About

Braddock Linsley is a Lamont Research Professor and the Director of the Lamont-Doherty Stable Isotope and Trace Element Laboratory at Columbia University. He joined Lamont in 2011 after spending 16 years as a Professor in the Department of Atmospheric and Environmental Sciences at the University at Albany-SUNY. His research focuses on paleoceanography, utilizing marine sediment cores and coral records to study past oceanographic and climate conditions. Dr. Linsley's work has significantly advanced understanding of interannual to multidecadal climate dynamics and millennial-scale variability in the ocean. His paleoclimate research has taken him to remote sites across the Pacific, including sediment and coral cores from locations such as Panamá, Clipperton Atoll, Fanning Atoll, Rarotonga, Fiji, Tonga, Samoa, the Great Barrier Reef, the Makassar Strait in Indonesia, the Sulu Sea, and the New Guinea margin. He teaches courses on Monitoring and Analysis of Marine and Estuary Systems and Stable Isotope Geochemistry at Columbia University.

Research topics

• Oceanography
• Geology
• Climatology
• Geography
• Meteorology
• Ecology
• Environmental science

Selected publications

• Expanded Composite Coral Indices of South Pacific Convergence Zone Oceanographic Variability Since 1848 CE

  Paleoceanography and Paleoclimatology · 2025-05-01

  articleOpen access

  Abstract In the South Pacific Convergence Zone (SPCZ), interannual to interdecadal oceanic and atmospheric variability is especially pronounced. The El Niño Southern Oscillation and the Interdecadal Pacific Oscillation significantly influence the SPCZ diagonal axis and salinity front. Regional coral‐based paleo‐environmental reconstructions extend the relatively short and discontinuous instrumental sea surface temperature (SST) and sea surface salinity (SSS) record to elucidate past variability. We present monthly resolved, composite indices of coral skeletal δ 18 O, Sr/Ca, and calculated δ 18 O sw utilizing coral geochemical time‐series from Rotuma, Fiji, Tonga, and Rarotonga, dubbed the SPCZ coral (SPCZ c ) indices. The new indices build upon previous efforts to describe variability and trends in the SPCZ region with expanded coverage due to a new northwestern coral addition from the SPCZ fresh pool. The increased spatial and temporal resolution of the new indices allows for higher‐fidelity sub‐annual reconstructions of SST and SSS in the region dating back to 1848. The results confirm the secular warming trend of 1°C in the SPCZ region and show a 0.4 S p freshening starting in the 1880s. The SPCZ c δ 18 O sw is the first regional reconstruction of δ 18 O sw and provides valuable insights into past SSS variability, including elucidating responses to El Niño and La Niña events, as well as identifying past SPCZ zonal events. The SPCZ c δ 18 O sw reconstruction extends the instrumental records by ∼100 years. The SPCZ c indices prove the utility of the compositing approach in describing regional oceanographic variability with the increased signal‐to‐noise ratio of the obtained coral climatic data.

  PublisherOA PDFDOI

• A three-coral Ba/Ca network provides a regional river discharge reconstruction in the Gulf of Chiriquí, Panama throughout the 20th century

  Palaeogeography Palaeoclimatology Palaeoecology · 2025-12-07

  articleOpen access

  The Ba/Ca ratio in stony corals (Ba/Ca cor ) has been shown in some settings to be a proxy for hydroclimate, specifically river discharge. While this relationship is well-established along the Pacific Coast of Panama, the degree to which temporal variations in Ba/Ca cor from different regions in the estuary replicate is still an area of uncertainity. Here, we present three near-monthly resolved Porites lobata Ba/Ca cor time-series from near-shore and off-shore locations in the Gulf of Chiriquí to illustrate how different corals can record gulf-wide hydroclimatic conditions. All three records are correlated ( r min = 0.48, r max = 0.92) and replicate one another at monthly, annual average, annual amplitude, wet season average, and dry season average resolutions. By averaging time-matched points, we generated a composite Ba/Ca cor record that yielded statistically significant river discharge calibrations. The Gulf of Chiriquí (GoC) is a prime location for the study of the Ba/Ca cor - river discharge relationship, as the region is not substantially impacted by seasonal upwelling or temperature variability due to the topographic blocking of the tradewinds and does not appear to be driven by barite formation in the water column. However, Ba originating from marsh sediment or mangrove forests might contribute to the signal recorded in the corals. Our reconstruction extends the instrumental discharge data by ~70 years and demonstrates the strong and consistent relationship between El Niño events and droughts in Panama with implications for understanding the functioning of the Panama Canal. Therefore, replicated Ba/Ca cor records in the GoC have the potential to not only improve our quantification of past river discharge, but also serve as a tool to supplement our understanding of paleo-ENSO and its impact on regional hydroclimate. • Three Ba/Ca coral records from the Gulf of Chiriquí replicate one another. • Coral Ba/Ca is correlated with river discharge, extending the instrumental record. • Anomalies in reconstructed river discharge can inform Panama Canal activities.

