Thursday, March 19, 2026

 

'Unprecedented' wildfires in tropical peatlands during 20th century



A new study reveals an unprecedented increase in wildfires in tropical peatlands during the 20th century.  




University of Exeter



A new study reveals an unprecedented increase in wildfires in tropical peatlands during the 20th century.  

Peatlands store vast quantities of carbon below the Earth’s surface – more than all the world’s forest biomass combined – but when they catch fire large amounts of the stored carbon is released into the atmosphere.  

Wildfires in tropical regions have been on the rise in recent decades, but the history and characteristics of wildfires in tropical peatlands remain largely unknown.  

Researchers therefore analysed charcoal records preserved in peat deposits across Central and South America, Africa, Southeast Asia and Australasia to reconstruct wildfire activity stretching back more than two millennia.  

Historically, peatland fire patterns are closely linked to climate fluctuations, particularly the length and severity of droughts.  

The researchers found that wildfire activity in tropical peatlands declined for more than 1,000 years, in line with changes in global temperatures and other natural climate variables. 

But in the last century, there was a dramatic increase in the number of wildfires, and regional differences in the results point to human activities being the root cause.  

The increase in wildfires was mainly confined to the Southeast Asia and Australasian regions, where drainage for agriculture, deforestation and land conversion has left peat soils more vulnerable to ignition.  

But in less accessible peatland regions across South America and Africa, there were no such increases, although lead author Dr Yuwan Wang warns these regions could experience more wildfires too as population density increases and commercial agriculture and infrastructure expands.  

“To avoid large carbon emissions that further contribute to global warming we urgently need to protect these carbon-dense ecosystems,” said Dr Wang from the University of Exeter. 

“A reduction in tropical peatland burning could be achieved through peatland conservation, and promoting sustainable resource management and ecosystem restoration, but this requires the collaboration of multiple groups and has to be carried out at sufficiently large scale.” 

“Unprecedented burning in tropical peatlands during the 20th century compared to the previous two millennia” is published in Global Change Biology. 

 

 

Sunlight-driven “schottky” catalyst quickly removes fulvic acid—a tough drinking-water pollutant precursor





Maximum Academic Press





FA contains complex aromatic and oxygen-containing functional groups, making it chemically stable and difficult to degrade. Although photocatalysis can generate reactive oxygen species under light irradiation, its efficiency is often limited by poor visible-light utilization and rapid charge recombination.

FA, a major humic-substance fraction, forms from long-term transformation of plant residues and microbial metabolites and is widespread in soils, sediments, and surface waters. Its heterogeneous macromolecules contain aromatic moieties, carboxyls, and phenolic hydroxyls that complex metals and co-contaminants, altering their mobility and bioavailability. In drinking-water treatment, FA is troublesome because chlorination can convert it into disinfection by-products such as trihalomethanes and haloacetic acids, raising health concerns and hindering purification. Although photocatalysis generates electron–hole pairs and reactive oxygen species, limited visible-light absorption and fast charge recombination restrict FA removal. Coupling photocatalysis with persulfate AOPs (e.g., PMS) can add oxidants to accelerate degradation and improve mineralization of organics.

A study (DOI:10.48130/aee-0025-0014) published in Agricultural Ecology and Environment on 20 January 2026 by Guangshan Zhang & Chunyan Yang’s team, Qingdao Agricultural University, offers a promising strategy to enhance radical generation and achieve faster, deeper FA degradation in water treatment systems.

