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carbon8.bsky.social
Kau)))
@carbon8.bsky.social
3.1K followers 330 following 420 posts
Earth/Ocean Scientist @ UArizona, #Tucson | Originally from #Bengaluru 🇮🇳 | #birds, #geology, #isotopes, mindfulness, #monsoons, #oceans, #paleoclimate, & weird music.

eBird: https://ebird.org/profile/MTM0Njk2MA

Web: thirumalai.geo.arizona.edu
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carbon8.bsky.social
It's amusing to me how geologists use *extremely* high-resolution datasets for topography, but then forget (?/ignore/don't know?) that equally high-resolution data exists for the atmosphere... and that unrealistic/artistic/fantastical depictions of winds are not necessary (nor scientific). /rant
A map depicting much of central and South Asia, the Indian Ocean, with very high resolution topography, with a number of cave sites depicted, and absolutely fantastic(/unrealistic) singular wind arrows purported to represent different wind regimes.
September 26, 2025 at 9:22 PM
carbon8.bsky.social
🚨New work🚨 led by Ph.D. student Dipesh Chuphal (IIT Gandhinagar), shows that the recent drying of the Ganga River basin is unprecedented in 1,300 years—more severe than historical famines. This ~multidecadal drying appears forced, but many models do not capture it. ☔️ 🌧️

www.pnas.org/doi/10.1073/...
Time series of standardized streamflow anomaly for the Ganga River from year 700 to 2020 (derived from a hydrological model and from the Monsoon Asia Drought Atlas built from tree rings). The plot shows mostly balanced wet (blue/green bars) and dry (brown bars) years until the 20th century, when the black moving-average line dips sharply after 1990. The 1991–2020 mean (blue horizontal line) is well below the range of previous 1,300 years. Orange dots mark major documented historical droughts, but the recent drying is clearly the most severe. Observed changes in precipitation and temperature between 1951 and 2020. Spatial distribution of change in (A) annual precipitation (%) and (B) annual mean temperature (°C) between 1951 and 2020 based on the Sen’s slope calculation. Grids with statistically significant trends (P <= 0.05), based on the Mann–Kendall test, are highlighted with stippling. The Inset panels in (A) and (B) represent the interannual variability in precipitation anomaly (%) and temperature (°C) averaged for the Ganga River Basin (blue boundary). The total change in average precipitation and temperature over the GRB during 1951−2020, estimated using the Sen’s slope, is statistically significant (P-value <= 0.05) based on the Mann–Kendall test.
September 22, 2025 at 7:45 PM
carbon8.bsky.social
🌊 🔬 New in #Marine #Geology:

Ph.D. student Ammoose Jayan (CU Kerala/Fulbright @uarizona.bsky.social) shows that "pink" #foraminifera Globigerinoides ruber survived in the Indian Ocean until 8 kyr BP—and did not go extinct in the Indian Ocean at 120 ka!

🔗 doi.org/10.1016/j.margeo.2025.107656
Microscope images of Globigerinoides ruber (pink) shells from Bay of Bengal core MGS30. Panels show the same specimens in different orientations: umbilical, spiral, and ventral views. Left side: light microscope and high-resolution color images showing pink to orangish-pink shell tint. Right side: scanning electron microscope (SEM) images highlighting surface texture and chamber structure. Map of the Bay of Bengal and Arabian Sea showing sea surface salinity in winter (left panel) and summer (right panel). Core site MGS30 is marked with a star in the eastern Bay of Bengal, with additional sites U1457, U1446, MD77, and RVS2 labeled. Seasonal arrows show East India Coastal Current (EICC) and West India Coastal Current (WICC) flow directions. Color shading indicates salinity, with fresher water in blue and saltier water in yellow.
September 16, 2025 at 6:53 PM
carbon8.bsky.social
I got lucky with this stunning Indian White-Eye seen slightly outside #Bengaluru, #India!

