Marine Micropaleontology最新文献

Phyletic evolution of calcareous nannofossil species Reticulofenestra oamaruensis: An example of microevolution preserved at IODP Site U1553 (Southern Pacific Ocean)

IF 1.5 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2025-02-26 DOI: 10.1016/j.marmicro.2025.102452

Valentina Catelli , Davide Persico , Davide Righi , Isabella Raffi , Chiara Fioroni , Giuliana Villa

The IODP Expedition 378 in the Southern Ocean (Campbell Plateau) recovered a Paleogene sedimentary section at Site U1553, cored through multiple holes (A - E) in the late Eocene-early Oligocene interval. Stratigraphic continuity and good preservation of calcareous nannofossils offered the opportunity to study the phyletic origin of Reticulofenestra oamaruensis, the biostratigraphic marker for the Eocene/Oligocene Transition (EOT) in the Southern Ocean (SO). We performed biometric and morphological analyses on R. oamaruensis and the related species Reticulofenestra clatrata, revealing intermediate morphotypes with characters between R. clatrata and R. oamaruensis. These transitional morphotypes, labeled Reticulofenestra transitional form 1 (R. t1) and Reticulofenestra transitional form 2 (R. t2), differ in size from the end members and are distinguished in two size categories: 10–12 μm and 12–14 μm respectively. The intraspecific evolutionary trend shows a gradual size increase of R. clatrata(8–10 μm) that, through intermediate steps represented by R. t1 and R. t2, leads to R. oamaruensis (≥14 μm). The two morphotypes are included in the species identification of R. oamaruensis and enter the stratigraphic record at successive levels, thus delineating a “lineage zone” useful in SO biostratigraphy. R. clatrata and medium – large R. oamaruensis disappear close to the Eocene/Oligocene Boundary. Based on the morphological homology, the progressively increasing size trend from R. clatrata to R. oamaruensis, their stratigraphic range continuity, and their same geographical distribution, we document a phyletic strain endemic to high southern latitudes, of which R. clatrata would represent the archetype.

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引用次数: 0

An integrative analysis of Plectocapillus antarcticus gen. et sp. nov. from Antarctica: Morphology, chemical composition, and phylogeny

IF 1.5 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2025-02-17 DOI: 10.1016/j.marmicro.2025.102451

Somin Lee , Michael A. Kaminski , Fabrizio Frontalini , Jisu Yeom , Nayeon Park , Wonchoel Lee

In this study, Plectocapillus antarcticus gen. et sp. nov., belonging to the Family Pseudobolivinidae Wiesner, 1931, Superfamily Spiroplectamminoidea Cushman, 1927, was described from Maxwell Bay, King George Island, Antarctica. The species is distinguished by its elongate, slender, and entirely biserial test, fragile, thin agglutinated wall, a globular, organic proloculus, and the areal, rounded to arch-like aperture. Notably, this species previously assigned taxonomically as Spiroplectammina filiformis Earland, 1934 or Textularia tenuissima Earland, 1933, in nearby areas. However, morphological comparison revealed differences in chamber arrangement, biserial pair number, test width, and proloculus wall composition. SEM-DES analysis identified Al, Ca, Fe, Mg, Si, and Ti as major chemical elements present in the test wall, along with the traces of K, Mn, Na, P, Ce, Cl, F, S, Sr, and Zr. Phylogenetic analysis of partial SSU rRNA and mitochondrial COI gene sequences confirmed that P. antarcticus forms a well-supported clade, sister to Spiroplectammina biformis. The slender, flexible test, organic proloculus, and inclusion of heavy element-rich minerals suggests potential adaptation to hypoxic or interstitial habitats. By integrating morphological, chemical, and molecular data, this study contributes to the expanding fundamental database and understanding of Antarctic foraminiferal diversity and emphasizes the necessity for continued research in the region.

