Marine Micropaleontology最新文献

{"title":"Unraveling the palaeoecology of Paralia sulcata-dominated assemblages from Late Miocene marine deposits of Patagonia (South Atlantic, Argentina)","authors":"Aylén Allende Mosquera ,&nbsp;Rocío Fayó ,&nbsp;Camilo Andrés Vélez-Agudelo ,&nbsp;Marcela Alcira Espinosa ,&nbsp;José Ignacio Cuitiño","doi":"10.1016/j.marmicro.2024.102421","DOIUrl":"10.1016/j.marmicro.2024.102421","url":null,"abstract":"<div><div>The study of fossil diatom assemblages constitutes an effective tool for inferring past water conditions. Several studies from around the world suggest the Miocene was a key period in the evolutionary history of diatoms. However, Miocene diatom assemblages from the southwestern Atlantic Ocean are nearly unknown. This study aims to provide a palaeoenvironmental interpretation of the analysed succession. Additionally, to highlight temporal and regional changes, the assemblage is compared with known modern and fossil assemblages from Patagonia and other regions of the world. Finally, we provide a detailed description of the extinct diatom taxa recognised throughout the sedimentary succession. A total of 36 diatom taxa were recognised in the 25 analysed samples. Despite the evidence from sedimentology and macro-palaeontology indicating temporal changes from inner shelf to estuarine environments, the diatom assemblages are dominated by the coastal marine <em>Paralia sulcata sensu lato</em> throughout the succession. An important freshwater input into the coastal system is interpreted from our results reflecting more humid climatic conditions when compared with modern diatom assemblages from the same location. In addition, four extinct species were recognised: <em>Thalassiosira</em> cf. <em>yabei</em>, <em>Pseudopodosira westii</em>, <em>Rhaphoneis diamantella,</em> and <em>Lancineis rectilatus</em>. The presence of <em>R. diamantella</em> and <em>L. rectilatus</em> in the analysed deposits would imply an expansion of their geological range.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"193 ","pages":"Article 102421"},"PeriodicalIF":1.5,"publicationDate":"2024-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723009","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":"Ocean gateways and circulation dynamics: Unveiling the deep water-mass properties in the western equatorial Pacific since the Middle Miocene","authors":"Himanshu Bali,&nbsp;Anil K. Gupta","doi":"10.1016/j.marmicro.2024.102420","DOIUrl":"10.1016/j.marmicro.2024.102420","url":null,"abstract":"<div><div>Tectonically driven adjustments in the ocean gateways, such as the constriction and closure of the Central American Seaway (CAS), have been linked to the significant variations in deep water circulations across the Atlantic and Pacific Oceans in the Miocene. The changes in these tectonic gateways had substantial consequences on the Atlantic Meridional Overturning Circulation (AMOC), the Antarctic Circumpolar Current (ACC) and consequently Antarctic ice sheet growth, and deep water circulation pathways across the ocean basins. The timing of the closure of the deep water connection between the Atlantic and Pacific Oceans, through CAS, and related changes in deep water circulation in the western Pacific are still debatable. We examined foraminiferal relative abundances of epibenthic genus <em>Cibicidoides</em> (a synonym of <em>Cibicides</em>) and its stable isotopic ratios to decipher the timing of tectonically controlled changes in deep water circulation since the Middle Miocene at ODP Site 807, western equatorial Pacific. Our findings, correlated with previously published data, suggest the North Component Water (NCW) incursion from the Atlantic to the western Pacific (Site 807) via CAS between ∼12.5 and ∼ 9.5 Ma. An abrupt decrease in benthic foraminifer <em>Cibicidoides kullenbergi</em> at ∼9.5 Ma suggests the initiation of a significant shift in the deep water mass, coinciding with the major δ¹³C divergence between the Atlantic and Pacific oceans.