The Pacific Walker circulation—the tropical Pacific zonal overturning circulation of the atmosphere—and the associated sea surface temperature distribution in the tropical Pacific significantly impact global climate. However, climate model historical simulations cannot capture the observed Walker circulation enhancement since around 1980. Although a number of mechanisms have been proposed to explain the observed change, quantitative discussion and clues for reconciling the model-observation discrepancy have not yet been settled. Here we show that the Walker circulation strengthening between 1980 and 2020 can be quantitatively explained by the remote influence of subtropical and extratropical sea surface temperature changes. This conclusion is obtained from climate model pacemaker experiments in which sea surface temperature anomalies outside the tropics are restored towards observations. Influence from the southeastern Pacific, which cools the eastern tropical Pacific, is especially crucial for the Walker circulation strengthening. This equatorward influence occurs mostly through the atmosphere and its thermal coupling with the ocean. We further show that current generation climate models have biases in southeastern Pacific surface temperature changes, which may cause the failure in reproducing the Walker circulation trend. Our results suggest that improved representation of air–sea coupling in this region could enable better projections of future climate. Subtropical and extratropical sea surface temperature changes can explain recent observed Walker circulation strengthening, according to climate model experiments.
{"title":"Walker circulation strengthening driven by sea surface temperature changes outside the tropics","authors":"Masaki Toda, Yu Kosaka, Ayumu Miyamoto, Masahiro Watanabe","doi":"10.1038/s41561-024-01510-5","DOIUrl":"10.1038/s41561-024-01510-5","url":null,"abstract":"The Pacific Walker circulation—the tropical Pacific zonal overturning circulation of the atmosphere—and the associated sea surface temperature distribution in the tropical Pacific significantly impact global climate. However, climate model historical simulations cannot capture the observed Walker circulation enhancement since around 1980. Although a number of mechanisms have been proposed to explain the observed change, quantitative discussion and clues for reconciling the model-observation discrepancy have not yet been settled. Here we show that the Walker circulation strengthening between 1980 and 2020 can be quantitatively explained by the remote influence of subtropical and extratropical sea surface temperature changes. This conclusion is obtained from climate model pacemaker experiments in which sea surface temperature anomalies outside the tropics are restored towards observations. Influence from the southeastern Pacific, which cools the eastern tropical Pacific, is especially crucial for the Walker circulation strengthening. This equatorward influence occurs mostly through the atmosphere and its thermal coupling with the ocean. We further show that current generation climate models have biases in southeastern Pacific surface temperature changes, which may cause the failure in reproducing the Walker circulation trend. Our results suggest that improved representation of air–sea coupling in this region could enable better projections of future climate. Subtropical and extratropical sea surface temperature changes can explain recent observed Walker circulation strengthening, according to climate model experiments.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 9","pages":"858-865"},"PeriodicalIF":15.7,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142089942","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-29DOI: 10.1038/s41561-024-01517-y
Laetitia Parc, Hugo Bellenger, Laurent Bopp, Xavier Perrot, David T. Ho
Rain alters local sea surface physical and biogeochemical properties but its spatiotemporal variability has led to its overlook in global ocean carbon uptake studies. Different physical and chemical processes in the gaseous and liquid phases control the transfer of carbon dioxide (CO2) between the atmosphere and ocean. Rain impacts the interfacial flux by (1) increasing turbulence in the ocean and (2) modulating the air–sea CO2 concentration gradient. Concurrently, raindrops inject CO2 absorbed during their fall into the ocean through wet deposition. Here this study presents a comprehensive estimate of these effects on the global ocean carbon uptake over 2008–2018 based on observational products (satellite and in situ) and reanalysis. Using various representations of the ocean surface response to rainfall and different rain products, we show that rain increases the ocean carbon sink by +0.14–0.19 PgC yr−1 over 2008–2018, representing an increase of 5–7% of the ocean carbon uptake (2.66 PgC yr−1). Rain-induced interfacial flux and wet deposition have comparable orders of magnitude. The former mainly increases the CO2 sink in the tropics because strong rain rates and weak winds induce noticeable salinity and CO2 dilution. The latter is important in the tropics, storm track regions and the Southern Ocean. About 6% of the total uptake of carbon dioxide by the ocean is due to rainfall, according to an analysis of satellite observations and ERA5 reanalysis data from 2008 to 2018.
