Review of Palaeobotany and Palynology最新文献_第6页

Impact of climatic factors on pollen grains development in Black alder (Alnus glutinosa (L.) Gaertn) 气候因子对黑桤木（Alnus glutinosa）花粉粒发育的影响Gaertn)

IF 1.7 3区地球科学 Q2 PALEONTOLOGY

Review of Palaeobotany and Palynology

Pub Date : 2025-08-20 DOI: 10.1016/j.revpalbo.2025.105429

Abdelouahab Sahli , Hassan Ennouni , Khalil Kadaoui , Mhammad Houssni , Hasnae Ben Sbih , Soufian Chakkour , Mohammed Ater

Fertile pollen is of significance for the successful propagation of plants. It is sensitive to environmental conditions, especially climatic factors. However, there is a paucity of information about the effects of climatic factors on pollen development in the Alnus genus. Alnus glutinosa is an Eurasian species with a wide geographical distribution. It has particular ecological importance in riparian ecosystems, where it plays a crucial role in soil stabilization and biodiversity maintenance. The objective of the present study was to evaluate the effect of climatic factors on pollen development from eleven distinct populations, each characterized by a unique combination of 13 environmental factors. Fresh pollen samples were examined using three distinct viability tests: Acetocarmine staining, Lugol staining, and in vitro germination. The results revealed significant variations in pollen viability between populations. Acetocarmine staining revealed that pollen from Alnus glutinosa exhibited robust cytoplasmic integrity and an absence of significant meiotic anomalies. However, Lugol staining revealed a substantial decline in pollen viability, which can be attributed to a decrease in starch content in fresh pollen in response to elevated temperatures. Pollen germination rates were generally low and exhibited a dependence on altitude variations. Consequently, it is imperative to prioritize the investigation of the impact of warming on pollen viability and the sexual reproduction of forest plants, as they are susceptible to the adverse effects of climate change, akin to other plant species.

花粉的可育性对植物的成功繁殖具有重要意义。它对环境条件，特别是气候因素很敏感。然而，关于气候因素对桤木属花粉发育的影响的研究却很少。Alnus glutinosa是一种地理分布广泛的欧亚树种。它在河岸生态系统中具有特别的生态重要性，在土壤稳定和生物多样性维持中起着至关重要的作用。本研究的目的是评价气候因子对11个不同种群花粉发育的影响，每个种群都有13个环境因子的独特组合。用三种不同的活力测试检测新鲜花粉样品：乙酰胭脂红染色、Lugol染色和体外萌发。结果表明，不同种群间花粉活力存在显著差异。乙酰胭脂红染色表明，桤木花粉具有较强的细胞质完整性，且没有明显的减数分裂异常。然而，Lugol染色显示花粉活力明显下降，这可能是由于温度升高导致新鲜花粉中淀粉含量下降。花粉发芽率普遍较低，且与海拔变化有关。因此，研究变暖对森林植物花粉活力和有性生殖的影响是当务之急，因为森林植物与其他植物一样容易受到气候变化的不利影响。

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引用次数: 0

Evaluating Post-K/Pg persistence of Classopollis: Evidence from exceptionally preserved reworked Pollen in Paleogene sub and inter-Volcanic Sediments from Northern Ireland 评价Classopollis的后k /Pg持久性：来自北爱尔兰古近系亚火山和火山间沉积物中异常保存的再加工花粉的证据

