Pub Date : 2025-01-04DOI: 10.1016/j.gloplacha.2025.104694
Haibo He, Zaihua Liu, Jingan Chen, Dongli Li, Yuyouting Wang, Yongqiang Han, Xing Liu, Hailong Sun, Quan Chen, Wenfang Cao
Lakes exhibit a biological pump (BP) effect, akin to marine systems, acting as a carbon sequestration mechanism. In karst lakes, the BP works in synergy with a more efficient carbonate pump (CP), enhancing phosphorus (P) removal. This synergy provides a plausible explanation for the observed P enrichment in karst lake sediments. It is hypothesized that an enhanced BP effect drives the CP, accelerating the co-precipitation of carbonates with P, resulting in the accumulation of calcium-bound P compounds (CaP). However, these hypotheses remain largely unquantified and unverified. Research into centennial-scale multi-proxy sedimentary records from Fuxian Lake, a representative karst lake in China, showed significant correlations among organic and inorganic carbon, including contents, fluxes, and isotopic profiles, demonstrating the interplay between the BP and the CP. Carbonate δ18O data further support the conclusion that the BP is the primary driver of the CP. Moreover, a strong correlation (r > 0.6, P < 0.0001) between organic-inorganic carbon proxies and sedimentary P has been identified. Compared to phytoplankton, submerged plants significantly boost P co-precipitation (forming CaP) through the BP mechanism by facilitating a more efficient CP. CaP, the main component within stable sedimentary P reservoirs, saw a post-1950 burial flux increase to 3.5 times that of the preceding period, reaching 0.24 g P m−2 yr−1. This underscores the CP's effectiveness in P sequestration under increased anthropogenic pressure. Given the uniquely high weathering rates, Ca2+, pH, and dissolved inorganic carbon content of karst lakes, we suggest that their strong BP effect, combined with the CP, significantly enhances P removal, offering an autogenic solution to eutrophication.
湖泊表现出生物泵（BP）效应，类似于海洋系统，作为碳固存机制。在喀斯特湖泊中，BP与更高效的碳酸盐泵（CP）协同工作，增强了磷(P)的去除。这种协同作用为观察到的喀斯特湖泊沉积物中磷的富集提供了合理的解释。假设BP效应的增强驱动CP，加速碳酸盐与P的共沉淀，导致钙结合P化合物（CaP）的积累。然而，这些假设在很大程度上仍未被量化和验证。通过对中国代表性喀斯特湖泊抚仙湖100年多代沉积记录的研究，发现有机碳和无机碳在含量、通量和同位素剖面等方面具有显著的相关性，证明了BP与CP之间的相互作用。碳酸盐岩δ18O数据进一步支持了BP是CP的主要驱动因素的结论。0.6, P <；0.0001)，有机质-无机碳代用物与沉积P之间存在差异。与浮游植物相比，沉水植物通过BP机制显著促进P共降水（形成CaP），促进更有效的CP。CaP是稳定沉积P储层的主要成分，其埋藏通量在1950年后增加到前一时期的3.5倍，达到0.24 g P m−2 yr−1。这强调了在人为压力增加的情况下，CP在固磷方面的有效性。鉴于喀斯特湖泊独特的高风化速率、Ca2+、pH和溶解无机碳含量，我们认为它们强大的BP效应，加上CP，显著增强了P的去除，为富营养化提供了自源解决方案。
{"title":"Enhanced biological pump and carbonate pump synergy: The primary pathway for phosphorus clearance in the century-long dynamics of a karst lake","authors":"Haibo He, Zaihua Liu, Jingan Chen, Dongli Li, Yuyouting Wang, Yongqiang Han, Xing Liu, Hailong Sun, Quan Chen, Wenfang Cao","doi":"10.1016/j.gloplacha.2025.104694","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2025.104694","url":null,"abstract":"Lakes exhibit a biological pump (BP) effect, akin to marine systems, acting as a carbon sequestration mechanism. In karst lakes, the BP works in synergy with a more efficient carbonate pump (CP), enhancing phosphorus (P) removal. This synergy provides a plausible explanation for the observed P enrichment in karst lake sediments. It is hypothesized that an enhanced BP effect drives the CP, accelerating the co-precipitation of carbonates with P, resulting in the accumulation of calcium-bound P compounds (Ca<ce:glyph name=\"sbnd\"></ce:glyph>P). However, these hypotheses remain largely unquantified and unverified. Research into centennial-scale multi-proxy sedimentary records from Fuxian Lake, a representative karst lake in China, showed significant correlations among organic and inorganic carbon, including contents, fluxes, and isotopic profiles, demonstrating the interplay between the BP and the CP. Carbonate δ<ce:sup loc=\"post\">18</ce:sup>O data further support the conclusion that the BP is the primary driver of the CP. Moreover, a strong correlation (<ce:italic>r</ce:italic> > 0.6, <ce:italic>P</ce:italic> < 0.0001) between organic-inorganic carbon proxies and sedimentary P has been identified. Compared to phytoplankton, submerged plants significantly boost P co-precipitation (forming Ca<ce:glyph name=\"sbnd\"></ce:glyph>P) through the BP mechanism by facilitating a more efficient CP. Ca<ce:glyph name=\"sbnd\"></ce:glyph>P, the main component within stable sedimentary P reservoirs, saw a post-1950 burial flux increase to 3.5 times that of the preceding period, reaching 0.24 g P m<ce:sup loc=\"post\">−2</ce:sup> yr<ce:sup loc=\"post\">−1</ce:sup>. This underscores the CP's effectiveness in P sequestration under increased anthropogenic pressure. Given the uniquely high weathering rates, Ca<ce:sup loc=\"post\">2+</ce:sup>, pH, and dissolved inorganic carbon content of karst lakes, we suggest that their strong BP effect, combined with the CP, significantly enhances P removal, offering an autogenic solution to eutrophication.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"2 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975634","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 : 2025-01-04DOI: 10.1016/j.gloplacha.2025.104695
Karol O. Duarte, Igor M. Venancio, Rodrigo A. Nascimento, Ana Luiza S. Albuquerque, Thiago P. Santos, Stefano Crivellari, Cristiano M. Chiessi, IODP Expedition 383 Shipboard Scientists
