Marine Micropaleontology最新文献

Dinoflagellate cysts in sediment traps from the Nordic Seas: Implications for their use as proxies in paleoceanography 北欧海沉积物捕集器中的鞭毛藻囊：它们作为古海洋学代用物的意义

IF 1.6 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2026-03-01 Epub Date: 2026-02-18 DOI: 10.1016/j.marmicro.2026.102554

Amy L. Dale , Barrie Dale

The Nordic seas are important for bottom water formation and heat transfer in global climate, and dinoflagellate cysts are a major microfossil group in cored sediments from high latitudes where mineralized fossils are absent due to dissolution. This first basin-wide study of dinoflagellate cysts in deep-sea sediment traps reassesses the basic assumptions of paleoceanographic proxies: that dinoflagellate cysts in bottom sediments represent primary environmental signals from overlying surface waters carried by cysts sinking without significant lateral transport. We studied 126 samples collected at 12–30 day intervals over one year from traps (approximately 400 m above bottom) at 9 stations. We recorded 27 cyst taxa quantitatively (cyst fluxes) and as assemblages calculated from the fluxes. Correspondence analysis was used to compare cyst assemblages from traps with those in recent bottom sediments used to create proxies. The generally high correlation shown between fluxes of cysts and lithogenic particles suggests common transport mechanisms for both. We show three different sources of cysts and environmental signals: primary, from oceanic surface waters; secondary, transported in from shallow adjoining waters and ocean currents; and tertiary, older cysts resuspended from shelves. We found poor correspondence between cysts in traps and those in bottom sediments mainly due to the dominance of O. centrocarpum in the sediments, but correspondence analysis identified the main current regimes in both. We propose that O. centrocarpum here and elsewhere in oceanic sediments reflects an opportunistic response to mixing of oceanic/shelf waters. Consideration of factors highlighted here should help to improve the use of proxies.

北欧海对全球气候的底水形成和热传递具有重要意义，而鞭毛藻囊是高纬度地区岩心沉积物中主要的微化石群，由于溶解作用而缺乏矿化化石。这是对深海沉积物圈闭中鞭毛藻包囊的首次全流域研究，重新评估了古海洋学代用物的基本假设：即底部沉积物中的鞭毛藻包囊代表了由包囊下沉而无显著横向运输的上覆地表水携带的主要环境信号。我们研究了在一年内每隔12-30天从9个站点的陷阱（距离底部约400米）收集的126个样本。我们定量记录了27个囊群（囊通量）和根据通量计算的组合。对应分析用于比较圈闭中的囊肿组合与用于创建代理的近期底部沉积物中的囊肿组合。囊泡的通量与造石颗粒之间普遍显示出高度的相关性，这表明两者具有共同的运输机制。我们展示了三种不同的囊肿和环境信号来源：主要来自海洋表层水；其次，从邻近的浅水和洋流中运来；第三代，更老的囊肿从架子上重新出现。圈闭中囊泡与底部沉积物中囊泡的对应性较差，主要是由于沉积物中O. centrocarpum的优势，但对应分析确定了两者的主要现状。我们认为，这里和其他地方的海洋沉积物中的O. centrocarpum反映了海洋/陆架水混合的机会性反应。考虑这里强调的因素应该有助于改进代理的使用。

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引用次数: 0

Gradual turnover in the composition of benthic foraminiferal assemblages across the Sinemurian/Pliensbachian boundary in the Transcarpathian Ukraine (Pieniny Klippen Belt, Eastern Carpathians) 乌克兰外喀尔巴阡山脉Sinemurian/Pliensbachian边界上底栖有孔虫组合的逐渐转换（东喀尔巴阡山脉Pieniny Klippen带）

IF 1.6 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2026-03-01 Epub Date: 2026-01-17 DOI: 10.1016/j.marmicro.2026.102551

