Marine Micropaleontology最新文献

{"title":"Microfossil fragmentation across the Paleocene-Eocene transition at ODP Site 1209 (North Pacific): Implication for reconstructing nannofossil fluxes.","authors":"Nicolas Pige ,&nbsp;Guillaume Suan ,&nbsp;Eddy Buiron ,&nbsp;Vincent J. Langlois ,&nbsp;Alyssa Mehir ,&nbsp;Arnauld Vinçon-Laugier ,&nbsp;Emanuela Mattioli","doi":"10.1016/j.marmicro.2023.102213","DOIUrl":"10.1016/j.marmicro.2023.102213","url":null,"abstract":"<div><p>The Paleocene-Eocene period was punctuated by several hyperthermal events likely triggered by massive injection of greenhouse gases, the best-known being the PETM (∼56 Ma). Environmental changes during hyperthermals severely impacted planktonic organisms, especially calcareous nannoplankton<span> producing tiny calcite<span><span> platelets. These calcite platelets (coccoliths) accumulate at the sea floor and constitute a major component of deep-sea sediments. As calcareous nannoplankton contribute to the biological carbon pump and carbonate counter pump, a better knowledge of their production dynamics in surface ocean and their dissolution throughout the water column is pivotal to produce realistic carbon budgets across hyperthermal events. In this work, we quantitatively assessed calcareous </span>nannofossil<span> abundances and nannofossil fragments from deep sea sediments<span> of late Thanetian<span> to early Ypresian<span> age (55.63–57.42 Ma) from ODP Site 1209 (North Pacific). We developed a new method, based on the shape and number of fragments, to reconstruct an all-inclusive nannofossil absolute abundance (including entire specimens and fragments) in the sediments. The reconstructed values of absolute abundance estimated integrating fragments are on average 25% higher. We also analysed different dissolution proxies (planktonic foraminifera fragmentation, benthic/planktonic ratios, coarse fraction). The fragmentation of planktonic foraminifera does not covary with nannofossil fragmentation, suggesting distinct controlling factors. Foraminiferal proxies and nannofossil assemblages point to episodes of intense dissolution across the PETM as well as during an event pre-dating the PETM by 300–700 kyrs that we identify as the Late Paleocene Event (LPE).</span></span></span></span></span></span></p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48596449","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":"Nutrients and hydrography explain the composition of recent Mediterranean planktonic foraminiferal assemblages","authors":"Lucia A. Azibeiro ,&nbsp;Michal Kučera ,&nbsp;Lukas Jonkers ,&nbsp;Angela Cloke-Hayes ,&nbsp;Francisco J. Sierro","doi":"10.1016/j.marmicro.2022.102201","DOIUrl":"10.1016/j.marmicro.2022.102201","url":null,"abstract":"<div><p>The composition of planktonic foraminiferal assemblages in surface sediments of the Mediterranean Sea shows a pronounced zonal gradient. This gradient is different from what is observed in the open ocean, indicating that the assemblage composition may respond to environmental variables other than the otherwise dominant surface water temperature. Here we make use of a dataset of census counts of 18 taxonomic categories in 124 surface-sediment samples extracted from the ForCenS database to understand the main environmental factors affecting the composition of recent Mediterranean planktonic foraminiferal assemblages. The tested explanatory variables include temperature, salinity, chlorophyll, nitrate and phosphate concentrations in the surface waters, temperature, nitrate and phosphate concentrations at depth and thermal, salinity and density vertical gradients. The composition of the assemblages is aligned along two environmental gradients and redundancy analysis reveals that the tested variables explain a large portion (&gt;70%) of the variance in the compositional data. The first environmental gradient reflects the nutrient content in the deep waters, affecting nutrient availability in the productive zone, while the second gradient is driven by higher (northern area) and lower (southern area) upward nutrient advection due to differences in density stratification, conditioned by the regional hydrography. Although sea surface temperature is the most reconstructed environmental variable from fossil assemblages of planktonic foraminifera, it seems to play a secondary role in the Mediterranean Sea. This, has implications for reconstructions of past oceanographic conditions in this region, opening up the possibility to reconstruct productivity instead, or next to, temperature.