Marine Micropaleontology最新文献

{"title":"Progress, challenges and future directions in marine organic-walled dinoflagellate cyst research: New insights from an international workshop","authors":"Iria García-Moreiras , Ana Amorim , Vera Pospelova , Karin Zonneveld , Donald M. Anderson , Girish Beedessee , Amy Dale , Barrie Dale , Ophélie David , Anne de Vernal , Eugenia Fatourou , Emilie Folie-Boivin , Javier Helenes , María García-Portela , Fang Gu , Haifeng Gu , Vincent Iratçabal , Jan Janouškovec , Audrey Limoges , Fabienne Marret , Kenneth Neil Mertens","doi":"10.1016/j.marmicro.2025.102502","DOIUrl":"10.1016/j.marmicro.2025.102502","url":null,"abstract":"<div><div>Cysts are resistant life-cycle stages that play a key role in the survival and dispersal of some dinoflagellate species. Given their preservation and fossilisation potential, the organic-walled dinoflagellate cysts have been widely used as bioindicators of past and present environmental conditions. Living cysts are studied extensively due to their roles in bloom initiation, termination, and species adaptation. The use of cysts in various fields such as taxonomy, biogeography, evolution, (palaeo)ecology, and (palaeo)oceanography has expanded significantly in recent years. In this paper, we review recent developments, identify research needs, and outline future directions in marine organic-walled dinoflagellate cyst research based on round-table discussions held during the International Workshop on Dinoflagellate Cysts, which took place from 18 to 21 June 2024 in Vigo (Spain).</div><div>Key priorities in taxonomy, evolution, and biogeography include the need to continue establishing connections between the cyst and motile forms along with their associated sequences, particularly for Harmful Algal Bloom (HAB) species, and updating reference databases for metabarcoding studies. Emerging molecular techniques, such as metabarcoding, provide complementary information on cyst diversity, distribution, and geographic connectivity, thereby aiding in the monitoring and reconstruction of HAB dynamics. Given the impacts of climate change on biogeographical ranges, cysts could serve as valuable indicators for tracking HAB shifts. Combining multi-omics with morphological methods could offer deeper insights into character evolution and support the construction of the dinoflagellate tree of life. Advances in the biogeochemical analysis of dinoflagellate cyst walls, particularly through the detailed study of dinosporin, are also promising for evolutionary research, as demonstrated by recent methodological advances in Fourier Transform Infrared (FTIR) and Raman spectroscopy. In palaeoceanography and palaeoecology, improving quantitative cyst-based reconstructions requires expanding the database of living cyst assemblages and their relationships with environmental variables, especially in underrepresented regions, notably in the Southern Hemisphere. Despite progress towards standardisation, there remains no universally adopted standardised methods for extracting and concentrating cysts from sediments or for quantifying cysts—essential steps for inter-site comparisons. Additionally, sediment trap studies and field observations of associated plankton are needed to complement surface sediment research and enhance our understanding of species ecology. The emerging field of palaeogenomics is promising as it complements cyst-based research. Finally, the integration of biological and geological studies to address key scientific questions is emphasised. For example, investigating the discrepancy between the accepted geological emergence of dinoflagellates and earli","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"201 ","pages":"Article 102502"},"PeriodicalIF":1.6,"publicationDate":"2025-08-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145027133","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":"Aberrant coiling signatures reveal the specialised reproductive strategy of the planktonic foraminifera Neogloboquadrina pachyderma under Central Arctic perennial sea ice","authors":"Tirza M. Weitkamp ,&nbsp;Clare Bird ,&nbsp;Kate F. Darling ,&nbsp;Allison Y. Hsiang ,&nbsp;Jemma Ramsay ,&nbsp;Flor Vermassen ,&nbsp;Helen K. Coxall","doi":"10.1016/j.marmicro.2025.102503","DOIUrl":"10.1016/j.marmicro.2025.102503","url":null,"abstract":"<div><div>The perennially sea-ice covered Central Arctic Ocean (CAO) hosts a single planktonic foraminifera species, <em>Neogloboquadrina pachyderma</em>, a polar specialist that predominantly exhibits sinistral-coiling. Widely used as a palaeoceanographic proxy for polar conditions, it displays a range of morphologies, including an uncommon dextral form which resembles its subpolar relative, <em>Neogloboquadrina incompta</em>. The biological significance of dextral coiling in <em>N. pachyderma</em> remains unclear, complicating climate reconstructions and interpretations of its reproduction