Global and Planetary Change最新文献

{"title":"Summer amplification of interannual variability changes in surface air temperature during the last interglacial period","authors":"Jiawen Shi ,&nbsp;Zhiping Tian ,&nbsp;Xianmei Lang ,&nbsp;Dabang Jiang","doi":"10.1016/j.gloplacha.2025.104787","DOIUrl":"10.1016/j.gloplacha.2025.104787","url":null,"abstract":"<div><div>Temperature variability refers to temperature fluctuations around the mean state, which closely connects with the probability of extreme events. Examining temperature variability during past warm periods in Earth's history is essential for elucidating its future trends. We quantitatively analyze the interannual variability changes in near-surface air temperature and associated mechanisms during the last interglacial period (LIG, ∼127 ka) using the Paleoclimate Modeling Intercomparison Project Phase 4 (PMIP4) models. Relative to the preindustrial period, the LIG interannual variability of temperature increases slightly at the global scale. Summertime variability varies more dramatically at the regional scale, especially in high latitudes, East Asia, and North Africa, where it increases by more than 15 % in comparison to small changes for the winter and annual mean. In high-latitude oceans, radiation fluxes notably contribute to temperature variability change due to sea ice melting. Cloudiness changes dominate enhanced summer temperature variability in East Asia and both tropical land and oceans, while net surface heat flux and atmospheric energy convergence minus storage (CONV) influence other land regions. Additionally, CONV plays a larger role in the mid-to-high latitudes during winter than during summer. In low-latitude oceans, the distribution of temperature variability change is shaped by the mutual compensation between net surface heat flux and CONV. Simulated temperature variability changes generally agree with proxy data, although discrepancies exist in North Asia, East Asia, North Africa, North America, and South America.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"249 ","pages":"Article 104787"},"PeriodicalIF":4.0,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143601653","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":"Early Cretaceous deep-water bedforms west of the Guinea Plateau revise the opening history of the Equatorial Atlantic Gateway","authors":"Debora Duarte ,&nbsp;Elisabetta Erba ,&nbsp;Cinzia Bottini ,&nbsp;Thomas Wagner ,&nbsp;Benedict Aduomahor ,&nbsp;Tom Dunkley Jones ,&nbsp;Uisdean Nicholson","doi":"10.1016/j.gloplacha.2025.104777","DOIUrl":"10.1016/j.gloplacha.2025.104777","url":null,"abstract":"<div><div>The Equatorial Atlantic Gateway (EAG) was critical to Earth's climatic and oceanographic evolution during the Mesozoic, yet its early opening history remains enigmatic. Here, we present new 2D seismic reflection data and biostratigraphic ages from DSDP Site 367, integrated with tectonic reconstruction models, to constrain the sedimentary response to the evolution of the gateway. Seismic analysis reveals five stratigraphic units (<em>U1</em> to <em>U5</em>) documenting tectonic and oceanographic changes in the Guinea Plateau margin. Morphosedimentary features identified in units <em>U2</em> to <em>U4</em>, including sediment waves and contourite drifts, document changing current dynamics during EAG opening. We propose a two-stage model for the initial gateway opening: <em>i)</em> middle-late Aptian (∼117 to ∼113 Ma) formation of a marginal sea in the western EAG and overflow of Equatorial waters into the Central Atlantic, producing large sediment waves northwest of the gateway, and <em>ii)</em> latest Aptian-late Albian (from ∼113 Ma onwards) widening and deepening of the gateway, establishing more continuous water exchange and leading to the transition into contourite deposition. This direct sedimentary evidence shows the establishment of a marine connection started at around 117 Ma, significantly earlier than previous estimates, and coinciding with the onset of global climate cooling. These findings show the dynamic interplay between gateway opening, ocean circulation, and climate change during the middle Cretaceous, highlighting the pivotal role of ocean gateways in Earth's climate system.