Štefan Józsa , Adam Tomašových , Ján Schlögl , Christian Meister , Vladimír Šimo

The Sinemurian/Pliensbachian boundary interval in the eastern part of the Pieniny Klippen Belt (Eastern Carpathians, Ukraine) is preserved in a succession formed by a marl-limestone alternation that was deposited in a low-energy, outer shelf environment on the NW margin of the Tethys shelf (Euroboreal Province). Assemblages with benthic foraminifers are diverse, with fifteen agglutinated species and 64 calcareous species. Although most species range across the Sinemurian/Pliensbachian boundary, the assemblages of agglutinated and calcareous benthic foraminifers exhibit a gradual and protracted change in abundance of species, genera, and functional morphogroups during this time interval. The increase in abundance of lenticular (C8) and elongated-flattened (C6) morphogroups and the decline in abundance of elongated morphogroups with a straight periphery (C8) across the boundary is gradual. This turnover in taxonomic and functional composition can be related to an increase in ventilation and bottom currents that decreased any incidences of oxygen depletion, reduced organic matter preservation, and allowed the onset of sponge biostromes during the earliest Pliensbachian. In contrast to stratigraphic changes in abundance of individual species, alpha species (mean = 21) and genus (mean = 11) diversity remains rather constant across the S/P boundary and the overall assemblage composition is persistently dominated by deposit-feeders and grazing omnivores both in the uppermost Sinemurian and the lowermost Pliensbachian. Therefore, although the overall shallowing-up trend in outer-shelf habitats contributed to directional changes in abundance of some species, genera and morphogroups, they did not induce any major turnover, extirpation or immigration at species or genus level.

Pieniny Klippen带（乌克兰东喀尔巴阡山脉）东部的Sinemurian/Pliensbachian边界段保存在一个由泥灰岩交替形成的序列中，该序列沉积在特提斯大陆架（欧洲北方省）西北缘的低能量外大陆架环境中。底栖有孔虫的组合是多样的，有15个凝集种和64个钙质种。虽然大多数物种分布在Sinemurian/Pliensbachian界线上，但在这段时间间隔内，黏结和钙质底栖有孔虫的种类、属和功能形态群的丰度表现出逐渐和持久的变化。透镜状（C8）和细长扁平（C6）形态群的丰度逐渐增加，边缘呈直线的细长型（C8）形态群的丰度逐渐下降。这种分类和功能成分的转换可能与通风和底流的增加有关，这减少了氧气消耗的发生率，减少了有机物的保存，并使海绵生物层在最早的Pliensbachian时期出现。与个体物种丰度的地层变化相反，α种（平均21种）和属（平均11种）多样性在S/P界线上保持相当稳定，总体组合组成在最上层的Sinemurian和最下层的Pliensbachian中都持续以沉积物食性动物和放牧杂食动物为主。因此，尽管陆架外生境的总体浅化趋势导致了某些物种、属和形态群丰度的方向性变化，但它们并未在种或属水平上引起任何重大的更替、灭绝或迁移。

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引用次数: 0

Increase the magnification, they are shrinking! Morphometric variations of the planktic foraminifera Globigerina bulloides in response to environmental changes over the last 27.4 ka in the Ligurian Sea 放大，他们在缩小！近27.4 ka利古里亚海浮游有孔虫球状虫形态变化对环境变化的响应

IF 1.6 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2026-03-01 Epub Date: 2026-01-20 DOI: 10.1016/j.marmicro.2026.102552

Pierluigi Martinelli , Isabel Cacho , Elena Cavallero , Antonio Cascella , Letizia Di Bella , Fabrizio Lirer , Mar Selvaggi , Rocco Gennari

This study investigates the test size variability of the planktic foraminifera Globigerina bulloides over the past 27.4 ka from sediment core NDT_22_2016, collected in the Ligurian Sea. This climatically sensitive region provides an ideal setting to explore how large-scale glacial-interglacial oscillations influenced the phenotypic plasticity of the non-symbiotic planktic foraminifer G. bulloides through changes in surface-water conditions.

We explore the relationships between test size and sea surface temperature (SST), relative salinity (δ¹⁸Osw-ivc), and atmospheric CO₂. To test this, over 3400 specimens from 110 samples were analysed. Morphometric data were obtained through high-resolution imaging and automated area measurements, while environmental variables were derived from Mg/Ca-based SST reconstructions and stable isotope analyses, both performed on G. bulloides tests, and from published ice core CO₂ records.

Descriptive statistics reveal a significant reduction in test size from the Pleistocene to the Holocene, with the largest specimens recorded during the Younger Dryas. Generalized linear mixed models (GLMMs) indicate that G. bulloides tests size responds significantly to environmental forcing: size decreases with increasing SST, consistent with Atkinson's temperature-size rule; increases (although less significantly) with increasing δ¹⁸Osw-ivc; and exhibits a non-linear (quadratic) relationship with CO₂. The occurrence of larger tests at lower temperatures and higher salinities could also be related to higher productivity in a paleoceanographic context that favoured water-column mixing and surface fertilization. To test the possible productivity-size relationship, we used the abundance of G. bulloides as a proxy for productivity, but no significant relationship was revealed by the GLMM.