  PublisherDOI

• Controls on Sr/Ca, S/Ca, and Mg/Ca in Benthic Foraminifera: Implications for the Carbonate Chemistry of the Pacific Ocean Over the Last 350 ky

  Geochemistry Geophysics Geosystems · 2024-08-01 · 4 citations

  articleOpen access

  Abstract Boron to calcium (B/Ca) records in benthic foraminifera, used for reconstructing the carbonate ion saturation state (ΔCO 3 ) of the deep ocean, suggest that carbon sequestration in the Southern Pacific contributed to lowering atmospheric CO 2 during the last glacial interval. However, the spatial and temporal extent of this storage is debated due to limited ΔCO 3 records. To increase available ΔCO 3 records, we explored using strontium and sulfur to calcium (Sr/Ca, S/Ca) in Planulina wuellerstorfi as additional proxies for ΔCO 3 based on comparison with paired B/Ca down‐core records from Pacific Sites U1486 (1,332 m depth) and U1487 (874 m depth) cored during the International Ocean Discovery Program Expedition 363. The Sr/Ca and S/Ca records from P. wuellerstorfi closely covary with the B/Ca‐derived ΔCO 3 records. Temperature, reconstructed using Uvigerina peregrina magnesium to calcium (Mg/Ca), has no discernible effect on Sr/Ca, whereas S/Ca also varies with Mg/Ca in both U. peregrina and P. wuellerstorfi , suggesting an additional temperature effect. Mg/Ca records from P. wuellerstorfi are affected by both temperature and ΔCO 3 . We assess calibrations of Sr/Ca to ΔCO 3 for the Atlantic, Pacific, and Indian Oceans and recommend using the down‐core rather than core‐top calibrations as they yield consistent sensitivity, though with offsets, in all ocean basins. Reconstructing Pacific ΔCO 3 records from sites U1486, U1487, and DSDP 593, we demonstrate the benefit of using Sr/Ca as an additional ΔCO 3 proxy to assess the contribution of the Southern Pacific to the increase of atmospheric CO 2 at glacial terminations.

  PublisherOA PDFDOI

• Biomineralization and biomechanical trade-offs under heterogeneous environments in the eastern oyster <i>Crassostrea virginica</i>

  Journal of Molluscan Studies · 2024-09-30 · 7 citations

  article

  ABSTRACT Accurate biological models are critical to reliably predict vulnerability of marine organisms and ecosystems to rapid environmental changes. Current predictions on the biological impacts of climate change and human-caused disturbances primarily stem from controlled experiments but lack assessments of the mechanisms underlying biotic variations in natural systems, especially for habitat-forming, climate-sensitive species with key ecological roles. This study aimed to characterize and quantify spatial patterns of shell biomineralization and biomechanical properties in a key reef-building oyster, Crassostrea virginica, collected from restored reefs along natural estuarine gradients in the Hudson River Estuary (NY, USA). We characterized patterns of oyster shell deposition, structure, composition and mechanical performance at the macro- and microscale. Eastern oysters show a strong capacity for adjustments in shell biomineralization and biomechanics to maintain shell production and protective functions. We reveal salinity as a key predictor of oyster shell structure, mechanical integrity and resistance to dissolution, and describe the functional role of chalky calcite in shaping shell mechanical performance. Changes in shell production along salinity gradients indicate formation of shells with (1) high mechanical resistance but increased vulnerability to dissolution under marine conditions and (2) lower structural integrity but higher protection from dissolution under brackish conditions. Our work illustrates that biomineralization and biomechanical trade-offs may act as mechanisms in eastern oysters to maintain overall performance under heterogeneous estuarine environments and could represent a cornerstone for calcifying organisms to acclimate and maintain their ecological functions in a rapidly changing climate.