Southern-sourced intermediate waters play a central role in global ocean oxygenation and nutrient transport to low latitudes. However, the glacial-interglacial variability in their formation rate and geometry are not well constrained. Here we present a new ca. 787 thousand years-long benthic foraminifera stable carbon isotopic record from the Southeast Pacific, near the main formation region of Antarctic Intermediate Water (AAIW), which allows the investigation of changes in the formation rate and transport of AAIW over the last 787 kyr. Our results show glacial-interglacial changes in AAIW transport, with more AAIW being exported towards the Atlantic Ocean during interglacials, and to the low-latitude Pacific Ocean during glacials. We hypothesize that the AAIW exportation from the Pacific to the Atlantic Ocean is controlled by transport through the Drake Passage, which is reduced (increased) during glacial (interglacial) periods. The observed pattern is probably related to a combination of factors, including reduced (increased) sea-ice extent and southward (northward) shift of oceanic fronts and/or the westerlies during interglacials (glacials). Our mechanism reconciles the greater influence of AAIW in the northern Chilean margin during glacial periods, concurrent with the previously suggested decrease in formation rate and shallowing of this water mass. Ultimately, the glacial-interglacial variability in AAIW exportation to the Atlantic Ocean may be closely linked with changes in the stability of Atlantic Meridional Overturning Circulation during these distinct climate background states.
{"title":"Glacial-interglacial changes in Antarctic Intermediate Water advection in the Southeast Pacific during the last 787 kyr","authors":"Karol O. Duarte, Igor M. Venancio, Rodrigo A. Nascimento, Ana Luiza S. Albuquerque, Thiago P. Santos, Stefano Crivellari, Cristiano M. Chiessi, IODP Expedition 383 Shipboard Scientists","doi":"10.1016/j.gloplacha.2025.104695","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2025.104695","url":null,"abstract":"Southern-sourced intermediate waters play a central role in global ocean oxygenation and nutrient transport to low latitudes. However, the glacial-interglacial variability in their formation rate and geometry are not well constrained. Here we present a new ca. 787 thousand years-long benthic foraminifera stable carbon isotopic record from the Southeast Pacific, near the main formation region of Antarctic Intermediate Water (AAIW), which allows the investigation of changes in the formation rate and transport of AAIW over the last 787 kyr. Our results show glacial-interglacial changes in AAIW transport, with more AAIW being exported towards the Atlantic Ocean during interglacials, and to the low-latitude Pacific Ocean during glacials. We hypothesize that the AAIW exportation from the Pacific to the Atlantic Ocean is controlled by transport through the Drake Passage, which is reduced (increased) during glacial (interglacial) periods. The observed pattern is probably related to a combination of factors, including reduced (increased) sea-ice extent and southward (northward) shift of oceanic fronts and/or the westerlies during interglacials (glacials). Our mechanism reconciles the greater influence of AAIW in the northern Chilean margin during glacial periods, concurrent with the previously suggested decrease in formation rate and shallowing of this water mass. Ultimately, the glacial-interglacial variability in AAIW exportation to the Atlantic Ocean may be closely linked with changes in the stability of Atlantic Meridional Overturning Circulation during these distinct climate background states.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"29 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975633","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 : 2025-01-03DOI: 10.1016/j.gloplacha.2025.104696
Jiahao Han, Shibo Fang, Xiaomao Lin, Zhanhao Zhang, Man Li, Yanru Yu, Wen Zhuo, Xinyu Wang
Increased atmospheric water vapor pressure due to the warming climate has led to more frequent and extreme precipitation events, which has resulted in incalculable losses. The hydrothermal circulation suggests that extreme daytime and nighttime precipitation patterns can have many distinct consequences,ranging from changes in various scale hydrological cycles to social security concerns. However, the spatio-temporal patterns of daytime and nighttime precipitation events remain underexplored, lacking quantitative analysis. Therefore, our study analyzed daily precipitation data (including 24-h, daytime, and nighttime) from 1981 to 2022 across China to investigate extreme precipitation patterns at a half-day scale (daytime and nighttime). Fourteen monthly extreme indices associated with atmospheric circulations and sea surface temperatures were examined to clarify precipitation distribution patterns using random forest and optimal fingerprinting techniques. The main findings are: (1) A clear upward trend was found in cumulative precipitation, intensifying the frequency of extreme precipitation events. Notably, the increase in both accumulated 24-h precipitation and the rate of nighttime precipitation exceeded the rate of daytime precipitation between 1981 and 2022. This trend became more pronounced as precipitation events became more extreme. (2) Most regions in China exhibited an increasing trend in both cumulative precipitation days and total precipitation, particularly in the North China Plain, although the Yunnan-Guizhou Plateau saw significant decreases in both variables. (3) Extreme precipitation events were primarily driven by changes in the different types of the Subtropical High (Western Pacific, South China Sea, and Northern Hemisphere Subtropical High), along with the typhoons southeast of the Hu Huanyong line. These findings enhance the understanding of hydrothermal exchange processes and extreme precipitation, providing a useful basis for climate change adaptations in China.