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"193 ","pages":"Article 102420"},"PeriodicalIF":1.5,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723010","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":"Bashkirian-Moscovian (Lower–Middle Pennsylvanian) conodonts from the Amazonas Basin, northern Brazil: Biostratigraphy, biofacies, and paleobiogeographic significance for Western Gondwana","authors":"Martín A. León-Caffroni ,&nbsp;Ana K. Scomazzon ,&nbsp;Tamara I. Nemyrovska ,&nbsp;Sara Nascimento ,&nbsp;Andrés F.R. Mantilla ,&nbsp;Sanmya K.R. Dias ,&nbsp;Amanda P. da Rosa ,&nbsp;Jordana M. Viccari ,&nbsp;Paulo A. Souza ,&nbsp;Valesca B. Lemos","doi":"10.1016/j.marmicro.2024.102407","DOIUrl":"10.1016/j.marmicro.2024.102407","url":null,"abstract":"<div><div>Bashkirian-Moscovian (Lower to Middle Pennsylvanian) Itaituba Formation is well exposed in the Itacimpasa Quarry at the southern platform of the Amazonas Basin, northern Brazil. An abundant and diverse conodont fauna was recovered from this predominantly carbonate formation, with a total of 19 species belonging to 8 genera identified. The following species were documented and systematically described for the first time in the basin: <em>Declinognathodus marginodosus</em>, <em>Declinognathodus donetzianus</em>, <em>Idiognathoides postsulcatus</em>, <em>Idiognathoides fossatus</em>, <em>Diplognathodus benderi</em>, <em>Adetognathus spathus</em>, and <em>Idioprioniodus conjunctus</em>, providing significant stratigraphic and environmental insights into the Bashkirian-Moscovian boundary (BMB) interval. The <em>Declinognathodus marginodosus</em> – <em>Neognathodus atokaensis</em> (upper Bashkirian Stage) and the <em>Declinognathodus donetzianus</em> – <em>Diplognathodus ellesmerensis</em> (lower Moscovian Stage) zones are recognized. The distribution of conodonts studied through cluster analysis reveals the conodont biofacies <em>Idiognathodus</em>/<em>Adetognathus</em> and <em>Declinognathodus</em>/<em>Idiognathoides</em> biofacies. Changes in these conodont biofacies are interpreted as the result of a marine ingression event in Western Gondwana during the BMB interval. The fauna recorded in the studied section shows affinities with conodont faunas reported from Paleo-Tethys Ocean regions indicating a faunal connection of this ocean with the Panthalassa in Western Gondwana. These findings contribute significantly to the refinement of the biostratigraphy and paleobiogeography of the Bashkirian-Moscovian boundary interval in the Amazonas Basin and Western Gondwana.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"192 ","pages":"Article 102407"},"PeriodicalIF":1.5,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142433710","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":"Calcareous Nannofossil variability controlled by Milankovitch and sub-Milankovitch periodicity in the Monte San Nicola section (Gelasian GSSP / MIS 100–104)","authors":"Sergio Bonomo ,&nbsp;Elena Zanola ,&nbsp;Alessandro Incarbona ,&nbsp;Agata Di Stefano ,&nbsp;Salvatore Distefano ,&nbsp;Viviana Barbagallo ,&nbsp;Patrizia Ferretti ,&nbsp;Eliana Fornaciari ,&nbsp;Patrizia Macrì ,&nbsp;Isabella Raffi ,&nbsp;Nadia Sabatino ,&nbsp;Fabio Speranza ,&nbsp;Mario Sprovieri ,&nbsp;Enrico Di Stefano ,&nbsp;Rodolfo Sprovieri ,&nbsp;Domenico Rio ,&nbsp;Luca Capraro","doi":"10.1016/j.marmicro.2024.102397","DOIUrl":"10.1016/j.marmicro.2024.102397","url":null,"abstract":"<div><p>The Quaternary marks the beginning of the ice ages, with the establishment of a stable Northern Hemisphere ice sheet. The Monte San Nicola section, southern Sicily (Italy) is the Global Boundary Stratotype Section and Point of the Gelasian Stage of the Lower Quaternary Subseries and is attracting new attention for providing valuable information on paleoclimate evolution.</p><p>Here we present a paleoenvironmental reconstruction based on new data from calcareous nannoplankton, the phytoplankton organisms that are sensitive to sea surface changes and water column dynamics. We adopt statistical and signal analysis to support our paleoenvironmental model. The most evident paleoenvironmental signal throughout the investigated interval is the contrast between the abundance patterns of placoliths and <em>Florisphaera profunda</em>, the former pointing to surface productivity (water column mixing, shallow nutricline), the latter to the establishment of a deep nutricline. The observed nutricline depth shift occurred with a regular precessional pace, following Northern Hemisphere summer insolation and, likely, North African monsoon activity. A significant periodicity of 8 kyr, in tune with late Quaternary Heinrich events, is also observed in nannoplankton taxa, supporting previous findings on the existence of suborbital climatic variability even at the Pliocene-Pleistocene transition.</p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"192 ","pages":"Article 102397"},"PeriodicalIF":1.5,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0377839824000677/pdfft?md5=e9e62edcb14e48537ccc5dbd5e8458e6&pid=1-s2.0-S0377839824000677-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142274669","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}

