#IWD #IWD25 #IWD2025
(1/4)
Utilizing Probability Estimates from Machine Learning and Pollen to Understand the Depositional Influences on Branched GDGT in Wetlands, Peatlands, and Lakes
Abstract. Branched glycerol dialkyl glycerol tetraethers (brGDGTs) serve as critical molecular biomarkers for the quantitative reconstruction of past environments, ambient temperature and pH across va...
egusphere.copernicus.org
March 8, 2025 at 5:30 PM
rabergj.bsky.social
For context, I had asked DeepResearch to write a paper on brGDGTs and dissolved oxygen. I currently have a paper on the subject in review, so wanted to see how it performed.

Here's the Lake Qaupat paper it was trying to summarize: agupubs.onlinelibrary.wiley.com/doi/full/10....
Intact Polar brGDGTs in Arctic Lake Catchments: Implications for Lipid Sources and Paleoclimate Applications
Intact polar branched glycerol dialkyl glycerol tetraether (brGDGT) lipids in soils were distinct from those in lakes In lake sediments, core brGDGTs were lacustrine in origin, and intact monogly...
agupubs.onlinelibrary.wiley.com
February 27, 2025 at 3:44 PM
ninadavtian.bsky.social
On this #InternationalDayOfWomenAndGirlsInScience, here is a great story presented in two papers led by a 👩‍🔬 (Jingjing Guo) and last authored by another 👩‍🔬 (Francien Peterse).
Paper #1: doi.org/10.5194/cp-2...
Paper #2: doi.org/10.1016/j.or...
🧪 ⚒️ 🦣 👩‍🔬
#PaleoSky
#GDGTs #brGDGTs
#IDWGS #IDWGS2025
Towards quantitative reconstruction of past monsoon precipitation based on tetraether membrane lipids in Chinese loess
Abstract. Variations in the oxygen isotope composition (δ18O) of cave speleothems and numerous proxy records from loess–paleosol sequences have revealed past variations in East Asian monsoon (EAM) int...
doi.org
February 11, 2025 at 9:09 AM
ninadavtian.bsky.social
Bacterial tetraether lipids as paleothermometers once again! #brGDGTs

Lauren O’Connor et al. (2024) Science Advances, with @docsabine.bsky.social:
doi.org/10.1126/scia...

🧪 ⚒️ 👩‍🔬
#PaleoSky
Terrestrial evidence for volcanogenic sulfate-driven cooling event ~30 kyr before the Cretaceous–Paleogene mass extinction
Terrestrial proxy evidence for sulfur-induced cooling event linked to Deccan Trap eruptions 30 ka before K–Pg boundary.
doi.org
December 20, 2024 at 2:02 PM
ninadavtian.bsky.social
In short, Martin et al. (2020) found:
1) A thermal maximum recorded by brGDGTs and pollen during the early Holocene
2) Rapid climate events recorded by brGDGTs and pollen during the Holocene
3) No evidence for a seasonal bias in the brGDGT or pollen temperature signals
NB: Two-part ALT text.
(14/14)
First part of ALT text for Fig. 7 in Martin et al. (2020) QSR (https://doi.org/10.1016/j.quascirev.2019.106109). Holocene climatic variations in the northern hemisphere and a focus on Western Europe. A. July insolation at 45°N (Laskar et al., 2004 https://doi.org/10.1051/0004-6361:20041335). B. Stacked temperature anomaly (from the AD 1961–1990 mean) for middle and high latitudes of the northern hemisphere obtained from a compilation of proxy-based temperature reconstructions with 1σ uncertainty (shading) from Marcott et al. (2013 https://doi.org/10.1126/science.1228026). C. Mean annual temperature reconstruction for North America and Europe based on fossil pollen data with 2.5 and 97.5% uncertainty bands (shading) from Marsicek et al. (2018 https://doi.org/10.1038/nature25464). D. Temperature anomaly for the northern hemisphere obtained from a compilation of proxy-based temperature reconstructions from land areas and its 200-year Butterworth low-pass filtered values (brown line) from Pei et al. (2017 https://doi.org/10.1007/s00704-016-1932-5). E. Reconstructed temperature from argon and nitrogen isotopes for Greenland with 2σ error bands from Kobashi et al. (2017 https://doi.org/10.1038/s41598-017-01451-7). F. Sea surface temperature provided by relative proportion of the di- and tri-alkenones of 37 carbons from ODP Site 161-976 and sediment core MD95-2043 (Cacho et al., 1999 https://doi.org/10.1029/1999PA900044; Martrat et al., 2014 https://doi.org/10.1016/j.quascirev.2014.06.016). G. Spliced and stacked chironomid-based reconstruction for the northern and central Alpine area at 1000 m from Heiri et al. (2015 https://doi.org/10.1177/0959683614556382) with standard error