Global and Planetary Change最新文献

{"title":"Radium fingerprinting traces hydrology of the global cryosphere under climate warming","authors":"Zhe Zhang,&nbsp;Lixin Yi,&nbsp;Ruotong Li,&nbsp;Tianxue Lyu,&nbsp;Chenyi Liu,&nbsp;Yingchun Dong","doi":"10.1016/j.gloplacha.2024.104654","DOIUrl":"10.1016/j.gloplacha.2024.104654","url":null,"abstract":"<div><div>Dynamic changes in the cryosphere have profound implications for global warming. This study, through case studies of seasonal ice lakes and glacier-originated rivers, complemented by global data, offers novel insights into radium (Ra) isotopes' characteristic in the cryosphere. It elucidates the quantification of the “Ra quartet” as tracers in frozen hydrological processes across various timescales. (1) Theoretical case studies. Significant differences in water chemistry and Ra activities were observed, highlighting distinct Ra supply and depletion mechanisms. The improved Ra mass model was utilized to estimate the freezing duration of the lakes and the groundwater discharge beneath the ice, while also elucidating the recharge dynamics of groundwater along glacial rivers. (2) Global scale theoretical discoveries. The low ²²⁴Ra/²²⁸Ra ratio, including the case studies presented, may be a significant characteristic of the non-subterranean cryosphere. This phenomenon can be attributed to various processes, including decay, particulate scavenging, groundwater discharge, upwelling, and glacial meltwater. In contrast, the ratio observed in permafrost is more complex, potentially influenced by diverse hydrogeological conditions and intricate sampling protocols. While Ra isotopes are well-traced in the ocean cryosphere—covering groundwater discharge, water exchange, and composition-particle interactions—their application in terrestrial and atmospheric cryospheric studies remains underexplored. Our study provides novel perspectives on Ra isotopes in the cryosphere, offering crucial theoretical and practical implications for addressing ongoing climate warming.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"244 ","pages":"Article 104654"},"PeriodicalIF":4.0,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721907","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}

{"title":"Late Cretaceous ecosystem dynamics in the southern incipient Arctic Ocean: A micropaleontological and geochemical perspective","authors":"J.F. Diaz ,&nbsp;L. Schwark ,&nbsp;P.K. Pedersen ,&nbsp;J.M. Galloway ,&nbsp;M. Bringué ,&nbsp;S.E. Grasby","doi":"10.1016/j.gloplacha.2024.104643","DOIUrl":"10.1016/j.gloplacha.2024.104643","url":null,"abstract":"<div><div>Micropaleontological and geochemical analyses in samples from the Coniacian-Maastrichtian-aged Smoking Hills and Mason River formations in the Anderson Basin of the northern mainland coast of Arctic Canada provide a refined picture of the environmental conditions occurring in the incipient southern Arctic Ocean at the end of the Cretaceous. These units were deposited within a 22 myr time span in an outer shelf setting characterized by relatively stable tectonic conditions and low sedimentation rates. The Coniacian-middle Campanian Smoking Hills Formation was deposited during times of marine transgression and water column stratification. Surface waters were highly productive and dominated by dinoflagellates, red algae, green algae and likely diatoms and silicoflagellates. Bottom waters were predominantly anoxic-euxinic, but the presence of benthic foraminifera and variations of geochemical signatures in some intervals indicate episodic ventilation. The deposition of the Smoking Hills Formation is temporally consistent with the Oceanic Anoxic Event 3 (OAE3), but the duration of these anoxic conditions is much longer in the Anderson Basin. During the middle Campanian, relative sea level reached a highstand, fostering the expansion of planktic siliceous microorganisms, including diatoms, silicoflagellates and radiolarians. During the late Campanian to at least the Maastrichtian, sediments of the Mason River Formation were deposited during a regressive sedimentation phase characterized by high productivity fueled by river run-off and the proliferation of diatoms, red and green algae. Despite high productivity, bottom waters were oxygenated. This study highlights the importance of data integration to reconstruct the environmental conditions of the past as many, if not all, of the proxies utilized to this end are subjected to preservational and diagenetic bias.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"244 ","pages":"Article 104643"},"PeriodicalIF":4.0,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721906","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}