in the CAO. While culture studies link coiling direction to a biphasic life cycle involving an asexual stage producing both coiling types, supporting field data are lacking. This study analysed <em>N. pachyderma</em> collected from eight plankton net and four box core stations in the CAO beneath permanent sea ice. Morphometric and genetic analyses identified six <em>N. pachyderma</em> morphotypes concentrated in the upper 100 m, dominated by relatively small specimens (80–125 μm). Unusually high proportions of dextral coilers (up to 32 %) were observed in the water column, compared to ∼6 % in the underlying sediment. Proloculus (first chamber) size-analysis and Gaussian Mixture Modelling revealed three proloculus-size means in the water column, suggesting the presence of an asexual clonal schizont generation alongside the typical sexual-asexual cycle. These observations provide the first in situ evidence of schizont reproduction in natural <em>N. pachyderma</em> populations, a strategy that may facilitate rapid population growth and adaptability in the CAO. These results clarify the biological significance of coiling direction in <em>N. pachyderma's</em> life cycle, and reduce the risk of misidentifying <em>N. incompta</em> in Arctic palaeoclimatic studies.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"201 ","pages":"Article 102503"},"PeriodicalIF":1.6,"publicationDate":"2025-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145005225","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":"Palynological approach to identifying the Pliocene-Pleistocene boundary and paleoenvironmental evolution in the southeastern continental shelf, East Sea","authors":"Yongmi Kim ,&nbsp;Sangheon Yi ,&nbsp;Dong-Geun Yoo ,&nbsp;Seok-Hwi Hong ,&nbsp;Gwang-Soo Lee ,&nbsp;Yunseok Choi","doi":"10.1016/j.marmicro.2025.102499","DOIUrl":"10.1016/j.marmicro.2025.102499","url":null,"abstract":"<div><div>The Plio–Pleistocene boundary coincides with Northern Hemisphere glaciation (NHG) and represents a critical period for understanding climatological and environmental changes. A comprehensive palynological analysis of core 19ESDP-104 from the southeastern continental shelf of Korea was conducted to establish this boundary and reconstruct paleoenvironmental evolution since the Pliocene. Pollen and dinoflagellate cysts are effective biostratigraphic markers due to their sensitivity to climate change and distinct assemblage shifts, particularly in coastal deposits where terrestrial–marine interactions are well preserved. Based on CONISS analysis of terrestrial and marine palynomorphs and palynodebris, six distinct biozones were identified. The Plio–Pleistocene boundary was established at depth of 85 m through integrated analysis of key biostratigraphic markers, including the last appearance datum of <em>Liquidambar</em>, <em>Carya</em>, and <em>Fagus</em> pollen. Pollen–dinoflagellate cyst ratios and bisaccate/non-bisaccate ratios effectively traced terrestrial influences and relative sea level changes. Pollen assemblages exhibited a gradual compositional shift from temperate to boreal taxa across the Plio–Pleistocene transition, reflecting cooling associated with NHG. Marine dinoflagellate cyst assemblages indicated a warm current influence during the Pliocene, which weakened toward the Pleistocene. Distinct glacial–interglacial vegetation changes were observed at the MIS 7/6 and 5/4 boundaries in the upper core section. Our multi-proxy approach facilitated the precise establishment of the Plio–Pleistocene boundary and provided new insights into Quaternary climate dynamics and sea level fluctuations. The chronological framework contributes valuable data for understanding geological evolution and paleoenvironmental reconstruction in the East Sea continental shelf region.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"200 ","pages":"Article 102499"},"PeriodicalIF":1.6,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144749164","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":"Species-specific mechanisms of benthic foraminifera in response to shell dissolution","authors":"Maxime Daviray,&nbsp;Milla Lesut,&nbsp;Emmanuelle Geslin,&nbsp;Edouard Metzger,&nbsp;Inge van Dijk,&nbsp;Julia Courtial","doi":"10.1016/j.marmicro.2025.102490","DOIUrl":"10.1016/j.marmicro.2025.102490","url":null,"abstract":"<div><div><em>Ammonia confertitesta</em> and <em>Haynesina germanica</em> are two common estuarine benthic foraminifera subject to sediment acidification. Nevertheless, mechanisms involved in their response to acidification are still poorly understood. Since <em>H. germanica</em> is kleptoplastic and photosynthetically active, unlike <em>A. confertitesta,</em> these species were cultured in controlled experiments to determine whether these mechanisms could mitigate acidification-induced shell dissolution. Both living and dead specimens were incubated at two pH (8.0 and 6.8) and two