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"249 ","pages":"Article 104777"},"PeriodicalIF":4.0,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143592677","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":"Undervalued CO2 emissions from soil to the atmosphere in seismic areas: A case study in Tangshan, North China","authors":"Le Hu ,&nbsp;Ying Li ,&nbsp;Zhaofei Liu ,&nbsp;Chang Lu ,&nbsp;Giovanni Martinelli ,&nbsp;Galip Yuce ,&nbsp;Jianguo Du","doi":"10.1016/j.gloplacha.2025.104778","DOIUrl":"10.1016/j.gloplacha.2025.104778","url":null,"abstract":"<div><div>A large quantity of CO₂ produced in the Earth's interior is emitted to the atmosphere via soil diffusion, especially in active tectonic areas. Due to the lack of extensive in situ measurements, however, estimations of soil CO₂ output have been poorly constrained thus far, leading to the perception that soil CO₂ seems to be a marginal source of global carbon emissions. Here, the contribution of soil CO₂ to the atmosphere is discussed based on soil degassing rates measured at 187 sites in the Tangshan seismic area, North China. The measured degassing rates ranged from 9.04 g m⁻²d⁻¹ to 230.42 g·m⁻²d⁻¹, with an average of 87.46 g·m⁻²d⁻¹, suggesting that high degassing rates are common throughout the region. Carbon isotopic results show that the soil CO₂ comes mainly from the deep-seated carbonates and shallow biogenetic processes. Using the threshold value of the data population (96.20 g·m⁻²d⁻¹), the background and anomalous areas are distinguished. We find that anomalous degassing areas overlap well with epicenters of earthquakes with magnitudes greater than 5. The total annual CO₂ output in anomalous areas was estimated to be 38 Mt. This extremely high value can be attributed to the enlarged degassing areas and enhanced CO₂ emissions induced by regional active faults and frequent seismic activities. Our results indicate that the impact of soil CO₂ emissions in seismic regions should receive increased attention.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"249 ","pages":"Article 104778"},"PeriodicalIF":4.0,"publicationDate":"2025-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143563238","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":"Analysis of estuarine marine heatwaves in an upwelling system: The Ría de Arousa as a case study","authors":"M. Des,&nbsp;A. Castro-Olivares,&nbsp;M. deCastro,&nbsp;M. Gómez-Gesteira","doi":"10.1016/j.gloplacha.2025.104776","DOIUrl":"10.1016/j.gloplacha.2025.104776","url":null,"abstract":"<div><div>Marine heatwaves are prolonged periods of anomalously high water temperatures and have significant ecological and economic impacts. While these events are well-documented in open ocean systems, their characteristics and drivers in estuarine environments, particularly within upwelling systems, are less understood. This study analyzes estuarine marine heatwaves (EMHWs) in the Ría de Arousa, a productive estuary influenced by the upwelling dynamics of the NW Iberian Peninsula, using measured data from 2008 to 2023. Thirty-eight EMHW events were identified, with their occurrence strongly linked to oceanic thermal anomalies.</div><div>Among large-scale climate indexes, the Atlantic Multidecadal Oscillation (AMO) exhibited a significant positive correlation with EMHWs, explaining 13.8 % of their variability. In contrast, the East Atlantic (EA) and North Atlantic Oscillation (NAO) indexes showed no significant relationship. MHWs and extreme temperature events (METDs) at the continental shelf and open ocean were the strongest predictors of EMHWs. In contrast, atmospheric heatwaves (AHWs) have a minor influence.</div><div>The upwelling index exhibited a weak negative correlation, explaining only 0.17 % of EMHW variability, while wind intensity accounted for 0.32 %, suggesting a limited buffering effect of upwelling on EMHWs. A marked seasonal pattern was observed, with EMHWs being more intense in October than in summer, likely due to reduced upwelling activity in autumn. While upwelling may exert a mild regulatory effect, its capacity to mitigate extreme events appears limited. Understanding these interactions is crucial for improving predictive models and managing the impacts of EMHWs in ecologically and economically significant estuarine environments.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"249 ","pages":"Article 104776"},"PeriodicalIF":4.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143548798","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":"Super paleo-typhoons striking southern Hainan Island in the northern South China Sea during the mid-late Holocene: Coral boulder evidence from a fringing reef","authors":"Shengnan Zhou ,&nbsp;Qi Shi ,&nbsp;Shichen Tao ,&nbsp;Xiyang Zhang ,&nbsp;Hongqiang Yan ,&nbsp;Huiling Zhang ,&nbsp;Zhiwei Hou ,&nbsp;Wenlong Jing ,&nbsp;Ji Yang","doi":"10.1016/j.gloplacha.2025.104775","DOIUrl":"10.1016/j.gloplacha.2025.104775","url":null,"abstract":"<div><div>Hainan Island, situated at the northern margin of the South China Sea, is highly vulnerable to typhoon impacts, particularly super typhoons, which have caused catastrophic damage. Despite their persistent threats, research on these extreme events remains limited. At the Xiaodonghai Fringing Reef (XFR) in southern Hainan Island, coral boulders (CBs) distributed across the reef flat are interpreted as typhoon-transported features, serving as proxies for reconstructing past typhoon activity. This study establishes the relationships between (1) typhoon landfall wind velocities and wave heights along the South China and East China coasts, and (2) the mass of CBs on