IF 1.7 3区地球科学 Q2 PALEONTOLOGY

Review of Palaeobotany and Palynology

Pub Date : 2025-08-18 DOI: 10.1016/j.revpalbo.2025.105424

Manuel Vieira , David Jolley

The Cheirolepidiaceae, an extinct family of coniferous plants that thrived during the Mesozoic Era, are well known through their distinctive Classopollis pollen. Although long thought to have declined globally during the Late Cretaceous, isolated occurrences of Classopollis in Paleocene deposits have sparked debate regarding the survival or reworking of this lineage beyond the Cretaceous–Paleogene (K/Pg) boundary. In this study, we document the occurrence of exceptionally well-preserved Classopollis pollen within Paleocene inter-volcanic sedimentary rocks of the Antrim Lava Group in Northern Ireland. Detailed morphological analyses using transmitted light microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) reveal Classopollis pollen with uniformly thick tectate exines, well-developed baculate infratectal layers, and a dense nano-spinulose supratectal ornamentation. These features can be compared with Barremian-aged English specimens and support a Cretaceous origin. Palynological assemblages also include other reworked Cretaceous taxa and clastic components derived from the underlying Ulster White Limestone Formation, a Santonian–Early Maastrichtian unit exposed within the catchment. The stratigraphic context and preservation state of the Classopollis grains suggest that they were reworked rather than representing in situ Paleocene vegetation. This study supports the interpretation that post-K/Pg occurrences of Classopollis in the Antrim Basin are best explained by sedimentary recycling of Late Cretaceous deposits, adding to the broader discussion on Cheirolepidiaceae persistence and paleoecological relict status in the Paleogene.

Cheirolepidiaceae是一个灭绝的针叶植物家族，在中生代繁荣，因其独特的Classopollis花粉而闻名。尽管人们一直认为，在晚白垩世，Classopollis在全球范围内已经减少，但在古新世沉积物中孤立出现的Classopollis引发了关于该谱系在白垩纪-古近纪（K/Pg）界限之外是否存在或改造的争论。在这项研究中，我们记录了北爱尔兰安特里姆熔岩群古新世火山间沉积岩中保存异常完好的Classopollis花粉的存在。利用透射光镜、扫描电镜和透射电镜对其进行了详细的形态学分析，结果显示，Classopollis花粉具有均匀厚的盾状外壁，发育良好的小管状花序，以及致密的纳米级细刺状的直肠上纹饰。这些特征可以与巴雷米亚时代的英国标本进行比较，并支持白垩纪起源。孢粉组合还包括其他经过改造的白垩纪分类群和碎屑组分，这些碎屑组分来自于下部的阿尔斯特白灰岩组，这是一个暴露在集水区的圣安东尼奥-早期马斯特里赫特单元。Classopollis颗粒的地层背景和保存状态表明它们是被重新加工过的，而不是代表古新世的原位植被。本研究支持了用晚白垩世沉积物的沉积再循环来解释Antrim盆地后k /Pg产状的解释，为进一步探讨Cheirolepidiaceae在古近系的存续和古生态遗存状态提供了理论依据。

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引用次数: 0

Palynotaxonomy of species and genera of the Cyanocladus and Trichocladus clades (Lamiaceae: Hyptidinae) 青枝和毛枝的种属分类（紫枝科：棘枝科）

IF 1.7 3区地球科学 Q2 PALEONTOLOGY

Review of Palaeobotany and Palynology

Pub Date : 2025-08-17 DOI: 10.1016/j.revpalbo.2025.105428

Renata Jacomo Paixão de Carvalho , Raymond Mervey Harley , José Floriano Barêas Pastore , Cláudia Barbieri Ferreira Mendonça , Vania Gonçalves-Esteves

This study analyzed the pollen morphology of 22 taxa of the Cyanocladus and Trichocladus clades. The aim was to describe and characterize pollen grains and assess whether pollen morphology corroborates the recent taxonomy of the group. Only genera occurring in Brazil were studied, including Cyanocephalus (Pohl ex Benth.) Harley & J.F.B.Pastore (7 spp.), the endemic genus Eplingiella Harley & J.F.B.Pastore (3 spp.), Marsypianthes Mart. ex Benth. (4 spp.), Martianthus Harley & J.F.B.Pastore (3 spp.), and Medusantha Harley & J.F.B.Pastore (5 spp.). Acetolyzed pollen grains were measured, described, and photomicrographed. Non-acetolyzed pollen grains were examined by scanning electron microscopy. All taxa analyzed have pollen grains shed in monads, medium to large in size, isopolar, (4)-6-(8–10)colpate, ranging from suboblate to prolate, with a small to very small polar area. The colpi are long to very long, broad, with ornamented membranes and an acute apex, and lack distinct margins. An operculum was observed in all species of Cyanocephalus. The sexine is bireticulated in all other species and genera. The results showed that the pollen morphology of the studied genera was informative in classifying taxa and distinguishing genera, demonstrating some notable parallels with current taxonomic opinion. In principal component analysis and hierarchical cluster analysis, morphometric characteristics approximated and grouped, respectively, species of the genera Eplingiella and Martianthus. These genera exhibited great variation in pollen shape.