🪶
A photograph of an Indian White-Eye perched on a green stem of a plant—the bird has a bright yellow head with a brilliant white eye-ring, piercing brown eyes, and an angular tiny black beak. A photograph of an Indian White-Eye perched on a brown stem of a plant—the bird has a bright yellow head and back, with black feather tips, and has a brilliant white eye-ring, piercing brown eyes, and an angular tiny black beak.
September 9, 2025 at 7:52 PM
carbon8.bsky.social
Here's a magnificent (albeit somewhat clunky) male #Peafowl in flight seen close to #Bengaluru last week.

#peacock #birds

🪶
A peacock—a brilliant blue bird with a long neck, a tiny crown of feathers above the head, white eyestripes, and scaled feathers perched on a rock. A peacock in flight—with large rufous wings spread apart, and brilliant green tail feathers tangled together in flight. A peacock in flight Fourth photo of a peacock in flight
September 8, 2025 at 8:34 PM
carbon8.bsky.social
Now at #ICP15, River Shen from #NTU #Taiwan gives our first talk on #spleothems incl. their use as #hydroclimate records, how his team is pushing the bounds of U/Th #geochronology, & various applications of #speleothem #geochemistry including for #temperature change, #weathering, and #pollution.
A photograph of Dr. River Shen from National Taiwan University on stage at #ICP15 with a slide entitled “Recent advances in U-Th chronology and geochemical proxies for reconstructing Asian monsoon variability from speleothems.”
September 4, 2025 at 6:57 AM
carbon8.bsky.social
Happening now at #ICP15: @triptychphrases.bsky.social shifts gears from Asia & provides a comprehensive overview of #Quaternary changes in the North American #Monsoon & talks abt plausible parallels between past and future climate #extremes 🌊
A photograph of Dr. Tripti Bhattacharya on stage at #ICP15 at the #IISc auditorium—with a slide behind her showing a global map of precipitation.
September 4, 2025 at 6:32 AM
carbon8.bsky.social
After coffee ☕️, Ed Hathorne from @geomarkiel.bsky.social talks about how marine sedimentary #clays & radiogenic #isotopes can be used to constrain long-term changes in #weathering, and thus, Indian summer #monsoon intensity in Bay of Bengal sediments. 🌊
A photograph of Dr. Ed Hathorne on stage at #ICP15 at the #IISc auditorium—with a slide behind him titled “South Asian Monsoon climate control of Neogene to Pleistocene silicate weathering”. A photograph of Dr. Ed Hathorne from #GEOMAR on stage at #ICP15 at the #IISc auditorium—with a slide behind him containing many photographs of core sections of Bay of Bengal sediments.
September 4, 2025 at 6:25 AM
carbon8.bsky.social
Last but not least in the morning #ICP15 session, a fantastic overview of #Neogene and(/versus) #Cenozoic evolution of the Indian summer #monsoon in response to changes in topography/orography & ocean circulation in simulations & paleo-records by @antacl.bsky.social

🌊 (3/3)
A photograph of Dr. Anta Clarisse Sarr on stage at #ICP15 at the #IISc auditorium—with a slide behind her titled “What is the South Asian summer monsoon”.
September 4, 2025 at 6:18 AM
carbon8.bsky.social
Next, Pedro DiNezio talked abt how assessments of future #tropical hydroclimate responses to global change (including #monsoons), must factor in changes in the #AMOC —paper here: www.nature.com/articles/s41...