{"title":"Half-day (daytime and nighttime) precipitation extremes in China: Changes and attribution from 1981 to 2022","authors":"Jiahao Han, Shibo Fang, Xiaomao Lin, Zhanhao Zhang, Man Li, Yanru Yu, Wen Zhuo, Xinyu Wang","doi":"10.1016/j.gloplacha.2025.104696","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2025.104696","url":null,"abstract":"Increased atmospheric water vapor pressure due to the warming climate has led to more frequent and extreme precipitation events, which has resulted in incalculable losses. The hydrothermal circulation suggests that extreme daytime and nighttime precipitation patterns can have many distinct consequences,ranging from changes in various scale hydrological cycles to social security concerns. However, the spatio-temporal patterns of daytime and nighttime precipitation events remain underexplored, lacking quantitative analysis. Therefore, our study analyzed daily precipitation data (including 24-h, daytime, and nighttime) from 1981 to 2022 across China to investigate extreme precipitation patterns at a half-day scale (daytime and nighttime). Fourteen monthly extreme indices associated with atmospheric circulations and sea surface temperatures were examined to clarify precipitation distribution patterns using random forest and optimal fingerprinting techniques. The main findings are: (1) A clear upward trend was found in cumulative precipitation, intensifying the frequency of extreme precipitation events. Notably, the increase in both accumulated 24-h precipitation and the rate of nighttime precipitation exceeded the rate of daytime precipitation between 1981 and 2022. This trend became more pronounced as precipitation events became more extreme. (2) Most regions in China exhibited an increasing trend in both cumulative precipitation days and total precipitation, particularly in the North China Plain, although the Yunnan-Guizhou Plateau saw significant decreases in both variables. (3) Extreme precipitation events were primarily driven by changes in the different types of the Subtropical High (Western Pacific, South China Sea, and Northern Hemisphere Subtropical High), along with the typhoons southeast of the Hu Huanyong line. These findings enhance the understanding of hydrothermal exchange processes and extreme precipitation, providing a useful basis for climate change adaptations in China.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"59 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142935463","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 : 2025-01-02DOI: 10.1016/j.gloplacha.2025.104693
Tony Reimann, Christine Heim, Dietmar Quandt, Tibor J. Dunai, Martin Melles, Benedikt Ritter
The availability of water influences the evolution of life as well as the evolution of the Earth's land surface. Until recently, role of geomorphological and biological (geo-bio) processes including their interactions and inferred co-evolution have been poorly understood for extremely water-limited (hyper-arid) environments. This emerging field lies at the nexus of weathering, soil (crust) formation and erosion but also involves landform evolution, which creates barriers or corridors for life across varied geological time scales. To address the complex issues that arise from this field, the German Research Foundation (DFG) has funded Collaborative Research Centre CRC1211 (Earth–Evolution at the Dry Limit) through interdisciplinary research. The natural laboratories used for this work are the hyper-arid cores of the Atacama and Namib deserts, and the main objective has been to gain improved understanding of the evolution of the geosphere and biosphere in hyper-arid environments and to evaluate interactions between these spheres. We hypothesize that phases or events of higher water-availability (by fog, dew or rain) are the key drivers of geo-bio co-evolution. Furthermore, we hypothesize that barriers of geological, geomorphological, and climatic origin are the main controls on present-day biodiversity at various heirarchies including ecosystem dynamics. To test these hypotheses, the studies reported in this virtual special issue (VSI) combine expertise from the fields of population and (phylo-) genetics, molecular biology, biogeography, ecology, soil sciences, geomorphology, meteorology, (palaeo-) climatology, (isotope-) geochemistry and geochronology to shed new light on the trajectories and thresholds of the evolution and isolation of life. This article collection reports recent progress in the hope of motivating and inspiring scientists from all over the world to collaborate on a more comprehensive and quantitative understanding of dry-limited systems, with a view to implementing this understanding into overarching Earth system models.
