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Palaeoenvironmental dynamics of an Early Miocene palaeolake in eastern Iberia: vegetation, climate, and hydrology 伊比利亚东部早中新世古湖泊的古环境动力学：植被、气候和水文

IF 5.7 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2026-04-01 Epub Date: 2026-02-13 DOI: 10.1016/j.catena.2026.109909

Manuel Casas-Gallego , Rafael Carballeira , Pere Anadón , Yul Altolaguirre , José María Postigo-Mijarra , Rafael Pablo Lozano , Rafael Moreno-Domínguez , Eduardo Barrón

The Rubielos de Mora lacustrine basin in eastern Spain is a key site for understanding Early Miocene ecosystems due to its exceptional fossil record, which preserves diverse taxa from multiple biological groups. Previous studies have interpreted the basin's vegetation and hydrology as reflecting varying degrees of xeric conditions, with some even proposing sub-desertic environments and steppe-like landscapes. These interpretations contrast with broader European trends, where forested environments predominated during the Early Miocene. Owing to these distinctive vegetation reconstructions, the basin has become central to discussions on southwestern European landscapes during the early Neogene. Here, we revisit the Rubielos de Mora Basin using a multiproxy approach that integrates palynological, diatom, and geochemical data from two well-studied surface sections from the eastern and western sectors of the basin to reassess its palaeoenvironmental evolution and situate it within the broader context of Cenozoic vegetation dynamics in Europe. Our results from both sectors converge on a consistent picture of regional vegetation dominated by diverse semi-open forests or woodlands during the Burdigalian. These habitats were mostly composed of thermophilous evergreen taxa adapted to relatively xeric conditions, possibly co-existing with mesic, deciduous elements. The flora of Rubielos de Mora reveals a largely forested ecosystem with increasing signs of xericity prior to the Miocene Climate Optimum. From a hydrological perspective, the Rubielos paleolake underwent alternating humid and dry phases, which affected lake productivity and water chemistry. Geochemical and palynological indicators suggest that these climatic fluctuations led to oxic–anoxic sediment cycles. Palaeoclimatic reconstructions indicate warm conditions during the Burdigalian, with mean annual temperatures of at least 16.8–18.5 °C and coldest-month means above 10 °C, suggesting a frost-free climate with pronounced seasonality.

西班牙东部的Rubielos de Mora湖盆因其独特的化石记录而成为了解早中新世生态系统的关键地点，该盆地保存了来自多个生物类群的多种分类群。以前的研究将盆地的植被和水文解释为反映了不同程度的干旱条件，有些甚至提出了亚沙漠环境和类似草原的景观。这些解释与更广泛的欧洲趋势形成对比，在那里，森林环境在中新世早期占主导地位。由于这些独特的植被重建，该盆地已成为讨论新近纪早期欧洲西南部景观的中心。在这里，我们使用多代理方法重新审视Rubielos de Mora盆地，该方法整合了来自盆地东部和西部两个经过充分研究的表面剖面的孢粉学，硅藻和地球化学数据，以重新评估其古环境演化，并将其置于欧洲新生代植被动态的更广泛背景下。我们从这两个部门得到的结果都集中在一个一致的图像上，即在Burdigalian期间，以各种半开放森林或林地为主的区域植被。这些生境主要由适应相对干旱条件的喜热常绿类群组成，可能与介系、落叶类植物共存。Rubielos de Mora的植物区系揭示了在中新世气候最佳之前，一个主要的森林生态系统有越来越多的干旱迹象。从水文角度看，Rubielos古湖泊经历了湿润和干燥交替的阶段，影响了湖泊生产力和水化学。地球化学和孢粉学指标表明，这些气候波动导致了缺氧-缺氧沉积物循环。古气候重建显示Burdigalian时期气候温暖，年平均气温至少为16.8-18.5°C，最冷月平均气温在10°C以上，表明无霜气候具有明显的季节性。

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引用次数: 0

Spatiotemporal analysis of rainfall erosivity in Oklahoma 俄克拉荷马州降雨侵蚀力的时空分析

IF 5.7 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2026-04-01 Epub Date: 2026-01-29 DOI: 10.1016/j.catena.2026.109853

Mengting Chen , Jaime Catherine Schussler , Deb Mishra

The Universal Soil Loss Equation (USLE) and its family of models have been used for soil loss prediction and erosion mitigation. These empirical models relied on precipitation data predating 1957 to calculate the Rainfall Erosivity (R-factor) value; however, the isoerodent map published in AH703 is still widely used in soil loss estimations today. Climatic and precipitation changes have presented questions about the validity and reliability of using these estimation methods. Additionally, instrumentation, precipitation gauging networks, and data availability have improved since the original publication of the AH703 isoerodent map. This study conducted a spatiotemporal analysis in the GIS environment to estimate modern rainfall erosivity across Oklahoma using high-resolution rainfall data. Average annual and monthly rainfall erosivity factors, R-factor and