降雨会改变局部海面的物理和生物地球化学特性，但其时空变异性使其在全球海洋碳吸收研究中被忽视。气态和液态的不同物理和化学过程控制着大气和海洋之间二氧化碳（CO2）的传输。雨水通过（1）增加海洋湍流和（2）调节海气二氧化碳浓度梯度来影响界面通量。同时，雨滴通过湿沉降将其下落过程中吸收的二氧化碳注入海洋。本研究基于观测产品（卫星和现场）和再分析，全面估算了 2008-2018 年期间这些效应对全球海洋碳吸收的影响。利用降雨对海洋表面响应的各种表示方法和不同的降雨产品，我们表明在 2008-2018 年期间，降雨使海洋碳汇增加了 +0.14-0.19 PgC yr-1，相当于海洋碳吸收量（2.66 PgC yr-1）增加了 5-7%。雨水引起的界面通量和湿沉降的数量级相当。前者主要增加了热带地区的二氧化碳汇，因为强降雨率和弱风会导致明显的盐度和二氧化碳稀释。后者在热带、风暴区和南大洋非常重要。
{"title":"Global ocean carbon uptake enhanced by rainfall","authors":"Laetitia Parc, Hugo Bellenger, Laurent Bopp, Xavier Perrot, David T. Ho","doi":"10.1038/s41561-024-01517-y","DOIUrl":"10.1038/s41561-024-01517-y","url":null,"abstract":"Rain alters local sea surface physical and biogeochemical properties but its spatiotemporal variability has led to its overlook in global ocean carbon uptake studies. Different physical and chemical processes in the gaseous and liquid phases control the transfer of carbon dioxide (CO2) between the atmosphere and ocean. Rain impacts the interfacial flux by (1) increasing turbulence in the ocean and (2) modulating the air–sea CO2 concentration gradient. Concurrently, raindrops inject CO2 absorbed during their fall into the ocean through wet deposition. Here this study presents a comprehensive estimate of these effects on the global ocean carbon uptake over 2008–2018 based on observational products (satellite and in situ) and reanalysis. Using various representations of the ocean surface response to rainfall and different rain products, we show that rain increases the ocean carbon sink by +0.14–0.19 PgC yr−1 over 2008–2018, representing an increase of 5–7% of the ocean carbon uptake (2.66 PgC yr−1). Rain-induced interfacial flux and wet deposition have comparable orders of magnitude. The former mainly increases the CO2 sink in the tropics because strong rain rates and weak winds induce noticeable salinity and CO2 dilution. The latter is important in the tropics, storm track regions and the Southern Ocean. About 6% of the total uptake of carbon dioxide by the ocean is due to rainfall, according to an analysis of satellite observations and ERA5 reanalysis data from 2008 to 2018.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 9","pages":"851-857"},"PeriodicalIF":15.7,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41561-024-01517-y.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142089940","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-29DOI: 10.1038/s41561-024-01496-0
T. M. Gernon, B. J. W. Mills, T. K. Hincks, A. S. Merdith, L. J. Alcott, E. J. Rohling, M. R. Palmer
Oceanic anoxic events are geologically abrupt phases of extreme oxygen depletion in the oceans that disrupted marine ecosystems and brought about evolutionary turnover. Typically lasting ~1.5 million years, these events occurred frequently during the Mesozoic era, from about 183 to 85 million years ago, an interval associated with continental breakup and widespread large igneous province volcanism. One hypothesis suggests that anoxic events resulted from enhanced chemical weathering of Earth’s surface in a greenhouse world shaped by high volcanic carbon outgassing. Here we test this hypothesis using a combination of plate reconstructions, tectonic–geochemical analysis and global biogeochemical modelling. We show that enhanced weathering of mafic lithologies during continental breakup and nascent seafloor spreading can plausibly drive a succession of anoxic events. Weathering pulses collectively gave rise to substantial releases of the nutrient phosphorus to the oceans, stimulating biological primary production. This, in turn, enhanced organic carbon burial and caused widespread ocean deoxygenation on a scale sufficient to drive recurrent anoxia. This model complements volcanic outgassing-centred hypotheses for triggering these events by demonstrating well-quantified basaltic sources of phosphorus release during periods of intense weathering related to climate warmth. Our study highlights a close coupling between the solid Earth and biosphere during continental reorganization. Enhanced chemical weathering following continental breakup may have driven a succession of Mesozoic oceanic anoxic events, according to tectonic and biogeochemical modelling.