本研究描述了来自南极洲乔治王岛马克斯韦尔湾的 Plectocapillus antarcticus gen.该物种的特征是其细长、完全双列的试管，脆弱、薄的凝集壁，球状、有机的原核，以及圆形至拱形的等距孔。值得注意的是，该物种以前在附近地区被归类为 Spiroplectammina filiformis Earland, 1934 或 Textularia tenuissima Earland, 1933。然而，通过形态学比较发现，它们在腔室排列、双列对数、测试宽度和原核壁组成方面存在差异。SEM-DES 分析表明，Al、Ca、Fe、Mg、Si 和 Ti 是试验壁中存在的主要化学元素，此外还有微量的 K、Mn、Na、P、Ce、Cl、F、S、Sr 和 Zr。对部分 SSU rRNA 和线粒体 COI 基因序列进行的系统进化分析证实，南极蛙形成了一个支持良好的支系，是双形蛙的姊妹蛙。纤细、柔韧的试管、有机的增殖体以及富含重元素的矿物质表明，南极蛛可能适应缺氧或间隙栖息地。通过整合形态学、化学和分子数据，该研究为不断扩大的基础数据库和对南极有孔虫多样性的了解做出了贡献，并强调了在该地区继续开展研究的必要性。

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引用次数: 0

Sessile foraminifera from mobile substrates: Hidden organisms and big mistakes – The essential is invisible to the eyes

IF 1.5 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2025-02-15 DOI: 10.1016/j.marmicro.2025.102450

Joicce Dissenha , Sibelle Trevisan Disaró , José Rodolfo Angulo , Rodrigo Aluizio

Two case studies conducted on the inner continental shelf off southeastern Brazil revealed an unexpectedly high abundance and diversity of foraminifera attached to or encrusted in sediment grains. Samples were stained with Rose Bengal, fixed in formalin, and subjected to trichloroethylene flotation to isolate free foraminifera. Following screening, the residual fraction was rigorously examined, uncovering numerous attached individuals and robust agglutinate forms that incorporate sediment grains into their tests. This fauna includes little-known genera rarely documented in unconsolidated mobile substrates. Comparisons between floated and residual fractions revealed notable discrepancies, emphasizing the underestimation of sessile and robust forms when residual fractions are overlooked. Neglecting these forms can compromise environmental and paleoenvironmental interpretations, as rarefaction curves illustrate, particularly in high-hydrodynamic regions typically seen as challenging environments for fauna. This study underscores the importance of including sessile foraminifera in biodiversity assessments in dynamic marine areas. We propose a new zone, the “high-hydrodynamic inner coastal shelf,” for Murray's (1973) ternary diagram. Additionally, our findings indicate that inadequate screening methods may leave significant gaps in taxonomic records. Many attached foraminifera remain “invisible to the eye” of researchers, often due to their shape, a lack of prior knowledge, or insufficient attention, resulting in underestimations of their density and richness. Consequently, these organisms are often overlooked in environmental characterizations, taxonomic records, and especially in paleoecological studies and monitoring efforts.

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引用次数: 0

Dinoflagellate cyst assemblages in recent sediments of Iran's tropical mangrove forests

IF 1.5 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2025-02-08 DOI: 10.1016/j.marmicro.2025.102449

Gilan Attaran-Fariman , Sima Abir , Faezeh Dolatabadi , Ehsan Abedi , Fatemeh Sayareh