本文研究了利古里亚海NDT_22_2016沉积物岩心中浮游有孔虫Globigerina bulloides在过去27.4 ka的试验尺寸变化。这一气候敏感区为探索大规模冰期-间冰期振荡如何通过地表水条件的变化影响非共生浮游有孔虫G. bulloides的表型可塑性提供了理想的环境。我们探讨了试验尺寸与海表温度（SST）、相对盐度（δ18Osw-ivc）和大气CO₂之间的关系。为了验证这一点，研究人员分析了110个样本中的3400多个样本。形态测量数据通过高分辨率成像和自动面积测量获得，而环境变量则来自基于Mg/ ca的海温重建和稳定同位素分析，这两种方法都是在G. bulloides测试中进行的，并来自已发表的冰芯CO₂记录。描述性统计显示，从更新世到全新世，测试尺寸显著减少，新仙女木时期记录的最大样本。广义线性混合模型（glmm）表明，球藻试验尺寸对环境强迫响应显著：尺寸随海温的增加而减小，符合Atkinson温度-尺寸规则；δ 18ows -ivc随δ 18ows -ivc的增加而增加（尽管不太显著）；与CO₂呈非线性（二次）关系。在较低温度和较高盐度下进行较大的试验也可能与古海洋学环境下较高的生产力有关，这种环境有利于水柱混合和地表施肥。为了检验可能的生产力-大小关系，我们使用了丰度作为生产力的代理，但GLMM没有显示出显著的关系。

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引用次数: 0

Foraminiferal biostratigraphy, paleoenvironmental interpretation, and sequence stratigraphy of the latest Maastrichtian–Thanetian succession in the Southern Galala Plateau, Eastern Desert, Egypt 埃及东部沙漠南加拉拉高原最新马萨-塔尼梯演替的有孔虫生物地层学、古环境解释和层序地层学

IF 1.6 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2026-03-01 Epub Date: 2026-02-12 DOI: 10.1016/j.marmicro.2026.102555

Aziz M. Abu Shama , Sherif Farouk , Ahmed Abdelwahhab , Youssef S. Bazeen

We present an integrated study of two stratigraphic sections from the Southern Galala Plateau that combines foraminiferal biostratigraphy with quantitative paleoenvironmental proxies and sequence stratigraphic analysis across the latest Maastrichtian–Thanetian interval. High-resolution planktic zonations (Maastrichtian CF2–CF1; Paleocene P1c–P4c) reveal variable temporal hiatuses at the Cretaceous/Paleogene (K/Pg) boundary, with an abrupt planktic foraminifera extinction, a low benthic foraminiferal extinction (∼9%), and drops in TFN, HOFS%, and paleodepth, followed by increased EBFOI, reflecting improved bottom water oxygenation in the Danian. The Latest Danian Event (LDE) is recorded only in South Wadi El-Maheer, characterized by brown nodular calcareous shale, high HOFS%, low EBFOI, a paleodepth drawdown, and the invasion of the Neoeponides duwi assemblage. The Danian/Selandian (D/S) boundary exhibits a pronounced sea-level fall, mirroring the global signal. Its placement varies between both sections due to differences in hiatus magnitude, which is greater in Wadi Ragela, as indicated by an abrupt planktic foraminiferal assemblage shift and the reduced thickness of P3a and P3b. The sequence stratigraphic analysis revealed seven third-order depositional sequences in Wadi Ragela and five in South Wadi El-Maheer. The proposed sequence stratigraphic framework confirms that the study area was influenced by eustatic changes and regional tectonic activities.

