436 results match your criteria: "Lamont-Doherty Earth Observatory of Columbia University[Affiliation]"

How animals respond to seasonal resource availability has profound implications for their dietary flexibility and realized ecological niches. We sought to understand seasonal dietary niche partitioning in extant African suids using intra-tooth stable isotope analysis of enamel. We collected enamel samples from canines of red river hogs/bushpigs ( spp.

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Article Synopsis
  • The Ghana Randomized Air Pollution and Health Study (GRAPHS) analyzed the impact of daily maximum shaded wet bulb globe temperature (WBGTmax) and heat index (HImax) on aspects like birth weight and gestational age in pregnant individuals from 2013 to 2015 in Ghana.
  • Results indicated that higher WBGTmax in specific trimesters affected newborn characteristics differently, with higher temperatures linked to increased head circumference but adverse effects on birth weight and length, highlighting the importance of monitoring temperature variations during pregnancy.
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Recurrent association between colonies and calcifying amoebae.

ISME Commun

January 2024

The Fredy and Nadine Herrmann Institute of Earth Sciences, Hebrew University of Jerusalem, The Edmond J. Safra Campus, Jerusalem 9190401, Israel.

Colonies of the N-fixing cyanobacterium spp. constitute a consortium with multiple microorganisms that collectively exert ecosystem-level influence on marine carbon and nitrogen cycling, shunting newly fixed nitrogen to low nitrogen systems, and exporting both carbon and nitrogen to the deep sea. Here we identify a seasonally recurrent association between puff colonies and amoebae through a two-year survey involving over 10 000 colonies in the Red Sea.

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Modern African ecosystems as landscape-scale analogues for reconstructing woody cover and early hominin environments.

J Hum Evol

December 2024

Division of Earth Sciences, National Science Foundation, 2415 Eisenhower Ave, Alexandria, VA 22314, USA.

Reconstructing habitat types available to hominins and inferring how the paleo-landscape changed through time are critical steps in testing hypotheses about the selective pressures that drove the emergence of bipedalism, tool use, a change in diet, and progressive encephalization. Change in the amount and distribution of woody vegetation has been suggested as one of the important factors that shaped early hominin evolution. Previous models for reconstructing woody cover at eastern African hominin fossil sites used global-scale modern soil comparative datasets.

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Ocean waves are significantly damped by biogenic surfactants, which accumulate at the sea surface in every ocean basin. The growth, development, and breaking of short wind-driven surface waves are key mediators of the air-sea exchange of momentum, heat and trace gases. The mechanisms through which surfactants suppress waves have been studied in great detail through careful laboratory experimentation in quasi-one-dimensional wave tanks.

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Northeast China's Early Cretaceous Yixian Formation preserves spectacular fossils that have proved extraordinarily important in testing evolutionary hypotheses involving the origin of birds and the distribution of feathers among nonavian dinosaurs. These fossils occur either flattened with soft tissue preservation (including feathers and color) in laminated lacustrine strata or as three-dimensional (3D) skeletons in "life-like" postures in more massive deposits. The relationships of these deposits to each other, their absolute ages, and the origin of the extraordinary fossil preservation have been vigorously debated for nearly a half century, with the prevailing view being that preservation was linked to violent volcanic eruptions or lahars, similar to processes that preserved human remains at Pompeii.

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Abundant proxy records suggest a profound reorganization of the Atlantic Meridional Overturning Circulation (AMOC) during the Last Glacial Maximum (LGM, ~21,000 y ago), with the North Atlantic Deep Water (NADW) shoaling significantly relative to the present-day (PD) and forming Glacial North Atlantic Intermediate Water (GNAIW). However, almost all previous observational and modeling studies have focused on the zonal mean two-dimensional AMOC feature, while recent progress in the understanding of modern AMOC reveals a more complicated three-dimensional structure, with NADW penetrating from the subpolar North Atlantic to lower latitude through different pathways. Here, combining Pa/Th reconstructions and model simulations, we uncover a significant change in the three-dimensional structure of the glacial AMOC.

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The end-Triassic extinction (ETE) on land was synchronous with the initial lavas of the Central Atlantic Magmatic Province (CAMP) and occurred just after the brief 26 thousand year (kyr) reverse geomagnetic polarity Chron E23r that can be used for global correlation. Lava-by-lava paleomagnetic secular variation data, previously reported from Morocco and northeastern United States combined with our data for the North Mountain Basalt from the Fundy Basin of Canada show that the initial phase of CAMP volcanism occurred in only five directional groups or pulses each occupying less than a century. The first four directional groups occur during a ~40 kyr period based on available astrochronology and U-Pb geochronology.

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The paucity of fine particulate matter (PM) measurements limits estimates of air pollution mortality in Sub-Saharan Africa. Well calibrated low-cost sensors can provide reliable data especially where reference monitors are unavailable. We evaluate the performance of Clarity Node-S PM monitors against a Tapered element oscillating microbalance (TEOM) 1400a and develop a calibration model in Mombasa, Kenya's second largest city.

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Article Synopsis
  • The late Paleocene and early Eocene periods were marked by long-term global warming and short, abrupt warming events called hyperthermals, largely influenced by greenhouse gases but possibly affected by other factors like tectonics.
  • Researchers analyzed data from planktic foraminifera to reconstruct sea surface temperatures and CO levels, focusing on key events such as the Paleocene-Eocene Thermal Maximum (PETM) and Eocene Thermal Maximum 2 (ETM-2).
  • Findings indicate a strong connection between CO and temperature, with different carbon sources contributing to the CO increases during these periods, and the emissions from these events are comparable to future projections, highlighting their relevance to current climate change discussions.
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Mass coral bleaching on the Great Barrier Reef (GBR) in Australia between 2016 and 2024 was driven by high sea surface temperatures (SST). The likelihood of temperature-induced bleaching is a key determinant for the future threat status of the GBR, 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.