{"title":"Molybdenum isotopic evidence for linked changes in North Pacific Intermediate Water and subtropical Northwest Pacific redox conditions over the last 200 k.y","authors":"Yanguang Dou ,&nbsp;Chenghui Sun ,&nbsp;Shouye Yang ,&nbsp;Xuefa Shi ,&nbsp;Yonghua Wu ,&nbsp;Jingyi Cong ,&nbsp;Yong Zhang ,&nbsp;Fengmei Wang ,&nbsp;Feng Cai ,&nbsp;Peter D. Clift","doi":"10.1016/j.gloplacha.2024.104637","DOIUrl":"10.1016/j.gloplacha.2024.104637","url":null,"abstract":"<div><div>Through biological productivity and ocean-atmosphere CO₂ exchange, North Pacific mid-depth ventilation has the potential to regulate regional climate over glacial timescales. Nevertheless, the subtropical Northwest Pacific currently lacks continuous long redox records that would enable us to evaluate this process. In this instance, we present δ^98/95Mo and redox-sensitive trace element data derived from Okinawa Trough sediments to reconstruct redox conditions and assess their possible significance in regulating atmospheric CO₂ in the subtropical Northwest Pacific over the last 200 k.y. Enhanced oxic conditions induced by a strengthened Kuroshio Current during Marine Isotope Stage (MIS) 1 suggest the presence of enhanced deep water ventilation and upwelling in the Okinawa Trough, which likely contributed to high atmospheric CO₂ concentrations during interglacial periods. The Okinawa Trough may have been oxic and served as a regional net carbon sink during MIS2 and MIS6, due to glacial North Pacific Intermediate Water (GNPIW) and a weak Kuroshio Current. During interglacials, high productivity brought on by the stronger East Asian Summer Monsoon (EASM) leads to an increase in organic matter burial and oxygen consumption. This substantial positive excursion in δ^98/95Mo values during MIS4 and early MIS3 can be linked to the anaerobic oxidation of methane (AOM) and the release of methane-rich fluids from methane hydrate decomposition. Our findings highlight potential links between higher upwelling, GNPIW expansion, and the underlying processes regulating the atmospheric CO₂ budget in the subtropical North Pacific during the late Quaternary.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"244 ","pages":"Article 104637"},"PeriodicalIF":4.0,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721826","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}

{"title":"Possible influence of low latitude wetland area changes on the Holocene global atmospheric methane concentration trend","authors":"Yunping Song ,&nbsp;Hai Xu ,&nbsp;Kevin M. Yeager","doi":"10.1016/j.gloplacha.2024.104655","DOIUrl":"10.1016/j.gloplacha.2024.104655","url":null,"abstract":"<div><div>Understanding the causes of variations in global atmospheric methane concentration (GAMC) is an important issue in the study of global climatic changes. Long-term GAMC varied rhythmically on glacial-interglacial timescales, and broadly followed the orbital/suborbital cycles in northern hemisphere solar insolation. Yet the late Holocene has witnessed an increasing GAMC trend since the mid-Holocene, which decouples with the global atmospheric CO₂ concentration trend and the northern hemisphere solar insolation trend. The causes of this decoupling have been extensively studied, but remain highly debated. Here we show that the Holocene GAMC trend closely follows the long-term trend in global low latitude wetland extent as inferred from our lake-level reconstruction and from other existing hydroclimate records. We contend that changes in low latitude wetland extent play an important role in shaping the GAMC trend. We propose that reduced low latitude wetland areas during the mid-Holocene, which were likely due to the submersion of tropical wetlands by rising sea levels, and reduced low latitude wetland areas inferred from lower lake levels, could be responsible for the observed mid-Holocene GAMC drop. Increasing global low latitude wetland areas during the late Holocene are likely responsible for the contemporary increasing GAMC trend.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"244 ","pages":"Article 104655"},"PeriodicalIF":4.0,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721908","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}