本文对南加拉拉高原的两个地层剖面进行了综合研究，将有孔虫生物地层学与定量古环境代用指标和层序地层学分析相结合，分析了最新的马斯特里赫特-塔内梯段。高分辨率浮游生物分带（Maastrichtian CF2-CF1；古新世P1c-P4c）揭示了白垩纪/古近纪（K/Pg）边界的变化时间中断，浮游有孔虫突然灭绝，低底栖有孔虫灭绝（~ 9%），TFN、HOFS%和古深度下降，随后EBFOI增加，反映了大年纪底水氧合的改善。最新丹尼世事件（late Danian Event， LDE）仅在南Wadi El-Maheer有记录，其特征为棕色结节状钙质页岩，高HOFS%，低EBFOI，古深度下降，并侵入了Neoeponides duwi组合。Danian/Selandian （D/S）边界显示出明显的海平面下降，反映了全球信号。由于裂孔大小的不同，其位置在两个剖面之间有所不同，Wadi Ragela的裂孔更大，这表明浮游有孔虫组合的突变和P3a和P3b的厚度减少。层序地层学分析显示，在瓦迪拉格拉有7个三级沉积层序，在南瓦迪马希尔有5个三级沉积层序。所建立的层序地层格架证实了研究区受海平面上升变化和区域构造活动的影响。

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引用次数: 0

Changes in pteropod assemblage driven by monsoonal variability and associated oceanographic conditions since the last Glacial Maximum in the eastern Arabian Sea 末次盛冰期以来阿拉伯海东部季风变率和相关海洋学条件下翼足类动物组合的变化

IF 1.6 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2026-03-01 Epub Date: 2026-02-24 DOI: 10.1016/j.marmicro.2026.102561

Jeet Majumder , Anil K. Gupta , Vipul Singh Rathaur

We present a record of well preserved aragonitic shell bearing pteropods from core SK291/GC17, eastern Arabian Sea. The study is aimed to investigate the temporal changes in pteropod assemblage and their preservation state linked to changes in the surface condition driven by the Indian Summer Monsoon (ISM) from ∼25,000 to 3500 calibrated year before present (cal yr BP). Heliconoides inflatus (earlier known as Limacina inflata) is the most dominant pteropod species, followed by Limacina trochiformis, Creseis spp., Limacina bulimoides, and Gleba cordata as other important component of the pteropod assemblage. Pteropod shells show only a primary level of dissolution evident from low values of Limacina Dissolution Index (LDX) which ranges between 0.8 and 2.5. Milky white shells (LDX ∼2.5) of H. inflatus can be seen mainly during the middle to late Holocene, possibly due to influence of oxygen minimum zone water. Higher relative abundance and larger shell size of H. inflatus are positively correlated with the elevated surface productivity caused by ISM-induced upwelling in the Holocene. On the other hand, low abundance and smaller shells of H. inflatus are mostly found in the last glacial maximum (LGM) and 4.2 ka event. Other pteropod species such as L. trochiformis, Creseis spp., L. bulimoides, and G. cordata seem to be less influenced by the surface productivity, and correlate more with the changes in sea surface temperature and salinity in the Eastern Arabian Sea.

本文报道了阿拉伯海东部SK291/GC17岩心中保存较好的文石壳翼足类化石。本研究旨在探讨由印度夏季风（ISM）驱动的地表条件变化与翼足类组合的时间变化及其保存状态的关系，这些变化与距今约25000至3500校准年（cal yr BP）有关。Heliconoides inflatus（早期称为Limacina inflata）是最主要的翼足类，其次是Limacina trochiformis， Creseis spp.， Limacina bulimoides和Gleba cordata是翼足类的重要组成部分。翼足类甲壳仅显示初级溶解水平，其Limacina溶解指数（LDX）值较低，在0.8 ~ 2.5之间。H. inflatus的乳白色壳（LDX ~ 2.5）主要出现在全新世中晚期，可能是受氧最小带水的影响。相对丰度高、壳尺寸大与全新世ism上升流导致的地表生产力升高呈正相关。另一方面，在末次盛冰期（LGM）和4.2 ka事件中发现了低丰度和较小的膨胀螺壳。其他翼足类物种如盘形翼足类（L. trochiformis）、Creseis spp.、L. bulimoides和G. cordata似乎受海面生产力的影响较小，而与东阿拉伯海海面温度和盐度变化的相关性更大。

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引用次数: 0

Palynology of the Upper Triassic strata from Tabas, east-central Iran: Biostratigraphic, paleoenvironmental, and paleobiogeographic inferences 伊朗中东部Tabas地区上三叠统地层孢粉学：生物地层、古环境和古生物地理推论

IF 1.6 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2026-03-01 Epub Date: 2026-02-21 DOI: 10.1016/j.marmicro.2026.102558