R_{m}

-factor, respectively, were estimated using 5-min interval rainfall data collected from 111 Oklahoma Mesonet sites. The sites had an average historical precipitation record of 28 years. Using new rainfall erosivity values, spatial variation was assessed within two geographical segments: a) NOAA-defined state climate divisions and b) EPA-defined Level III ecoregions. Temporal analysis revealed that rainfall erosivity occurring between April and October contributed 86% of the annual R-factor. This study also developed an updated isoerodent map for the state of Oklahoma. The updated R-factor significantly differed from the original AH703 isoerodent map. Specifically, comparing the isoerodent maps revealed that the R-factor changed between −20% and 112%. The reasons contribute to the discrepancies between the two maps are also discussed.

通用土壤流失方程（USLE）及其模型族已被用于土壤流失预测和侵蚀减缓。这些经验模型基于1957年以前的降水资料来计算降雨侵蚀力（r因子）值；然而，AH703发表的等侵蚀图至今仍被广泛应用于土壤流失估算。气候和降水变化对这些估算方法的有效性和可靠性提出了质疑。此外，自AH703等蚀图最初出版以来，仪器仪表、降水测量网络和数据可用性都得到了改进。本研究在GIS环境下进行了时空分析，利用高分辨率降雨数据估计俄克拉荷马州的现代降雨侵蚀力。利用从俄克拉荷马州111个Mesonet站点收集的5分钟间隔降雨数据，分别估算了年平均和月平均降雨侵蚀力因子、r因子和rm因子。这些地点的平均历史降水记录为28年。利用新的降雨侵蚀力值，在两个地理区域内评估了空间变化：a) noaa定义的州气候区和b) epa定义的III级生态区。时间分析表明，4 - 10月的降雨侵蚀力贡献了年r因子的86%。这项研究还为俄克拉何马州开发了一份更新的等蚀地图。更新后的r因子与原来的AH703等侵蚀图有显著差异。具体来说，比较等侵蚀图显示r因子在- 20%到112%之间变化。本文还讨论了导致两幅地图差异的原因。

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引用次数: 0

Integrating ensemble learning and rocky desertification indices improves accuracy and interpretability of soil thickness prediction in karst landscapes 将集合学习与石漠化指标相结合，提高了喀斯特景观土壤厚度预测的准确性和可解释性

IF 5.7 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2026-04-01 Epub Date: 2026-02-06 DOI: 10.1016/j.catena.2026.109876

Fayong Fang , Ruyi Zi , Tingsheng Chen , Qilian Zhu , Zhen Han , Rui Hou , Wanyang Yu , Longshan Zhao

Soil thickness, a critical parameter for hydrological partitioning, ecosystem functioning, and biogeochemical cycling, is challenging to predict spatially in complex karst landscapes—hampered by high heterogeneity, intricate natural/anthropogenic impacts, and rocky desertification. Here, we integrate interpretable machine learning (ML) with rocky desertification information indices (RIs) to enhance soil thickness prediction in typical karst regions. We evaluated six individual ML models and three stacking ensembles (with/without RIs). RIs significantly boosted model explanatory power and consistency (average 7% improvement, 4%–11%), capturing the heterogeneity of soil thickness associated with karst-specific soil degradation processes. Stacking ensembles reduced RMSE (1.33–2.95 cm) and MAE (0.99–2.73 cm); the stacking model with linear regression as meta-model performed best (R² = 0.47, RMSE = 31.50 cm), while the Cubist base model showed highest accuracy (CCC = 0.63, R² = 0.45). Shapley additive explanations and permutation feature importance highlighted dominant drivers (rock exposure, vegetation cover, topography), improving transparency. Uncertainty assessments (prediction interval width and prediction interval ratio) validated robustness and identified high-uncertainty areas (steep topography, severe rocky desertification, model disagreement and sparse sampling). Our RIs-integrated model improves soil thickness prediction in karst regions, presents a potentially scalable framework for analogous complex landscapes, advances understanding of soil formation processes in karst systems, and thereby delivers targeted decision support for regional soil management practices.