{"title":"Iron isotope fractionation during granite weathering under different climates","authors":"Meng Qi ,&nbsp;Chengshuai Liu ,&nbsp;Ting Gao ,&nbsp;Zhengrong Wang ,&nbsp;Yuhui Liu ,&nbsp;Yafei Xia","doi":"10.1016/j.gloplacha.2024.104653","DOIUrl":"10.1016/j.gloplacha.2024.104653","url":null,"abstract":"<div><div>Climate controls chemical weathering of silicate rocks on the transport of iron (Fe) and its isotopes from continent to the ocean, impacting the global Fe geochemical cycle. However, it's elusive if Fe isotope fractionation during silicate weathering reflects variations in climate factors. This study examines two granite-derived regolith profiles; one in Beijing (BJ), representing a temperate climate, and the other in Guangdong (GD), representing a tropical climate, to investigate their mineralogy, Fe-bearing phases, element concentrations, and Fe isotope compositions. Our results show that, despite climate differences, the two granite weathering profiles have average δ⁵⁶Fe_{bulk regolith} values within analytical uncertainty (0.09 ± 0.02 ‰ vs. 0.12 ± 0.04 ‰, 2SD). The δ⁵⁶Fe_{bulk regolith} values of temperate and tropical regolith are similar to or slightly higher than those of their respective bedrocks and remain steady along the entire weathering profile. The limited variation of Fe isotope composition in weakly weathered temperate regolith likely reflects the dissolution of primary minerals rather than the formation of secondary minerals. The Rayleigh fractionation calculations also show a Δ⁵⁶Fe_{pore solution-regolith} value of ∼0 ‰ between pore solution and regolith. In contrast, in the tropical profile, despite the abundance of secondary minerals and the differences in δ⁵⁶Fe values among the extracted Fe-pools exceeding 0.68 ‰, only limited Fe isotope fractionation is observed in the bulk regolith (0.01 ‰ to 0.24 ‰). These variations are likely driven by the formation of Fe oxides, relying on the atomic distribution of Fe in hematite and goethite. The linear regression analysis estimates the apparent Fe isotope fractionation factor between hematite and goethite as 0.46 ± 0.07 ‰ (Δ⁵⁶Fe_{hematite-goethite}, 1SE). These findings indicate that the sensitivity of Fe isotope fractionation in bulk regolith to variations in climate factors is relatively limited. However, combined with results from other weathering profiles in different climate zones, two models suggest that changes in δ⁵⁶Fe values of easily leachable and silicate-bound Fe pools are likely influenced by climate factors such as temperature and precipitation. This work advances our understanding of the Fe isotope fractionation during silicate weathering and its potential climate connection on Earth's surface.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"244 ","pages":"Article 104653"},"PeriodicalIF":4.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142721909","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}

{"title":"Impact of ENSO on extreme precipitation in Southwest Asia","authors":"Omid Alizadeh ,&nbsp;Morteza Mousavizadeh","doi":"10.1016/j.gloplacha.2024.104645","DOIUrl":"10.1016/j.gloplacha.2024.104645","url":null,"abstract":"<div><div>The El Niño-Southern Oscillation (ENSO) is a primary driver of interannual variability in extreme precipitation in many regions worldwide. Understanding the relationship between ENSO and extreme precipitation is crucial, as it has implications for understanding the interannual variability of flood risk. We investigated the frequency of extreme daily precipitation in Southwest Asia across different seasons during El Niño and La Niña using the daily GPCP and ERA5 precipitation datasets for the period 1997–2022. Extreme precipitation at