Freshteh Sajjadi Hezaveh , Firoozeh Hashemi-Yazdi

Subsurface data from Well no. 954, Tabas, east-central Iran, constitute the foundation for an integrated palynological, paleoenvironmental, and paleobiogeographical analysis of the Upper Triassic (Rhaetian) Qadir Member of the Nayband Formation. The assemblage consists of diverse, moderately preserved spores and pollen. Of the latter, such taxa as Falcisporites nuthallensis, Lunatisporites rhaeticus, Ovalipollis ovalis, Ricciisporites tuberculatus, and Araucariacites australis dominate the assemblages. Representatives of such trilete spores as Dictyophyllidites mortonii, Gleicheiniidites senonicus Kyrtomisporis laevigatus, Limbosporites spp., and Lophotriletes bauhiniae, are essentially abundant in the palynofloras examined. Vertical distribution of miospores allows recognition of Dictyophyllidites-Striatella seebergensis-Ricciisporites tuberculatus assemblage zone (Rhaetian). The inferred natural relationships of the sporae dispersae indicate a parental flora derived from, in descending order: Pterophyta, Cycadophyta, Pteridospermophyta, Coniferophyta, Lycopodophyta, Ginkgophyta, and Bryophyta. Fern abundance suggests a moist, warm climate. Sporomorph EcoGroup (SEG) analysis shows dominant lowland/plain communities over upland and coastal/tidal ones, indicating deposition during relatively low sea level in shallow marine conditions. Palynological analysis identifies three palynofacies following Tyson's methodology. Palynofacies I represents very proximal, shallow shelf environments during sea-level fall and regression. Palynofacies II suggests dysoxic to anoxic, restricted shallow-water settings. Palynofacies VI indicates conditions from low-oxygen coastal to anoxic shelf environments. Key proxies—the transparent/opaque AOM ratio, equidimensional/blade-shaped opaque phytoclasts (P1/P2) ratio, and terrestrial/marine (T/M) ratio—support this interpretation. The palynofloras show strong biogeographic affinities with both northern Gondwana and southern Laurasia, highlighting Iran's position as a biogeographic crossroads on the southern margin of Eurasia during the Late Triassic.

井号的地下数据954, Tabas，伊朗中东部，为Nayband组上三叠统（Rhaetian） Qadir段的孢粉学、古环境和古生物地理学综合分析奠定了基础。该组合由多种多样、保存适度的孢子和花粉组成。在后者中，Falcisporites nuthallensis、Lunatisporites rhaeticus、ovalipolis ovalis、Ricciisporites tuberculatus和Araucariacites australis等类群占主导地位。这些孢子的代表，如Dictyophyllidites mortonii， gleicheinidiites senonicus Kyrtomisporis laevigatus, Limbosporites spp.和Lophotriletes bauhiniae，在所研究的孢群中基本上是丰富的。小孢子的垂直分布允许识别dictyophylliites - striatella seebergensis-Ricciisporites tuberculatus组合带（Rhaetian）。由此推断的孢子传播的自然关系表明，亲本植物区系由大到小依次为：蕨类植物、苏铁植物、蕨类植物、针叶植物、石松植物、银杏植物和苔藓植物。蕨类植物的丰富表明这里气候湿润、温暖。SEG （Sporomorph EcoGroup）分析显示，低地/平原群落优势于高地和海岸/潮汐群落，表明在相对低海平面的浅海条件下沉积。孢粉学分析根据泰森的方法确定了三种孢粉相。孢粉相I代表海平面下降和回归期间非常近的浅陆架环境。孢粉相II提示缺氧至缺氧，受限浅水环境。孢粉相ⅵ反映了低氧海岸到缺氧陆架环境的变化。透明/不透明AOM比率、等维/叶片状不透明植物碎屑（P1/P2）比率和陆相/海相（T/M）比率等关键指标支持这一解释。孢粉植物与冈瓦纳北部和劳拉亚南部具有很强的生物地理亲缘关系，突出了伊朗在晚三叠世欧亚大陆南缘生物地理十字路口的地位。

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引用次数: 0

Paleoenvironmental significance of Early Miocene coralline red algae from the Qom Formation, Central Iran 伊朗中部库姆组早中新世珊瑚红藻的古环境意义

IF 1.6 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2026-03-01 Epub Date: 2026-02-17 DOI: 10.1016/j.marmicro.2026.102556