  PublisherDOI

• Highest ocean heat in four centuries places Great Barrier Reef in danger

  Nature · 2024-08-07 · 77 citations

  articleOpen accessSenior author

  Abstract Mass coral bleaching on the Great Barrier Reef (GBR) in Australia between 2016 and 2024 was driven by high sea surface temperatures (SST) 1 . The likelihood of temperature-induced bleaching is a key determinant for the future threat status of the GBR 2 , but the long-term context of recent temperatures in the region is unclear. Here we show that the January–March Coral Sea heat extremes in 2024, 2017 and 2020 (in order of descending mean SST anomalies) were the warmest in 400 years, exceeding the 95th-percentile uncertainty limit of our reconstructed pre-1900 maximum. The 2016, 2004 and 2022 events were the next warmest, exceeding the 90th-percentile limit. Climate model analysis confirms that human influence on the climate system is responsible for the rapid warming in recent decades. This attribution, together with the recent ocean temperature extremes, post-1900 warming trend and observed mass coral bleaching, shows that the existential threat to the GBR ecosystem from anthropogenic climate change is now realized. Without urgent intervention, the iconic GBR is at risk of experiencing temperatures conducive to near-annual coral bleaching 3 , with negative consequences for biodiversity and ecosystems services. A continuation on the current trajectory would further threaten the ecological function 4 and outstanding universal value 5 of one of Earth’s greatest natural wonders.

  PublisherOA PDFDOI

• Western Pacific Warm Pool Warming and Salinity Front Expansion Since 1821 Reconstructed From Paired Coral δ¹⁸O, Sr/Ca, and Reconstructed δ¹⁸O_sw

  Paleoceanography and Paleoclimatology · 2024-12-01 · 2 citations

  articleOpen access

  Abstract The Southwest Pacific region is of great importance to global climate variability, but instrumental climate observations before the 1980s lack in numbers and quality. Despite efforts in complementing instrumental records with proxy sea surface temperature (SST) and sea surface salinity (SSS) reconstructions based on coral Sr/Ca and δ 18 O sw records, few of them are longer than a century. This study introduces a northwestern extension to the existing records of South Pacific coral study sites with monthly‐resolved Sr/Ca, δ 18 O, and δ 18 O sw reconstructions from Rotuma dating back to 1821. Additionally, we present new monthly‐resolved Sr/Ca and reconstructed δ 18 O sw from a coral from Tonga dating back to 1848. Results reveal 1.5°C warming in the Western Pacific Warm Pool, while the adjacent coral from Tonga shows 1°C warming over the twentieth century. The Rotuma Sr/Ca record reveals thermal stress events impacting the Sr/Ca‐SST relationship in the following months. Coral δ 18 O sw results reveal significant freshening of 0.45 S p (practical salinity unit) in Tonga since the early twentieth century, suggesting the southeastward expansion of the South Pacific Convergence Zone salinity front. The δ 18 O sw inferred SSS provides a valuable extension into the past considering the short and inconsistent instrumental records available. This study demonstrates the utility of coral‐based reconstructions in capturing long‐term and regional climate variations in the Southwest Pacific and the necessity of expanding replicated studies to other underrepresented areas to enhance our understanding of regional climate dynamics.