土壤厚度是水文分区、生态系统功能和生物地球化学循环的关键参数，但在复杂的喀斯特景观中，由于高度异质性、复杂的自然/人为影响和石漠化，土壤厚度的空间预测具有挑战性。本文将可解释机器学习（ML）与石漠化信息指数（RIs）相结合，增强典型喀斯特地区土壤厚度预测。我们评估了6个独立的ML模型和3个堆叠集成（带/不带RIs）。RIs显著提高了模型的解释力和一致性（平均提高7%，4%-11%），捕获了与喀斯特特定土壤退化过程相关的土壤厚度的异质性。叠加集成降低了RMSE （1.33 ~ 2.95 cm）和MAE (0.99 ~ 2.73 cm)；以线性回归为元模型的叠加模型精度最高（R2 = 0.47, RMSE = 31.50 cm），立体主义基础模型精度最高（CCC = 0.63, R2 = 0.45）。Shapley加性解释和排列特征强调了主要驱动因素（岩石暴露、植被覆盖、地形）的重要性，提高了透明度。不确定性评估（预测区间宽度和预测区间比）验证了鲁棒性，并识别出高不确定性区域（陡峭地形、严重石漠化、模型不一致和采样稀疏）。我们的ris集成模型改进了喀斯特地区的土壤厚度预测，为类似的复杂景观提供了一个潜在的可扩展框架，促进了对喀斯特系统土壤形成过程的理解，从而为区域土壤管理实践提供了有针对性的决策支持。

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引用次数: 0

Textural features of sand fraction grains as a source of information on the transfer of alluvial sediments in step-pool channels in small forested mountain catchments 小森林山区集水区阶梯式水池河道冲积沉积物转移的砂粒结构特征研究

IF 5.7 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2026-04-01 Epub Date: 2026-02-02 DOI: 10.1016/j.catena.2026.109877

Ewa Słowik-Opoka , Dawid Piątek , Dominika Wrońska-Wałach , Mateusz P. Sęk , Anna Michno

In small mountain catchments, hillslope and fluvial processes interact closely in both spatial and temporal dimensions. Understanding their interplay is essential for interpreting sediment supply, transport, and deposition in fluvial systems. This study analyzed the sand fraction of sediments collected from the channel of the Dupniański Stream. From these, 100 grains of each of three textural types were selected: Q – pure quartz, QW – „weathered” quartz, and S – sandstone. For each grain, shape parameters were measured: circular equivalent diameter (CE), HS circularity (HS), convexity (CON), aspect ratio (AR), solidity (SOL), and elongation (ELO). Relationships between grain features (above and below of log (LS) and boulder (BS) steps) and variables such as contributing catchment area (A), channel slope (SS), and height (H) and width (W) of the step were examined. Differentiation was based on grain type, deposition location, and the step type. The aim was to assess whether grain texture can indicate sediment processing and transfer in step-pool mountain streams. Three hypotheses were tested: (H:1) Various sand grain types provide insight into sediment sources and processing; (H:2) Grain shaping reflects catchment and channel morphometry; (H:3) Textural features can define a transition zone (TZ) between hillslope and fluvial systems.The study confirmed that using sand grains of varied textures is an effective method for analyzing sediment transfer in small mountain catchments. Grain features reflect their origin (e.g., hillslopes or eroded rock steps) and evolve as they move downstream. This analysis precisely identified the transition zone and revealed links between grain shape and channel morphology.

在小的山地集水区，山坡和河流过程在空间和时间维度上密切相互作用。了解它们之间的相互作用对于解释河流系统中的沉积物供应、运输和沉积至关重要。本研究分析了从Dupniański河流河道中收集的沉积物中的砂组分。从这些颗粒中，选择了三种纹理类型的100粒：Q -纯石英，QW -“风化”石英和S -砂岩。测量每个颗粒的形状参数：圆形等效直径（CE）、HS圆度（HS）、凸度（CON）、长径比（AR）、固体度（SOL）和伸长率（ELO）。考察了颗粒特征（原木（LS）和巨石（BS）台阶的上方和下方）与流域面积(A)、河道坡度（SS）、台阶高度(H)和宽度(W)等变量之间的关系。分异主要基于颗粒类型、沉积位置和台阶类型。目的是评估颗粒结构是否可以指示台阶池山溪的泥沙加工和转移。检验了三个假设：（H:1）不同的沙粒类型提供了沉积物来源和加工过程的见解；（H:2）颗粒形状反映了流域和河道形态；（H:3）地形特征可以定义斜坡与河流系统之间的过渡带（TZ）。研究证实，利用不同质地的沙粒是分析山区小流域泥沙转移的有效方法。颗粒特征反映了它们的起源（例如，山坡或侵蚀的岩石台阶），并随着它们向下游移动而演变。该分析精确地确定了过渡带，并揭示了颗粒形状和河道形态之间的联系。