Using integrated structural and catalytic diagnostics, the researchers first characterized the BiOCl/MXene photocatalyst by SEM/EDS mapping, TEM/HRTEM, XRD, N₂ adsorption–desorption (BET), and XPS to elucidate morphology, crystallinity, surface area, and interfacial electron transfer. They then evaluated visible-light/PMS performance through synthesis optimization (hydrothermal temperature/time and MXene loading), comparative degradation experiments, kinetic modeling, quantum-yield estimation, and robustness tests across catalyst dosage, FA concentration, pH, coexisting anions, water matrices, recycling cycles, and pollutant types. Photoelectrochemical analyses (UV–vis, PL, EIS, TRPL, Mott–Schottky, photocurrent), radical quenching, and EPR identified charge-transfer behavior and active species, while SUVA, 3D-EEM fluorescence, and TOC tracked structural breakdown and mineralization. SEM and TEM confirmed that BiOCl nanosheets were uniformly anchored on layered MXene with tight interfacial contact, and EDS showed homogeneous Bi/O/Ti/C/Cl distribution. HRTEM resolved BiOCl (101)/(110) and MXene (002) planes, while XRD verified phase coexistence. BET revealed mesoporosity (2–10 nm) and a marked surface-area increase to 41.73 m² g⁻¹ (vs 9.17 m² g⁻¹ for BiOCl), indicating more active sites and improved mass transfer. XPS peak shifts and Bi–O–C bond formation evidenced electron transfer and Schottky-junction construction, promoting carrier separation. Under visible light with PMS, the optimized composite (160 °C, 10 h, 15% MXene) achieved 98.43% FA removal in 30 min, with k = 0.1388 min⁻¹ (3.27× BiOCl) and a synergy factor of 5.28; the apparent quantum yield was ~1.33%, reflecting PMS-assisted electron trapping. High efficiency persisted across pH 3–9 and FA 20–100 mg L⁻¹, with optimal performance at 0.8 g L⁻¹ catalyst and ~2 mM PMS. The catalyst retained >80% activity after five cycles, removed >70% FA in lake water, and effectively degraded antibiotics, dyes, and phenols. Photoelectrochemical data confirmed enhanced visible absorption and faster charge transfer, quenching/EPR identified h⁺ and O₂•⁻ as dominant oxidants, and spectroscopic plus TOC analyses showed rapid chromophore destruction but partial mineralization (49.95%).

FA control is crucial for reducing DBP formation potential before chlorination and improving overall drinking-water safety. This work suggests a practical route: a recyclable visible-light catalyst that activates PMS efficiently, tolerates varied pH and ionic conditions, and performs in complex waters. Beyond FA, the system showed broad activity against different pollutant classes (e.g., antibiotics, dyes, phenols), implying potential use as a flexible AOP platform for mixed-contaminant waters.

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References

DOI

10.48130/aee-0025-0014

Original Souce URL

https://doi.org/10.48130/aee-0025-0014

Funding information

The work was supported by the National Natural Science Foundation of China (Grant Nos 52370174, 52500009), Natural Science Foundation of Shandong Province, China (Grant No. ZR2022ME128), and Harbin Institute of Technology (Weihai) Qingdao Research Institute (Grant No. IQTA10100026).

About Agricultural Ecology and Environment

Agricultural Ecology and Environment (e-ISSN 3070-0639) is a multidisciplinary platform for communicating advances in fundamental and applied research on the agroecological environment, focusing on the interactions between agroecosystems and the environment. It is dedicated to advancing the understanding of the complex interactions between agricultural practices and ecological systems. The journal aims to provide a comprehensive and cutting-edge forum for researchers, practitioners, policymakers, and stakeholders from diverse fields such as agronomy, ecology, environmental science, soil science, and sustainable development.

 

Microwave vegetation monitoring gets a climate upgrade




Journal of Remote Sensing

Correlations between the growing-season VPD anomaly and VOD anomalies in China for 2012 to 2022. 

image: 

 Correlations between the growing-season VPD anomaly and VOD anomalies in China for 2012 to 2022. Correlations of the growing-season anomaly from MODIS NDVI (A), AMSR-E/AMSR2 LPDR X-band (LPDR-X; B), AMSR2 LPRM X-band (LPRM-X; C), AMSR2 LPRM C2-band (LPRM-C2; D), AMSR2 LPRM C1-band (LPRM-C1; E), SMAP operational L-band DCA product (SMAP-DCA; F), SMAP MCCA L-band (MCCA-SMAP; G), and SMOS/SMAP fused L-band VOD product (SMOSMAP-IB; H), with VPD anomaly are shown. Pixels with black dots indicate significant (P < 0.05) correlations. Correlations are estimated from 2012 to 2022, except for SMAP-DCA and MCCA-SMAP, for which correlations are calculated from 2015 to 2022.