estimates (shading). H. Mean annual air temperature obtained from fluid inclusions in speleothems from Milandre Cave in Switzerland (Affolter et al., 2019 https://doi.org/10.1126/sciadv.aav3809) with uncertainty (shading). Second part of ALT text for Fig. 7 in Martin et al. (2020) QSR (https://doi.org/10.1016/j.quascirev.2019.106109). I. Mean annual temperature reconstructed from pollen of Lake St Front with Weighted Averaging Partial Least Squares (WAPLS, black curve) and Modern Analog Technique (MAT, green curve) methods with its uncertainty (grey dashed lines and green shading, respectively). J. Corrected mean annual air temperature (MAAT) obtained from the binary mixing model with the Sun et al. (2011 https://doi.org/10.1029/2010JG001365) calibration for Lake St Front (red continuous line) with the error associated to the propagation of end-member variability (red shading) and its running average on 5 points (black dashed line) compared with the mean Holocene temperature (black dotted line). K. Difference between the mean annual temperatures obtained from brGDGTs and pollen with the MAT method, the black dashed line indicates equality between both results. L. 14C calibrated ages and 210Pb dates for Lake St Front for the Holocene (Martin et al., 2019 https://doi.org/10.1016/j.orggeochem.2019.06.005). M. Advances (blue rectangles) and recessions (orange rectangles) of Alps glaciers (Holzhauser et al., 2005 https://doi.org/10.1191/0959683605hl853ra; Joerin et al., 2006 https://doi.org/10.1191/0959683606hl964rp; Nicolussi and Patzelt, 2000 https://www.researchgate.net/publication/309456923_Untersuchungen_zur_holozanen_Gletscherentwicklung_von_Pasterze_und_Gepatschferner_Ostalpen; Solomina et al., 2015 https://doi.org/10.1016/j.quascirev.2014.11.018). Blue shaded rectangles correspond to cold events. The period of permanent human occupation is marked by a hatched rectangle. The dotted rectangle shows the period with high Corylus percentages. MHC=Mid-Holocene Cooling, MHO=Mid-Holocene Optimum, RCC=Rapid Climate Change, IACE = Iron Age Cold Epoch, RWP=Roman Warm Period, RWPC=Roman Warm Period Cooling, DA=Dark Ages, MCA=Medieval Climate Anomaly.
December 15, 2024 at 8:05 PM
ninadavtian.bsky.social
In short, Martin et al. (2019) concluded that:
1) Downcore brGDGTs in Lake Saint Front (Massif Central, France) have mixed sources
2) Sources of brGDGTs gradually shifted over the Holocene
3) Vegetation changes and human activities further impact brGDGT distributions in Lake Saint Front
(10/14)
Fig. 5 in Martin et al. (2019) OG (https://doi.org/10.1016/j.orggeochem.2019.06.005). Sedimentological, geochemical, and palynological evolution of the Holocene recorded at Lake St Front. A. Simplified sedimentation rate obtained from the Bacon program. B. Magnetic susceptibility. C. Total Organic Carbon (TOC, Rhoujjati, 1995 https://theses.fr/1995AIX22025). D. Percentage of arboreal pollen (brown curve) and percentages of pollen from thermophilous (beige area, sum of Acer, Corylus, Hedera, Ilex, Lonicera, Ostrya, deciduous Quercus, Quercus ilex t., Pistacia, Sambucus, Sorbus, Tilia, Ulmus, Viburnum, Viscum) and mesophilous (green area, sum of Abies, Carpinus, Fagus) tree pollen. E. Cumulative percentages of pollen of nitrophilous taxa (light green area, Plantago lanceolata, P. major, Rumex, Chenopodiaceae, Urtica), cereals (orange area, Cerealia, Secale), and Juglans (burgundy area). F. C/N ratio (Rhoujjati, 1995 https://theses.fr/1995AIX22025); note that the axis has been reversed for improved readability. The dashed line represents the upper limit of production in the aquatic realm. G. BIT index with analytical errors (1σ values); note that the axis has been reversed. H. Fractional abundance of IIIa″ with analytical errors (1σ values). I. ΣIIIa/ΣIIa ratio (red curve) with analytical errors (1σ values). The dashed lines represent the upper limit of production in the terrestrial realm and the lower limit of production in the aquatic realm defined by Xiao et al. (2016 https://doi.org/10.5194/bg-13-5883-2016). J. 14C calibrated ages and 210Pb dates. Shaded rectangles highlight the periods when ΣIIIa/ΣIIa values are below the upper limit for soil origin. The period of permanent human occupation is marked by a hatched symbol. RP: Roman Period, MP: Modern Period.