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引用次数: 0

Plant–microbe interactions underpin contrasting enzymatic responses to flooding intensity variation in the cascade reservoir riparian areas 植物与微生物的相互作用支撑了梯级水库河岸区对洪水强度变化的对比酶反应

IF 5.7 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2026-04-01 Epub Date: 2026-02-01 DOI: 10.1016/j.catena.2026.109869

Nan-ping Wu , Shan-ze Li , Kailang Yin , Yu-chun Wang , Zheng Sun , Xuming Xu , Qingkong Chen , Yufei Bao , Jie Wen

Periodic anoxia, induced by flooding and erosion, has been regarded as a protective mechanism for soil organic carbon (SOC) by limiting microbial decomposition. However, this effect was not observed uniformly across riparian zones. This study distinguishes S-type from Non-S-type riparian areas, where the former retains SOC through microbial limitation, while the latter experiences accelerated SOC loss due to high reducible metals and organic carbon. To explore these dynamics, field experiments were conducted across 19 plots in the riparian areas of cascade reservoirs along the Jinsha River, China. In older reservoirs with prolonged flooding, phenol oxidase activity was suppressed (12 years: 4.033 ± 0.240 μmol g⁻¹ h⁻¹; 13 years: 5.442 ± 0.199 μmol g⁻¹ h⁻¹) compared to a 5-year-old reservoir (8.430 ± 0.340 μmol g⁻¹ h⁻¹). Non-S-type riparian areas exposed to high flooding intensity (FI) showed significantly higher phenol oxidase activity (high FI: 6.336 ± 0.236 μmol g⁻¹ h⁻¹ vs. low FI: 3.801 ± 0.181 μmol g⁻¹ h⁻¹), along with reduced lignin-derived compounds. These Non-S-type riparian areas exhibited higher microbial diversity, dominated by r-strategist taxa (e.g., Proteobacteria), enhanced bacterial connectivity, and hosted three fungal guilds acting as network connectors—traits absent in S-type areas. Furthermore, microbial communities in Non-S-type riparian zones showed structural stability through iron-reducing and phenol oxidation-related carbon metabolism. Mantel's test analysis showed that the weak correlation between lignin-derived compounds and phenol oxidase-producing microbes dynamics in these areas suggested that lignin-degrading taxa, resilient to hydrological perturbations (S-type: P < 0.05, Non-S-type: P > 0.05), mitigate the impact of lignin on carbon metabolism. These findings disclosed the presence of distinct microbial resilience mechanisms in response to hydrological extremes, highlighting the capacity of Non-S-type zones to maintain ecological functions under fluctuating environmental conditions.

洪水和侵蚀引起的周期性缺氧被认为是通过限制微生物分解来保护土壤有机碳（SOC）的机制。然而，这种效应并不是在整个河岸带中均匀观察到的。该研究区分了s型和非s型河岸区，前者通过微生物限制保留了有机碳，而后者由于高可还原金属和有机碳而加速了有机碳的损失。为了探索这些动态，在金沙江梯级水库河岸区进行了19个样地的现场试验。在长期驱替的老旧储层中，苯酚氧化酶活性（12年：4.033±0.240 μmol g−1 h−1；13年：5.442±0.199 μmol g−1 h−1）比5年储层（8.430±0.340 μmol g−1 h−1）受到抑制。暴露于高洪水强度（FI）的非s型河岸区显示出显著更高的酚氧化酶活性（高FI: 6.336±0.236 μmol g−1 h−1，低FI: 3.801±0.181 μmol g−1 h−1），以及木质素衍生化合物的减少。这些非s型河岸区表现出更高的微生物多样性，以r-战略类群（如变形菌门）为主，细菌连通性增强，并有3个真菌行会作为网络连接者，这些特征在s型河岸区是不存在的。此外，非s型河岸带微生物群落通过铁还原和酚氧化相关的碳代谢表现出结构稳定性。Mantel的试验分析表明，这些地区木质素衍生化合物与产生酚氧化酶的微生物动力学之间存在弱相关性，这表明木质素降解分类群对水文扰动具有弹性（s型：P <； 0.05，非s型：P >； 0.05），减轻了木质素对碳代谢的影响。这些发现揭示了在极端水文条件下存在不同的微生物恢复机制，突出了非s型带在波动环境条件下维持生态功能的能力。

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引用次数: 0

Straw incorporation affects soil organic carbon pools by modulating microbial communities and associated metabolic activities 秸秆还田通过调节微生物群落和相关代谢活动影响土壤有机碳库

