Marine Micropaleontology最新文献

{"title":"Changes in pteropod assemblage driven by monsoonal variability and associated oceanographic conditions since the last Glacial Maximum in the eastern Arabian Sea","authors":"Jeet Majumder ,&nbsp;Anil K. Gupta ,&nbsp;Vipul Singh Rathaur","doi":"10.1016/j.marmicro.2026.102561","DOIUrl":"10.1016/j.marmicro.2026.102561","url":null,"abstract":"<div><div>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). <em>Heliconoides inflatus</em> (earlier known as <em>Limacina inflata</em>) is the most dominant pteropod species, followed by <em>Limacina trochiformis</em>, <em>Creseis</em> spp., <em>Limacina bulimoides</em>, and <em>Gleba cordata</em> 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 <em>H. inflatus</em> 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 <em>H. inflatus</em> 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 <em>H. inflatus</em> are mostly found in the last glacial maximum (LGM) and 4.2 ka event. Other pteropod species such as L. <em>trochiformis, Creseis</em> spp.<em>, L. bulimoides,</em> and <em>G. cordata</em> 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.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"203 ","pages":"Article 102561"},"PeriodicalIF":1.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147399404","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Palynology of the Upper Triassic strata from Tabas, east-central Iran: Biostratigraphic, paleoenvironmental, and paleobiogeographic inferences","authors":"Freshteh Sajjadi Hezaveh ,&nbsp;Firoozeh Hashemi-Yazdi","doi":"10.1016/j.marmicro.2026.102558","DOIUrl":"10.1016/j.marmicro.2026.102558","url":null,"abstract":"<div><div>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 <em>Falcisporites nuthallensis</em>, <em>Lunatisporites rhaeticus</em>, <em>Ovalipollis ovalis</em>, <em>Ricciisporites tuberculatus</em>, and <em>Araucariacites australis</em> dominate the assemblages. Representatives of such trilete spores as <em>Dictyophyllidites mortonii, Gleicheiniidites senonicus Kyrtomisporis laevigatus</em>, <em>Limbosporites</em> spp., and <em>Lophotriletes bauhiniae</em>, are essentially abundant in the palynofloras examined. Vertical distribution of miospores allows recognition of <em>Dictyophyllidites-Striatella seebergensis-Ricciisporites tuberculatus</em> assemblage zone (Rhaetian). The inferred natural relationships of the <em>sporae dispersae</em> 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.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"203 ","pages":"Article 102558"},"PeriodicalIF":1.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147399405","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Paleoenvironmental significance of Early Miocene coralline red algae from the Qom Formation, Central Iran","authors":"Suman Sarkar ,&nbsp;Mehdi Hadi ,&nbsp;Yaghub Nasiri ,&nbsp;Mohsen Allameh","doi":"10.1016/j.marmicro.2026.102556","DOIUrl":"10.1016/j.marmicro.2026.102556","url":null,"abstract":"<div><div>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 (<em>Mesophyllum</em>-dominant) and Corallinales. Conversely, the abundance of Hapalidiales (<em>Lithothamnion</em>-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.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"203 ","pages":"Article 102556"},"PeriodicalIF":1.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147399408","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sudden disappearance of the foraminifer Calcarina gaudichaudii in the boundary between the Southern and Central Kuroshio ecoregions in the Ryukyu Archipelago, Japan","authors":"Bryan Gabriel P. Tan ,&nbsp;Goushi Moribe ,&nbsp;Kazuhiko Fujita","doi":"10.1016/j.marmicro.2026.102559","DOIUrl":"10.1016/j.marmicro.2026.102559","url":null,"abstract":"<div><div>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, <em>Baculogypsina sphaerulata</em> was found in all samples and dominant in the north, while <em>C. gaudichaudii</em> was the most common in Amami Oshima but disappeared entirely in the northern region. The results clearly indicate that the latitudinal limit of <em>Calcarina gaudichaudii</em> 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.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"203 ","pages":"Article 102559"},"PeriodicalIF":1.