{"title":"Solid Earth forcing of Mesozoic oceanic anoxic events","authors":"T. M. Gernon, B. J. W. Mills, T. K. Hincks, A. S. Merdith, L. J. Alcott, E. J. Rohling, M. R. Palmer","doi":"10.1038/s41561-024-01496-0","DOIUrl":"10.1038/s41561-024-01496-0","url":null,"abstract":"Oceanic anoxic events are geologically abrupt phases of extreme oxygen depletion in the oceans that disrupted marine ecosystems and brought about evolutionary turnover. Typically lasting ~1.5 million years, these events occurred frequently during the Mesozoic era, from about 183 to 85 million years ago, an interval associated with continental breakup and widespread large igneous province volcanism. One hypothesis suggests that anoxic events resulted from enhanced chemical weathering of Earth’s surface in a greenhouse world shaped by high volcanic carbon outgassing. Here we test this hypothesis using a combination of plate reconstructions, tectonic–geochemical analysis and global biogeochemical modelling. We show that enhanced weathering of mafic lithologies during continental breakup and nascent seafloor spreading can plausibly drive a succession of anoxic events. Weathering pulses collectively gave rise to substantial releases of the nutrient phosphorus to the oceans, stimulating biological primary production. This, in turn, enhanced organic carbon burial and caused widespread ocean deoxygenation on a scale sufficient to drive recurrent anoxia. This model complements volcanic outgassing-centred hypotheses for triggering these events by demonstrating well-quantified basaltic sources of phosphorus release during periods of intense weathering related to climate warmth. Our study highlights a close coupling between the solid Earth and biosphere during continental reorganization. Enhanced chemical weathering following continental breakup may have driven a succession of Mesozoic oceanic anoxic events, according to tectonic and biogeochemical modelling.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 9","pages":"926-935"},"PeriodicalIF":15.7,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41561-024-01496-0.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142090342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-29DOI: 10.1038/s41561-024-01532-z
A. Sanfilippo, A. Stracke, F. Genske, S. Scarani, M. Cuffaro, V. Basch, G. Borghini, D. Brunelli, C. Ferrando, A. A. Peyve, M. Ligi
Seafloor anomalies along mid-ocean ridges with exceptionally thick and compositionally distinct basaltic crust, for example, at Iceland, suggest that the underlying mantle is hotter and chemically different from the adjacent subridge mantle. Here we present hafnium and neodymium isotope ratios of peridotites from the Charlie Gibbs Transform Zone, which is located at the southern end of the Reykjanes Ridge south-west of Iceland. These peridotites are strongly depleted in incompatible elements with extremely high hafnium isotope ratios, suggesting that they had already melted to a large extent before being incorporated into the plume, at least 1 billion years ago, and thereby also became less dense. We argue that seismic velocity anomalies, geodynamic models and geochemical affinities of ridge basalts connect the peridotites from the Charlie Gibbs Transform Zone to the ‘Iceland plume’. The thermochemical buoyancy of the moderately hot Iceland plume, but also that of other plumes worldwide, may therefore be strongly influenced by composition. Variable peridotite depletion along the rising Iceland plume could also cause the transient, density-driven pulses in plume flux, which have formed the V-shaped Reykjanes Ridge south of Iceland. Overall, expansion of a ridge-centred plume along adjacent ridges and melting of heterogeneous plume material explains the topographic swell, the seismic anomaly and the formation of V-shaped ridges, as well as the regional distribution of basalts with Icelandic affinity. The upwelling mantle beneath Iceland underwent melt depletion at least 1 billion years ago and is therefore compositionally buoyant, according to a study of neodymium and hafnium isotope ratios in peridotites from the Charlie Gibbs Transform Zone.