IF 5.7 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2026-04-01 Epub Date: 2026-01-29 DOI: 10.1016/j.catena.2026.109871

Lingxu Meng , Jieyun Guo , Jing He , Yunxiang Cheng , Huhe

The microbial carbon pump (MCP) is essential for the turnover and long-term stabilization of soil organic carbon (SOC). Fertilization (organic and inorganic) regulates soil microbial communities and associated functions, shaping the formation of soil carbon pools in croplands. However, the mechanisms by which straw incorporation promotes the microbial degradation of plant and microbial biomass for SOC stabilization in croplands remain unclear. Therefore, we conducted a three-year field experiment with four fertilization practices to investigate how straw incorporation shapes microbial community composition, carbohydrate-active enzyme (CAZyme), and extracellular enzyme activities, in order to track microbial-mediated SOC formation in croplands. Fertilization significantly altered microbial community composition and function and enhanced microbial respiration. Straw incorporation significantly expanded SOC stocks, which was closely associated with shifts in the fungal community. Fertilization, particularly straw incorporation, significantly increased the abundance of CAZyme genes involved in the degradation of lignocellulose (by 1.42%–182.93%), pectin/starch (by 67.05%–314.48%), bacterial-derived carbon (by 63.09%–170.94%), and fungal-derived carbon (β-glucan/chitin) (by 25.44%–115.44%), indicating enhanced utilization of organic carbon from diverse sources. The proportion of microbial CAZymes decomposing plant components (75.18%–83.29%) exceeded that of CAZymes degrading microbial components (16.71%–24.82%), suggesting a greater microbial capacity for the degradation of plant biomass in cropland soils. Furthermore, enzyme activity was significantly correlated with CAZyme gene abundance. In conclusion, shifts in CAZyme genes encoding the degradation of diverse carbon sources may facilitate the formation of SOC and its fractions in straw-incorporated soils via MCP regulation.

微生物碳泵（MCP）对土壤有机碳（SOC）的周转和长期稳定至关重要。施肥（有机和无机）调节土壤微生物群落及其相关功能，塑造农田土壤碳库的形成。然而，秸秆还田促进植物微生物降解和微生物生物量稳定农田有机碳的机制尚不清楚。因此，我们进行了为期三年的四种施肥方式的田间试验，研究秸秆施肥对微生物群落组成、碳水化合物活性酶（CAZyme）和细胞外酶活性的影响，以追踪微生物介导的农田有机碳形成。施肥显著改变微生物群落组成和功能，增强微生物呼吸作用。秸秆还田显著增加了土壤有机碳储量，这与真菌群落的迁移密切相关。施肥，特别是秸秆施肥，显著增加了参与木质纤维素（1.42% ~ 182.93%）、果胶/淀粉（67.05% ~ 314.48%）、细菌碳（63.09% ~ 170.94%）和真菌碳（β-葡聚糖/几丁质）（25.44% ~ 115.44%）降解的CAZyme基因的丰度，表明对不同来源有机碳的利用增强。分解植物组分的微生物酶所占比例（75.18% ~ 83.29%）超过降解植物组分的微生物酶所占比例（16.71% ~ 24.82%），表明农田土壤中微生物具有更大的降解植物生物量的能力。酶活性与CAZyme基因丰度显著相关。综上所述，编码不同碳源降解的CAZyme基因的变化可能通过MCP调控促进秸秆土壤有机碳及其组分的形成。

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引用次数: 0

Sedimentary and environmental changes of terminal lake in the arid region of Mongolia during the last two millennia 近两千年来蒙古干旱区终端湖的沉积与环境变化

IF 5.7 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2026-04-01 Epub Date: 2026-01-30 DOI: 10.1016/j.catena.2026.109872

Shuukhaaz Ganbat , Noriko Hasebe , Davaadorj Davaasuren , Keisuke Fukushi , Shinya Ochiai , Kazumasa Miura , Akihiro Tamura , Baasansuren Gankhurel , Uyangaa Udaanjargal