本研究分析了青枝门和毛枝门22个分类群的花粉形态。目的是描述和表征花粉粒，并评估花粉形态是否证实了该群体的最新分类。只研究了发生在巴西的属，包括Cyanocephalus （Pohl ex Benth.）。Harley &； J.F.B.Pastore（7种），特有属Eplingiella Harley &； J.F.B.Pastore（3种），Marsypianthes Mart。Benth交货。（4席）、马田苏斯·哈利& j.f.b.帕斯托雷（3席）和梅杜莎·哈利& j.f.b.帕斯托雷（5席）。对乙酰化的花粉粒进行测量、描述和显微照相。用扫描电镜观察未乙酰化的花粉粒。所分析的所有分类群花粉粒均以单元体形式脱落，大小从中到大，等极性，(4)-6-(8-10)colpate，从近卵圆形到长形，极面积很小到很小。鞘长到非常长，宽，具装饰的膜和一个锐尖的先端，并且缺乏明显的边缘。在所有种类的蓝头科植物中都观察到有盖。在所有其他物种和属中，性器官都是双网状的。结果表明，所研究属的花粉形态对分类群的划分和属的区分具有重要的参考价值，与目前的分类观点有显著的相似之处。在主成分分析和层次聚类分析中，分别对Eplingiella属和Martianthus属的形态特征进行了近似和分组。这些属在花粉形态上表现出很大的差异。

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引用次数: 0

Pollen morphology of Pseudanthus (Picrodendraceae) 拟蕨科植物花粉形态研究

IF 1.7 3区地球科学 Q2 PALEONTOLOGY

Review of Palaeobotany and Palynology

Pub Date : 2025-08-13 DOI: 10.1016/j.revpalbo.2025.105426

Angelika Till , Silvia Ulrich , David J. Cantrill , Friðgeir Grímsson

This is the first comprehensive investigation on the pollen morphology of Pseudanthus, a small genus within the Picrodendraceae, comprising nine species all endemic to Australia. This study presents the pollen morphology of eight out of the nine currently accepted Pseudanthus species using light and scanning electron microscopy. Pollen from five of the species (incl. subspecies) are described here for the first time. Pollen from different Pseudanthus species appears alike, sharing many overlapping features, including sculpture patterns observed with both LM and SEM. However, detailed examination reveals species-specific differences such as size and aperture number, that aid in discriminating pollen of the individual species. In general, Picrodendraceae pollen is mostly isodiametric to oblate, spherical to spheroidal in shape, and either exhibits a pantoporate or stephanoporate aperture configuration, as well as echinate sculpture. Although, Pseudanthus pollen shares these morphological features, being isodiametric to slightly oblate, pantoporate, and echinate, the pollen of this genus can be differentiated from other closely related Picrodendraceae (Kairothamnus, Micrantheum, Neoroepera, Scagea, and Stachystemon) based on set of traits observed with combined LM and SEM.

本文首次对拟花属（Pseudanthus）花粉形态进行了全面的研究。拟花属是拟花科（Picrodendraceae）中的一个小属，由澳大利亚特有的9个品种组成。本文利用光镜和扫描电镜研究了目前公认的9种假花属植物中8种的花粉形态。其中5种（包括亚种）的花粉为首次报道。不同假药属植物的花粉看起来很相似，具有许多重叠的特征，包括用LM和SEM观察到的雕刻图案。然而，详细的研究揭示了物种特有的差异，如大小和孔数，这有助于区分单个物种的花粉。一般来说，Picrodendraceae花粉的形状大多为等径至扁圆，球形至球形，并表现出宽孔或深孔的孔径结构，以及刺状雕刻。虽然假花属的花粉具有等径到略平球形、泛孔状和棘刺状的形态特征，但根据LM和SEM结合观察到的一组性状，该属的花粉可以与其他密切相关的Picrodendraceae （Kairothamnus、Micrantheum、Neoroepera、Scagea和Stachystemon）区分开来。