冰岛等大洋中脊的海底异常现象表明，其下的地幔温度较高，化学性质与邻近的海岭下地幔不同。在这里，我们展示了来自查理-吉布斯转换带的橄榄岩的铪和钕同位素比率，该转换带位于冰岛西南部雷克珍海脊的南端。这些橄榄岩中的不相容元素严重贫化，铪同位素比值极高，这表明它们在被纳入羽流之前（至少 10 亿年前）已经在很大程度上熔化，因此密度也变得较低。我们认为，地震速度异常、地球动力学模型和山脊玄武岩的地球化学亲缘关系将查理-吉布斯转换带的橄榄岩与 "冰岛羽流 "联系在一起。因此，中温冰岛羽流以及全球其他羽流的热化学浮力可能受到成分的强烈影响。冰岛羽流上升沿线的橄榄岩消耗量变化不定，这也可能导致羽流流量出现密度驱动的瞬时脉冲，从而在冰岛南部形成了 V 形雷克雅内斯海脊。总之，以海脊为中心的羽流沿邻近海脊扩展和异质羽流物质的熔化解释了地形膨胀、地震异常和 V 形海脊的形成，以及与冰岛有亲缘关系的玄武岩的区域分布。
{"title":"Upwelling of melt-depleted mantle under Iceland","authors":"A. Sanfilippo, A. Stracke, F. Genske, S. Scarani, M. Cuffaro, V. Basch, G. Borghini, D. Brunelli, C. Ferrando, A. A. Peyve, M. Ligi","doi":"10.1038/s41561-024-01532-z","DOIUrl":"10.1038/s41561-024-01532-z","url":null,"abstract":"Seafloor anomalies along mid-ocean ridges with exceptionally thick and compositionally distinct basaltic crust, for example, at Iceland, suggest that the underlying mantle is hotter and chemically different from the adjacent subridge mantle. Here we present hafnium and neodymium isotope ratios of peridotites from the Charlie Gibbs Transform Zone, which is located at the southern end of the Reykjanes Ridge south-west of Iceland. These peridotites are strongly depleted in incompatible elements with extremely high hafnium isotope ratios, suggesting that they had already melted to a large extent before being incorporated into the plume, at least 1 billion years ago, and thereby also became less dense. We argue that seismic velocity anomalies, geodynamic models and geochemical affinities of ridge basalts connect the peridotites from the Charlie Gibbs Transform Zone to the ‘Iceland plume’. The thermochemical buoyancy of the moderately hot Iceland plume, but also that of other plumes worldwide, may therefore be strongly influenced by composition. Variable peridotite depletion along the rising Iceland plume could also cause the transient, density-driven pulses in plume flux, which have formed the V-shaped Reykjanes Ridge south of Iceland. Overall, expansion of a ridge-centred plume along adjacent ridges and melting of heterogeneous plume material explains the topographic swell, the seismic anomaly and the formation of V-shaped ridges, as well as the regional distribution of basalts with Icelandic affinity. The upwelling mantle beneath Iceland underwent melt depletion at least 1 billion years ago and is therefore compositionally buoyant, according to a study of neodymium and hafnium isotope ratios in peridotites from the Charlie Gibbs Transform Zone.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 10","pages":"1046-1052"},"PeriodicalIF":15.7,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41561-024-01532-z.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142090113","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-28DOI: 10.1038/s41561-024-01536-9
Michael P. Byrne
{"title":"Author Correction: Amplified warming of extreme temperatures over tropical land","authors":"Michael P. Byrne","doi":"10.1038/s41561-024-01536-9","DOIUrl":"10.1038/s41561-024-01536-9","url":null,"abstract":"","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 10","pages":"1065-1065"},"PeriodicalIF":15.7,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.nature.com/articles/s41561-024-01536-9.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142397595","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-26DOI: 10.1038/s41561-024-01508-z
Zhi-Ping Zhong, Olivier Zablocki, Yueh-Fen Li, James L. Van Etten, Ellen Mosley-Thompson, Virginia I. Rich, Lonnie G. Thompson, Matthew B. Sullivan
Glaciers archive time-structured information on climates and ecosystems, including microorganisms. However, the long-term ecogenomic dynamics or biogeography of the preserved viruses and their palaeoclimatic connections remain uninvestigated. Here we use metagenomes to reconstruct viral genomes from nine time horizons, spanning three cold-to-warm cycles over the past >41,000 years, preserved in an ice core from Guliya Glacier, Tibetan Plateau. We recover genomes of 1,705 approximately species-level viral operational taxonomic units. Viral communities significantly differ during cold and warm climatic conditions, with the most distinct community observed ~11,500 years ago during the major climate transition from the Last Glacial Stage to the Holocene. In silico analyses of virus–host interactions reveal persistently high viral pressure on Flavobacterium (a common dominant glacier lineage) and historical enrichment in the metabolism of cofactors and vitamins that can contribute to host adaptation and virus fitness under extreme conditions. Biogeographic analyses show that approximately one-fourth of Guliya viral operational taxonomic units overlap with the global dataset, primarily with the Tibetan Plateau metagenomes, suggesting regional associations of a subset of the Guliya-preserved viruses over time. We posit that the cold-to-warm variations in viral communities might be attributed to distinct virus sources and/or environmental selections under different temperature regimes. Genomes recovered from a Tibetan Plateau ice core extending back 41,000 years show that preserved viral communities varied substantially with cold-to-warm climate cycles.