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Credit: Journal of Remote Sensing




A new study shows that satellite-based vegetation optical depth, or Vegetation optical depth (VOD), can reveal how plants across China respond to climate stress in very different ways depending on the microwave frequency used. By comparing seven VOD products from 2012 to 2022, researchers found that these signals respond more strongly to water stress than to temperature, and that higher-frequency products are especially effective for detecting short-term vegetation changes. 

Vegetation health is closely tied to climate, but tracking its response over large areas remains difficult. Traditional optical indices such as Normalized Difference Vegetation Index (NDVI) can be affected by cloud cover and atmospheric conditions, while microwave-based Vegetation optical depth (VOD) is more sensitive to changes in vegetation water content and biomass. Even so, scientists have not fully understood how VOD products from different frequencies and retrieval algorithms compare under changing climate conditions. This question is especially important in China, where vegetation greening has accelerated since 2000 and where ecosystems range from humid forests to arid and semiarid landscapes. Based on these challenges, deeper research is needed into how multi-frequency VOD products capture vegetation responses to climate change.

Researchers from Beijing Normal University, Tongji University, INRAE, the University of Montana, NASA Goddard Space Flight Center, Southwest University, and Chalmers University of Technology published the study (DOI: 10.34133/remotesensing.1028) on February 2, 2026, in the Journal of Remote Sensing. The work tackles a practical challenge in Earth observation: selecting the right microwave vegetation signal to monitor how ecosystems respond to heat, atmospheric dryness, and soil water shortage. The findings offer a clearer basis for choosing remote-sensing tools for drought assessment, ecosystem monitoring, and climate-impact studies across China.

The team analyzed seven VOD products spanning X-, C-, and L-band microwave frequencies and found that retrieval frequency mattered more than algorithm choice in explaining differences among products. Across plant functional types, all seven products showed stronger responses to atmospheric and soil water stress than to air temperature, highlighting VOD’s strength for monitoring vegetation water status. X- and C-band VOD products generally captured faster canopy responses and stronger seasonal variation, while L-band products, which penetrate deeper into vegetation, were more sensitive to woody structure and longer-term biomass-related signals. The study also showed that VOD could detect climate carry-over effects, especially in water-limited ecosystems.

The analysis covered China from 2012 to 2022 and focused on seven major plant functional types, including temperate forests, subtropical forests, temperate non-forests, alpine grassland, and three cropland classes. The researchers compared two X-band products, two C-band products, and three L-band products using growing-season anomalies against air temperature, vapor pressure deficit, and surface soil moisture. Among all vegetation types, temperate non-forests stood out as especially water-limited and showed strong positive soil-moisture relationships in X- and C-band VOD products. Across China as a whole, LPDR-X showed the highest positive correlation with soil moisture at r = 0.16, while MCCA-SMAP showed the strongest negative response at r = −0.40, underscoring how differently products can behave. The team also found that including climate conditions from the previous month improved many VOD–climate relationships, particularly for soil moisture, revealing clear one-month carry-over effects in arid and semiarid regions.

Suggested expert quote for press use: “Our results show that VOD is not a single universal indicator. Different frequencies capture different parts of vegetation behavior, and the strongest signal often comes from water stress rather than temperature alone. This means future climate and ecosystem studies can be more precise if they choose the VOD product that best matches the ecological question.” This wording is adapted from the authors’ conclusions.

The study combined seven freely available satellite VOD datasets from AMSR-E, AMSR2, SMAP, and SMOS, covering X-, C-, and L-band microwave observations. All datasets were resampled to 25 km and analyzed during the growing season from April to September. The researchers calculated anomalies relative to monthly climatology and used Pearson correlations to test how VOD changed with temperature, vapor pressure deficit, and soil moisture. They also added a one-month lag analysis to detect carry-over effects from previous climate conditions.