{"title":"Editorial preface to special issue: Earth-evolution at the Dry Limit","authors":"Tony Reimann, Christine Heim, Dietmar Quandt, Tibor J. Dunai, Martin Melles, Benedikt Ritter","doi":"10.1016/j.gloplacha.2025.104693","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2025.104693","url":null,"abstract":"The availability of water influences the evolution of life as well as the evolution of the Earth's land surface. Until recently, role of geomorphological and biological (geo-bio) processes including their interactions and inferred co-evolution have been poorly understood for extremely water-limited (hyper-arid) environments. This emerging field lies at the nexus of weathering, soil (crust) formation and erosion but also involves landform evolution, which creates barriers or corridors for life across varied geological time scales. To address the complex issues that arise from this field, the German Research Foundation (DFG) has funded Collaborative Research Centre CRC1211 (<ce:italic>Earth–Evolution at the Dry Limit</ce:italic>) through interdisciplinary research. The natural laboratories used for this work are the hyper-arid cores of the Atacama and Namib deserts, and the main objective has been to gain improved understanding of the evolution of the geosphere and biosphere in hyper-arid environments and to evaluate interactions between these spheres. We hypothesize that phases or events of higher water-availability (by fog, dew or rain) are the key drivers of geo-bio co-evolution. Furthermore, we hypothesize that barriers of geological, geomorphological, and climatic origin are the main controls on present-day biodiversity at various heirarchies including ecosystem dynamics. To test these hypotheses, the studies reported in this virtual special issue (VSI) combine expertise from the fields of population and (phylo-) genetics, molecular biology, biogeography, ecology, soil sciences, geomorphology, meteorology, (palaeo-) climatology, (isotope-) geochemistry and geochronology to shed new light on the trajectories and thresholds of the evolution and isolation of life. This article collection reports recent progress in the hope of motivating and inspiring scientists from all over the world to collaborate on a more comprehensive and quantitative understanding of dry-limited systems, with a view to implementing this understanding into overarching Earth system models.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"14 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975644","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 : 2024-12-30DOI: 10.1016/j.gloplacha.2024.104691
Jimin Sun, Weiguo Liu, Brian F. Windley, Longxiao Xu, Tongyan Lü
The Junggar Basin, located in mid-latitude Central Asia, is an inland basin that is one of the remotest area from any open seas on Earth. Knowledge about the paleoclimatic change and the relevant driving factors in this specific geographical region is critically important for understanding the Cenozoic aridification processes in the Asian hinterland. In this study, we focused on Miocene strata in the northwestern Junggar Basin, which consist of middle Miocene fluviolacustrine sediments and a late Miocene aeolian/reworked red clay. Our data of the paleoclimatic indices of color index, magnetic susceptibility and stable isotopes indicate a middle Miocene warm humid climate between 17.5 and 14 Ma, and a subsequent shift to an arid climate after 14 Ma. This paleoclimatic shift was synchronous with a biotic turnover marked by a transition from a high degree of mammal diversity dominated by large-sized mammals living in a humid forest grassland during the Middle Miocene Climatic Optimum to a late Miocene small-sized mammal-dominant fauna living in dry open steppe. The above correlations imply an intrinsic link between environmental change and biotic evolution. We suggest that a decrease in sea surface temperature and the westward retreat of Paratethys induced by global cooling were the key factors responsible for the enhanced aridity of the Asian inland after 14 Ma, which controlled the reduced water vapor transported by the Westerlies to the interior of Asia.
{"title":"Enhanced aridity in the interior of Asia after the Middle Miocene Climatic Optimum driven by global cooling","authors":"Jimin Sun, Weiguo Liu, Brian F. Windley, Longxiao Xu, Tongyan Lü","doi":"10.1016/j.gloplacha.2024.104691","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104691","url":null,"abstract":"The Junggar Basin, located in mid-latitude Central Asia, is an inland basin that is one of the remotest area from any open seas on Earth. Knowledge about the paleoclimatic change and the relevant driving factors in this specific geographical region is critically important for understanding the Cenozoic aridification processes in the Asian hinterland. In this study, we focused on Miocene strata in the northwestern Junggar Basin, which consist of middle Miocene fluviolacustrine sediments and a late Miocene aeolian/reworked red clay. Our data of the paleoclimatic indices of color index, magnetic susceptibility and stable isotopes indicate a middle Miocene warm humid climate between 17.5 and 14 Ma, and a subsequent shift to an arid climate after 14 Ma. This paleoclimatic shift was synchronous with a biotic turnover marked by a transition from a high degree of mammal diversity dominated by large-sized mammals living in a humid forest grassland during the Middle Miocene Climatic Optimum to a late Miocene small-sized mammal-dominant fauna living in dry open steppe. The above correlations imply an intrinsic link between environmental change and biotic evolution. We suggest that a decrease in sea surface temperature and the westward retreat of Paratethys induced by global cooling were the key factors responsible for the enhanced aridity of the Asian inland after 14 Ma, which controlled the reduced water vapor transported by the Westerlies to the interior of Asia.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"35 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142935474","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 : 2024-12-29DOI: 10.1016/j.gloplacha.2024.104689
Reema Kasera, Vijay K. Minocha
The adverse impact of El Niño on Indian summer monsoon rainfall (ISMR) is well established, with documented physical mechanisms linking different flavors of El Niño and ISMR. However, few studies have discussed the pathways that connect different onsets of El Niño and ISMR. The present study identifies the two ENSO categories (spring and summer) depending on the occurrence time of positive sea surface temperature anomalies (SSTA) in the Niño-3.4 region of the Pacific Ocean. The distinct impacts of these El Niño types on ISMR were investigated by analyzing extensive composites of rainfall anomalies, Sea Surface Temperature (SST) patterns, and atmospheric circulation dynamics. It was found that the Indian region experiences a significant average negative deviation of 26 % from normal rainfall across 30 % of the country during spring El Niño (SPE) (February to May). Whereas a summer El Niño (SUE) (June to September) is distinguished by a significant negative deviation over 15 % of the Indian region with an average deviation of 22 % across the country. SPE events showed strong warmth with an average of 1.27 °C, while SUE events had milder warmth, averaging 0.84 °C. Further, a strong positive Indian Ocean dipole (IOD) phenomenon was observed during the SPE event, which was associated with a strong easterly wind. This positive IOD phenomenon was progressively developed from June to September, heading to the establishment of low pressure over Western Indian Ocean (WIO), resulting in altered or weakened Walker circulation. The study elucidates the intricate interaction between El Niño events and the Indian monsoon system, providing a vital understanding of the mechanisms that govern seasonal rainfall variability across the Indian subcontinent.