We investigated the distribution and composition of dinoflagellate cysts, including potential harmful algal bloom (HAB) species, in Iranian mangroves bordering the Persian Gulf and Oman Sea. Sediment samples were collected from 62 stations across 10 locations in three provinces (Bushehr, Hormozgan, Sistan & Baluchestan) in autumn 2020. Analysis of dinoflagellate cysts revealed a diverse assemblage encompassing 56 species, including 10 known to be triggers of harmful algal blooms (HABs). Genus Protoperidinium was dominant, exhibiting a 21.4 % abundance and comprising 14 species across 60 sampling stations. In contrast, genus Margalefidinium was present in 34 stations with only a single species. Margalefidinium polykrikoides was the key species of dissimilarity between provinces, driving distinct compositions in all pairwise comparisons. Scrippsiella acuminata was a significant contributor to the dissimilarity observed between the Bu and S&B, as well as the Ho and S&B assemblages. DistLM, dbRDA, and marginal tests confirmed that environmental parameters significantly (P > 0.05) influenced cyst composition across the provinces. Regular monitoring of environmental parameters alongside analyses of dinoflagellate cyst assemblages is a potential use for predicting HABs and also provide valuable insights into the well-being of essential mangrove ecosystems.

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引用次数: 0

Orbital-scale biotic and paleoceanographic changes in Japan Sea during the late Miocene global cooling (LMGC)

IF 1.5 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2025-01-28 DOI: 10.1016/j.marmicro.2025.102448

Mizuki Tojima , Masayuki Ikeda , Kenji M. Matsuzaki

The late Miocene global cooling (LMGC; ca. 7.9–5.8 Ma) was accompanied by global environmental changes including monsoon intensity, ocean circulation, and biotic turnover. Recent studies have revealed drastic environmental and biotic changes in the Japan Sea across the LMGC; the radiolarian fauna in the Japan Sea suggested decreased inflow of Pacific Central Water (PCW) species Tricolocapsa papillosa, increased subarctic species Cycladophora sphaeris and extinction of a dominant endemic radiolarian Cycladophora nakasekoi. These radiolarian fluxes showed ∼100-kyr eccentricity signals; however, the dominant paleoclimatic/paleoceanographic signal during the LMGC appeared to be ∼40-kyr obliquity cycle, which was not detected in the radiolarian fluxes possibly due to lower sampling resolution. Thus, orbital-scale variations of these radiolarian fluxes and their potential forcing mechanisms remain unclear.

In this study, we establish changes in the abundance of selected radiolarian species with a resolution that exceeds the 10-kyrs and suggest obliquity-paced changes in the paleoceanography in the Japan Sea during the LMGC. We detected ∼40-kyr cycles in abundance of T. papillosa, suggesting that PCW inflow into the Japan Sea was controlled by a 40-kyr obliquity-paced glacial cycle. We also detected a ∼ 40-kyr signal in C. sphaeris abundance, implying that the obliquity-paced winter monsoon probably promoted the inflow of subarctic water into the Japan Sea. Contrary, variation in C. nakasekoi abundance lacks a ∼ 40-kyr signal. A 100-kyr cycle is also observed in a summer monsoon proxy from lacustrine sediment in China. Hence, it is possible that C. nakasekoi decreased with weakened summer monsoon across the LMGC.

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引用次数: 0

Variations in the morphometric characteristics of Fragilariopsis kerguelensis in the Southwest Pacific sector of the Southern Ocean over the past 40,000 years

IF 1.5 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2025-01-27 DOI: 10.1016/j.marmicro.2025.102447

Xavier Crosta, Thibault Sutre

High-throughput measurements demonstrated the presence of two morphotypes of Fragilariopsis kerguelensis in the Atlantic sector of the Southern Ocean, the proportions of which in downcore samples may be used to reconstruct past sea-surface temperatures quantitatively. We here measured the mean length, width, area, and rectangularity in core SO136–111 to assess variations in both morphotypes in the Polar Front Zone of the western Pacific sector of the Southern Ocean over the past 40,000 years. Mean length, width, and area increased rapidly at the end of the glacial period when the Polar Front migrated southward to reach the core site, ocean temperature increased, and sea ice was no longer present. In contrast, mean rectangularity decreased at the end of the glacial period, when the proportion of the cold-water, high-rectangularity morphotype declined as the ocean warmed at the core site. Downcore patterns and quantitative values of all morphometric characteristics in the southwest Pacific sector agree well with previous studies from the Atlantic sector, suggesting the presence of a similar population of F. kerguelensis in the open Southern Ocean. Nevertheless, rectangularity-based relationships can ultimately produce unrealistic estimates of sea-surface temperatures in core SO136–111 when the proportion of the high-rectangularity morphotype is too low, indicating that these approaches are now limited to temperatures below 3–4 °C.