  PublisherOA PDFDOI

• PANAMA HYDROLOGY AND EASTERN PACIFIC INTERTROPICAL CONVERGENCE ZONE (ITCZ) RESPONSE TO ENSO AND VOLCANIC ERUPTIONS SINCE THE EARLY 1700S

  Abstracts with programs - Geological Society of America · 2023-01-01

  article1st authorCorresponding
  PublisherDOI

• Obliquity-driven subtropical forcing of the thermocline after 240 ka in the southern sector of the Western Pacific Warm Pool

  Palaeogeography Palaeoclimatology Palaeoecology · 2023-04-20 · 7 citations

  article
  PublisherDOI

• Biomineralization and biomechanical trade-offs under heterogeneous environments in the eastern oyster <i>Crassostrea virginica</i>

  bioRxiv (Cold Spring Harbor Laboratory) · 2023-11-29

  preprintOpen access

  ABSTRACT Accurate biological models are critical to reliably predict vulnerability of marine organisms and ecosystems to rapid environmental changes. Current predictions on the biological impacts of climate change and human-caused disturbances primarily stem from controlled experiments but lack assessments of the mechanisms underlying biotic variations in natural systems. Such information is key to translating experimental models to natural populations, especially for habitat-forming, climate sensitive species with key ecological roles. This study aimed to characterize and quantify spatial patterns of shell biomineralization and biomechanical properties in a key reef-building oyster, Crassostrea virginica , collected from restored reefs along natural estuarine gradients in the Hudson River Estuary (NY, U.S.). We characterized patterns of oyster shell production (i.e., shape and thickness), structure (i.e., abundance of foliated and chalky calcite), mineralogy (i.e., crystal size and density), composition (i.e., organic matrix and Mg/Ca ratios), and mechanical performance (i.e., elastic modulus and hardness) at the macro and micro scale. Our results demonstrate a strong protective capacity of C. virginica for compensatory adjustments in shell biomineralization and biomechanics to maintain shell production and protective functions as a response to biotic and abiotic stressors. We reveal salinity as a key predictor of oyster shell structure, mechanical integrity, and resistance to dissolution, and describe the functional role of chalky calcite in shaping shell mechanical performance. Compensatory adjustments along salinity gradients indicate that oysters produce shells with i ) high mechanical resistance but increased vulnerability to dissolution under marine conditions, and ii ) lower structural integrity but higher protection from dissolution under brackish conditions. Our work illustrates that biomineralization and biomechanical adjustments may act as compensatory mechanisms in eastern oysters to maintain overall performance under heterogeneous estuarine environments, and could represent a cornerstone for calcifying organisms to acclimate and maintain their ecological functions in a rapidly changing climate.

  PublisherOA PDFDOI

• Evaluating the reproducibility and paleo-hydroclimate potential of coral skeletal Ba/Ca in the Gulf of Chiriquí, Panama

  Continental Shelf Research · 2023-08-29 · 4 citations

  article
  PublisherDOI

Recent grants

• Collaborative Research: Reconstructing river discharge and hydrologic variability in Panama via coral geochemistry: Implications for management of the Panama Canal

  NSF · $338k · 2020–2024

• Centennial-Millennial Scale Oscillations in the East Asian Monsoon

  NSF · $120k · 1997–2001

• Collaborative Research: Temperature reconstruction of the western equatorial Pacific thermocline during the last ~2000 years: a paleo perspective for modern observations

  NSF · $94k · 2009–2012

• Geochemical Calibration of Modern Isopora and Acropora Corals from the Great Barrier Reef and Application to IODP Leg 325 Fossil Corals

  NSF · $184k · 2014–2017

• Climate Records from Corals in the Central and Western Sectors of the Tropical South Pacific

  NSF · $32k · 1999–2000

Frequent coauthors

• Yair Rosenthal

  Rutgers, The State University of New Jersey

  160 shared

• Samantha C. Bova

  San Diego State University

  104 shared

• Luc Beaufort

  Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement

  102 shared

• Kelly A. Gibson

  University of South Carolina Aiken

  99 shared

• Denise K. Kulhanek

  Kiel University

  97 shared

• Ann Holbourn

  Kiel University

  97 shared

• Yuho Kumagai

  96 shared

• Haowen Dang

  96 shared

Education

• Ph.D., Geology

  University of New Mexico

  1990

• M.S., Geology

  University of South Carolina

  1984

• B.S. Geology w/honors, Geology Department

  Saint Lawrence University

  1982

Awards & honors

• Columbia SPS CUNY Fellowship
• Columbia HBCU Fellowship Program