🌊 (2/3)
A photograph of Dr. Pedro DiNezio on stage at #ICP15 at the #IISc auditorium—with a slide behind him titled “Glacial lessons on future monsoon change”.
September 4, 2025 at 6:18 AM
carbon8.bsky.social
Yup...! Coincidentally, in our 2020 paper (agupubs.onlinelibrary.wiley.com/doi/full/10....), we show that the magnitude of millennial-scale variability of Antarctic ice core δD intensifies over the late Pleistocene, onsetting at ~400-425 ka (!)
A plot from Thirumalai et al. 2020 GRL (https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GL087613) showing how Antarctic ice core isotopes intensify in their millennial (1-10 kyr band) variability.
September 3, 2025 at 6:13 PM
carbon8.bsky.social
Great talks today at #ICP15 Day #3 with @hl-ford.bsky.social providing a comprehensive overview of Pliocene tropical Pacific 🏝️ model-data 🖥️ comparisons, & Lukas Jonkers highlighting recent advances in foraminiferal 🐚 paleoecology & pelagic paleobiogeography 🌊
A photograph of Dr. Heather Ford on stage at ICP15 Indian institute of science with a slide behind her stating “Tropical Pacific influences global climate”. A photograph of Dr. Lukas Jonkers on stage at ICP15 Indian institute of science with a slide behind him stating “Decadal-centennial gap in pelagic biodiversity time series”.
September 3, 2025 at 6:47 AM
carbon8.bsky.social
Happening now @ #ICP15: Sophie Hines from @whoi.edu delves deep into deep #ocean #carbon storage, neodymium isotopes, and circulation at 900 ka & how Southern Ocean processes were involved (no crisis!) in the mid-Pleistocene transition, when #glacial cyclicity shifted from 40-kyr to 100-kyr pacing!
A photograph of Dr. Sophie Hines on stage at ICP15 at IISc, Bengaluru, under a spotlight, with a screen behind her showing a slide titled "Geochemical tracers can reconstruct past circulation"
September 2, 2025 at 7:05 AM
carbon8.bsky.social
Next up #ICP15: I really enjoyed Xu Zhang's interesting new results on how #Antarctic ice-sheet dynamics may have played a pivotal role in modulating atmospheric CO₂ and the resulting intensification of #interglacials after the mid-Brunhes event around 400,000 years ago!
A photograph of Dr. Xu Zhang on stage at ICP15 at IISc, Bengaluru, under a spotlight, with a screen behind him showing a slide titled "Antarctic ice-sheet dynamics drive mid-Brunhes Transition in interglacial warming intensity".
September 2, 2025 at 6:37 AM
carbon8.bsky.social
After the coffee break, Margit H. Simon gave a v interesting talk showing how #sea #ice in the Nordic Sea may be a key region for the initiation & propagation of abrupt-scale Dansgaard/Oeschger events observed in the last ice age; marine radiocarbon leads the NGRIP ice core by ~centuries! #ICP15
A photograph of Dr. Margit Simon on stage at ICP15 at IISc, Bengaluru, under a spotlight, with a screen behind her showing a slide titled "Nordic Sea convection led abrupt North Atlantic warm events during Dansgaard-Oeschger cycles"
September 2, 2025 at 6:32 AM
carbon8.bsky.social
Day #2 of #ICP15 kicks off with talks on Overturning #ocean Circulation variability & impacts—1st, Cristiano Chiessi on how Atlantic MOC changes need to be factored into Amazonian tipping-point assessments. Now: Frerk Pöppelmeier on future #AMOC changes & how a "full collapse" may not be likely...
A photograph of Dr. Cristiano Chiessi on stage at ICP15 at IISc, Bengaluru, under a spotlight, with a screen behind him showing a powerpoint slide of paleoclimate timeseries. A photograph of Dr. Frerk Pöppelmeier on stage at ICP15 at IISc, Bengaluru, under a spotlight, with a screen behind him titled "Will the AMOC collapse in the Future?"
September 2, 2025 at 5:03 AM
carbon8.bsky.social
Raja Ganeshram delivered yesterday's plenary lecture on #ocean #deoxygenation variability & showcased some amazing decadal-scale #nitrogen isotope δ¹⁵N records across multiple (de)glacial #climate states. #ICP15
A photograph of Dr. Raja Ganeshram on stage at ICP15 at IISc, Bengaluru, under a spotlight, with a screen in the middle of the photo entitled "Climate forcing on Ocean De-oxygenation"
September 2, 2025 at 4:28 AM
carbon8.bsky.social