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引用次数: 0

Distribution of Miocene dinoflagellate cysts in the paralic basins of Tunisia: Paleogeographic and paleoecological reconstruction and eustatic movements

IF 1.5 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2025-01-19 DOI: 10.1016/j.marmicro.2025.102443

Nadia Ben Moktar , Amel Mahjoubi-Ghanmi , Beya Mannai-Tayech

The Miocene deposits of northeastern and central-eastern Tunisia are primarily of clastic, deltaic-type. These deposits are organized into complex sedimentary sequences shaped by tectonic activity, eustatic fluctuations, and changes in climatic conditions. This study presents the evolution of dinoflagellate cysts associations extracted from Miocene-age deposits. These deposits ranged from 16 million to 5.3 million years ago. They are taken from three boreholes and three sections in northeastern and central Tunisia. Dinocysts serve as valuable indicators of climatic variations and sea-level fluctuations. Their study supports the results obtained from the analysis of pollen grains. It sheds light on paleoecology, paleogeography, and eustatic conditions during that period.

Various associations (oceanic, neritic, climatic, etc.) were established based on the ecological preferences of these marine microorganisms. Oceanic conditions are characterized by the presence of Impagidinium. Shallow marine environments are defined by the presence of Cordosphaeridium inodes minimus. Meanwhile, Nematosphaeropis and Tectatodinium indicate a neritic to oceanic environment. It is confirmed by the abundance of Lejeunecysta, Operculodinium, israelianum, Polysphardium zoharyi, Homotryblium, Spiniferites, Cleistosphaeridium, and Lingulodinium machaerophorum. These results align with lithological and biostratigraphic data related to paleobathymetry and paleogeography.

Changes in dinocyst taxa relative abundances helped track the shoreline's evolution during the Miocene. Variations in the relative abundance of Impagidinium and Cordosphaeridium inodes minimus, or their absence, indicate environmental shifts. This shift reflects a transition from a neritic environment (Aïn Grab Formation) to an oceanic one (Mahmoud Formation). The Saouaf Formation is marked by a eustatic drop at its base (Unit I). However, Units II and III are defined by eustatic rises in pulsations. The Somaa sands were deposited in a neritic and/or epicontinental environment, followed by a return to an oceanic setting (Melquart Formation).

{"title":"Distribution of Miocene dinoflagellate cysts in the paralic basins of Tunisia: Paleogeographic and paleoecological reconstruction and eustatic movements","authors":"Nadia Ben Moktar , Amel Mahjoubi-Ghanmi , Beya Mannai-Tayech","doi":"10.1016/j.marmicro.2025.102443","DOIUrl":"10.1016/j.marmicro.2025.102443","url":null,"abstract":"<div><div>The Miocene deposits of northeastern and central-eastern Tunisia are primarily of clastic, deltaic-type. These deposits are organized into complex sedimentary sequences shaped by tectonic activity, eustatic fluctuations, and changes in climatic conditions. This study presents the evolution of dinoflagellate cysts associations extracted from Miocene-age deposits. These deposits ranged from 16 million to 5.3 million years ago. They are taken from three boreholes and three sections in northeastern and central Tunisia. Dinocysts serve as valuable indicators of climatic variations and sea-level fluctuations. Their study supports the results obtained from the analysis of pollen grains. It sheds light on paleoecology, paleogeography, and eustatic conditions during that period.</div><div>Various associations (oceanic, neritic, climatic, etc.) were established based on the ecological preferences of these marine microorganisms. Oceanic conditions are characterized by the presence of <em>Impagidinium</em>. Shallow marine environments are defined by the presence of <em>Cordosphaeridium inodes minimus</em>. Meanwhile, <em>Nematosphaeropis</em> and <em>Tectatodinium</em> indicate a neritic to oceanic environment. It is confirmed by the abundance of <em>Lejeunecysta</em>, <em>Operculodinium</em>, <em>israelianum</em>, <em>Polysphardium zoharyi</em>, <em>Homotryblium</em>, <em>Spiniferites</em>, <em>Cleistosphaeridium</em>, and <em>Lingulodinium machaerophorum</em>. These results align with lithological and biostratigraphic data related to paleobathymetry and paleogeography.</div><div>Changes in dinocyst taxa relative abundances helped track the shoreline's evolution during the Miocene. Variations in the relative abundance of <em>Impagidinium</em> and <em>Cordosphaeridium inodes minimus</em>, or their absence, indicate environmental shifts. This shift reflects a transition from a neritic environment (Aïn Grab Formation) to an oceanic one (Mahmoud Formation). The Saouaf Formation is marked by a eustatic drop at its base (Unit I). However, Units II and III are defined by eustatic rises in pulsations. The Somaa sands were deposited in a neritic and/or epicontinental environment, followed by a return to an oceanic setting (Melquart Formation).</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"195 ","pages":"Article 102443"},"PeriodicalIF":1.5,"publicationDate":"2025-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143098429","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}