each grid point is defined as daily accumulated precipitation exceeding the 95th percentile on wet days, where a wet day is defined as one with at least 0.1 mm rainfall. El Niño is associated with an overall increase in the frequency of extreme precipitation in Southwest Asia during autumn, winter, and spring, whereas La Niña shows the opposite effect. To explore the dynamics of El Niño and La Niña teleconnections to Southwest Asia, we applied a feature tracking method on the ERA5 relative velocity at 850 hPa in different seasons. Overall, the storm track density and the mean intensity of storms increase in Southwest Asia during El Niño and decrease during La Niña in autumn, winter, and spring. In summer, El Niño favors less frequent extreme precipitation in the southern parts of Southwest Asia, where the tropical summer monsoon circulation is dominated, while La Niña is associated with more frequent extreme precipitation in this region. This pattern is expected, as the monsoon circulation is weaker during El Niño and stronger during La Niña. In line with this, we identified a decrease in the mean intensity of storms in the southern parts of Southwest Asia during El Niño, with the opposite occuring during La Niña. Our findings have important implications for understanding interannual variability of extreme precipitation in Southwest Asia and providing a framework for predicting such events.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"244 ","pages":"Article 104645"},"PeriodicalIF":4.0,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700875","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}

{"title":"Effects of climate change and methane-rich fluid activity on sedimentary sulfur geochemical records in the northern South China Sea since mid-Pleistocene","authors":"Junxi Feng ,&nbsp;Yufei Zhang ,&nbsp;Niu Li ,&nbsp;Jianhou Zhou ,&nbsp;Jinqiang Liang ,&nbsp;Qianyong Liang ,&nbsp;Shengxiong Yang ,&nbsp;Duofu Chen ,&nbsp;Harunur Rashid","doi":"10.1016/j.gloplacha.2024.104644","DOIUrl":"10.1016/j.gloplacha.2024.104644","url":null,"abstract":"<div><div>Microbial sulfate reduction (MSR) and associated pyritic sulfide formation are important diagenetic processes in marine sediments. The sulfur isotopic composition of pyrite (δ³⁴S_pyr) is proven to be sensitive to changes in sedimentation rates and the content and reactivity of organic carbon, especially on the continental shelves and upper slopes (water depth &lt; 350 m). However, the diagenetic responses of sulfur to variations in climatic and depositional conditions in the deep-sea sediments are still poorly understood. This study combines element contents and isotopes to characterize diagenetic interplays of sulfur, organic carbon, and methane in the continental slope sediments of the northern South China Sea since the mid-Pleistocene. Our data suggest that the total organic carbon (TOC) increased during glacial times, implying enhanced primary productivity due to increased nutrient supply by the East Asian Winter Monsoon, in addition to efficient transfer of organic carbon and better preservation of organic carbon due to reduced bottom water oxygen. Total sulfur and chromium reduction sulfur contents varied concomitantly with the TOC, suggesting an increased burial of organic carbon that enhanced the organoclastic sulfate reduction (OSR) and the formation of authigenic pyrite. The environmental changes did not induce a significant shift in δ³⁴S_pyr, due most likely to relatively low sedimentation rates and large fractionation in sulfur isotope through OSR during the glacial-interglacial cycles. Instead, it is hypothesized that the sulfate-driven anaerobic methane oxidation promoted the formation of a higher amount of authigenic pyrite. Consequently, it created a closed diagenetic system leading to positive excursions in δ³⁴S_pyr at the sulfate-methane transition zone. Our results suggest the vulnerability of pyrite formation and its sulfur isotopic composition to the changes in monsoon-driven primary productivity and the methane-rich fluid migrations in the continental margin sediments. This study complements the growing evidence for the local diagenetic controls on sedimentary sulfur geochemical records by highlighting the importance of early diagenesis in paleoenvironment reconstruction based on the content and sulfur isotopic composition of pyrite.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"244 ","pages":"Article 104644"},"PeriodicalIF":4.0,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700893","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}