{"title":"Benthic foraminifera biomass on the continental slope and São Paulo plateau of Santos Basin (SE Brazil): Comparison of different estimation methods","authors":"Amanda Vilar ,&nbsp;Thaisa Marques Vicente ,&nbsp;Maria Virginia Alves Martins ,&nbsp;Silvia Helena de Mello e Sousa","doi":"10.1016/j.marmicro.2024.102396","DOIUrl":"10.1016/j.marmicro.2024.102396","url":null,"abstract":"<div><p>The biomass of benthic foraminifera stands out in marine environments compared to other meiofaunal organisms. Estimating the biomass of these organisms is a valuable biotic descriptor for understanding the carbon cycle and the flow of particulate organic matter. This study estimates the biomass of benthic foraminifera on the slope and plateau of the Santos Basin (SE Brazil) using the biovolume and cytoplasmic occupancy methodology. This work applies a non-destructive biovolume method of estimating biomass by the direct visualization of cytoplasmic occupancy (DV) compared with pre-established (in the literature) percentages of cytoplasmic occupation of the test volume: an average of 32 % (GE) and 35 % (AL). Although there was no statistically significant difference (<em>p</em> &lt; 0.05) between DV and cytoplasmic percentages, it is recognized that the calculation of GE and AL can bias the results. We, therefore, emphasize the need to assess biomass according to species composition and ultrastructural variability. The species with the biggest individuals (&gt;250 μm) contributed most to biomass in the Santos Basin and are considered k-strategists. In contrast, the species with smaller specimens (250–63 μm) are considered r-strategists, contributing more to the density in the study area. This study highlights the discrepancy between the abundant species biomass results by measuring all specimens and the extrapolation of the population for less sample effort, probably due to biological (e.g. intra/inter species variations) and environmental (e.g. availability of food and oxygen) factors. Based on the ecology of the species, the biomass estimates seem to reveal a relationship with the quantity and quality of organic matter, which will be investigated in the future. Future studies should consider the internal structures and address potential errors resulting from cytoplasm dehydration when staining and drying are performed.</p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"192 ","pages":"Article 102396"},"PeriodicalIF":1.5,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142274670","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":"Analysis of the latitudinal and longitudinal (coastal and pelagic zones) variability of coccolithophore assemblages in the water column of the Western Iberian Margin in late summer of 2022","authors":"María González-Martín ,&nbsp;Andrés S. Rigual-Hernández ,&nbsp;Emilia Salgueiro ,&nbsp;Fátima Abrantes ,&nbsp;José A. Flores","doi":"10.1016/j.marmicro.2024.102398","DOIUrl":"10.1016/j.marmicro.2024.102398","url":null,"abstract":"<div><div>This study investigates the abundance, composition, and biogeographical distribution of coccolithophores in the water column of the northwestern Iberian coastal upwelling system during late summer 2022. Coccolithophore data were compared with in situ measurements of physical, chemical, and biological parameters, as well as with satellite data and the upwelling index (UI) for the study area. Canonical Correspondence Analysis (CCA) was performed to determine the relationships between coccolithophore assemblages and environmental variables. The results reveal a latitudinal and longitudinal gradient in coccolithophore abundance, with higher concentrations towards the north and east, indicating a stronger influence of coastal upwelling near the coast (stations CA-7, CA-8, CA-4). Our data suggest that the source of upwelled water in the north (Eastern North Atlantic Central Waters of subpolar origin, ENACWsp) differs from that in the south (ENACWst, of subtropical origin). Significant correlations between UI and the total abundance of coccoliths and coccospheres underscore the role of upwelling in coccolithophore distribution. Additionally, correlations with fluorescence and turbidity indicate that coccolithophores contribute substantially to primary production in the region. Certain species are proposed as paleoenvironmental indicators due to their affinity for specific environmental conditions. The small Noëlaerhabdaceae group (small <em>Gephyrocapsa</em> group + <em>Emiliania huxleyi</em>) serves as a proxy for primary productivity and intense upwelling, while <em>Florisphaera profunda</em> is associated with upwelling relaxation and low productivity. Discrepancies with satellite data are attributed to their limitations in detecting subsurface biological processes. This study also supports the use of the N-ratio in water column samples, not just in sediments, and improves the understanding of primary productivity at the Western Iberian Margin during the upwelling season.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"192 ","pages":"Article 102398"},"PeriodicalIF":1.5,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142421128","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}