light conditions (0 and 24 μmol photon m^-2.s^-1) for 18 days. For each species, respiration and photosynthesis rates were calculated based on oxygen measurements. At the end of incubation, foraminiferal viability was assessed with CellTracker Green™ biomarker, and each test was categorised according to a dissolution scale (DS) using SEM. For both species, in acidic conditions, the tests of dead specimens were significantly more dissolved than the tests of living specimens, suggesting active mechanisms providing tolerance to acidification. For the living specimens, no significant difference in the DS distribution was observed between the two species at both conditions, suggesting that kleptoplast photosynthetic activity in <em>H. germanica</em> does not provide additional resistance to acidification. Until at least day 12, respiration data revealed a different biological activity for the two species, and we observed distinct behaviours (e.g., encystment and pseudopod emission). These suggest each species exhibits species-specific responses to cope with acidification. On day 18, respiration rates and binocular observations showed low biological activity, suggesting dormancy or death. Further investigation is required to identify the cellular mechanisms involved to counter acidification stress.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"200 ","pages":"Article 102490"},"PeriodicalIF":1.5,"publicationDate":"2025-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144685983","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":"Foram3D: A pipeline for 3D synthetic data generation and rendering of foraminifera for image analysis and reconstruction","authors":"Sanjana Banerjee ,&nbsp;Turner Richmond ,&nbsp;Thomas Marchitto ,&nbsp;Michael Daniele ,&nbsp;Edgar Lobaton","doi":"10.1016/j.marmicro.2025.102486","DOIUrl":"10.1016/j.marmicro.2025.102486","url":null,"abstract":"<div><div>Foraminifera play an important role in oceanographic and paleoceanographic research. The test morphology and chemistry within species, as well as the presence or absence of certain species, are affected by environmental conditions. Classification of different species of foraminifera is a crucial yet tedious task for researchers. Deep-learning approaches can help with morphological studies and aid in species classification; however, they require large-scale datasets that are challenging to obtain and annotate because of the extremely small size and delicate handling of these microorganisms. In this work, we expand on an existing mathematical model for foraminifera shell growth to generate 3D synthetic models to aid in these studies. We define parameter spaces for the model which are intended to approximate seven randomly chosen foraminifera taxa. Along with providing an open-source code base to support other researchers in generating models and studying growth patterns, we further extend the synthetic data generation to include a rendering component that mimics two existing robotic imaging systems. We provide two use cases for our synthetic dataset. First, we show how orientation can affect the automated classification of different species and how incorporating aleatoric uncertainty indicators can help select the next views of the samples to significantly improve classification accuracy from 82% to 89%. Next, we show how a sparse set of synthetic 2D images can be used to extract 3D morphology of foraminifera using Neural Radiance Fields (NeRFs).</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"200 ","pages":"Article 102486"},"PeriodicalIF":1.5,"publicationDate":"2025-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144670930","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":"Large-sized benthic foraminifera at the northern limit of subtropical zone: southern Kochi, Shikoku Island, Japan","authors":"Bryan Gabriel P. Tan ,&nbsp;Kazuhiko Fujita","doi":"10.1016/j.marmicro.2025.102489","DOIUrl":"10.1016/j.marmicro.2025.102489","url":null,"abstract":"<div><div>Large benthic foraminifera (LBF) are relatively large (&gt;0.5 mm), symbiotic with microalgae, and can be found in tropical to subtropical, clear, shallow waters. LBF are commonly studied in lower latitudes but are less studied in higher latitudes close to their current limit of geographic distribution. As climate change progresses, poleward extension is expected to proceed apace, thus it is important to characterize benthic foraminiferal fauna in these higher latitude zones in order to track the progress of their habitat extensions. The present study examined large-sized (0.5 to 2 mm size fraction) benthic foraminifera, both symbiotic and non-symbiotic, in one such region: Kochi Prefecture in Shikoku Island, Japan. Living foraminifera attached to algae as well as in sediment, and dead foraminiferal tests in sediment were collected from three stations in the study area. A total of 64 taxa were identified, of which 17 were found living in algae, 8 living in sediment, and 60 were dead in sediment. <em>Amphistegina lobifera</em> was the dominant species in the region, making up almost 50 % of all specimens identified, followed by other symbiotic foraminifera. Compared to foraminiferal living communities and dead assemblages in lower latitudes (the Ryukyu Island Arc), amphisteginids and textulariids were more common in Kochi. Calcarinids which are dominant in the Ryukyu Island Arc were not found in this study.