Happening now at #ICP15: Arvind Singh from Physical Research Labs, Ahmedabad, talks about #iodine (I/Ca) measurements in planktic #foraminifera from Arabian Sea #sediments recording glacial-era expansion of the oxygen minimum zone.
A picture of Dr. Arvind Singh on stage at ICP15, with him in the bottom left corner (under a spotlight) and a screen behind him with a slide that is titled "Mechanisms to understand the oxygen changes"
September 1, 2025 at 7:06 AM
carbon8.bsky.social
Great talk by @seavdavis.bsky.social right now—highlighting dynamic #oxygenation changes over the last glacial cycle & showing how Globorotaloides hexagonus is a key species that is able ot survive in low-oxygen marine environments. #ICP15
A picture of Dr. Cait Davis on stage at ICP15 and a screen behind with a slide that is titled "Oxygen isotopes as a depth tracer"
September 1, 2025 at 6:38 AM
carbon8.bsky.social
Following on the #ICP15 Day 1 #biogeochemistry theme, Alexandra Auderset gave a v interesting talk on how foraminiferal nitrogen isotopes may be applied to reconstruct large-scale changes in nutrients & ocean (de)oxygenation, but also be used to understand foram #calcification depth habitats.
A picture of Dr. Alexandra Auderstage on stage at #ICP15 in the corner left with a spotlight on, and a screen behind with a slide that is titled "Nitrogen isotopes to study nutrient cycling"
September 1, 2025 at 6:30 AM
carbon8.bsky.social
Next up #ICP15: @jfarmersalmanac.bsky.social gave a fantastic talk on the utility & current+plausible future applications of foraminiferal-bound δ¹⁵N—with a focus on last glacial #Arctic #paleoceanography, including implications for Bering Strait exposure and global sea-level change.
A picture of Dr. Jesse Farmer on stage at ICP15 with him in the corner left spotlight and a screen behind him with a slide that is titled "Foraminifera-bound nitrogen isotopes"
September 1, 2025 at 6:17 AM
carbon8.bsky.social
This week, I am grateful to be at the International Conference on Paleoceanography #ICP15. Great start this morning with a tour of #Boron isotopes & #Cenozoic CO₂ reconstructions from @eleniwater.bsky.social & @chalkyoceans.bsky.social. Nice to see all the paleoceanographers in #Bengaluru!
A photograph inside the JD Tata Auditorium in Bengaluru on the Indian Institute of Science campus—the photograph shows a large number of people seateed in the auditorium with Dr. Thomas Chalk (CEREGE) on stage showcasing a slide on CO₂ reconstructions.
September 1, 2025 at 5:03 AM
carbon8.bsky.social
V nice talk by @ocnogrphr.bsky.social this morning at the Indian Institute of Science #IISc on his recently published work on the deglacial “salty blob” in the southeastern Indian Ocean (www.nature.com/articles/s41...)
Dr. Ryan Glaubke-wearing a green shirt-stands behind a desk in front of a screen with a title slide that says “Elevated Shallow Water salinity in the Indian Ocean was sourced from the Deep”.
August 26, 2025 at 11:54 AM
carbon8.bsky.social
New work published in #PaleoceanographyAndPaleoclimatology by James et al. demonstrates how comparing speleothem δ¹⁸O to single (lat/season) insolation curves can "oversimplify the complex relationship b/n orbital forcing & hydroclimate variability"

agupubs.onlinelibrary.wiley.com/doi/full/10....
Figure 4 in their paper which shows how “murmuration” plots (used in their analysis) are constructed, and how insolation month and offset are interchangeable when interpreting correlations between any signal and insolation.
August 12, 2025 at 4:23 AM
carbon8.bsky.social
Led by U. LA Lafayette Ph.D. student Gracie Babineaux, we have a new paper out in #EPSL showing how individual foraminiferal δ¹³C analyses of benthic Pyrgo spp. can record short-lived #methane seepage events from the seafloor. 🌊

www.sciencedirect.com/science/arti...
A schematic showing carbon isotope values for different benthic foraminiferal species living in sedimentary habitats reflecting different methane and dissolved inorganic carbon (DIC) values. IFA = individual foraminiferal analyses. SMTZ = sulfate-methane transition zone. A scanning electron microscope image of an intact versus a broken benthic foraminiferal test belonging to the genus Pyrgo.
July 28, 2025 at 5:00 AM