December 15, 2024 at 8:05 PM
terriblelagarto.pmartoza.com
Honestly I thought my cloud was going to be a single gigantic "GDGT" 🤣 ⚒️🧪
Cloud of words in various colors and sizes based on the Google Scholar profile for Pablo Martínez-Sosa. Some of the largest words include lacustrine, branched, environmental, gdgt, response, brgdgt, brgdgts, gdgts, organic, paleoenvironmental, proxies, soil, temperature, bayesian, calibration, determining, development, effect, global, impact, lake, learning, machine, mesocosm, microcosms, orizaba, pico, quality, reworking, and sediments
November 26, 2024 at 12:42 PM
ninadavtian.bsky.social
I am so glad to be one of the two ICTA-UAB representants—the other is Joan Villanueva—for the interlaboratory study led by @cindydejonge.bsky.social and @francien.bsky.social! #GDGTs #brGDGTs
Let's summarize this important study for #PaleoSky and ⚒️ people with the following thread! 👇🏻 (1/7)
🧪 👩‍🔬
Nina Davtian (that's me!) at her work office, with the laptop screen showing the header of her co-authored article by De Jonge et al. (2024) GGG (https://doi.org/10.1029/2024GC011583) and her index finger showing where her name appears in the author list.
October 24, 2024 at 4:19 PM
ninadavtian.bsky.social
My regular poster presentation will contribute to the CL5.4 session convened by e.g. @olakwiecen3.bsky.social and @cindydejonge.bsky.social.

It goes without saying that I will contribute for both #TeamArchaea (regular and hydroxylated #iGDGTs) and #TeamBacteria (#brGDGTs) at #EGU24 this year! (3/5)
EGU24-17926 abstract QR code
April 14, 2024 at 5:03 PM
geobiomaggie.bsky.social
Haha, spectacular. You will be the first to know if I get a culture of press grubbing microbes going. I presume they will make brGDGTs
February 19, 2024 at 3:19 AM
cindydejonge.bsky.social
Her first chapter can be found published here: it’s both a plea and warning for using mesocosms for testing the temperature response of brGDGTs, as a system with high control but low realism. Interestingly, warming impacts brGDGTs stronger than cooling. doi.org/10.1016/j.or...
Redirecting
doi.org
February 3, 2024 at 8:19 PM
ninadavtian.bsky.social
To further support this finding, we took the opportunity to analyze brGDGTs in five well-described soil profiles along an altitudinal transect in northwestern Vietnam.
The soil profile descriptions are published in Podwojewski et al. (2011) Catena:
doi.org/10.1016/j.ca... (4/6)
Fig. 2 in Davtian et al. (2016) OG https://doi.org/10.1016/j.orggeochem.2016.09.002 Localization and description of the study site of Davtian et al. (2016) OG, which consists in an altitudinal soil profile transect selected for brGDGT analysis. All selected soil profiles were previously described in detail by Podwojewski et al. (2011) Catena: https://doi.org/10.1016/j.catena.2011.06.002
December 5, 2023 at 11:02 PM
ninadavtian.bsky.social
To GDGT-lovers: I am not done yet with these archaeal (iGDGTs and OH-GDGTs) and bacterial (brGDGTs) membrane lipids!
Stay tuned for more scientific publications, with GDGTs or other biomarkers, including pyrogenic biomarkers!
Thank you for your attention! (27/27)
November 14, 2023 at 10:22 PM
jeromeollier.bsky.social
Enhanced production of highly methylated brGDGTs linked to anaerobic bacteria from sediments of the Mariana Trench - @FrontMarineSci https://www.frontiersin.org/articles/10.3389/fmars.2023.1233560/full?utm_source=S-TWT&utm_medium=SNET&utm_campaign=ECO_FMARS_XXXXXXXX_auto-dlvrit
Frontiers | Enhanced production of highly methylated brGD...
Branched glycerol dialkyl glycerol tetraethers (brGDGTs) ...
www.frontiersin.org
January 15, 2025 at 3:45 AM