</p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44213113","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":"Diversity and evolution of late Eocene to late Oligocene silicoflagellates from IODP Expedition 378 Holes U1553A and U1553B, southwest Pacific Ocean","authors":"Kevin McCartney ,&nbsp;Arindam Chakraborty ,&nbsp;Amit K. Ghosh ,&nbsp;Emanuel Soeding ,&nbsp;Vishwadeep Rout","doi":"10.1016/j.marmicro.2023.102215","DOIUrl":"10.1016/j.marmicro.2023.102215","url":null,"abstract":"<div><p><span><span>Study of the South Pacific Ocean<span> sediments from IODP Expedition 378, Holes U1553A and U1553B, shows 19 late Eocene to late </span></span>Oligocene silicoflagellate species. The late Eocene includes </span><em>Corbisema tajmahalii</em> n. sp., observed over a ∼ 8.4 m interval and proposed as a new subzone within the <em>Corbisema apiculata</em> Zone. The new species is characterized by the presence of basal ring that has three sides and an arrowhead-shaped outline with the two minor-axis corners more closely spaced. This study has found the first known <em>Bachmannocena</em> double skeleton, in corner-aligned configuration that suggests evolutionary relationship with the <em>Corbisema triacantha</em> group of Cenozoic silicoflagellates. Also observed is the apparent early evolution of <em>Stephanocha raupii</em> at ∼29.6 Ma, derived from a skeletal diversity related to <em>Distephanopsis crux</em>, thus the species is here transferred to <em>Distephanopsis</em> (abbreviated as <em>Ds</em>.)<em>.</em> Silicoflagellate skeletal abundance declines after the Eocene-Oligocene boundary, with generally low abundance except for two sediment samples immediately below the <em>Ds. raupii</em> n. comb. first appearance.</p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47158112","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":"High-latitude Cretaceous–Paleogene transition: New paleoenvironmental and paleoclimatic insights from Antarctica","authors":"Luiza Carine Ferreira da Silva, Alessandra Santos, G. Fauth, Leslie Marcela Elizabeth Manríquez Márquez, Karlos Guilherme Diemer Kochhann, Rodrigo do Monte Guerra, R. S. Horodyski, Jorge Villegas Martín, Rafael Ribeiro da Silva","doi":"10.1016/j.marmicro.2023.102214","DOIUrl":"https://doi.org/10.1016/j.marmicro.2023.102214","url":null,"abstract":"","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48556034","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 paleocene calcareous nannofossil: Carlamuelleria, Davidbukrya, Mauriceblackia, Noelia and Senelia","authors":"O. Varol","doi":"10.1016/j.marmicro.2023.102220","DOIUrl":"https://doi.org/10.1016/j.marmicro.2023.102220","url":null,"abstract":"","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41724114","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":"Molecular and morphological analysis of Biddulphia sensu lato: a new diagnosis of Biddulphia, with a description of the new genera Biddulphiella and Neobrightwellia","authors":"Patricia A. Sims ,&nbsp;Matt P. Ashworth ,&nbsp;Edward C. Theriot ,&nbsp;Schonna R. Manning","doi":"10.1016/j.marmicro.2022.102186","DOIUrl":"10.1016/j.marmicro.2022.102186","url":null,"abstract":"<div><p>The diatom genus <em>Biddulphia</em> Gray has hosted a tremendous amount of morphological diversity throughout its taxonomic history. SEM-assisted studies have significantly helped to sort this diversity into a classification based on specific valve characters, particularly the structure of pore fields on the valve apices, rather than gross morphology such as valve outline. Recent molecular phylogenetic analyses, however, have suggested that even the revised diagnosis of <em>Biddulphia</em><span> has not led to a monophyletic genus. In this study, we have surveyed the morphology of both fossil and extant taxa and have found a significant disparity in the number of </span><em>Biddulphia</em> taxa featuring valves with deep folds—sulci—rather than internal crosswalls—costae. Based on these observations, we have proposed several taxonomic revisions around this character, including the creation of two new genera—<em>Biddulphiella</em> gen. nov. and <em>Neobrightwellia</em> gen. nov.—and the transfers of several fossil and extant biddulphioid taxa to genera (<em>Donskinica</em> Kozyrenko, <em>Stoermeria</em> Kociolek, L.Escobar &amp; S.Richardson and <em>Tabulina</em> J. Brun) which are more appropriate to their morphology.</p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47338049","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 Aptian-Cenomanian ostracod \"Conchoecia?