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Disentangling inputs of aeolian dust, ice-rafted debris (IRD), and eroded continental detritus delivered by ocean currents to marine sediments provide important insights into Earth System processes and climate. This study uses Sr-Nd-Pb isotope ratios of the continent-derived (lithogenic) fraction in deep-sea core TN057-6 from the subantarctic Southern Ocean southwest of Africa over the past 150,000 y to identify source regions and quantify their relative contributions and fluxes utilizing a mixing model set in a Bayesian framework. The data are compared with proxies from parallel core Ocean Drilling Program Site 1090 and newly presented data from potential South America aeolian dust source areas (PSAs), allowing for an integrated investigation into atmospheric, oceanic, and cryospheric dynamics.

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A multitude of geochemical processes control the aqueous concentration and transport properties of trace metal contaminants such as arsenic (As) in groundwater environments. Effective As remediation, especially under reducing conditions, has remained a significant challenge. Fe(II) nitrate treatments are a promising option for As immobilization but require optimization to be most effective.

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Background: Between 52-86% of people who menstruate in the United States use tampons-cotton and/or rayon/viscose 'plugs'-to absorb menstrual blood in the vagina. Tampons may contain metals from agricultural or manufacturing processes, which could be absorbed by the vagina's highly absorptive tissue, resulting in systemic exposure. To our knowledge, no previous studies have measured metals in tampons.

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Explainable El Niño predictability from climate mode interactions.

Nature

June 2024

Frontiers Science Center for Deep Ocean Multispheres and Earth System, Physical Oceanography Laboratory, and Sanya Oceanographic Institution, Ocean University of China, Qingdao, China.

The El Niño-Southern Oscillation (ENSO) provides most of the global seasonal climate forecast skill, yet, quantifying the sources of skilful predictions is a long-standing challenge. Different sources of predictability affect ENSO evolution, leading to distinct global effects. Artificial intelligence forecasts offer promising advancements but linking their skill to specific physical processes is not yet possible, limiting our understanding of the dynamics underpinning the advancements.

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The origin of rupture segmentation along subduction zone megathrusts and linkages to the structural evolution of the subduction zone are poorly understood. Here, regional-scale seismic imaging of the Cascadia margin is used to characterize the megathrust spanning ~900 km from Vancouver Island to the California border, across the seismogenic zone to a few tens of kilometers from the coast. Discrete domains in lower plate geometry and sediment underthrusting are identified, not evident in prior regional plate models, which align with changes in lithology and structure of the upper plate and interpreted paleo-rupture patches.

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During Heinrich events, great armadas of icebergs episodically flooded the North Atlantic Ocean and weakened overturning circulation. The ice discharges of these episodes constrain the sensitivity of overturning circulation to iceberg melting. We reconstructed these ice discharges to be as high as 0.

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Article Synopsis
  • The study explored the link between arsenic levels in community water systems and private wells and the incidence of type 2 diabetes (T2D) among participants in two major studies: the Strong Heart Family Study (SHFS) and the Multi-Ethnic Study of Atherosclerosis (MESA).
  • A total of 7,568 participants (1,791 from SHFS and 5,777 from MESA) without T2D at baseline were monitored for new cases, finding a higher incidence of T2D associated with increased arsenic levels in the water supplies, particularly among certain demographics.
  • Results indicated that even low to moderate levels of arsenic in drinking water (<10 µ
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Prenatal Household Air Pollution Exposure and Childhood Blood Pressure in Rural Ghana.

Environ Health Perspect

March 2024

Kintampo Health Research Centre, Research and Development Division, Ghana Health Service, Kintampo North Municipality, Ghana.

Background: The association between prenatal household air pollution (HAP) exposure and childhood blood pressure (BP) is unknown.

Objective: Within the Ghana Randomized Air Pollution and Health Study (GRAPHS) we examined time-varying associations between ) maternal prenatal and ) first-year-of-life HAP exposure with BP at 4 years of age and, separately, whether a stove intervention delivered prenatally and continued through the first year of life could improve BP at 4 years of age.

Methods: GRAPHS was a cluster-randomized cookstove intervention trial wherein pregnant women were randomized to one of two stove interventions: ) a liquefied petroleum gas (LPG) stove or improved biomass stove, or ) control (open fire cooking).

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Synchronous retreat of Thwaites and Pine Island glaciers in response to external forcings in the presatellite era.

Proc Natl Acad Sci U S A

March 2024

Ion Beam Physics, Eidgenössische Technische Hochschule Zürich, Zürich 8093, Switzerland.

Today, relatively warm Circumpolar Deep Water is melting Thwaites Glacier at the base of its ice shelf and at the grounding zone, contributing to significant ice retreat. Accelerating ice loss has been observed since the 1970s; however, it is unclear when this phase of significant melting initiated. We analyzed the marine sedimentary record to reconstruct Thwaites Glacier's history from the early Holocene to present.

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In this study, we present a comprehensive atmospheric radiocarbon (C) record spanning from 1940 to 2016, derived from 77 single tree rings of Cedrela odorata located in the Eastern Amazon Basin (EAB). This record, comprising 175 high-precision C measurements obtained through accelerator mass spectrometry (AMS), offers a detailed chronology of post-1950 CE (Common Era) C fluctuations in the Tropical Low-Pressure Belt (TLPB). To ensure accuracy and reliability, we included C-AMS results from intra-annual successive cuts of the tree rings associated to the calendar years 1962 and 1963 and conducted interlaboratory comparisons.

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