El Niño对印度夏季季风降雨（ISMR）的不利影响已得到证实，有文献记录的物理机制将不同类型的El Niño与ISMR联系起来。然而，很少有研究讨论连接El Niño和ISMR不同发病的途径。根据太平洋Niño-3.4区域正海温异常（SSTA）的发生时间，本研究确定了两个ENSO类别（春季和夏季）。通过分析降雨异常、海温模式和大气环流动力学的广泛组合，研究了这些El Niño类型对ISMR的不同影响。研究发现，在春季El Niño (SPE)（2月至5月）期间，印度地区与全国30%的地区的正常降雨量平均负偏差为26%。而夏季厄尔尼诺Niño (SUE)（6月至9月）在印度地区的显著负偏差超过15%，全国平均偏差为22%。SPE事件表现出较强的升温，平均为1.27°C，而SUE事件表现出较弱的升温，平均为0.84°C。此外，SPE事件期间观测到强烈的印度洋正偶极子（IOD）现象，该现象与强烈的东风有关。从6月到9月，这一正IOD现象逐渐发展，走向西印度洋（WIO）低压的建立，导致Walker环流改变或减弱。该研究阐明了El Niño事件与印度季风系统之间复杂的相互作用，为理解控制整个印度次大陆季节性降雨变化的机制提供了重要的理解。
{"title":"Impact of El Niño onset timing on Indian Monsoon Rainfall patterns","authors":"Reema Kasera, Vijay K. Minocha","doi":"10.1016/j.gloplacha.2024.104689","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104689","url":null,"abstract":"The adverse impact of El Niño on Indian summer monsoon rainfall (ISMR) is well established, with documented physical mechanisms linking different flavors of El Niño and ISMR. However, few studies have discussed the pathways that connect different onsets of El Niño and ISMR. The present study identifies the two ENSO categories (spring and summer) depending on the occurrence time of positive sea surface temperature anomalies (SSTA) in the Niño-3.4 region of the Pacific Ocean. The distinct impacts of these El Niño types on ISMR were investigated by analyzing extensive composites of rainfall anomalies, Sea Surface Temperature (SST) patterns, and atmospheric circulation dynamics. It was found that the Indian region experiences a significant average negative deviation of 26 % from normal rainfall across 30 % of the country during spring El Niño (SPE) (February to May). Whereas a summer El Niño (SUE) (June to September) is distinguished by a significant negative deviation over 15 % of the Indian region with an average deviation of 22 % across the country. SPE events showed strong warmth with an average of 1.27 °C, while SUE events had milder warmth, averaging 0.84 °C. Further, a strong positive Indian Ocean dipole (IOD) phenomenon was observed during the SPE event, which was associated with a strong easterly wind. This positive IOD phenomenon was progressively developed from June to September, heading to the establishment of low pressure over Western Indian Ocean (WIO), resulting in altered or weakened Walker circulation. The study elucidates the intricate interaction between El Niño events and the Indian monsoon system, providing a vital understanding of the mechanisms that govern seasonal rainfall variability across the Indian subcontinent.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"60 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142905665","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 : 2024-12-29DOI: 10.1016/j.gloplacha.2024.104690
Wei Shang, Keqin Duan, Wei Yu, Li Xing, Peihong Shi
The freezing level height (FLH) reflects the thermal conditions in the troposphere and implies cryospheric changes on the Tibetan Plateau (TP). This study aims to understand whether variations in the FLH over the TP are linked to midlatitude and tropical signals, which is currently unknown. An empirical orthogonal function analysis is utilized to investigate the east-west dipole pattern of the summer FLH over the TP during the period of 1961–2019. The results show that the dipole pattern of the FLH is mainly associated with the circumglobal teleconnection (CGT) waves, propagating from the North Atlantic Ocean to East Asia. A pair of anomalous cyclone and anticyclone related to the CGT pattern is observed, in favor for cooling and warming over the western and eastern TP, respectively. The thermodynamic equation diagnosis demonstrate that the CGT-related upward and downward motions accompanied by adiabatic cooling and heating, primarily contribute to the decreases and increases of FLH. As the thermal effect of the east-west dipole FLH occurs, the CGT waves are strengthened downstream to North Pacific and North America. Meanwhile, the lower-level easterly anomalies and westerly anomalies winds appear over the Indian Ocean and tropical Pacific. From summer to the following winter, anomalous westerly winds persistently prevail over the tropical Pacific, weakening the Walker circulation and leading to subsequent El Niño–Southern Oscillation (ENSO) events. Without the dipole mode of the TP FLH impact, the CGT-ENSO relationship could be weakened. The results suggest that the dipole pattern of the TP FLH acts as a linking bridge between the CGT pattern and ENSO events, which also verify the key role of TP in connecting the midlatitude and tropical climate variabilities.