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引用次数: 0

Evaluating Quercus pollen as a valuable archive of past UV-B levels in the Central Mediterranean: Insights from comparative infrared spectroscopy analyses 评价栎花粉作为地中海中部过去UV-B水平的宝贵档案：来自比较红外光谱分析的见解

IF 1.7 3区地球科学 Q2 PALEONTOLOGY

Review of Palaeobotany and Palynology

Pub Date : 2025-08-13 DOI: 10.1016/j.revpalbo.2025.105427

H. Saleh , P. Meyvisch , F. Di Rita , A. Spina , G. Margaritelli , D. Magri , M. Ghilardi , M. Alunni Cardinali , A. Di Michele

The relative abundance of ultraviolet-absorbing compounds (UACs) in pollen and spore exine increases with prolonged and higher exposure to ultraviolet B (UV-B) radiation. This relationship has been extensively studied via transmission Fourier-transform infrared microspectroscopy (transmission micro-FTIR), primarily in Lycopodium spores and airborne Pinus pollen. However, traditional transmission micro-FTIR methods are prone to infrared light scattering and interference, resulting in spectral deformations and reduced reproducibility. Additionally, bisaccate pollen, like Pinus, can travel long distances and may not accurately reflect local UV-B levels. This study compares transmission and attenuated total reflection (ATR) micro-FTIR methods to assess their reproducibility and investigates Quercus pollen as a potential local UV-B proxy in the Central Mediterranean. Samples containing fresh (in situ), trapped (in mosses), and fossilized (from Holocene sediments) pollen grains were subjected to various chemical treatments, after which the macromolecular composition of single and clustered grains was characterized. Results show that ATR micro-FTIR yields significantly more reproducible data than transmission micro-FTIR, demonstrating the suitability of this method for systematic chemo-palynological studies. Quercus ilex pollen consistently display UAC-related absorption bands across modern and fossil samples, and treatment with hydrochloric acid, hydrofluoric acid, and sodium hydroxide does not significantly alter these signatures. A comparison with fresh and trapped Q. cerris and Q. pubescens pollen further supports these findings. These results suggest that relative UAC concentrations in modern and fossil Quercus exine likely reflect accumulated UV-B dosage, pinpointing Quercus pollen as a valuable local UV-B proxy for reconstructing past UV-B levels in the Central Mediterranean.

花粉和孢子外皮中紫外线吸收化合物（UACs）的相对丰度随暴露于紫外线B （UV-B）辐射的时间延长而增加。这种关系已经通过透射傅里叶变换红外微光谱（transmission micro-FTIR）进行了广泛的研究，主要是在石松孢子和空气中的松花粉中。然而，传统的透射显微ftir方法容易受到红外光的散射和干扰，导致光谱变形，再现性降低。此外，像松属植物一样的双花花粉可以长距离传播，可能无法准确反映当地的UV-B水平。本研究比较了透射和衰减全反射（ATR）微傅里叶变换红外（ftir）方法的可重复性，并研究了栎花粉作为地中海中部地区潜在的UV-B代用物的可能性。对新鲜（原位）、捕获（苔藓中）和化石（来自全新世沉积物）花粉颗粒进行了不同的化学处理，然后对单个和簇状花粉颗粒的大分子组成进行了表征。结果表明，ATR微傅里叶红外比透射微傅里叶红外产生的可重复性数据要高得多，表明该方法适用于系统的化学孢粉学研究。在现代和化石样品中，栓皮栎花粉始终显示出与uac相关的吸收带，盐酸、氢氟酸和氢氧化钠处理不会显著改变这些特征。对新鲜花粉和捕获花粉的比较进一步支持了这些发现。这些结果表明，现代和化石栎皮中的相对UAC浓度可能反映了累积的UV-B剂量，确定栎花粉是重建地中海中部过去UV-B水平的有价值的当地UV-B代理。