{"title":"Stalagmite records of spatiotemporal hydroclimatic variations in monsoonal China during 47–12 ka BP","authors":"Miaomiao Wang,&nbsp;Haiwei Zhang,&nbsp;Youwei Li,&nbsp;Rui Zhang,&nbsp;Jian Wang,&nbsp;Hanying Li,&nbsp;Yuteng Zhao,&nbsp;Xiaomei Zhang,&nbsp;Zeyuan Liang,&nbsp;Youfeng Ning,&nbsp;Hai Cheng","doi":"10.1016/j.gloplacha.2024.104639","DOIUrl":"10.1016/j.gloplacha.2024.104639","url":null,"abstract":"<div><div>Recent high-resolution sediment records, such as Greenland ice cores and Chinese stalagmites, have greatly enhanced our understanding of millennial-scale climate variability during Heinrich Stadials (HSs) of the Last Glacial Period, particularly highlighting the diminished intensity of the Asian Summer Monsoon (ASM). These records reveal precise temporal correlations between high-latitude climate changes and low-latitude monsoon variability, especially in the Asian monsoon region. However, the scarcity of stalagmite records from southeastern China has limited our understanding of the spatio-temporal patterns of monsoonal precipitation variability during these abrupt climate events, as most published records are concentrated in central-northern and southwestern China. In this study, we present a high-resolution hydroclimate reconstruction based on stalagmite YXG01 from Yindi Cave, Hubei Province, China, using 42 U-Th dates and 698 δ¹⁸O and δ¹³C isotope measurements, spanning the 11.92–47.47 ka BP interval. Our δ¹⁸O record shows four positive excursions, indicating significantly weakened ASM intensity during the four most recent HSs (HS1 to HS4), consistent with previous studies. During these HSs, freshwater influx into the North Atlantic weakened the Atlantic Meridional Overturning Circulation, cooled Northern Hemisphere temperatures, and reduced ASM circulation/intensity, resulting in consistent positive δ¹⁸O shifts in precipitation and stalagmites across the East Asian monsoon region. We found that the amplitude of stalagmite δ¹⁸O variations during the HSs decreases progressively from Southwest China to Southeast China, a trend that aligns with simulated changes in precipitation δ¹⁸O. The smaller amplitude of δ¹⁸O shifts in southeastern China during the HSs may be linked to increased moisture contributions from the western Pacific Ocean and enhanced local precipitation. During these HSs, anti-phased variations between YXG01 δ¹⁸O and δ¹³C, together with temperature reconstructions and model simulations, suggest favorable hydroclimatic conditions in the mid-lower reaches of the Yangtze River Valley. Increased precipitation and moderate temperature may have enhanced vegetation growth, resulting in lower speleothem δ¹³C values despite the overall weakening of ASM circulation. Our new speleothem YXG01 record reveals two important observations from Southeast China: a smaller amplitude of speleothem δ¹⁸O shifts and anti-phased δ¹⁸O and δ¹³C variations during the HSs. Further model simulations are necessary to fully explore the underlying climate dynamics driving these patterns.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"244 ","pages":"Article 104639"},"PeriodicalIF":4.0,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142718380","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}