Understanding past environmental and climate changes is essential for understanding their influence on human history and for predicting future trends. The Valley of Gobi Lake in Mongolia is highly sensitive to climate changes. We analyzed two sediment cores from Boontsagaan Lake, the largest in the Valley of Gobi Lakes and only permanent lake: a 111 cm core (East-20240226) close to the inflow river mouth and a 141 cm core (North-20240227) located 8 km away from the river mouth. Grain size differences between the cores indicate coarser material deposition near the river mouth (East-20240226) due to the density underflow, whereas the distant core (North-20240227) shows finer fluvial and aeolian inputs. The radiocarbon and optically stimulated luminescence dating methods applied to the North-20240227 core. Sandy layers below the lacustrine sediment sequence probably indicate dramatic lake level lowering between ∼300 CE and 1200 CE, corresponding dry phase in the region. A subsequent recovery of lake conditions, linked to the increased river inflow by the topographic shifts, marks a wetter phase after ∼1200 CE and coinciding with the expansion of the Mongolian empire. After ∼1400 CE, enhanced carbonate precipitation suggests another dry period, which potentially coincided with the decline of Mongolian empire. The high sediment rate and coarsening grain size in the North-20240227 core show intensified aeolian input due to continued lake shrinkage after ∼1850 CE. The sediment record from this permanent lake captures key environmental transitions over the last two millennia, regional climate changes and sociopolitical developments in Mongolian territory, including the rise and decline of the Mongolian Empire.

了解过去的环境和气候变化对于了解它们对人类历史的影响和预测未来趋势至关重要。蒙古的戈壁湖山谷对气候变化非常敏感。我们分析了来自Boontsagaan湖的两个沉积物岩心，该湖是戈壁湖区最大的湖泊，也是唯一的永久性湖泊：靠近流入河口的111厘米岩心（东-20240226）和距离河口8公里的141厘米岩心（北-20240227）。岩心之间的粒度差异表明，靠近河口（东-20240226）的物质沉积较粗，而远离河口（北-20240227）的物质沉积较细。放射性碳和光学激发发光测年方法应用于北-20240227岩心。湖相沉积物层序下的砂质层可能表明在~ 300 CE和1200 CE之间湖泊水位急剧下降，对应于该地区的干燥阶段。随后湖泊条件的恢复，与地形变化引起的河流流入增加有关，标志着公元1200年之后的一个湿润阶段，与蒙古帝国的扩张相吻合。公元1400年之后，碳酸盐降水的增加表明另一个干旱时期，这可能与蒙古帝国的衰落相吻合。北-20240227岩心的高沉积速率和粗粒度表明，自~ 1850 CE以来，湖泊持续萎缩导致风成风输入增强。这个永久湖泊的沉积物记录了过去两千年来主要的环境变化、区域气候变化和蒙古领土上的社会政治发展，包括蒙古帝国的兴衰。

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引用次数: 0

Microbial functional shifts amplify the temperature sensitivity of soil nitrogen across the erosion-deposition continuum 微生物功能变化放大了土壤氮在侵蚀-沉积连续体中的温度敏感性

IF 5.7 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2026-04-01 Epub Date: 2026-01-30 DOI: 10.1016/j.catena.2026.109875

Tianming Zhang, Zhongmin Fan, Jia Shi, Yumei Peng, Xiang Wang

Soil erosion drives biogeochemical decoupling of nitrogen (N) transformation pathways via spatial segregation of microbial processing hotspots along toposequences. However, the mechanisms governing this decoupling are poorly understood. Therefore, erosion-mediated reorganization of N cycling processes was investigated using high-resolution quantitative PCR (qPCR)-based functional gene quantification, N fractions analysis, and temperature-gradient incubations. Soil samples were collected in early April from a black soil region in Northeast China. Total N (TN) and mineral N (NO³⁻-N and NH4⁺-N) were determined. Temperature-controlled incubations (15 °C vs. 25 °C) were performed to determine net N mineralization, and qPCR was used to quantify genes involved in N cycling. The results demonstrated that 50.40% of TN and 54.88% of mineral N were depleted in eroding soil compared with non-eroding soil, whereas N accumulated in deposition-enriched subsoil primarily through mineral-associated N accumulation, accounting for 80.22%–93.71% of TN. Functional gene analysis revealed that the denitrification potential was intensified in eroding topsoils, as evidenced by a 3.3-fold upregulation of nirK and a 4.6-fold upregulation of norB. In contrast, depositional sites exhibited preferential activation of nitrification pathways. The temperature sensitivity of N mineralization was spatially divergent; it was 13.3 times higher in eroding topsoil than in depositional sites. Deposition depressed depth-dependent temperature sensitivity. This spatial biogeochemical partitioning establishes a climate-sensitive feedback loopin which erosional hotspots sustain N losses mediated by denitrification, and depositional microsites amplify temperature-contingent nitrification. The functional divergence between nitrification (depositional sites) and denitrification (eroding sites) hotspots is thermally modulated, creating distinct microbial metabolic regimes. These findings demonstrate how erosion–deposition interfaces potentiate soil N-cycling in topsoil and subsoil along a sloping landscape, providing a theoretical basis for preserving soil microbial function and resilience of the soil nitrogen pool in response to erosion and climate warming.