the XFR reef flat and their inferred typhoon wave heights. Utilizing these relationships, nine CBs were identified as having been transported by super typhoons. Through field positioning, radiometric dating, and comparisons with modern typhoon records, we identify five distinct phases of super paleo-typhoon (SuperPTY) that struck southern Hainan Island during the mid-late Holocene: 6970–6310 cal. aBP, 5890–5840 cal. aBP, 2490–1890 cal. aBP, 1630–1600 cal. aBP, and 1490–1450 cal. aBP. Notably, no super typhoons impacts have been recorded in recent decades. These SuperPTY phases correlate with atmospheric-oceanic teleconnections driven by the El Niño-Southern Oscillation and the Pacific Decadal Oscillation, as well as regional sea level fluctuations—factors that may also influence future super typhoon activity around Hainan Island under global warming. Further investigations into high-resolution sedimentary archives are recommended to advance understanding of spatiotemporal patterns in super typhoon occurrence.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"248 ","pages":"Article 104775"},"PeriodicalIF":4.0,"publicationDate":"2025-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143528292","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":"A link between the paleoenvironment and PETM via trace element proxies in Southwest Atlantic sediments","authors":"Xiaowen Liu ,&nbsp;Xiaole Sun ,&nbsp;Weidong Sun ,&nbsp;Yufei Hao ,&nbsp;Jing Huang","doi":"10.1016/j.gloplacha.2025.104774","DOIUrl":"10.1016/j.gloplacha.2025.104774","url":null,"abstract":"<div><div>To investigate paleo-ocean environmental variations during the Paleocene Eocene Thermal Maximum (PETM), we conducted a geochemical analysis of high-resolution sediment samples from ODP Site 1267 in the Southwest Atlantic. Our results suggest that volcanic materials may have been introduced into the ocean prior to the negative carbon isotope excursion (CIE), while terrestrial debris became the predominant input during the recovery phase of the CIE. Characteristic shifts in trace metal enrichment factors (e.g., Mn_EF, Mo_EF, Ni_EF, Cu_EF, Co_EF) indicate a transient period of hypoxia in the bottom seawater of the Southwest Atlantic during the onset and development phase of the CIE, likely caused by the oxidation of methane released from the seafloor. Elevated levels of nutrient elements (e.g., Sr/Ca ratio, biogenic barium [Ba_bio], and organic phosphorus [P_org]) in sediments suggest a sustained increase in primary productivity during both the development and recovery phases of the CIE. This increase is likely linked to hypoxic and acidic conditions during the development phase of the CIE and the influx of terrestrial debris during the recovery phase of the CIE. Ocean hypoxia and acidification likely facilitated the release of phosphorus and barium from sediments, which were transported to surface seawater via upwelling, further stimulating primary productivity. Additionally, intensified continental weathering during the recovery phase of the CIE contributed to sustained growth in productivity. The high-resolution trace element analysis provides critical insights into the temporal and causal relationships among volcanic activity, ocean hypoxia, enhanced weathering, and increased productivity during PETM events.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"248 ","pages":"Article 104774"},"PeriodicalIF":4.0,"publicationDate":"2025-02-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143512283","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":"Collapse of prehistoric cultures in central-eastern China linked to the El Niño-like states during the 4.2 ka event","authors":"Shiwei Jiang ,&nbsp;Wuhong Luo ,&nbsp;Xin Zhou ,&nbsp;Zhi-Bo Li ,&nbsp;Yong Luo ,&nbsp;Anze Chen ,&nbsp;Xuanqiao Liu ,&nbsp;Hongfei Zhao ,&nbsp;Guangcheng Zhang ,&nbsp;Juzhong Zhang","doi":"10.1016/j.gloplacha.2025.104772","DOIUrl":"10.1016/j.gloplacha.2025.104772","url":null,"abstract":"<div><div>The Huai River Basin, located in the transition zone between the Yangtze and Yellow River basins, plays a significant role in the integration and development of Neolithic cultures. Lack of precipitation reconstructions from the Huai River Basin limits our knowledge on patterns and mechanisms of precipitation in the East Asian monsoon (EAM) region during the 4.2 ka event, which also hinders our understanding of the relationship between Neolithic culture transitions and climate change. In this study, we report a pollen record from the Wufan profile in the upper Huai River Basin. Our record indicates a wetter climate condition during the 4.2 ka event, which is in contrast to the reconstructed dry conditions in northern China. We further integrated accurately dated precipitation records of the 4.2 ka event and found a significant “dry-wet-dry” precipitation pattern in the EAM region during this cooling period. Specifically, northern China was relatively dry, the Jianghuai region was relatively wet, and the southwestern region was relatively dry. This pattern was likely driven by El Niño-like conditions in the tropical Pacific. In addition, we discovered a close link between the collapse of Neolithic cultures and the increased precipitation in central-eastern China, which is likely dominated by the El Niño-like states in the tropical Pacific.