{"title":"Glacier-preserved Tibetan Plateau viral community probably linked to warm–cold climate variations","authors":"Zhi-Ping Zhong, Olivier Zablocki, Yueh-Fen Li, James L. Van Etten, Ellen Mosley-Thompson, Virginia I. Rich, Lonnie G. Thompson, Matthew B. Sullivan","doi":"10.1038/s41561-024-01508-z","DOIUrl":"10.1038/s41561-024-01508-z","url":null,"abstract":"Glaciers archive time-structured information on climates and ecosystems, including microorganisms. However, the long-term ecogenomic dynamics or biogeography of the preserved viruses and their palaeoclimatic connections remain uninvestigated. Here we use metagenomes to reconstruct viral genomes from nine time horizons, spanning three cold-to-warm cycles over the past >41,000 years, preserved in an ice core from Guliya Glacier, Tibetan Plateau. We recover genomes of 1,705 approximately species-level viral operational taxonomic units. Viral communities significantly differ during cold and warm climatic conditions, with the most distinct community observed ~11,500 years ago during the major climate transition from the Last Glacial Stage to the Holocene. In silico analyses of virus–host interactions reveal persistently high viral pressure on Flavobacterium (a common dominant glacier lineage) and historical enrichment in the metabolism of cofactors and vitamins that can contribute to host adaptation and virus fitness under extreme conditions. Biogeographic analyses show that approximately one-fourth of Guliya viral operational taxonomic units overlap with the global dataset, primarily with the Tibetan Plateau metagenomes, suggesting regional associations of a subset of the Guliya-preserved viruses over time. We posit that the cold-to-warm variations in viral communities might be attributed to distinct virus sources and/or environmental selections under different temperature regimes. Genomes recovered from a Tibetan Plateau ice core extending back 41,000 years show that preserved viral communities varied substantially with cold-to-warm climate cycles.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 9","pages":"912-919"},"PeriodicalIF":15.7,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142085127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The surface of Antarctica is continuously shaped by erosion, blowing snow and deposition, resulting in diverse aeolian bedforms akin to those observed in subtropical sand deserts. However, although dunes are universally recognized as a climate and environmental proxy, the properties of snow dunes are not well understood. Here, using satellite images covering most of Antarctica, we report the widespread occurrence (>95% of the area studied) of linear dunes that are between 100 and 1,000 m in length and aligned with the local resultant snow drift direction (61% are longitudinal dunes). On the basis of sand dune theory, we suggest that these snow dunes grow by elongation, often under unidirectional wind regimes. The predominance of the elongating mode indicates a low availability of mobile snow particles. This limited availability prevails at the continental scale due to a subtle balance between snow sintering, which limits erosion, and strong winds, which rapidly remove snowfall. These characteristics result from specific meteorological conditions that distinguish Antarctica from other snow-covered regions, and may shift with future climate changes. We suggest that snow sintering not only influences Antarctic aeolian landform evolution but also regulates the amount of snow sublimated during transport, an uncertain term in the ice-sheet mass balance. Linear aeolian dunes aligned in the direction of snow drift are widespread across Antarctica, indicating a limited supply of mobile snow particles controlled by snow sintering, according to an analysis of satellite imagery.