土壤侵蚀通过微生物加工热点沿拓扑序列的空间分离驱动氮转化途径的生物地球化学解耦。然而，人们对这种分离的机制知之甚少。因此，利用基于高分辨率定量PCR （qPCR）的功能基因定量、N组分分析和温度梯度孵育，研究了侵蚀介导的N循环过程重组。4月初在东北某黑土区采集土壤样品。测定了总氮（TN）和无机氮（NO3−-N和NH4+-N）。温度控制孵育（15°C vs. 25°C）测定净氮矿化，qPCR用于量化参与氮循环的基因。结果表明，与非侵蚀土壤相比，侵蚀土壤中总氮的50.40%和矿物氮的54.88%被耗尽，而富沉积土壤中的N主要通过矿物相关N积累，占总氮的80.22% ~ 93.71%。功能基因分析表明，侵蚀表层土壤的反硝化潜力增强，nirK上调3.3倍，norB上调4.6倍。相反，沉积位点表现出硝化途径的优先激活。氮矿化的温度敏感性具有空间发散性；侵蚀表层土比沉积表层土高13.3倍。沉积降低了与深度相关的温度敏感性。这种空间生物地球化学分区建立了一个气候敏感的反馈回路，其中侵蚀热点维持由反硝化介导的氮损失，而沉积微点则放大了随温度变化的硝化作用。硝化（沉积地点）和反硝化（侵蚀地点）热点之间的功能差异是热调节的，创造了不同的微生物代谢制度。这些发现揭示了侵蚀-沉积界面如何促进坡地表层土壤和底土的氮循环，为保护土壤微生物功能和土壤氮库对侵蚀和气候变暖的响应能力提供了理论基础。

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引用次数: 0

Seasonal flooding amplifies the positive asymmetric response of ecosystem carbon exchange along the precipitation gradient in saline wetlands 季节性洪水放大了咸化湿地生态系统碳交换沿降水梯度的正不对称响应

IF 5.7 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2026-04-01 Epub Date: 2026-01-29 DOI: 10.1016/j.catena.2026.109865

Xinge Li , Wenbo Zhu , Lianqi Zhu , Weimin Song , Peiguang Li , Xiaojie Wang , Guangxuan Han

Intensified precipitation variability profoundly affects saline wetland hydrological dynamics, potentially interfering with key carbon processes within ecosystems. However, the mechanisms underlying how precipitation changes affect ecosystems carbon processes in saline wetland remain unclear. Moreover, whether seasonal flooding influences wetland ecosystems' carbon processes response to precipitation changes is still poorly understood. Based on a six-year field precipitation experiment including five precipitation levels (−60%, −40%, +0%, +40%, and + 60% of ambient precipitation) in the Yellow River Delta wetlands, we examined how seasonal flooding regulated ecosystem CO₂ exchange (NEE), gross ecosystem production (GEP) and ecosystem respiration (ER) response to precipitation changes. Over three years, ecosystem carbon fluxes exhibited a positive asymmetric response along the precipitation gradient, with the increment under wet treatments exceeding the reduction under dry treatments. Compared with the control, the −60% treatment significantly reduced GEP and ER by 9.7% and 9.3% respectively; whereas the +40% and + 60% treatments significantly increased GEP, ER, and NEE by 18.0%, 23.5%, 15.4%, 19.4%, 22.1%, and 29.0% respectively. Moreover, the observed positive asymmetry in ecosystem carbon flux arose because, under reduced precipitation, vegetation coverage and total biomass were less affected by high soil salinity. Additionally, plants coverage responded differently to flooding under precipitation treatments: saline plants were most affected under reduced precipitation, while gramineous plants showed no significant difference. Our results demonstrated that acclimation of vegetation to salinization leads to the asymmetric response of ecosystem carbon exchange along the precipitation gradient, while seasonal flooding may amplify the positive asymmetric response by affecting vegetation community composition in saline wetlands. The findings underscore the importance of seasonal flooding in modulating wetland ecosystem responses within global change manipulation experiments.