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引用次数: 0

The use of transmission electron microscopy when investigating fossil angiosperm pollen: A review and suggestions for future applications 透射电镜在被子植物花粉化石研究中的应用：综述及未来应用的建议

IF 1.7 3区地球科学 Q2 PALEONTOLOGY

Review of Palaeobotany and Palynology

Pub Date : 2025-08-06 DOI: 10.1016/j.revpalbo.2025.105423

Silvia Ulrich , Carola Purgina , Johannes Martin Bouchal , Christian Geier , Friðgeir Grímsson

It has been more than 65 years since transmission electron microscopy (TEM) was first used to study fossil angiosperm pollen. Since then, significant progress has been made in sample preparation protocols and TEM equipment, particularly in contrasting methods used to reveal detailed ultrastructural differences in pollen walls, as well as sensitive, high-resolution cameras needed for documentation. Early TEM studies on fossil angiosperm pollen focused on determining whether ultrastructure could be used to assign palynomorphs to spore-producing plants, gymnosperms, or angiosperms. Later research became more taxonomically focused, comparing fossil pollen walls to those of extant angiosperms. Most TEM research on fossil angiosperm pollen has until now been conducted in the USA, Western/Central Europe, and Russia, with limited contributions from other parts of the scientific community. There is a clear relation between the sample origin (country, locality) and author group, and between the type of pollen specimens (dispersed versus in situ) and the taxonomic resolution. In situ pollen from fossil flowers is usually assigned to families and genera, while most dispersed pollen is noted as Incertae sedis. Despite the obvious advantages of TEM analyses for determining the taxonomic placement and phylogenetic relations of fossil pollen, little effort has been put into this subject over the last decades. To increase the understanding of angiosperm evolution, TEM investigations of fossil pollen need to be routinely applied. New generations of palynologists need to pick up on this method, and an effort to investigate Cenozoic angiosperm pollen from a taxonomic point of view is overdue.

透射电子显微镜（TEM）首次用于研究被子植物花粉化石已有65多年的历史。从那时起，在样品制备方案和TEM设备方面取得了重大进展，特别是在用于揭示花粉壁详细超微结构差异的对比方法，以及用于记录的灵敏、高分辨率相机方面。早期对被子植物化石花粉的透射电镜研究主要集中在确定超微结构是否可以用来为产孢植物、裸子植物或被子植物分配花粉形态。后来的研究更加注重分类学，将化石花粉壁与现存被子植物的花粉壁进行比较。迄今为止，大多数被子植物化石花粉的透射电镜研究都是在美国、西欧/中欧和俄罗斯进行的，其他科学界的贡献有限。样品来源（国家、地区）与作者群体之间、花粉标本类型（分散与原位）与分类分辨率之间存在明显的关系。来自化石花的原位花粉通常被划分为科和属，而大多数分散的花粉被称为Incertae sedis。尽管TEM分析在确定花粉化石的分类位置和系统发育关系方面具有明显的优势，但在过去的几十年里，这方面的研究很少。为了增加对被子植物进化的理解，需要常规应用透射电镜对化石花粉进行研究。新一代的孢粉学家需要学习这种方法，从分类学的角度研究新生代被子植物花粉的努力已经过期。

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引用次数: 0

Reassessment of the chronostratigraphic and paleogeographic distribution of the Permian prepollen genus Nuskoisporites 二叠纪前花粉属Nuskoisporites的年代地层和古地理分布的再评价

IF 1.7 3区地球科学 Q2 PALEONTOLOGY

Review of Palaeobotany and Palynology

Pub Date : 2025-08-05 DOI: 10.1016/j.revpalbo.2025.105425

Iván R. Barreiro , José B. Diez , Anna Fijałkowska-Mader , Elke Schneebeli-Hermann , Amalia Spina , Evelyn Kustatscher