引用次数: 0

Machine Learning for identification and classification of Foraminifera: Testing on monothalamids

IF 1.5 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2025-01-18 DOI: 10.1016/j.marmicro.2025.102442

Anna Sabbatini , Francesca Caridi , Domenico Potena , Alessandra Negri

Here we propose an AI-based approach using machine learning (ML) to assist species identification and reduce morphotype redundancy in the study of monothalamous foraminifera. In fact, this group of protists, is often overlooked in taxonomic studies due to their morphological simplicity and diversity. These single-celled organisms with “soft” tests are poorly studied, with only a few species identified, while many morphotypes remain undescribed. Taxonomic research on monothalamids is limited by challenges in identification, lack of fossilization, and the time-intensive nature of the work. This gap may lead to underestimating biodiversity and hinder detecting ecosystem degradation. Despite these challenges, monothalamids play key roles in marine ecosystems, making their diversity crucial for conservation and resource management. With this in mind, we analyzed images from the scientific literature, extracting key morphological traits, such as chamber shape, shell type, composition, and aperture type, through objective human annotation to build a dataset processed by ML algorithms. Clustering techniques, such as K-Means, revealed that basic shape, followed by shell type and composition, were the primary features distinguishing clusters. This approach enabled more objective morphotype classification, improving consistency and reducing human bias.

These findings align with recent taxonomic revisions and demonstrate that applying unsupervised ML methods enhances species identification accuracy and streamlines the analysis of high-dimensional datasets.

{"title":"Machine Learning for identification and classification of Foraminifera: Testing on monothalamids","authors":"Anna Sabbatini , Francesca Caridi , Domenico Potena , Alessandra Negri","doi":"10.1016/j.marmicro.2025.102442","DOIUrl":"10.1016/j.marmicro.2025.102442","url":null,"abstract":"<div><div>Here we propose an AI-based approach using machine learning (ML) to assist species identification and reduce morphotype redundancy in the study of monothalamous foraminifera. In fact, this group of protists, is often overlooked in taxonomic studies due to their morphological simplicity and diversity. These single-celled organisms with “soft” tests are poorly studied, with only a few species identified, while many morphotypes remain undescribed. Taxonomic research on monothalamids is limited by challenges in identification, lack of fossilization, and the time-intensive nature of the work. This gap may lead to underestimating biodiversity and hinder detecting ecosystem degradation. Despite these challenges, monothalamids play key roles in marine ecosystems, making their diversity crucial for conservation and resource management. With this in mind, we analyzed images from the scientific literature, extracting key morphological traits, such as chamber shape, shell type, composition, and aperture type, through objective human annotation to build a dataset processed by ML algorithms. Clustering techniques, such as K-Means, revealed that basic shape, followed by shell type and composition, were the primary features distinguishing clusters. This approach enabled more objective morphotype classification, improving consistency and reducing human bias.</div><div>These findings align with recent taxonomic revisions and demonstrate that applying unsupervised ML methods enhances species identification accuracy and streamlines the analysis of high-dimensional datasets.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"195 ","pages":"Article 102442"},"PeriodicalIF":1.5,"publicationDate":"2025-01-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143098472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