{"title":"Widespread longitudinal snow dunes in Antarctica shaped by sintering","authors":"Marine Poizat, Ghislain Picard, Laurent Arnaud, Clément Narteau, Charles Amory, Fanny Brun","doi":"10.1038/s41561-024-01506-1","DOIUrl":"10.1038/s41561-024-01506-1","url":null,"abstract":"The surface of Antarctica is continuously shaped by erosion, blowing snow and deposition, resulting in diverse aeolian bedforms akin to those observed in subtropical sand deserts. However, although dunes are universally recognized as a climate and environmental proxy, the properties of snow dunes are not well understood. Here, using satellite images covering most of Antarctica, we report the widespread occurrence (>95% of the area studied) of linear dunes that are between 100 and 1,000 m in length and aligned with the local resultant snow drift direction (61% are longitudinal dunes). On the basis of sand dune theory, we suggest that these snow dunes grow by elongation, often under unidirectional wind regimes. The predominance of the elongating mode indicates a low availability of mobile snow particles. This limited availability prevails at the continental scale due to a subtle balance between snow sintering, which limits erosion, and strong winds, which rapidly remove snowfall. These characteristics result from specific meteorological conditions that distinguish Antarctica from other snow-covered regions, and may shift with future climate changes. We suggest that snow sintering not only influences Antarctic aeolian landform evolution but also regulates the amount of snow sublimated during transport, an uncertain term in the ice-sheet mass balance. Linear aeolian dunes aligned in the direction of snow drift are widespread across Antarctica, indicating a limited supply of mobile snow particles controlled by snow sintering, according to an analysis of satellite imagery.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 9","pages":"889-895"},"PeriodicalIF":15.7,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142042706","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-23DOI: 10.1038/s41561-024-01518-x
Guiyao Zhou, Nico Eisenhauer, Cesar Terrer, David J. Eldridge, Huimin Duan, Emilio Guirado, Miguel Berdugo, Lingyan Zhou, Shengen Liu, Xuhui Zhou, Manuel Delgado-Baquerizo
Terrestrial ecosystems are subjected to multiple global changes simultaneously. Yet, how an increasing number of global changes impact the resistance of ecosystems to global change remains virtually unknown. Here we present a global synthesis including 14,000 observations from seven ecosystem services (functions and biodiversity), as well as data from a 15-year field experiment. We found that the resistance of multiple ecosystem services to global change declines with an increasing number of global change factors, particularly after long-term exposure to these factors. Biodiversity had a higher resistance to multiple global changes compared with ecosystem functions. Our work suggests that we need to consider the combined effects of multiple global changes on the magnitude and resistance of ecosystem services worldwide, as ecosystem responses will be enhanced by the number of environmental stressors and time of exposure. Increasing the number of global changes reduces the resistance of ecosystem services worldwide, according to an analysis of global available observational data and field experiments.