The genus Nuskoisporites is a common component of Permian palynofloras, with biostratigraphic and paleogeographic importance. Despite the existence of previous revisions of its occurrence, there are still uncertainties concerning its complete stratigraphic range and paleogeographic distribution. This study presents a comprehensive review of historical records, complemented by new morphometric data derived from 446 Nuskoisporites specimens representing ten geographically distinct regions. Three morphometric variables were measured and analyzed using Principal Component Analysis (PCA): total size (diameter), the ratio of total size to central body diameter (P:CB), and the ratio of central body diameter to average laesurae length (CB:L). Two morphotypes can be distinguished based on those characters, each exhibiting different stratigraphic ranges. The older morphotype spans the Pennsylvanian to lower Guadalupian, while the younger form is confined to the upper Cisuralian through Lopingian. Current evidence supports the extinction of Nuskoisporites shortly before or at the Permian–Triassic boundary, thereby reflecting a genuine ecological turnover rather than reworking or preservation bias. Paleogeographic and paleoecological analyses indicate that Nuskoisporites initially had a broad distribution across multiple phytoprovinces and latitudes. However, a marked reduction of its geographic distribution is observed during the Lopingian, restricting the pollen to low-latitude regions of the western Tethys margin, coinciding with intensified global aridification and environmental stress. This integrated approach of Nuskoisporites provides a refined stratigraphic range for the genus and new insights into its ecological dynamics during the end of the Carboniferous and Permian.

Nuskoisporites属是二叠纪孢粉植物的共同组成部分，具有重要的生物地层学和古地理意义。尽管已有对其产状的修正，但其完整的地层范围和古地理分布仍存在不确定性。本研究对历史记录进行了全面的回顾，并辅以来自10个不同地理区域的446个Nuskoisporites标本的新的形态测量数据。采用主成分分析法（PCA）对3个形态计量变量进行了测量和分析：总大小（直径）、总大小与中心体直径之比（P:CB）和中心体直径与平均体长之比（CB:L）。根据这些特征可以区分出两种形态，每种形态表现出不同的地层范围。较老的形态跨越宾夕法尼亚纪至下瓜达鲁普纪，而较年轻的形态则局限于上西苏拉纪至洛平纪。目前的证据支持Nuskoisporites在二叠纪-三叠纪界线之前或附近的灭绝，从而反映了真正的生态更替，而不是重新加工或保存的偏见。古地理和古生态分析表明，Nuskoisporites最初在多个植物省和纬度具有广泛的分布。然而，在洛平纪期间，其地理分布明显减少，将花粉限制在特提斯西部边缘的低纬度地区，与全球干旱化和环境压力加剧相一致。Nuskoisporites的这种综合方法为该属提供了一个精细的地层范围，并为其在石炭纪和二叠纪末期的生态动态提供了新的见解。

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引用次数: 0

Morphological variation and evolutionary trends in pollen of Bacopa (Gratioleae-Plantaginaceae) 假马齿苋花粉形态变异及进化趋势

IF 1.7 3区地球科学 Q2 PALEONTOLOGY

Review of Palaeobotany and Palynology

Pub Date : 2025-07-28 DOI: 10.1016/j.revpalbo.2025.105422

María de las Mercedes Sosa , Mariela Nuñez-Florentín , María Betiana Angulo , Juan Manuel Coronel , Cristina Salgado Laurenti

Bacopa (Gratioleae-Plantaginaceae) is a plant genus with great morphological variability and little previous information on its palynology. Thus, the aim of the present study is to describe palynological characters of potential taxonomic significance for the delimitation of Bacopa species and to discuss their systematic implications. In addition, the evolution and systematic utility of palynological characters in the genus were also analyzed. The pollen grains were acetolyzed, observed and analyzed under light and scanning electron microscopy, measured and photographed. Analyses based on qualitative and quantitative data were performed based on descriptive and multivariate statistics. Also, the ancestral reconstruction of palynological characters was carried out by stochastic character mapping, based on previous phylogenies. The pollen morphology of 22 taxa was described for the first time. The pollen morphology of Bacopa contributes to taxonomic studies of the genus because it allows the formation of groups that coincide with previously proposed sections. The compound opening (tricolporate) was considered as an ancestral character state, as well as the tectate exine, small size and prolate-spheroidal shape. Bacopa is confirmed as an eurypalynous genus, the number and type of apertures allowed us to differentiate three pollen types that coincide with the subclades determined by molecular phylogeny.