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"248 ","pages":"Article 104772"},"PeriodicalIF":4.0,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143526816","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":"Modeling of non-floodplain wetlands in an upstream basin of the Pampa Plain, Argentina, during current hydro-climatic extreme conditions: Geomorphological thresholds controlling hydrodynamics","authors":"Pablo A. Cello ,&nbsp;Daniela M. Kröhling ,&nbsp;Ernesto Brunetto ,&nbsp;Marta Marizza ,&nbsp;M. Cecilia Zalazar ,&nbsp;Reinaldo García ,&nbsp;Mauro Nalesso ,&nbsp;Jacinto Artigas ,&nbsp;José R. Córdoba","doi":"10.1016/j.gloplacha.2025.104768","DOIUrl":"10.1016/j.gloplacha.2025.104768","url":null,"abstract":"<div><div>This contribution analyzes the processes related to the development of small, temporary, non-floodplain wetlands (NFWs) of neotectonic origin in the loessic North Pampa Plain under wet conditions. The study focuses on the Vila-Cululú upstream sub-basin (973 km²), a tributary of the Salado River belonging to the Paraná River basin. Under wet conditions, the flat landscape influences the surface runoff and favors the development of temporary NFWs, increasing flood vulnerability and compromising human activities. Late Pleistocene fluvial palaeochannels intercept small tectonic depressions and significantly restrict the present drainage network (low-order streams and artificial channels). This research involves an integrated approach, including geomorphic and morphometric analyses based on remotely sensed satellite imagery in a GIS platform and fieldwork, and 2D hydrologic-hydraulic simulations using HydroBID Flood to capture the system behavior during a rainfall event that recently occurred over several weeks and caused extended flooded areas. Simulation results show that the model significantly captures the system's hydrodynamics. The resulting flooded areas were comparable to those obtained from the analysis of satellite images. The dendritic runoff pattern towards the tectonic depressions, the water storage evolution, and the hydraulic connectivity were numerically replicated. Results indicates the Vila-Cululú sub-basin shows a significant delay in the hydraulic response downstream since the system must first satisfy groundwater and surface water storage. Once storage capacity is exceeded, the hydraulic behavior results in a dynamic process that involves the spilling and merging of ponds generated in small deflation hollows, generally nested within fluvial palaeochannels. Such a hierarchical structure controls surface runoff towards the shallow tectonic depressions. This mechanism allows the development of NFWs as simulation time progresses. Additionally, the surface runoff flow pattern exhibits significant lateral mobility and low connectivity downstream, although this varies depending on the magnitude of the storm. Despite the dense network of artificial channels developed to evacuate water excess to the outlet, geomorphological thresholds further control hydrodynamics by adding to surface water storage and limiting channel conveyance. Identifying critical geomorphological thresholds add to the knowledge of different levels of hydrological connectivity, providing a better assessment of flood hazards. This work is one of the first studies in North Pampa in which hydrological and geomorphological data are combined to explain the present hydrodynamics and that could be applied to other fluvial basins of large plains of South America.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"248 ","pages":"Article 104768"},"PeriodicalIF":4.0,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143534255","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":"The influence of grain size and mineralogical composition of terrestrial material inputs on organic carbon sequestration in the Bengal Fan since the last deglaciation","authors":"Md Hafijur Rahaman Khan ,&nbsp;Jianguo Liu ,&nbsp;Yun Huang ,&nbsp;Sui Wan ,&nbsp;Zhong Chen ,&nbsp;Ananna Rahman","doi":"10.1016/j.gloplacha.2025.104773","DOIUrl":"10.1016/j.gloplacha.2025.104773","url":null,"abstract":"<div><div>Exploring the intricate dynamics of organic carbon (OC) in marine sediments is essential for understanding global carbon cycling. This study examines how abrupt climate events, monsoonal variations, and mineral composition influence the delivery and burial of terrestrial organic matter (OM) in the western Bay of Bengal (BoB), focusing on the Bengal Fan (BF). Grain size and mineralogical composition have been critical