{"title":"Resistance of ecosystem services to global change weakened by increasing number of environmental stressors","authors":"Guiyao Zhou, Nico Eisenhauer, Cesar Terrer, David J. Eldridge, Huimin Duan, Emilio Guirado, Miguel Berdugo, Lingyan Zhou, Shengen Liu, Xuhui Zhou, Manuel Delgado-Baquerizo","doi":"10.1038/s41561-024-01518-x","DOIUrl":"10.1038/s41561-024-01518-x","url":null,"abstract":"Terrestrial ecosystems are subjected to multiple global changes simultaneously. Yet, how an increasing number of global changes impact the resistance of ecosystems to global change remains virtually unknown. Here we present a global synthesis including 14,000 observations from seven ecosystem services (functions and biodiversity), as well as data from a 15-year field experiment. We found that the resistance of multiple ecosystem services to global change declines with an increasing number of global change factors, particularly after long-term exposure to these factors. Biodiversity had a higher resistance to multiple global changes compared with ecosystem functions. Our work suggests that we need to consider the combined effects of multiple global changes on the magnitude and resistance of ecosystem services worldwide, as ecosystem responses will be enhanced by the number of environmental stressors and time of exposure. Increasing the number of global changes reduces the resistance of ecosystem services worldwide, according to an analysis of global available observational data and field experiments.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 9","pages":"882-888"},"PeriodicalIF":15.7,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142042707","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-23DOI: 10.1038/s41561-024-01520-3
Hongtao Xu, Hans W. Chen, Deliang Chen, Yingping Wang, Xu Yue, Bin He, Lanlan Guo, Wenping Yuan, Ziqian Zhong, Ling Huang, Fei Zheng, Tiewei Li, Xiangqi He
Wildfires cause critical shifts in ecosystem functions, such as dramatic reductions in vegetation productivity. However, how fast vegetation regains its pre-fire productivity levels and the key influencing factors remain poorly understood on a global scale. Here we present the global estimates of post-fire vegetation productivity recovery from 2004 to 2021 using gross primary productivity observations and related proxies at a spatial resolution of 10 km, employing a random forest model to identify the key factors influencing recovery time. Roughly 87% of burned vegetation regained pre-fire productivity levels within 2 years, with evergreen needleleaf forests and savannas displaying the lengthiest recovery periods. During the recovery phase, post-fire climate conditions, such as soil moisture, vapour pressure deficit and air temperature, had nonlinear impacts on recovery time globally. These climatic factors exhibited a dominant role in regional recovery time in ~89% of the globally assessed area. As climate aridity decreased, the areas where recovery time was dominated by soil moisture and vapour pressure deficit decreased, while the influence of temperature increased. Soil-moisture-dominated regions witnessed reduced proportions of promoting vegetation recovery as aridity decreased, whereas vapour pressure deficit and air-temperature-dominated regions saw an increase in such proportions. Regions with strong human interventions were associated with accelerated vegetation recovery compared with similar ecosystems with smaller human interventions. These findings had important implications for global carbon-cycle assessments and fire-management strategies. More than 80% of vegetation burned globally regained its pre-fire level of productivity within 2 years, according to an assessment of post-fire vegetation productivity from 2004 to 2021.