{"title":"Influence of the circumglobal teleconnection on the following ENSO: From the perspective of the freezing level height over the Tibetan Plateau","authors":"Wei Shang, Keqin Duan, Wei Yu, Li Xing, Peihong Shi","doi":"10.1016/j.gloplacha.2024.104690","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104690","url":null,"abstract":"The freezing level height (FLH) reflects the thermal conditions in the troposphere and implies cryospheric changes on the Tibetan Plateau (TP). This study aims to understand whether variations in the FLH over the TP are linked to midlatitude and tropical signals, which is currently unknown. An empirical orthogonal function analysis is utilized to investigate the east-west dipole pattern of the summer FLH over the TP during the period of 1961–2019. The results show that the dipole pattern of the FLH is mainly associated with the circumglobal teleconnection (CGT) waves, propagating from the North Atlantic Ocean to East Asia. A pair of anomalous cyclone and anticyclone related to the CGT pattern is observed, in favor for cooling and warming over the western and eastern TP, respectively. The thermodynamic equation diagnosis demonstrate that the CGT-related upward and downward motions accompanied by adiabatic cooling and heating, primarily contribute to the decreases and increases of FLH. As the thermal effect of the east-west dipole FLH occurs, the CGT waves are strengthened downstream to North Pacific and North America. Meanwhile, the lower-level easterly anomalies and westerly anomalies winds appear over the Indian Ocean and tropical Pacific. From summer to the following winter, anomalous westerly winds persistently prevail over the tropical Pacific, weakening the Walker circulation and leading to subsequent El Niño–Southern Oscillation (ENSO) events. Without the dipole mode of the TP FLH impact, the CGT-ENSO relationship could be weakened. The results suggest that the dipole pattern of the TP FLH acts as a linking bridge between the CGT pattern and ENSO events, which also verify the key role of TP in connecting the midlatitude and tropical climate variabilities.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"1 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142935467","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 : 2024-12-26DOI: 10.1016/j.gloplacha.2024.104685
Yuming Wang, Xiaohong Chen, Adam D. Switzer, Linlin Li, Yang Xu, Yukun Wang, Elaine Tan, Peizhen Zhang
The northern coast of the South China Sea (SCS) is a densely populated and economically important area. Despite the absence of any tsunamigenic events in the last century in this region, their occurrence on a much longer timescale remains largely unknown. Given the catastrophic consequences a potential tsunami event could bring, we aim to bridge this research gap by conducting high-resolution sedimentological, geochemical, and geochronological analyses on two well-preserved offshore sedimentary columns, B01 and D02, from the northern SCS, at depths of −27 and − 46 m, respectively. Using statistical methods, we identified two anomalous sediment units, each ∼30 to 40 cm thick, in both columns. These units are dominated by coarse-grained, poorly sorted sediments with a normally graded sequence. Each unit is rich in biogenic debris, devoid of parallel or cross-bedding, and has a unique set of elemental and isotopic signatures. They contain allochthonous biological species and record a disordered age-depth pattern. Such observations are indicative of the sudden input of marine components, suggesting an instantaneous high-energy event. The median calibrated ages, measured by accelerator mass spectrometry (AMS), from shell and foraminifera in the anomalous units, return the mixed ages of 4454–842 cal. yr BP and 2098–840 cal. yr BP, respectively. Shell and foraminifera above and below the anomalous units define AMS 14C ages of 951–779 cal. yr BP, with a median age of ∼868 cal. yr BP. Our data collectively point to a tsunami event at ∼868 cal. yr BP, equivalent to the North-Song Dynasty of ∼1000 years ago. This age pattern is consistent with reported tsunami events in and around the SCS, also compatible with historical accounts describing a “tidal overflow in Eastern Guangdong and Eastern Fujian at AD1067–1068” in Chinese documents. Combined with available data, the ca 868 cal. yr BP tsunami event in the SCS likely originated from the joint interaction of earthquakes induced by the Manila Subduction Zone and the Littoral Fault Zone, along with related landslide activities within the northern SCS.