High-resolution Danian–Selandian benthic foraminifera-based paleoenvironmental reconstruction and response to sequence stratigraphy: Inferences from the Elles section, El Kef Basin, Tunisia

IF 1.5 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2025-01-01 DOI: 10.1016/j.marmicro.2024.102433

Sherif Farouk , Islam El-Sheikh , Sreepat Jain , Fayez Ahmad , Zaineb Elamri , Jenö Nagy , Khaled Al-Kahtany , Youssef S. Bazeen

High-resolution (123 samples) benthic foraminiferal distribution patterns were analyzed for paleoenvironmental reconstruction from a section located at the southern edge of the El Kef Basin (El Haria Formation; Tunisia) spanning the Danian–Selandian interval (planktic foraminifera P1a–P4b zones). Five distinct clusters were identified, each representing different paleoenvironments and depths ranging from inner neritic to upper bathyal, with significant variations in species diversity, paleoproductivity, and bottom water oxygenation. The Dan-C2 hypothermal event is characterized by moderately oxygenated bottom waters, high species diversity, and lowered paleoproductivity within an upper bathyal setting. The LDE is marked by high species diversity, higher paleoproductivity, moderately oxygenated bottom waters, abundance of epifaunal species, and shallowing to middle neritic depths. The Danian-Selandian boundary records (a) a sudden abundance of the inner neritic infaunal species Bulimina strobila, (b) an increase in species diversity, (c) moderately‑oxygenated bottom waters, (d) a positive δ¹³C excursion, and (e) deepening, from inner to middle neritic settings. Four transgressive-regressive (T-R) cycles based on benthic foraminiferal assemblage-derived bathymetry, P% and the transfer function-based estimate mirror each other, and distinctly mirror paleodepth changes, correlating with global eustatic cycles but also reflecting local tectonic influences.

{"title":"High-resolution Danian–Selandian benthic foraminifera-based paleoenvironmental reconstruction and response to sequence stratigraphy: Inferences from the Elles section, El Kef Basin, Tunisia","authors":"Sherif Farouk , Islam El-Sheikh , Sreepat Jain , Fayez Ahmad , Zaineb Elamri , Jenö Nagy , Khaled Al-Kahtany , Youssef S. Bazeen","doi":"10.1016/j.marmicro.2024.102433","DOIUrl":"10.1016/j.marmicro.2024.102433","url":null,"abstract":"<div><div>High-resolution (123 samples) benthic foraminiferal distribution patterns were analyzed for paleoenvironmental reconstruction from a section located at the southern edge of the El Kef Basin (El Haria Formation; Tunisia) spanning the Danian–Selandian interval (planktic foraminifera P1a–P4b zones). Five distinct clusters were identified, each representing different paleoenvironments and depths ranging from inner neritic to upper bathyal, with significant variations in species diversity, paleoproductivity, and bottom water oxygenation. The Dan-C2 hypothermal event is characterized by moderately oxygenated bottom waters, high species diversity, and lowered paleoproductivity within an upper bathyal setting. The LDE is marked by high species diversity, higher paleoproductivity, moderately oxygenated bottom waters, abundance of epifaunal species, and shallowing to middle neritic depths. The Danian-Selandian boundary records (a) a sudden abundance of the inner neritic infaunal species <em>Bulimina strobila</em>, (b) an increase in species diversity, (c) moderately‑oxygenated bottom waters, (d) a positive δ<sup>13</sup>C excursion, and (e) deepening, from inner to middle neritic settings. Four transgressive-regressive (T-R) cycles based on benthic foraminiferal assemblage-derived bathymetry, P% and the transfer function-based estimate mirror each other, and distinctly mirror paleodepth changes, correlating with global eustatic cycles but also reflecting local tectonic influences.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"194 ","pages":"Article 102433"},"PeriodicalIF":1.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095809","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}