\"/Neorichterina: Taxonomic review and its paleoecological, paleobiogeographic, and biostratigraphic significance","authors":"Marcos Antonio Batista dos Santos Filho ,&nbsp;Daiane Ceolin ,&nbsp;Marta Claudia Viviers ,&nbsp;Gerson Fauth ,&nbsp;Karlos Guilherme Diemer Kochhann ,&nbsp;Henrique de Oliveira Lima","doi":"10.1016/j.marmicro.2022.102199","DOIUrl":"https://doi.org/10.1016/j.marmicro.2022.102199","url":null,"abstract":"<div><p>Though primarily a recent genus, <em>Conchoecia</em> Dana 1853 has had a number of Cretaceous forms dubiously attributed to it since the description of <em>Conchoecia cretacea</em> <span>Pokorný, 1964</span>. Recently, most of these species were reassigned to the genus <em>Neorichterina</em> <span>Tóth and Cséfán, 2018</span><span><span>, considered a Cretaceous representative of Family Entomozoidae. However, there are still taxonomic uncertainties regarding this assignment, and much is still unknown about the paleoecology, </span>paleobiogeography, and biostratigraphic significance of these taxa. This paper provides a revision of the taxon based on available literature on </span><em>Neorichterina</em> and the Cretaceous forms attributed to “<em>Conchoecia</em>”. Considering several problems with the taxonomic description of <em>Neorichterina</em><span>, we propose the removal of the genus from Family Entomozoidae, and identify two potential new species, which are left in open nomenclature. The earliest occurrence of the genus is the late Hauterivian–early Barremian of the Haha Basin, Morocco. After that, </span><em>Neorichterina</em><span><span><span> spread to the South Atlantic and Tethys oceans during the late Aptian–late </span>Albian, and became extinct in the lower </span>Cenomanian. </span><em>Neorichterina</em><span> was likely a planktonic genus with a preference for warm neritic environments, and was able to tolerate fluctuating oxygenation levels. It frequently occurred in association with blooms of Favusellid foraminifera, and was particularly abundant in the South Atlantic Ocean. Although </span><em>Neorichterina</em><span> has a broad stratigraphic range, it occurred only for a small time interval during the late Aptian of the Santos Basin, Brazil, suggesting that it could be a useful regional biostratigraphic marker in the southeastern Brazilian margin.</span></p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49726079","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":"Pentaplacodinium lapazense sp. nov. from Central and Southern Gulf of California, a new non-toxic gonyaulacalean resembling Protoceratium reticulatum","authors":"Kenneth Neil Mertens ,&nbsp;Lourdes Morquecho ,&nbsp;Consuelo Carbonell-Moore ,&nbsp;Pjotr Meyvisch ,&nbsp;Haifeng Gu ,&nbsp;Gwenael Bilien ,&nbsp;Audrey Duval ,&nbsp;Amélie Derrien ,&nbsp;Vera Pospelova ,&nbsp;Kasia K. Śliwińska ,&nbsp;Ismael Gárate-Lizárraga ,&nbsp;Beatriz Pérez-Cruz","doi":"10.1016/j.marmicro.2022.102187","DOIUrl":"10.1016/j.marmicro.2022.102187","url":null,"abstract":"<div><p>A new <em>Pentaplacodinium</em> species with six precingular plates is described from Bahía Concepción and Bahía de la Paz, Gulf of California. The non-fossil motile stage is described as <em>Pentaplacodinium lapazense</em><span>, whilst the fossil stage is described as </span><em>Operculodinium lapazense</em>. The cyst morphology is compared to topotype material of <em>Operculodinium israelianum</em>, which is larger, has longer processes and has a different wall structure. The motile cells display a plate formula of Po, Pt, X, 2′+*2′, 6′′, 6c, 7s, 5′′′, 1p, 1′′′′. A typical gonyaulacalean fission line and plate overlap are observed. SSU-ITS-LSU ribosomal DNA sequences demonstrate that <em>Pentaplacodinium saltonense</em> is its closest relative. The species is homothallic. This species occurs in relatively shallow and restricted coastal areas, and has a preference for higher sea-surface temperatures and salinities. Micro-FTIR spectra of the cysts are compared to spectra of cysts of other gonyaulacaleans and suggest very similar compositions. No yessotoxins were detected in any of the analyzed strains, hence, this species is unlikely to be responsible for the elevated yessotoxin concentration observed in shellfish on the southern and central coastal region of the Gulf of California.