{"title":"About 868 cal. yr BP tsunami event at the northern South China Sea revealed from offshore sediments","authors":"Yuming Wang, Xiaohong Chen, Adam D. Switzer, Linlin Li, Yang Xu, Yukun Wang, Elaine Tan, Peizhen Zhang","doi":"10.1016/j.gloplacha.2024.104685","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104685","url":null,"abstract":"The northern coast of the South China Sea (SCS) is a densely populated and economically important area. Despite the absence of any tsunamigenic events in the last century in this region, their occurrence on a much longer timescale remains largely unknown. Given the catastrophic consequences a potential tsunami event could bring, we aim to bridge this research gap by conducting high-resolution sedimentological, geochemical, and geochronological analyses on two well-preserved offshore sedimentary columns, B01 and D02, from the northern SCS, at depths of −27 and − 46 m, respectively. Using statistical methods, we identified two anomalous sediment units, each ∼30 to 40 cm thick, in both columns. These units are dominated by coarse-grained, poorly sorted sediments with a normally graded sequence. Each unit is rich in biogenic debris, devoid of parallel or cross-bedding, and has a unique set of elemental and isotopic signatures. They contain allochthonous biological species and record a disordered age-depth pattern. Such observations are indicative of the sudden input of marine components, suggesting an instantaneous high-energy event. The median calibrated ages, measured by accelerator mass spectrometry (AMS), from shell and foraminifera in the anomalous units, return the mixed ages of 4454–842 cal. yr BP and 2098–840 cal. yr BP, respectively. Shell and foraminifera above and below the anomalous units define AMS <ce:sup loc=\"post\">14</ce:sup>C ages of 951–779 cal. yr BP, with a median age of ∼868 cal. yr BP. Our data collectively point to a tsunami event at ∼868 cal. yr BP, equivalent to the North-Song Dynasty of ∼1000 years ago. This age pattern is consistent with reported tsunami events in and around the SCS, also compatible with historical accounts describing a “tidal overflow in Eastern Guangdong and Eastern Fujian at AD1067–1068” in Chinese documents. Combined with available data, the ca 868 cal. yr BP tsunami event in the SCS likely originated from the joint interaction of earthquakes induced by the Manila Subduction Zone and the Littoral Fault Zone, along with related landslide activities within the northern SCS.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"1 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142975682","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 : 2024-12-24DOI: 10.1016/j.gloplacha.2024.104687
Kaikai Wu, Xuefa Shi, Shengfa Liu, Franck Bassinot, Christophe Colin, Hui Zhang, Che Abd. Rahim Mohamed
Marine concretions are an important source of information regarding resources, climate, and environment. However, the genesis of ferruginous concretions on the continental shelf remains unclear. In this study, we present the radiocarbon ages (AMS14C), elemental compositions, and mineral compositions of ferruginous concretions obtained from a gravity core on the central Sunda Shelf. The results indicate that the formation ages of ferruginous concretions range from 10.5 to 7.5 cal ka BP from the bottom to the top of the core. The predominant mineral identified in these concretions is goethite, which cements clay and other minerals in colloidal form. Notably, Fe, Si, and Al display distinct ring-band rhythmic variations. Our study suggests that ferruginous concretions are formed in subaerial and aqueous environments, with a weathered stiff clay layer serving as the main stratum for concretion development. During periods of low sea levels (before 10.5 cal ka BP), paleo-channels likely provided fluctuating wet and dry conditions for the formation of light and dark concentric layers within ferruginous concretions. Between 10.5 and 7.5 cal ka BP, the Sunda Shelf was gradually inundated, leading to the partial transport of concretions from nearby channels. Subsequently, after 7.5 cal ka BP, the paleo-channels became completely submerged, halting the formation of ferruginous concretions on the Sunda Shelf. Meanwhile, ferruginous concretions on the seafloor became mixed with sediments and marine organisms due to hydrodynamic sorting. The presence of ferruginous concretions can serve as an indicator of paleo-channel locations, aiding in the reconstruction of paleo-channel systems during periods of low sea level on the shallow continental shelf.