引用次数: 0

Non-pollen palynomorphs as indicators of local environmental conditions in a Neotropical Estuary (Northeast Brazil)

IF 1.5 4区地球科学 Q2 PALEONTOLOGY

Marine Micropaleontology

Pub Date : 2025-01-01 DOI: 10.1016/j.marmicro.2024.102424

Pietro Martins Barbosa Noga , Anne de Vernal , Daniela Mariano Lopes da Silva , Doriedson Ferreira Gomes

Non-pollen palynomorphs (NPPs) are organic-walled microfossils derived from diverse aquatic and terrestrial organisms, frequently observed in palynological studies. This study documents the distribution of NPPs in surface sediment samples from the two main rivers of Camamu Bay (Northeast Brazil), analyzed to explore their response to estuarine environmental and nutritional gradients. Using standard palynological techniques, 69 NPP taxa were identified, spanning 40 divisions, including dinoflagellates, foraminiferal linings, chlorophytes, cyanobacteria, ciliates, amoebozoans, scolecodonts, zoological fragments, and fungal spores. Assemblages were dominated by fungal spores across most stations. Distinct environmental gradients were reflected in NPP distribution, for instance upstream stations with low salinity (3 psu) and high nutrient ratios favored chlorophytes, while downstream stations with higher salinity (up to 35 psu) and lower N:P ratios (<40 μM) were dominated by foraminiferal linings. Multivariate statistic analyses revealed that salinity and nutrient stoichiometry were significant drivers of assemblage composition. These findings highlight the utility of NPPs as indicators of environmental and biogeochemical conditions, particularly in low-latitude estuarine systems, and underscore their potential applications in paleoecological reconstruction.

{"title":"Non-pollen palynomorphs as indicators of local environmental conditions in a Neotropical Estuary (Northeast Brazil)","authors":"Pietro Martins Barbosa Noga , Anne de Vernal , Daniela Mariano Lopes da Silva , Doriedson Ferreira Gomes","doi":"10.1016/j.marmicro.2024.102424","DOIUrl":"10.1016/j.marmicro.2024.102424","url":null,"abstract":"<div><div>Non-pollen palynomorphs (NPPs) are organic-walled microfossils derived from diverse aquatic and terrestrial organisms, frequently observed in palynological studies. This study documents the distribution of NPPs in surface sediment samples from the two main rivers of Camamu Bay (Northeast Brazil), analyzed to explore their response to estuarine environmental and nutritional gradients. Using standard palynological techniques, 69 NPP taxa were identified, spanning 40 divisions, including dinoflagellates, foraminiferal linings, chlorophytes, cyanobacteria, ciliates, amoebozoans, scolecodonts, zoological fragments, and fungal spores. Assemblages were dominated by fungal spores across most stations. Distinct environmental gradients were reflected in NPP distribution, for instance upstream stations with low salinity (3 psu) and high nutrient ratios favored chlorophytes, while downstream stations with higher salinity (up to 35 psu) and lower N:P ratios (<40 μM) were dominated by foraminiferal linings. Multivariate statistic analyses revealed that salinity and nutrient stoichiometry were significant drivers of assemblage composition. These findings highlight the utility of NPPs as indicators of environmental and biogeochemical conditions, particularly in low-latitude estuarine systems, and underscore their potential applications in paleoecological reconstruction.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"194 ","pages":"Article 102424"},"PeriodicalIF":1.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095751","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}

引用次数: 0