{"title":"Global patterns and drivers of post-fire vegetation productivity recovery","authors":"Hongtao Xu, Hans W. Chen, Deliang Chen, Yingping Wang, Xu Yue, Bin He, Lanlan Guo, Wenping Yuan, Ziqian Zhong, Ling Huang, Fei Zheng, Tiewei Li, Xiangqi He","doi":"10.1038/s41561-024-01520-3","DOIUrl":"10.1038/s41561-024-01520-3","url":null,"abstract":"Wildfires cause critical shifts in ecosystem functions, such as dramatic reductions in vegetation productivity. However, how fast vegetation regains its pre-fire productivity levels and the key influencing factors remain poorly understood on a global scale. Here we present the global estimates of post-fire vegetation productivity recovery from 2004 to 2021 using gross primary productivity observations and related proxies at a spatial resolution of 10 km, employing a random forest model to identify the key factors influencing recovery time. Roughly 87% of burned vegetation regained pre-fire productivity levels within 2 years, with evergreen needleleaf forests and savannas displaying the lengthiest recovery periods. During the recovery phase, post-fire climate conditions, such as soil moisture, vapour pressure deficit and air temperature, had nonlinear impacts on recovery time globally. These climatic factors exhibited a dominant role in regional recovery time in ~89% of the globally assessed area. As climate aridity decreased, the areas where recovery time was dominated by soil moisture and vapour pressure deficit decreased, while the influence of temperature increased. Soil-moisture-dominated regions witnessed reduced proportions of promoting vegetation recovery as aridity decreased, whereas vapour pressure deficit and air-temperature-dominated regions saw an increase in such proportions. Regions with strong human interventions were associated with accelerated vegetation recovery compared with similar ecosystems with smaller human interventions. These findings had important implications for global carbon-cycle assessments and fire-management strategies. More than 80% of vegetation burned globally regained its pre-fire level of productivity within 2 years, according to an assessment of post-fire vegetation productivity from 2004 to 2021.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 9","pages":"874-881"},"PeriodicalIF":15.7,"publicationDate":"2024-08-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142042659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-20DOI: 10.1038/s41561-024-01512-3
Guopeng Liang, Artur Stefanski, William C. Eddy, Raimundo Bermudez, Rebecca A. Montgomery, Sarah E. Hobbie, Roy L. Rich, Peter B. Reich
The effects of long-term climate warming on soil respiration and its drivers remain unclear in forests, which store approximately 40% of global soil carbon. Here we conducted a climate change experiment for 13 years in forest plots planted with tree juveniles at two southern boreal forest sites. Treatments included simultaneous above- and below-ground warming (ambient, +1.7 °C and +3.3 °C) under different rainfall scenarios (100% and 60% of summer rainfall) and contrasting overstory canopy openness (open and closed). Soil respiration increased by 7% and 17% under +1.7 °C and +3.3 °C warming, respectively, averaged across all sites, treatments and years. These increases in respiration were higher than impacts per degree warming of the only two prior long-term, but soil-only, forest warming experiments. Moreover, warming effects on soil respiration varied significantly over time. Under almost all conditions, moist soil exhibited a greater increase in respiration in response to warming than dry soil. Our results suggest that a realistic range of anticipated conditions, including both above- and below-ground temperature and moisture, should be accounted for when predicting warming effects on soil respiration. Soil moisture greatly affects the response of soil respiration to warming, according to 13 years of warming experiments in a boreal forest.
{"title":"Soil respiration response to decade-long warming modulated by soil moisture in a boreal forest","authors":"Guopeng Liang, Artur Stefanski, William C. Eddy, Raimundo Bermudez, Rebecca A. Montgomery, Sarah E. Hobbie, Roy L. Rich, Peter B. Reich","doi":"10.1038/s41561-024-01512-3","DOIUrl":"10.1038/s41561-024-01512-3","url":null,"abstract":"The effects of long-term climate warming on soil respiration and its drivers remain unclear in forests, which store approximately 40% of global soil carbon. Here we conducted a climate change experiment for 13 years in forest plots planted with tree juveniles at two southern boreal forest sites. Treatments included simultaneous above- and below-ground warming (ambient, +1.7 °C and +3.3 °C) under different rainfall scenarios (100% and 60% of summer rainfall) and contrasting overstory canopy openness (open and closed). Soil respiration increased by 7% and 17% under +1.7 °C and +3.3 °C warming, respectively, averaged across all sites, treatments and years. These increases in respiration were higher than impacts per degree warming of the only two prior long-term, but soil-only, forest warming experiments. Moreover, warming effects on soil respiration varied significantly over time. Under almost all conditions, moist soil exhibited a greater increase in respiration in response to warming than dry soil. Our results suggest that a realistic range of anticipated conditions, including both above- and below-ground temperature and moisture, should be accounted for when predicting warming effects on soil respiration. Soil moisture greatly affects the response of soil respiration to warming, according to 13 years of warming experiments in a boreal forest.","PeriodicalId":19053,"journal":{"name":"Nature Geoscience","volume":"17 9","pages":"905-911"},"PeriodicalIF":15.7,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142007371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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