Suman Sarkar , Mehdi Hadi , Yaghub Nasiri , Mohsen Allameh

Understanding the evolution of shallow-marine biotic assemblages is not less important than deep-sea ecosystems in deciphering the climate dynamics of the Earth, yet attract lesser attention from the research community in terms of applied case studies. Representing a major shallow-marine biotic group, coralline red algae show very wide geographical distribution from tropics to the poles, and also have high potential as proxies in reconstruction of Cenozoic paleoenvironments. Here, Early Miocene coralline algae from a carbonate-dominated succession of the Qom Formation outcropping in Ghalibaf (central Iran) are evaluated to understand their paleoenvironmental affinities and significance. By referring to their qualitative assessment and relative abundance, coralline algal assemblages are used to interpret the depositional conditions. A depth range of 20–30 m is interpreted for the coralgal-foraminiferal facies based on the presence of abundant hermatypic corals and endosymbiont larger miliolid foraminifera with corallines pertaining to the orders Hapalidiales (Mesophyllum-dominant) and Corallinales. Conversely, the abundance of Hapalidiales (Lithothamnion-dominant) in association with smaller miliolids and poor quantities of Corallinales in the bryozoan-coralline algal (bryorhodalgal) and coralline algal (rhodalgal) skeletal associations relate to a deeper bathymetric range of 40–60 m. The environmental regime during the Early Miocene seems to have supported the growth and development of coralline algae in the Central Iran Basin.

了解浅海生物群落的进化在破译地球气候动力学方面的重要性并不亚于深海生态系统，但在应用案例研究方面却较少受到研究界的关注。珊瑚红藻是一种主要的浅海生物类群，从热带到极地分布非常广泛，在重建新生代古环境方面具有很高的潜力。本文对Ghalibaf（伊朗中部）库姆组碳酸盐为主演替的早中新世珊瑚藻进行了评价，以了解它们的古环境亲和性和意义。根据珊瑚藻的质量评价和相对丰度，用珊瑚藻组合来解释沉积条件。珊瑚-有孔虫相的深度范围为20-30 m，因为存在大量的两性珊瑚和内共生的较大的千层有孔虫，其中珊瑚属半虫目（中叶为主）和珊瑚目。相反，在苔藓虫-珊瑚藻（bryorhodalgal）和珊瑚藻（rhodalgal）骨骼组合中，大量的半藻目（Lithothamnion-dominant）与较小的千脂类相关，而少量的珊瑚目（Corallinales）与更深的深度范围（40-60 m）有关。中新世早期的环境状况似乎支持了中伊朗盆地珊瑚藻的生长和发育。

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引用次数: 0

Sudden disappearance of the foraminifer Calcarina gaudichaudii in the boundary between the Southern and Central Kuroshio ecoregions in the Ryukyu Archipelago, Japan 日本琉球群岛南黑潮和中黑潮生态边界上有孔虫Calcarina gaudichadii的突然消失

IF 1.6 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2026-03-01 Epub Date: 2026-02-19 DOI: 10.1016/j.marmicro.2026.102559

Bryan Gabriel P. Tan , Goushi Moribe , Kazuhiko Fujita

Ocean warming induces biogeographic range extension of coral reef-associated organisms toward higher latitudes. The Japanese Islands are one of the most suitable places to study the range extension. Biogeographic distributions of the Foraminiferal family Calcarinidae along the Ryukyu Archipelago (the Ryukyus), southwestern Japan, indicate a change in assemblage composition between the central and northern regions. To fully understand these changes near the boundary, we examined calcarinid assemblages in 36 surface sediments collected from a beach, shallow lagoon, and reef crest from the central (Amami Oshima) and the northern (Takara Jima and Kuchinoshima) regions. The results showed that of the 8 identified calcarinid species, Baculogypsina sphaerulata was found in all samples and dominant in the north, while C. gaudichaudii was the most common in Amami Oshima but disappeared entirely in the northern region. The results clearly indicate that the latitudinal limit of Calcarina gaudichaudii lies at ∼28.5°N. The possible controlling factor is the loss of foraminiferal habitats associated with the absence of shallow lagoons in the northern region. This study suggests that the northern region of the Ryukyus is the front line of biogeographic extension of shallow-water calcarinids, which needs to be monitored.