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"199 ","pages":"Article 102489"},"PeriodicalIF":1.5,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572785","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":"Paleoceanography and marine ecosystem over 250 ky offshore Southwest Western Australia; Insight from nannofossil assemblages","authors":"Maqsood Ur Rahman ,&nbsp;Tao Jiang ,&nbsp;Muhammad Sarim ,&nbsp;Qianru Wang ,&nbsp;Muhammad Hanif ,&nbsp;Cong Cheng","doi":"10.1016/j.marmicro.2025.102488","DOIUrl":"10.1016/j.marmicro.2025.102488","url":null,"abstract":"<div><div>Nannofossil fluctuations during glacial-interglacial cycles reveal paleo-ecosystem responses to climatic and oceanic changes. This study examines nannofossil assemblages from IODP Hole U1516B in the Mentelle Basin (offshore southwest Western Australia (SWWA)), a region influenced by the Western Australian Current (WAC), Leeuwin Undercurrent (LUC), Leeuwin Current (LC), and its eddies. Using nannofossil counts, diversity indices, and organic geochemistry over 250 ky, this study assesses how circulation shifts impacted communities and productivity. Results reveal LC dominance through its eddies, extending &gt;200 km westward offshore at Cape Leeuwin, unlike the 100 km width in offshore Western Australia. During glacials, LC weakened, assessed by small placoliths blooms, although persistence of <em>Florisphaera profunda</em> indicates weak LC influence. Total organic carbon (TOC) and nitrogen (TN) exhibit a moderate correlation, with slightly higher glacials TOC values reflecting enhanced productivity. Carbon‑nitrogen ratios (C/<em>N</em> &gt; 12) suggest mixed marine-terrestrial organic matter. Nannofossil abundance declines during glacials, likely due to aeolian or high terrigenous input, while diversity rises, indicating evenly distributed communities. Interglacials show high abundance but low diversity, dominated by <em>F. profunda</em>. These trends link LC strength to ecosystem structure, where during interglacial LC suppresses upwelling, favoring oligotrophic taxa like <em>F. profunda</em>, whereas during glacials, LC weakening permits WAC and LUC-driven mixing, boosting productivity and diversity. These findings emphasize how oceanic circulation and productivity shifts, driven by glacial-interglacial cycles, structured historical ecosystems. Similar dynamics may influence future ecological responses to climate change, particularly as warming alters current systems.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"199 ","pages":"Article 102488"},"PeriodicalIF":1.5,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144518977","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":"Response of calcareous nannofossils during the danian-thanetian isotopic events in the Elles Section, Central Tunisia","authors":"Mahmoud Faris ,&nbsp;Sherif Farouk ,&nbsp;Fayez Ahmad ,&nbsp;Zaineb Elamri ,&nbsp;Adel El Shahawy ,&nbsp;Fatma Shaker","doi":"10.1016/j.marmicro.2025.102487","DOIUrl":"10.1016/j.marmicro.2025.102487","url":null,"abstract":"<div><div>A high resolution quantitative study of calcareous nannofossils from the Elles section in Central Tunisia (North Africa) was conducted to assess local phytoplankton paleocommunities and infer paleoclimatic conditions. This research introduces a refined subdivision of the conventional NP4 nannofossil zone into six finer intervals (NTp6, NTp7A-B, NTp8A-C), a first for Tunisia, enhancing the biostratigraphic resolution of Paleocene stratigraphy in the region. The assemblages within these subzones exhibit moderate to good preservation and correlate globally with established Tethyan biozonations. Three key isotopic events were identified: The Dan-C2 event, characterized by a negative δ¹³C shift at the base of the NP2 Zone, associated with a significant increase in oligotrophic and warm-water taxa; the Latest Danian Event (LDE), which is divided into Pre- and Post-LDE intervals. The Pre-LDE interval is marked by a short-lived negative δ¹³C excursion within the lowermost part of NTp7A Subzone boundary, accompanied by a notable decline in the diversity and richness of calcareous nannofossils. The third event, the Selandian-Thanetian Transition Event (STTE), occurs at the base of NP7/8 and is biostratigraphically defined by the Lowest Occurrence (LO) of <em>Discoaster mohleri</em>, with a replacement of R-mode taxa by species adapted to warmer, more oligotrophic conditions. The Danian-Selandian transition is clearly delineated by a glauconite-rich hard marl layer (upper NTp8C). This integrated stratigraphic study provides high-resolution biostratigraphy and critical insights into paleoenvironmental changes during this period. The paleoenvironment shifted from warm, oligotrophic conditions during the events to cooler, eutrophic waters both before and after. These findings suggest that the three bioevents may correspond to an early Paleocene hyperthermal episode.