The findings could improve how scientists monitor drought, vegetation water stress, ecosystem resilience, and climate impacts using satellite data. They also suggest that no single VOD product should be used for every application: higher-frequency signals may be better for rapid canopy stress detection, while lower-frequency signals may be more useful for deeper structural changes. As climate extremes intensify, selecting the right microwave product could help refine regional ecological assessment, carbon-cycle research, and early warning systems in vulnerable drylands and agricultural zones.

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References

DOI

10.34133/remotesensing.1028

Original Source URL

https://spj.science.org/doi/10.34133/remotesensing.1028

Funding Information

This work was funded by the Major Program of the Natural Science Foundation of China (42090013) and the General Programs of the Natural Science Foundation of China (42471352).

About Journal of Remote Sensing

The Journal of Remote Sensingan online-only Open Access journal published in association with AIR-CAS, promotes the theory, science, and technology of remote sensing, as well as interdisciplinary research within earth and information science.

 

Researchers refine the clock of Earth’s early complex animal life




University of Lausanne

The study presents a new geological “rock clock” that allows major climate events from the dawn of complex animal life to be dated with unprecedented precision 

image: 

The researchers focused on exceptionally well-preserved sedimentary rocks deposited on ancient seafloors in what is now southern Sweden.

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Credit: Unil





How can we measure time more than 500 million years into the past? A study recently published in Nature Communications by researchers at the University of Lausanne presents a new geological “rock clock” that allows major climate events from the dawn of complex animal life to be dated with unprecedented precision.

The Cambrian Period (approximately 539 to 487 million years ago) represents a pivotal chapter in Earth’s history, marked by the rapid diversification of complex animal life in the oceans. Understanding this evolutionary turning point requires precise constraints on the timing of environmental changes that shaped early ecosystems. Until now, however, dating such ancient events remain challenging, as many sedimentary archives lack direct age markers.

To overcome this limitation, the researchers focused on exceptionally well-preserved sedimentary rocks deposited on ancient seafloors in what is now southern Sweden. These rocks accumulated continuously over millions of years and retain both fossil remains and chemical signatures of past environmental conditions. Using a drill core, the team carried out high-resolution geochemical analyses that capture subtle variations in chemistry and carbon isotopes, central component of Earth’s climate system.

The key advance came from combining these measurements with cyclostratigraphy, a method that identifies the imprint of regular climate cycles driven by small, predictable variations in Earth’s orbit around the Sun. These orbital cycles influence climate in a rhythmic way and leave repeating patterns in sedimentary rocks. By recognizing and quantifying these patterns, the researchers transformed a long sequence of rock strata into a precise, internally consistent timeline anchored directly in the geological record.

This new “rock clock” has made it possible, for the first time, to determine the timing and duration of a major global climate disturbance known as the DrumIan Carbon isotope Excursion (DICE). Beyond refining the geological timescale of the Cambrian, the results allow rock layers and fossil records from different continents to be correlated more accurately. They also provide new insights into how Earth’s climate system and early animal ecosystems responded to natural climate change in a greenhouse world, half a billion years ago.

Funded by an Ambizione grant from the Swiss National Science Foundation (SNSF), the study was carried out at the University of Lausanne in collaboration with researchers from partner institutions in Danemark (University of Copenhagen, Geological Survey of Denmark and Greenland), the United States (George Mason University) and Belgium (University of Liège).

Source : V. Jamart, Damien Pas, Linda A. Hinnov, Jorge E. Spangenberg, Thierry Adatte, Arne T. Nielsen, Niels H. Schovsbo, Nicolas Thibault, Michiel Arts & Allison C. Daley, Astronomical calibration of the middle Cambrian in Baltica: global carbon cycle synchronization and climate dynamics . Nature Communication (2026).