海洋沉积物是有关资源、气候和环境信息的重要来源。然而，大陆架上含铁结块的成因仍不清楚。本文报道了巽他陆架中部重力岩心中含铁结块的放射性碳年龄（AMS14C）、元素组成和矿物组成。结果表明，铁质结核的形成年龄从岩心底部到顶部为10.5 ~ 7.5 cal ka BP。在这些固结物中发现的主要矿物是针铁矿，它以胶体形式粘合粘土和其他矿物。值得注意的是，铁、硅和铝显示出明显的环带节奏变化。研究表明，含铁结垢形成于陆基和水环境中，风化硬化粘土层是结垢发育的主要地层。在低海平面时期（10.5 cal ka BP之前），古河道可能为含铁结岩内明暗同心层的形成提供了波动的干湿条件。在10.5 ~ 7.5 cal ka BP之间，巽他陆架逐渐被淹没，导致附近河道的部分凝块被搬运。随后，在7.5 cal ka BP之后，古河道完全被淹没，停止了巽他陆架上铁质结核的形成。同时，由于水动力分选，海底的含铁结块与沉积物和海洋生物混合在一起。含铁结块的存在可以作为古河道位置的指示物，有助于浅陆架低海平面时期古河道系统的重建。
{"title":"The origin of ferruginous concretions on the Sunda Shelf (SE Asia) and its environmental implications","authors":"Kaikai Wu, Xuefa Shi, Shengfa Liu, Franck Bassinot, Christophe Colin, Hui Zhang, Che Abd. Rahim Mohamed","doi":"10.1016/j.gloplacha.2024.104687","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104687","url":null,"abstract":"Marine concretions are an important source of information regarding resources, climate, and environment. However, the genesis of ferruginous concretions on the continental shelf remains unclear. In this study, we present the radiocarbon ages (AMS<ce:sup loc=\"post\">14</ce:sup>C), elemental compositions, and mineral compositions of ferruginous concretions obtained from a gravity core on the central Sunda Shelf. The results indicate that the formation ages of ferruginous concretions range from 10.5 to 7.5 cal ka BP from the bottom to the top of the core. The predominant mineral identified in these concretions is goethite, which cements clay and other minerals in colloidal form. Notably, Fe, Si, and Al display distinct ring-band rhythmic variations. Our study suggests that ferruginous concretions are formed in subaerial and aqueous environments, with a weathered stiff clay layer serving as the main stratum for concretion development. During periods of low sea levels (before 10.5 cal ka BP), paleo-channels likely provided fluctuating wet and dry conditions for the formation of light and dark concentric layers within ferruginous concretions. Between 10.5 and 7.5 cal ka BP, the Sunda Shelf was gradually inundated, leading to the partial transport of concretions from nearby channels. Subsequently, after 7.5 cal ka BP, the paleo-channels became completely submerged, halting the formation of ferruginous concretions on the Sunda Shelf. Meanwhile, ferruginous concretions on the seafloor became mixed with sediments and marine organisms due to hydrodynamic sorting. The presence of ferruginous concretions can serve as an indicator of paleo-channel locations, aiding in the reconstruction of paleo-channel systems during periods of low sea level on the shallow continental shelf.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"180 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142905666","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 oceanic carbon cycles have a significant effect on the climate transitions by influencing the atmospheric CO2 levels. As one of the largest carbon sinks, the Northwest Pacific is the key to understand how the carbon cycles react to past and future climate changes. In this study, the marine productivity in Northwest Pacific over the last 25,000 years has been comprehensively reconstructed using 230Th-normalized biogenic fluxes recorded in a series of sedimentary cores. Our results show contrasting onsets of productivity pulse between cores from the subarctic and the subtropical gyres, while both have been controlled by the nutrient supply related to ocean circulation. Specifically, the wind-driven southward shift of subarctic gyre combined with stronger East Asia winter monsoon during the Last Glacial Maximum and early deglaciation supplied more nutrients to the south and stimulated the subtropical productivity, while this process synchronously limited the subarctic productivity especially with downward extension of the North Pacific Intermediate Water (NPIW). The contraction of subarctic gyre associated with the collapse of the NPIW during the Bølling-Allerød generated the productivity pulse in subarctic region and lowered the subtropical productivity. Terrigenous inputs, reconstructed from 232Th fluxes, however, mainly affected the productivity in the subtropical gyre over the last glacial cycle, especially for the marginal region, in contrast to the pelagic subarctic gyre. Our findings reveal an interplay between subarctic and subtropical gyres and their integrated impacts on marine productivity, providing a paleoceanographic perspective to understand the carbon budget across different timescales in the Northwest Pacific.
{"title":"Marine productivity controlled by oceanic circulation in the Northwest Pacific over the last glacial cycle","authors":"Limin Hu, Hao Fang, Xuefa Shi, Yuying Zhang, Zhifei Duan, Chao Li, Jörg Lippold, Minoru Ikehara, Yiming Luo","doi":"10.1016/j.gloplacha.2024.104686","DOIUrl":"https://doi.org/10.1016/j.gloplacha.2024.104686","url":null,"abstract":"The oceanic carbon cycles have a significant effect on the climate transitions by influencing the atmospheric CO<ce:inf loc=\"post\">2</ce:inf> levels. As one of the largest carbon sinks, the Northwest Pacific is the key to understand how the carbon cycles react to past and future climate changes. In this study, the marine productivity in Northwest Pacific over the last 25,000 years has been comprehensively reconstructed using <ce:sup loc=\"post\">230</ce:sup>Th-normalized biogenic fluxes recorded in a series of sedimentary cores. Our results show contrasting onsets of productivity pulse between cores from the subarctic and the subtropical gyres, while both have been controlled by the nutrient supply related to ocean circulation. Specifically, the wind-driven southward shift of subarctic gyre combined with stronger East Asia winter monsoon during the Last Glacial Maximum and early deglaciation supplied more nutrients to the south and stimulated the subtropical productivity, while this process synchronously limited the subarctic productivity especially with downward extension of the North Pacific Intermediate Water (NPIW). The contraction of subarctic gyre associated with the collapse of the NPIW during the Bølling-Allerød generated the productivity pulse in subarctic region and lowered the subtropical productivity. Terrigenous inputs, reconstructed from <ce:sup loc=\"post\">232</ce:sup>Th fluxes, however, mainly affected the productivity in the subtropical gyre over the last glacial cycle, especially for the marginal region, in contrast to the pelagic subarctic gyre. Our findings reveal an interplay between subarctic and subtropical gyres and their integrated impacts on marine productivity, providing a paleoceanographic perspective to understand the carbon budget across different timescales in the Northwest Pacific.","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"23 1","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-12-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142905675","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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