{"title":"New Sea-ice biomarker data from Bering-Chukchi Sea surface sediments and its significance for pan-Arctic proxy-based sea-ice reconstruction","authors":"Jiang Yi-ao Zhang ,&nbsp;Xiaotong Xiao ,&nbsp;Ruediger Stein ,&nbsp;Wenshen Xiao ,&nbsp;Rujian Wang ,&nbsp;Yang Ding ,&nbsp;Lupeng Nie ,&nbsp;Meixun Zhao","doi":"10.1016/j.gloplacha.2024.104642","DOIUrl":"10.1016/j.gloplacha.2024.104642","url":null,"abstract":"<div><div>Sea ice is an essential component in polar regions and plays an important role in global climate changes. Knowing sea-ice variabilities on long-term time scales is critical to understand the rapid sea-ice decline in recent decades and to predict future Arctic changes. In this study, a suite of biomarkers including highly branched isoprenoids (IP₂₅ and HBI III (Z)) and sterols (brassicasterol and dinosterol) were measured in 55 surface sediments from the Bering-Chukchi Sea to central Arctic Ocean transect. PIP₂₅ indices were calculated with sea-ice biomarker IP₂₅ and phytoplankton biomarkers (brassicasterol, dinosterol and HBI III (Z)). The new data were combined with published data (<em>n</em> = 875) to complete the pan-Arctic dataset of biomarkers (<em>n</em> = 1062) in surface sediments. The compiled extended total data in general support previous pan-Arctic PIP₂₅ studies and by this the reliability of the PIP₂₅ approach for (paleo) sea-ice reconstructions. Furthermore, this study provides an extended basis for semi-quantitative paleo-sea-ice reconstruction in different regions of the Arctic Ocean. Phytoplankton biomarkers HBI III (Z) display highest values near the winter sea ice (WSI) edge in the pan-Arctic, reflecting the ice-edge conditions. P_IIIIP₂₅ show significant correlations with satellite spring/summer and autumn sea-ice concentration in the Pacific Sector of the pan-Arctic dataset (Bering-Chukchi Sea shelves, Chukchi Borderland and Canada Basin), and with spring/autumn sea-ice concentration in the Atlantic sector of the pan-Arctic dataset (Fram Strait, East Greenland shelf and Barents Sea). P_IIIIP₂₅ index seems to be reliable to reconstruct the paleo-sea-ice conditions in the Pan-Arctic, as well as P_BIP₂₅ and P_DIP₂₅ (using brassicasterol and dinosterol as phytoplankton biomarker, respectively). Furthermore, regional calibrations of comprehensive biomarker and PIP₂₅ datasets against known sea-ice conditions would add further confidence in their application for paleo-sea-ice reconstruction. Based on our extended HBI III dataset we did not find that the HBI TR₂₅ index was a reliable proxy for phytoplankton spring blooms on pan-Arctic scales. Certainly, deciphering the origin of certain biomarkers (e.g. HBI III (Z) and (E)) is still crucial for their application in further validation of PIP₂₅ and TR₂₅ indices application.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"244 ","pages":"Article 104642"},"PeriodicalIF":4.0,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700876","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}

{"title":"Human settlement and destructive activities disrupt the positive contribution of dust to plant biomass growth over the past 2000 years","authors":"Lin Chen ,&nbsp;Youliang Huang ,&nbsp;Menghan Qiu ,&nbsp;Zhilun Li ,&nbsp;Rui Yang ,&nbsp;Mengjing Li ,&nbsp;Huiling Sun ,&nbsp;Lixiong Xiang ,&nbsp;Shanjia Zhang ,&nbsp;Xiaozhong Huang ,&nbsp;Aifeng Zhou","doi":"10.1016/j.gloplacha.2024.104640","DOIUrl":"10.1016/j.gloplacha.2024.104640","url":null,"abstract":"<div><div>The dual pressures of global warming and increased anthropogenic activities pose significant threats to terrestrial vegetation ecosystems. To better understand the impacts of climate change and human activities on terrestrial vegetation ecosystems, we reconstructed the changes in vegetation and plant biomass over the past 4500 years using <em>n</em>-alkane records from sediments of two alpine lakes in northwestern China: Xiannv Lake and Tianchi Lake. Our results indicate that changes in the spatial variability of plant biomass are not related to temperature and precipitation. Furthermore, CO₂ fertilization and nutrient inputs from dust contributed to the observed changes in plant biomass. We also compared the history of human activities in the Tianshan Mountains, the eastern Silk Road, and the Hunsandak Sandy Land, and find that the demand for plant resources—whether for human settlement, military construction, or warfare—may have caused a sudden decline in terrestrial vegetation, thereby disrupting the positive effects of dust on plant biomass growth.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"244 ","pages":"Article 104640"},"PeriodicalIF":4.0,"publicationDate":"2024-11-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142700915","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}