假马齿苋是一个形态变异较大的植物属，前人对其孢粉学的研究很少。因此，本研究的目的是描述具有潜在分类意义的孢粉学特征，并讨论其系统意义。此外，还分析了该属孢粉学特征的演化及其系统利用。对花粉粒进行乙酰化处理，光镜、扫描电镜观察分析，测量拍照。基于描述性和多变量统计进行定性和定量数据分析。在前人系统发育的基础上，采用随机特征映射的方法进行孢粉特征的祖先重建。对22个分类群的花粉形态进行了首次描述。假马齿苋的花粉形态有助于该属的分类学研究，因为它允许形成与先前提出的部分一致的群。复合开口（三孔）被认为是一个祖先的特征状态，以及盾状外壁，小尺寸和延长的球体形状。假马齿苋属为全花粉属，花粉孔的数量和类型使我们能够区分出三种花粉类型，这些花粉类型与分子系统发育确定的亚支系一致。

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引用次数: 0

First record of fossil algal diversity in Lake Sevan, Armenia: Illuminating ecological dynamics and environmental parameters 亚美尼亚塞万湖化石藻类多样性的首次记录：阐明生态动态和环境参数

IF 1.7 3区地球科学 Q2 PALEONTOLOGY

Review of Palaeobotany and Palynology

Pub Date : 2025-07-23 DOI: 10.1016/j.revpalbo.2025.105420

N. Hayrapetyan , E. Hakobyan , M. Melkonian , A. Mamyan , E. Kvavadze , G. Zhamakochyan , A.A. Bruch , I. Gabrielyan

Algae serve as valuable proxies for paleoenvironmental reconstructions in sedimentary environments. Fossil algae from Middle to Late Holocene sediments, alongside pollen data, enrich our understanding of environmental changes, particularly evident in the Tsovinar-1 section of Lake Sevan, Armenia.

Botryococcus and Pediastrum/Pseudopediastrum are sensitive indicators of hydrological changes and reflect fluctuations in lake level. The comparatively high abundance of Pediastrum/Pseudopediastrum and Botryococcus from 6000 BC to 4400 ca. BC, when water levels were elevated, together with the occurrence of the genera Gomphonema, Fragilaria, Cymbella, and Epithemia during high lake level phases, underscores their utility as pelagic indicators. From 4400 to 2600 ca. BC, no aquatic vegetation is recorded at Tsovinar-1 under relatively more arid conditions. Later, from 2600 to 1400 ca. BC the lake level rose again and eutrophic conditions in some shallow areas along the coastal zone developed, indicated by high abundances of the nitrogen-fixing cyanobacterium Gloeotrichia. Later, after 600 ca. BC, further variations in water level occurred and are mirrored in algal abundances. Changes of pH followed those trends of water level and are mainly reflected in the occurrences of Zygnematophyceae, particularly with high numbers of Spirogyra and Mougeotia.

The results suggest that algal species hold a valuable potential for paleoecological reconstructions, calling for further studies across diverse environmental gradients. Notably, the first documentation of Gloeotrichia in the fossil record of the Caucasus provides a new proxy for the analysis of environmental changes in lakes and pools of the Armenian Highland.

藻类是沉积环境古环境重建的重要代用物。来自全新世中晚期沉积物的藻类化石，以及花粉数据，丰富了我们对环境变化的理解，特别是在亚美尼亚塞万湖的Tsovinar-1段。Botryococcus和Pediastrum/Pseudopediastrum是水文变化的敏感指标，反映了湖泊水位的波动。在公元前6000年至公元前4400年，当水位升高时，Pediastrum/Pseudopediastrum和Botryococcus的丰度相对较高，而在高水位阶段，Gomphonema、Fragilaria、Cymbella和Epithemia属的出现，强调了它们作为上层生物指标的作用。从公元前4400年到公元前2600年，在相对干旱的条件下，Tsovinar-1没有水生植被的记录。后来，从公元前2600年到公元前1400年，湖泊水位再次上升，沿海地带的一些浅水地区出现了富营养化状况，具有高丰度的固氮蓝藻Gloeotrichia。后来，公元前600年以后，水位发生了进一步的变化，反映在藻类的丰度上。pH值的变化与水位的变化趋势一致，主要体现在刺丝虫的出现上，特别是Spirogyra和Mougeotia的数量较多。结果表明，藻类在古生态重建中具有宝贵的潜力，需要在不同的环境梯度下进一步研究。值得注意的是，高加索地区化石记录中关于Gloeotrichia的第一份文件为分析亚美尼亚高地湖泊和池塘的环境变化提供了新的代理。