降水变异性的增强深刻地影响了咸水湿地的水文动态，潜在地干扰了生态系统内的关键碳过程。然而，降水变化如何影响盐碱地生态系统碳过程的机制尚不清楚。此外，季节性洪水是否影响湿地生态系统碳过程对降水变化的响应尚不清楚。基于黄河三角洲湿地6年的野外降水试验，研究了季节性洪水对生态系统CO2交换（NEE）、生态系统总生产量（GEP）和生态系统呼吸（ER）对降水变化的响应，包括5个降水水平（- 60%、- 40%、+0%、+40%和+ 60%）。3年内，生态系统碳通量沿降水梯度呈非对称正响应，湿处理的增量大于干处理的减少。与对照组相比，−60%处理的GEP和ER分别显著降低9.7%和9.3%；而+40%和+ 60%处理的GEP、ER和NEE分别显著提高了18.0%、23.5%、15.4%、19.4%、22.1%和29.0%。此外，观测到的生态系统碳通量正不对称的原因是，在降水减少的情况下，植被覆盖度和总生物量受高土壤盐度的影响较小。此外，不同降水处理下植物盖度对洪水的响应也不同：盐碱植物在降水减少下受影响最大，而禾本科植物无显著差异。研究结果表明，植被对盐碱化的适应导致生态系统碳交换沿降水梯度的不对称响应，而季节性洪水可能通过影响盐碱化湿地植被群落组成，放大了生态系统碳交换的正不对称响应。这些发现强调了季节性洪水在全球变化操纵实验中调节湿地生态系统响应的重要性。

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引用次数: 0

Summer zokor mounds as greenhouse gas hotspots compared to spring and autumn mounds on the Tibetan plateau 青藏高原春季和秋季丘丘与夏季丘丘相比，夏季丘丘是温室气体热点

IF 5.7 1区农林科学 Q1 GEOSCIENCES, MULTIDISCIPLINARY

Catena

Pub Date : 2026-04-01 Epub Date: 2026-02-05 DOI: 10.1016/j.catena.2026.109867

Zhiying Zhang , Bin Chu , Limin Hua , Rui Dong , Jian Sun , Xidong Zhu , Mulati Subinur , Yujie Niu

Small subterranean mammals, such as plateau zokors, disturb grassland topsoil through mound creation, potentially elevating greenhouse gas emissions. While the ecological impacts of mounds have been studied in spring and autumn, little attention has been given to summer mound creation, a period of peak microbial activity and intensified plant–soil interactions. This knowledge gap limits the understanding of seasonal dynamics and mechanisms of greenhouse gas emissions in alpine ecosystems. In this study, the static chamber method was used to quantify net ecosystem exchange, ecosystem respiration, and CH₄ and N₂O fluxes from zokor mounds during spring, summer, and autumn, alongside measurements of soil, plant, and fauna communities. Results showed that summer mounds shifted the alpine meadow from a net CO₂ sink to a source, with CH₄ emissions (65.85 μg/m²/h), and N₂O emissions (52.81 μg/m²/h) all significantly higher than those from spring and autumn mounds. Net global warming potential increased on summer mounds, whereas spring and autumn mounds tended to reduce relative to intact pasture. The structural equation model indicated that zokor mounding reduced vegetation coverage and biomass, increasing net global warming potential and turning localized areas from greenhouse gas sinks to sources. To reliably evaluate the impacts of zokor mounds on greenhouse gases and their balances, it is crucial to consider the seasonal variation of mound creation. Additionally, reducing summer mound creation through appropriate grassland grazing management could help mitigate greenhouse gas emissions and lessen the ecological impact of zokor burrowing activity.

小型地下哺乳动物，如高原动物，通过丘堆的形成扰乱了草地表层土壤，潜在地增加了温室气体的排放。虽然对春季和秋季土丘的生态影响进行了研究，但对夏季土丘的形成、微生物活动高峰和植物-土壤相互作用加剧的时期却很少关注。这种知识差距限制了对高山生态系统中温室气体排放的季节性动态和机制的理解。在本研究中，采用静态室法定量分析了春、夏、秋三季动物丘的净生态系统交换、生态系统呼吸、CH₄和N₂O通量，并测量了土壤、植物和动物群落。结果表明：夏季丘地使高寒草甸由净CO₂汇向净CO₂源转变，其nh4排放量（65.85 μg/m2/h）和N₂O排放量（52.81 μg/m2/h）均显著高于春季和秋季丘地；夏季丘地的净全球变暖潜势增加，而春季和秋季丘地相对于完整牧场有降低的趋势。结构方程模型表明，zozoor堆积减少了植被覆盖度和生物量，增加了全球净变暖潜势，使局部地区从温室气体汇向源转变。为了可靠地评价草堆对温室气体及其平衡的影响，必须考虑草堆形成的季节变化。此外，通过适当的草地放牧管理，减少夏季土丘的形成，有助于减少温室气体排放，减轻动物穴居活动对生态的影响。

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引用次数: 0