海洋变暖导致珊瑚礁相关生物的生物地理范围向高纬度地区扩展。日本列岛是最适合研究其活动范围扩展的地方之一。日本西南部琉球群岛有孔虫科Calcarinidae的生物地理分布表明中部和北部地区的组合组成发生了变化。为了充分了解这些边界附近的变化，我们检查了从中部（大岛天美）和北部（高原岛和久之岛）地区的海滩、浅泻湖和礁顶收集的36个表层沉积物中的钙石属组合。结果表明，8种钙碱类植物中，均以绿杆藻居多，在北部占优势，而高笛藻在大岛天美最常见，但在北部完全消失。结果清楚地表明，高笛甲的纬度极限在~ 28.5°N。可能的控制因素是有孔虫栖息地的丧失与北部地区浅泻湖的缺乏有关。该研究表明，琉球北部地区是浅水钙石类生物地理扩展的前沿，需要对其进行监测。

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引用次数: 0

Marine benthic foraminifera diversity in extreme environments: A case study from the Edisto Bay (Ross Sea, Antarctica) 极端环境下的海洋底栖有孔虫多样性：以南极洲罗斯海埃迪斯托湾为例

IF 1.6 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2026-03-01 Epub Date: 2026-01-22 DOI: 10.1016/j.marmicro.2026.102553

F. Caridi , L. Langone , A. Sartini , C. Morigi , G. Galli , P. Giordano , M. Bensi , V. Kovacevic , L. Ursella , N. Krauzig , A. Sabbatini

引用次数: 0

The promise of sedimentary ancient DNA as a proxy to understand Arctic Ocean palaeoecology and palaeoenvironments 沉积古DNA有望作为了解北冰洋古生态和古环境的代用物

IF 1.6 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2026-03-01 Epub Date: 2026-01-16 DOI: 10.1016/j.marmicro.2026.102543

Flore M.D. Wijnands , Matt O'Regan , Helen K. Coxall , Peter D. Heintzman

The Arctic Ocean is changing rapidly due to global warming, but how this will impact marine Arctic ecosystems remains uncertain. Several Pleistocene interglacials, like Marine Isotope Stages (MIS) 5e, 9 and 11 form potential analogues to a future warmer Arctic and can give important insights on how Arctic ecosystems may respond to climate warming. However, micro- and nannofossils are scarce in many Pleistocene marine sediment cores, and are often not in agreement with biomarker data. Sedimentary ancient DNA (sedaDNA) is an emerging method that does not require the preservation of fossils and can therefore be used to detect taxa without any hard body parts, like most protist groups and zooplankton. Thanks to this method, it is now possible to detect organisms from all trophic layers of marine ecosystems. SedaDNA provides us with new opportunities to reconstruct past sea ice conditions, changes to ocean currents, and borealisation of the Arctic Ocean. Developments in bioinformatics software and new techniques like shotgun metagenomics and hybridisation capture, now enable the study of ancient DNA from Middle and even Early Pleistocene sediments. Moreover, the marine sedaDNA field is working towards detecting within-species genetic variation, which can provide information on population bottlenecks, recolonisation histories, and may lead to important insights for marine conservation. Combined with traditional proxies, sedaDNA is a powerful tool for Arctic Ocean palaeo-environmental reconstructions and can help provide critical proxy data to facilitate climate model calibrations and ultimately improve climate and environmental predictions for the Arctic.

由于全球变暖，北冰洋正在迅速变化，但这将如何影响北极海洋生态系统仍不确定。几个更新世间冰期，如海洋同位素阶段（MIS） 5e、9和11，形成了未来变暖的北极的潜在类似物，可以为北极生态系统如何应对气候变暖提供重要的见解。然而，在许多更新世海洋沉积物岩心中，微化石和纳米化石很少，而且往往与生物标志物数据不一致。沉积古DNA （sedaDNA）是一种新兴的方法，它不需要保存化石，因此可以用来检测没有任何坚硬身体部位的分类群，比如大多数原生生物群体和浮游动物。由于这种方法，现在可以从海洋生态系统的所有营养层检测生物。SedaDNA为我们提供了重建过去海冰状况、洋流变化和北冰洋北方化的新机会。生物信息学软件的发展和新技术，如散弹枪宏基因组学和杂交捕获，现在可以研究中更新世甚至早更新世沉积物中的古代DNA。此外，海洋sedaDNA领域正致力于探测物种内的遗传变异，这可以提供关于种群瓶颈、再定居历史的信息，并可能为海洋保护提供重要的见解。sedaDNA是北冰洋古环境重建的有力工具，可以帮助提供关键的代理数据，促进气候模式校准，最终改善北极的气候和环境预测。

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