</p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44073096","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":"Oceanic anoxic event 2 in Sergipe-Alagoas Basin, Brazil: New paleoecological insights from calcareous nannofossils assemblages","authors":"Roberto Silva Jr ,&nbsp;Elisabetta Erba ,&nbsp;Aristóteles de Moraes Rios-Netto ,&nbsp;Silvia Clara Silva ,&nbsp;Thamara Daniel Alves ,&nbsp;André Luiz Gatto Motta ,&nbsp;Bruno Valle ,&nbsp;Leonardo Borghi ,&nbsp;Frances Abbots-Queiroz","doi":"10.1016/j.marmicro.2022.102197","DOIUrl":"10.1016/j.marmicro.2022.102197","url":null,"abstract":"<div><p>A boring core (UFRJ-2-LRJ-01-SE) from the Sergipe-Alagoas Basin, Brazil, is one of the best and most expanded sections of the late Albian–early Turonian<span><span> age within South America and includes one of the few records of Oceanic Anoxic Event 2 (OAE 2) in the South Atlantic Ocean. The aim of this study is to revise the calcareous nannofossil<span> biostratigraphy and reconstruct paleoclimatic-paleoceanographic patterns based on the quantitative analysis of nannofossil assemblages performed on 78 samples throughout the core UFRJ-2-LRJ-01-SE. The biostratigraphic revision corroborates the previously defined late Albian–early Turonian age for the studied section, however, a hiatus (∼ 4.7 Ma) has been identified, omitting the latest Albian–early </span></span>Cenomanian<span><span> time interval including OAE 1d. In addition, we confirm the occurrence of the OAE 2 interval within the studied section. Also, the revised nannofossil biostratigraphy integrated with chemostratigraphy pointed out the presence of the Middle Cenomanian Event (MCE), previously identified as the Lower Cenomanian Anoxic Event (LCAE). The relative abundances of selected calcareous nannofossil taxa suggest a prevalence of warmer surface waters during the late </span>Albian<span> and cooler conditions during the middle Cenomanian–early Turonian. The integration of diversity, species richness, Shannon diversity, equitability, nutrients (NI) and temperature (TI) indices separated four intervals recording different paleoecological conditions. The comparison with western Tethys data shows similarity between the temperature and fertility trends recognized in the studied section, suggesting global climate changes and similar fluctuations in ocean fertility during the late Albian–early Turonian.</span></span></span></p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41573874","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 Southern Ocean transfer function for subsurface temperature prediction using radiolarian assemblages","authors":"M. Civel-Mazens ,&nbsp;G. Cortese ,&nbsp;X. Crosta ,&nbsp;K.A. Lawler ,&nbsp;V. Lowe ,&nbsp;M. Ikehara ,&nbsp;T. Itaki","doi":"10.1016/j.marmicro.2022.102198","DOIUrl":"10.1016/j.marmicro.2022.102198","url":null,"abstract":"<div><p><span>Radiolarians are microzooplankton that produce siliceous shells that preserve well in sediments and allow for paleo-reconstructions. Previous studies have used them for </span>sea surface temperature<span> (SST) reconstructions. However, radiolarians peak in abundances between 100 and 400 m in the Southern Ocean (SO), suggesting that their assemblages are more representative of subsurface conditions. Here, we aim to develop a SO-wide transfer function (TF) for subsurface temperature reconstructions (subST) using the Southern Ocean RAdiolarian Dataset (SORAD), a compilation of data for about 240 radiolarian taxa in 228 surface sediment samples from the SO. This exhaustive dataset has been simplified using common TF criteria to minimize noise and optimize SORAD for subST prediction. Ordination tests and Q-mode Factor Analyses (QFA) were applied to the resulting training dataset, which includes 212 samples and 75 taxa (SORAD212_75). The results suggest that, out of six environmental variables, radiolarian assemblages in SORAD are mainly driven by summer temperatures at 200 m and that the first five factors of the QFA explained over 75% of SORAD212_75 variance. We applied common TF methods, IKM, MAT and Weighted-MAT (WMAT), to two data transformations (relative abundances of species and log-transformed). The six models of modern temperature predictions all show excellent performance over the −2 to 18 °C interval. To compare with previously published results generated with the same method, IKM% was applied to radiolarian census data of three cores from the Atlantic, Indian and Pacific sectors of the SO, thus calculating new subST reconstructions and testing the new TF performance.</span></p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":null,"pages":null},"PeriodicalIF":1.9,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45717456","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}