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147399407","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Marine benthic foraminifera diversity in extreme environments: A case study from the Edisto Bay (Ross Sea, Antarctica)","authors":"F. Caridi ,&nbsp;L. Langone ,&nbsp;A. Sartini ,&nbsp;C. Morigi ,&nbsp;G. Galli ,&nbsp;P. Giordano ,&nbsp;M. Bensi ,&nbsp;V. Kovacevic ,&nbsp;L. Ursella ,&nbsp;N. Krauzig ,&nbsp;A. Sabbatini","doi":"10.1016/j.marmicro.2026.102553","DOIUrl":"10.1016/j.marmicro.2026.102553","url":null,"abstract":"","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"203 ","pages":"Article 102553"},"PeriodicalIF":1.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146081018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 promise of sedimentary ancient DNA as a proxy to understand Arctic Ocean palaeoecology and palaeoenvironments","authors":"Flore M.D. Wijnands ,&nbsp;Matt O'Regan ,&nbsp;Helen K. Coxall ,&nbsp;Peter D. Heintzman","doi":"10.1016/j.marmicro.2026.102543","DOIUrl":"10.1016/j.marmicro.2026.102543","url":null,"abstract":"<div><div>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.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"203 ","pages":"Article 102543"},"PeriodicalIF":1.6,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146006525","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"History of current circulation and bottom redox conditions in the central Okinawa Trough over the last 19 ka: Foraminiferal and element geochemical records","authors":"Feifei Wang ,&nbsp;Bangqi Hu ,&nbsp;Jingtao Zhao ,&nbsp;Deqing Weng ,&nbsp;Jianwei Guo ,&nbsp;Xue Ding","doi":"10.1016/j.marmicro.2025.102538","DOIUrl":"10.1016/j.marmicro.2025.102538","url":null,"abstract":"<div><div>The Okinawa Trough (OT) is a critical archive of western Pacific paleoceanography, yet the glacial-interglacial evolution of its circulation and bottom-water redox conditions remain poorly constrained. This study provides a multi-proxy reconstruction from core CS2 in the central OT, revealing a 19-ka history of Kuroshio Current (KC) and intermediate water ventilation for bottom-water oxygenation. Our results show that during the last glaciation, lower sea levels isolated the trough, reducing KC inflow as evidenced by decreased abundances of tropical-subtropical planktonic foraminifera and a shoaled thermocline. Concurrently, bottom-water hypoxia developed, indicated by elevated infaunal benthic foraminifera, lower Mn/Al ratios, and reduced CaCO₃ content, collectively suggesting that the absence or shift of KC was the primary driver of poor ventilation. Furthermore, an anti-phase relationship between hypoxia intensity and North Pacific Intermediate Water (NPIW) ventilation can be observed: enhanced NPIW ventilation (Heinrich Stadial 1 and Younger Dryas) corresponded to weakened hypoxia, whereas reduced ventilation during the Bølling/Allerød intensified hypoxia. The consistently low CaCO₃ content precluded the possibility of hypoxia caused by organic matter consumption, further supporting the conclusion that glacial NPIW ventilation might be another modulator of bottom water oxygenation. During the postglacial period, the return of the KC into the OT improved bottom-water ventilation by reducing stratification and alleviated hypoxia. This study elucidates the evolution of circulation and bottom-water redox conditions to better understand organic carbon burial in the OT. Furthermore, the redox history provides a key mid-latitude archive for assessing the influence of glacial NPIW.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"202 ","pages":"Article 102538"},"PeriodicalIF":1.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145694926","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Machine learning approach to pore-proxy in benthic foraminifera for paleo-reconstruction of dissolved oxygen in a Lagoon","authors":"Rohan Subba ,&nbsp;Anupam Ghosh ,&nbsp;Akira Tsujimoto ,&nbsp;Punyasloke Bhadury","doi":"10.1016/j.marmicro.2025.102541","DOIUrl":"10.1016/j.marmicro.2025.102541","url":null,"abstract":"<div><div>The pore patterns in benthic foraminifera serve as a proxy for dissolved oxygen (DO) and nitrates (NO₃) in oxygen minimum zones (OMZs); however, their applicability in marginal marine settings, such as lagoons, estuaries and fjords, remains understudied. Chilika Lagoon (India) is undergoing a decrease in DO concentration due to eutrophication. Therefore, a novel machine learning (ML) approach