in transporting and depositing terrigenous material, thereby affecting subsequent OC sequestration. Fine-grained sediments, notably those in the 2.5–10 μm range, are conducive to the widespread distribution and sequestration of terrestrial OM, facilitated by the force of monsoonal currents. In contrast, larger particles, particularly in the 30–46 μm range, tend to impede OC deposition. The mineralogy of the sediments also has a significant impact. Illite, for instance, is beneficial for OC transport and accumulation as it shields OM from microbial degradation and oxidative processes. Conversely, smectite is detrimental to OC preservation. Its high permeability, poor adsorptive capabilities, and association with OM-degrading environments can result in the loss of OC during transport and sedimentation, particularly in more distal ocean settings. The interaction between lithogenic materials and OM from both marine and terrestrial sources highlights the complexity of sedimentation processes in the BF. This study underscores that mineral composition and grain size characteristics played a crucial role in controlling OC sequestration. Before 9.5 ka, terrestrial OM was a substantial contributor to OC deposition in association with marine OM, driven by more vigorous monsoons and active river channels during lower sea levels. However, after 9.5 ka, the rapid rise in sea level altered river channels and delta dynamics, leading to reduced sedimentation rates and a decreased OM accumulation in the western BoB. During the Holocene Climate Optimum (HCO: 9.5–5.5 ka), the increased input of freshwater from intense summer monsoons led to the stratification of the water column, which reduced upwelling and primary productivity, which, in turn, led to less OC accumulation and preservation. The study highlights the importance of the summer monsoon in transporting terrestrial and marine OM to the deep ocean, emphasizing its crucial role in regulating the global carbon budget.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"248 ","pages":"Article 104773"},"PeriodicalIF":4.0,"publicationDate":"2025-02-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143520136","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":"Organic matter burial and degradation in the southern South China Sea since the last glaciation","authors":"Fen Chen ,&nbsp;Shengyi Mao ,&nbsp;Wanqiu Zhou ,&nbsp;Gang Li ,&nbsp;Xiaowei Zhu ,&nbsp;Wen Yan","doi":"10.1016/j.gloplacha.2025.104771","DOIUrl":"10.1016/j.gloplacha.2025.104771","url":null,"abstract":"<div><div>Marine organic matter (OM) plays a crucial role in regulating global carbon cycling and climate change; however, its significance is often underestimated or even overlooked due to the relatively low proportion of organic carbon (OC) within marine carbon pool and the insufficient documentation of coupled relationships between marine OM processes and atmospheric CO₂ changes during major climatic events, periods and cycles. Here, we present a high-resolution record of bulk parameters, organic biomarkers and inorganic elements to explore the potential one-to-one connection between marine OM source-to-sink dynamics and atmospheric CO₂ variations over the last glacial periods. Our results reveal that sedimentary OM was mainly of marine origin throughout the last glaciation, albeit the increases in terrestrial-derived OM inputs during the low-sea-level Last Glacial Maximum (LGM) and the sea-level rapid-rise deglacial meltwater pulse events. In the LGM, the lower-oxygen (intermediate and deep) waters and higher sedimentation rates facilitated the deposition and preservation of OM in waters and sediments, hence leading to higher TOC contents and contributing to lower atmospheric CO₂ concentrations. On the contrary, during the deglaciation and Holocene, the higher-oxygen intermediate waters and lower sedimentation rates promoted the remineralization of OM in the upper water column, which correlated with the rise in atmospheric CO₂ levels. However, the oxygen-depleted intermediate waters and highest sedimentation rates in the Bølling-Allerød (B/A) time greatly accelerated the downward transportation of OM with insignificant degradation in upper waters. The sinking OM experienced further remineralization at water-sediment interface, as indicated by a marked negative excursion in bottom-water oxygenation. This process exemplifies the biological pump, thereby acting to slow down atmospheric CO₂ rise during the B/A warm interval. Our study presents a potential mechanism to interpret atmospheric CO₂ variability by invoking marine OM dynamics, with particular emphasis on the place where OM degradation takes.</div></div>","PeriodicalId":55089,"journal":{"name":"Global and Planetary Change","volume":"248 ","pages":"Article 104771"},"PeriodicalIF":4.0,"publicationDate":"2025-02-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143508304","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}