{"title":"Using foraminifera to assess changes in marine coastal habitats of Caribbean Panama since the Middle Holocene","authors":"Maria N. Gudnitz ,&nbsp;Laurel S. Collins","doi":"10.1016/j.marmicro.2024.102408","DOIUrl":"10.1016/j.marmicro.2024.102408","url":null,"abstract":"<div><div>Humans settled the Bocas del Toro archipelago of Caribbean Panama ∼690 CE. Coastal land was cleared for agriculture in the late 1880s and in recent decades water quality degradation has been detected. To investigate changes that support a decline in water quality and to assess differences in salinity caused by increased runoff from cleared lands, benthic foraminifera of Almirante Bay served as an environmental proxy to compare modern and Middle Holocene times. The foraminiferal community structure of 17 modern mangrove, seagrass, and coral reef habitats &lt;2 m deep was analyzed in combination with 18 samples of ∼6600-year-old coral reef, seagrass and muddy molluscan biofacies from Isla Colón island.</div><div>The foraminiferal communities' species and diversity overlap considerably among habitats of both ages, and there is more difference in species' proportions between the ages than among habitats of either age. These patterns reflect high connectivity across adjacent habitats in this embayed, patch-reef setting. Assemblages from Middle Holocene molluscan muds and modern mangroves are least diverse, fairly similar, and well differentiated from those of seagrass and coral habitats. Foraminiferal wall structure suggests more freshwater input in modern times, consistent with forest clear-cutting for agriculture, although both ages fall within the low end of normal salinity. Increased freshwater input influenced assemblage changes but they were not sufficient to reduce measured diversity. Reported declines in the bay's water quality have also not resulted in net foraminiferal diversity loss from ∼6600 years ago, indicating substantial resilience in these extremely shallow, tropical coastal communities.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"192 ","pages":"Article 102408"},"PeriodicalIF":1.5,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554079","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":"Relative sea-level reconstructions by using foraminiferal transfer functions","authors":"Yvonne Milker","doi":"10.1016/j.marmicro.2024.102410","DOIUrl":"10.1016/j.marmicro.2024.102410","url":null,"abstract":"<div><div>Transfer functions, that use benthic foraminifera, are widely applied for reconstructions of changes in paleoenvironments such as relative sea-level changes and tectonic-induced vertical coastal motions. Such reconstructions are based on a representative modern training data sets, often sampled along the environmental gradient to be reconstructed. The species-environment relationships in a training data set can be modeled by using an adequate numerical technique, and the resulting transfer function model can then be applied to a fossil data set to reconstruct paleo-environmental conditions such as relative sea-level changes. Although transfer functions models are relatively easy to develop and to apply, several studies have shown that there are also difficulties with this approach. This study describes and discusses various aspects that should be considered when using the transfer function approach for relative sea-level estimates. It concentrates on the modern species-environment relations with a special focus on marine environments, describes widely used numerical methods for transfer function development, discusses several validation methods and addresses applications.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"192 ","pages":"Article 102410"},"PeriodicalIF":1.5,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142535672","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}