is proposed for the quantitative reconstruction of DO based on the pore patterns of <em>Ammonia parkinsoniana</em> (benthic foraminifera). Random forest regression (RFR) and support vector regression (SVR) models were trained on the modern dataset of <em>A. parkinsoniana</em> (Rose Bengal-stained) for pore calibration. The SVR with a prediction accuracy of 87 % performed marginally better than the RFR (85 %). Subsequently, the SVR model was applied to the core sample for predicting DO across the period 1941–2023 CE. The predicted DO varies between 5.68 and 6.25 mgL⁻¹ (high oxic condition) with a model uncertainty of ±1.066 mgL⁻¹ for high oxic (3–6 mgL⁻¹) and ± 0.589 mgL⁻¹ for very high oxic (&gt; 6 mgL⁻¹) conditions. The predicted DO has been verified with multi-proxy records from foraminifera (pore patterns and abundance) and sediment geochemistry (Total organic C, Mn and Cd). Among pore size, porosity % and circularity index, pore density (<em>r</em> = 0.84, <em>p</em> ≤ 0.001) is the main controlling factor on DO, which confirms pores as a reliable proxy for DO. The outcomes of this research also include the development of ForCAST (<span><span>https://forcast-app.streamlit.app/</span><svg><path></path></svg></span>), which is a freely accessible ML-based web application for DO predictions.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"202 ","pages":"Article 102541"},"PeriodicalIF":1.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145791392","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corrigendum to <‘Evolution of Neogene fossil ceratoliths (Coccolithophores) by duplication title of article’> <[Marine Micropaleontology 201 (2025) Article 102530]>","authors":"Carlos Lancis ,&nbsp;J.E. Tent-Manclús ,&nbsp;Jorge Lancis ,&nbsp;Antonio Estévez ,&nbsp;José-Abel Flores","doi":"10.1016/j.marmicro.2025.102539","DOIUrl":"10.1016/j.marmicro.2025.102539","url":null,"abstract":"","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"202 ","pages":"Article 102539"},"PeriodicalIF":1.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146022726","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"X-rays have little impact on estimates of biodiversity from marine sedimentary ancient DNA metabarcoding","authors":"Danielle M. Grant ,&nbsp;Cooper D. Stacey ,&nbsp;Christopher F.G. Hebda ,&nbsp;Evan Morien ,&nbsp;Zhen Li ,&nbsp;Tyler J. Murchie ,&nbsp;McIntyre A. Barrera ,&nbsp;Linda Y. Rutledge","doi":"10.1016/j.marmicro.2025.102540","DOIUrl":"10.1016/j.marmicro.2025.102540","url":null,"abstract":"<div><div>Sedimentary ancient DNA (sedaDNA) recovered from marine sediments offers valuable insights into past ocean biodiversity through ecosystem reconstructions ranging from decadal to glacial-interglacial timescales. The current best-practice in ancient DNA research is to collect new sediment cores with clean sampling protocols in an effort to prevent modern DNA contamination and minimize post-collection DNA degradation. However, new core collection can pose a barrier to research due to the high costs associated with project-specific expeditions; it also excludes leveraging existing sediment core archives. In general, the recommendation is founded on an abundance of caution rather than evidence-based guidelines. Here, we present a comparative study on the impacts of X-Radiography sediment analysis and different extraction methods on marine sedaDNA outcomes in an archived core to help develop such guidelines. We found that exposure to standard X-ray imaging had no significant impact on sedaDNA recovery, co-extraction of inhibitors (e.g. humic acids), metabarcoding diversity metrics, community structure or composition. The extraction method, however, has a significant impact on sedaDNA recovery/inhibition, diversity metrics, community structure, and composition. Laboratory methodological design for marine sedaDNA studies is, therefore, a critical consideration for future research, whereas standard X-ray screening by marine geoscientists appears benign to the parameters measured. Our results support the use of archived sediments for prospective sedaDNA work, thus reducing a considerable barrier to the field.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"202 ","pages":"Article 102540"},"PeriodicalIF":1.6,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145884732","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}