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引用次数: 0

Palaeoenvironmental response to the Early Cretaceous volcanic ash fall: Evidence from palynology and palynofacies of the tonstein-bearing coal seam of Kharanor Deposit, Transbaikalia, Russia 早白垩世火山灰沉降的古环境响应：来自俄罗斯外贝加尔地区Kharanor矿区含铜煤层孢粉学和孢粉相的证据

IF 1.7 3区地球科学 Q2 PALEONTOLOGY

Review of Palaeobotany and Palynology

Pub Date : 2025-07-23 DOI: 10.1016/j.revpalbo.2025.105421

Andrey G. Fedyaevskiy , Alexey V. Vergunov , Sofia S. Shadrina

Volcanic ash falls, being one of the consequences of eruptive palaeoevents, are reflected in the geological record of coal-bearing sediments as tonsteins, thin clayey interlayers. Information on the palaeontological characteristics of tonsteins and assessments of the influence of ash on the palaeoenvironment are still fragmentary. This paper presents new palynological and palynofacies data obtained for the tonstein-bearing Kharanor coal deposit located in Transbaikalia, Russia. The spore and pollen assemblages indicate the early Albian (Cretaceous) age of the sediments. The tonstein palynomorph composition differs markedly from the host coal one, which is expressed in an increased number of fern spores and a decreased content of gymnosperm pollen. The palynofacies composition of the Kharanor tonstein is characterised by a high content of phytoclasts of the cutinite subgroup and an increased content of palynomorphs and amorphous organic matter, whereas the lower and upper coals are dominated by vitrinite and inertinite phytoclasts. The results indicate peat-forming conditions that existed in a swampy area where a predominantly gymnosperm-fern forest grew in a wet and warm-temperate climate. At one point the area was covered by a relatively thick layer of volcanic ash, resulting in the burial of the lower forest layers, possibly during their spore production period. Rapid rates of sedimentation and subsequent compaction resulted in the conservation of organic matter, including unstable soft plant tissues. However, the impact of the volcanic event on vegetation and palaeoenvironment had a noticeable but short-term effect. No fundamental changes in flora or sedimentation conditions followed in the long term.

火山灰落体是火山喷发古事件的结果之一，在含煤沉积物的地质记录中反映为薄粘土夹层。关于火山的古生物学特征和火山灰对古环境影响的评估的资料仍然是零碎的。本文介绍了俄罗斯外贝加尔地区含铜矿区Kharanor煤矿的孢粉学和孢粉相新资料。孢子和花粉组合表明沉积物的早白垩纪时代。其孢粉组成与寄主煤的孢粉组成明显不同，表现为蕨类孢子数量增加，裸子植物花粉含量减少。其孢粉相组成以高含量的角质质亚群植物碎屑为主，孢粉质和无定形有机质含量增加，而下部和上部煤则以镜质组和惰质组植物碎屑为主。结果表明，泥炭形成条件存在于沼泽地区，在潮湿和温暖的气候中，主要生长着裸子植物-蕨类森林。该地区一度被一层相对较厚的火山灰覆盖，导致较低的森林层被掩埋，可能是在它们产生孢子的时期。快速的沉积速率和随后的压实导致了有机物的保存，包括不稳定的软植物组织。然而，火山事件对植被和古环境的影响是明显的，但短期的。长期以来，植物群或沉积条件没有发生根本变化。

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引用次数: 0