{"title":"Recent deep-sea nematodes and agglutinated foraminifera select specific grains and bioclasts from their environments: Ecological implications","authors":"Sunil K. Das ,&nbsp;Raj K. Singh ,&nbsp;Mariem Saavedra-Pellitero ,&nbsp;Julia Gottschalk ,&nbsp;Carlos A. Alvarez Zarikian ,&nbsp;Lester Lembke-Jene ,&nbsp;Frank Lamy ,&nbsp;Gisela Winckler ,&nbsp;Jennifer L. Middleton ,&nbsp;Helge W. Arz ,&nbsp;Chandranath Basak ,&nbsp;Anieke Brombacher ,&nbsp;Oliver M. Esper ,&nbsp;Jesse R. Farmer ,&nbsp;Lisa C. Herbert ,&nbsp;Shinya Iwasaki ,&nbsp;Vera J. Lawson ,&nbsp;Li Lo ,&nbsp;Elisa Malinverno ,&nbsp;Elisabeth Michel ,&nbsp;Xiangyu Zhao","doi":"10.1016/j.marmicro.2024.102409","DOIUrl":"10.1016/j.marmicro.2024.102409","url":null,"abstract":"<div><div>The high-latitude regions are known for a diverse array of benthic meiofauna, yet our understanding of these communities remains limited, particularly in the deep ocean. This study aims to assess the variability and adaptation of nematodes and agglutinated foraminifera in the modern sediments of the Southern Pacific Ocean at &gt;3500 m water depth. Seawater and sediment slurry from the first piston cores (i.e., mudline samples) from International Ocean Discovery Program Sites U1539, U1540, U1541, and U1543 were analyzed for Rose Bengal stained nematode and agglutinated benthic foraminifera. During the microscopic study seven nematode specimens belonging to the genus <em>Desmoscolex</em>, with 16–17, 36 or 38 main rings were found. Scanning electron microscopy study suggest that one morphotype with 17 main rings used only coccoliths of the species <em>Calcidiscus leptoporus</em> while the other specimens used fine-grained siliciclastic material on their concretion ring. Besides nematodes, a few benthic agglutinated foraminifera specimens exclusively used a single species of planktic foraminifera (<em>Globoconella inflata</em>) and/or robust coccoliths, in addition to other fine-grained siliciclastic material, for their test construction. These patterns appear to be highly selective. Specimens of the same benthic nematode <em>Desmoscolex</em> genus and agglutinated foraminifera that have diverse grain types show that these specimens can adapt to their environments, choose specific grains as per their preference, and have no relationship with the grain/particle abundance. This study of <em>Desmoscolex</em> and agglutinated foraminifera species suggests low to moderate organic matter flux and increased ventilation in the abyssal depth of the Southern Pacific Ocean.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"192 ","pages":"Article 102409"},"PeriodicalIF":1.5,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142539414","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 resolution 3D images of sediment cores as powerful tool for exploring foraminiferal microhabitats","authors":"M.P. Nardelli ,&nbsp;N. Vanderesse ,&nbsp;M. Moller ,&nbsp;C. Guilhermic ,&nbsp;A. Mouret","doi":"10.1016/j.marmicro.2024.102394","DOIUrl":"10.1016/j.marmicro.2024.102394","url":null,"abstract":"<div><p>Benthic foraminifera are marine protists largely used as bioindicators and proxies of paleo- environments. Epifaunal species are supposed to live at or above the sediment surface and are therefore used as proxies for bottom water conditions, while infaunal inhabit the sediment column, thus tracing porewater chemistry. Traditional analytical methods based on core slicing, however, have a low resolution that does not allow to precisely characterise the preferential microhabitat(s) of indicator species.</p><p>In this study we performed microtomographic analyses on an experimental sediment core, to observe the life-position of living foraminifera of two surface-dwelling species <em>Ammonia confertitesta</em> and <em>Haynesina germanica</em>, reported both as epifaunal or shallow infaunal. The images we obtained offered for the first time the possibility to observe each individual in 3D space with a numerical resolution of 13 μm/voxel.</p><p>The results revealed that the two species are never located above or at the sediment surface and have their preferential microhabitats in a sub-superficial sediment layer constrained in the 0–500 μm interval below the surface. Rapid decrease of abundances below this layer suggests that their microhabitat could be even more specific than previously thought.</p><p>μCT-scan of sediment cores is also a valuable tool to obtain high-resolution information about foraminiferal ecology. The described method is useful to assess the effective microhabitat of all foraminiferal species that are usually used as proxies for paleorecords, to ensure that the information we can obtain from them is attributable to bottom water or to porewater conditions at a specific sediment depth.</p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"191 ","pages":"Article 102394"},"PeriodicalIF":1.5,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0377839824000641/pdfft?md5=827d2d5b8568a4649849315add7d5747&pid=1-s2.0-S0377839824000641-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142122201","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}