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"199 ","pages":"Article 102487"},"PeriodicalIF":1.5,"publicationDate":"2025-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144510989","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":"New dinoflagellate cyst species of the Areoligeraceae, Ceratiaceae, Gonyaulacaceae, and Peridiniaceae from the Santonian–Campanian (Upper Cretaceous) of the Nanaimo Group, British Columbia, Canada","authors":"Sandy M.S. McLachlan ,&nbsp;Vera Pospelova ,&nbsp;James W. Haggart ,&nbsp;Kenneth N. Mertens","doi":"10.1016/j.marmicro.2025.102485","DOIUrl":"10.1016/j.marmicro.2025.102485","url":null,"abstract":"<div><div>This is the first study of the late Santonian–early late Campanian dinoflagellate cyst assemblages from the Nanaimo Group strata along eastern Vancouver Island and Denman Island, British Columbia. Four new dinoflagellate cyst species are reported from twenty samples recovered from six localities from the Haslam, Trent River, and Cedar District formations: <em>Alterbidinium</em>? <em>fusiforme</em> sp. nov., <em>Canningia grahamii</em> sp. nov., <em>Nematosphaeropsis snunymuxwensis</em> sp. nov. and <em>Odontochitina kwutlkwuensis</em> sp. nov. Emended diagnoses are proposed for the genera <em>Alterbidinium</em> and <em>Odontochitina</em>, and each of the new species are presented in high resolution scanning electron microscopy images which extend the parameters of morphologies previously recognized as occurring within the families Areoligeraceae, Ceratiaceae, Gonyaulacaceae, and Peridiniaceae. These taxa carry biostratigraphic utility within a temporally constrained interval for the Late Cretaceous toward correlation with other regions in the Northern Hemisphere as well as applications for paleoenvironmental interpretations drawing from their relative and absolute abundances.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"199 ","pages":"Article 102485"},"PeriodicalIF":1.5,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144572784","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":"Enhanced sedimentary ancient DNA (sedaDNA) retrieval from Antarctic diatoms","authors":"Prashasti Singh ,&nbsp;João C. Teixeira ,&nbsp;Michael E. Weber ,&nbsp;Christopher Bolch ,&nbsp;Linda Armbrecht","doi":"10.1016/j.marmicro.2025.102477","DOIUrl":"10.1016/j.marmicro.2025.102477","url":null,"abstract":"<div><div>Diatom microfossils are key environmental indicators and an important proxy in paleoenvironmental reconstructions. Sedimentary ancient DNA (<em>sed</em>aDNA) complements microfossil analysis by detecting poorly preserved diatoms and distinguishing morphologically similar taxa, painting a more detailed picture of the past. However, retrieving diatom <em>sed</em>aDNA in marine environments can be challenging due to trace amounts being preserved in the sediment record. Optimising existing protocols is thus essential to maximise diatom <em>sed</em>aDNA yield. This study compares six methods to determine the best approach for recovering diatom <em>sed</em>aDNA from Antarctic marine sediment cores. The same six samples from two sites - U1536C (West Antarctica) and KC02 (East Antarctica), were extracted. Post shotgun sequencing, the methods were evaluated based on diatom <em>sed</em>aDNA recovery, fragment length, and species diversity. Results showed that method performance in retrieving the highest number of Bacillariophyta (diatom) reads is primarily driven by site (R² = 0.593, <em>p</em> = 0.001) and sample age (R² = 0.401, p = 0.001), while the extraction method had minimal influence (R² = 0.001, <em>p</em> = 0.064). The SiMAG method proved highly effective in U1536C but was entirely ineffective in KC02, where the COM Short method successfully recovered diatom <em>sed</em>aDNA. Other methods, including COM QG, PPKIT, and PB, consistently resulted in low <em>sed</em>aDNA yields. Differences in the diversity and the relative abundance of taxonomic classes were also seen across methods (χ2 88.04 to 99,664.17). This study serves as a focal point for experiments aiming to maximise diatom <em>sed</em>aDNA recovery enabling accurate reconstructions of Antarctic marine ecosystems.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"199 ","pages":"Article 102477"},"PeriodicalIF":1.5,"publicationDate":"2025-06-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144523045","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}