Marine Micropaleontology最新文献

{"title":"Controls on barium incorporation into tests of benthic foraminifera from the Aegean Sea (Eastern Mediterranean Sea) – Towards a species-specific Ba/Ca calibration","authors":"Jassin Petersen ,&nbsp;Gerhard Schmiedl ,&nbsp;Jacek Raddatz ,&nbsp;André Bahr ,&nbsp;Jörg Pross ,&nbsp;Meryem Mojtahid","doi":"10.1016/j.marmicro.2024.102431","DOIUrl":"10.1016/j.marmicro.2024.102431","url":null,"abstract":"<div><div>We have analysed Ba/Ca ratios of live and dead benthic foraminifera (<em>Uvigerina mediterranea</em> and <em>Melonis affinis</em>) from core tops of seven sites located in the Aegean Sea by laser ablation ICP-MS. There are no significant Ba/Ca differences in live and dead specimens of <em>U. mediterranea</em>. For <em>M. affinis</em> we apply a threshold criterion for extremely high Ba/Ca in live specimens in order to highlight the overall uniform Ba/Ca signal. The Ba/Ca intra-test variability varies between 16 and 24 % relative standard deviation per specimen. It is attributed to biomineralisation processes i.e., vital effects. The Ba/Ca ratios of <em>M. affinis</em> are significantly higher than those of <em>U. mediterranea</em> throughout most of the sites and their respective samples from different sediment depths. The influence on Ba/Ca of both species by biomineralisation processes and/or microhabitat effects remains open. Linking the Ba/Ca ratios to measured Ba concentration of bottom waters from one of the studied sites, shows partition coefficients of D_Ba = 0.34, and D_Ba = 0.49 for <em>U. mediterranea</em> and <em>M. affinis</em>, respectively. We could not identify trends of Ba/Ca ratios to observed/ modelled gradients of relevant environmental factors between the seven analysed sites, such as primary productivity and associated C_org fluxes or TOC concentrations. Despite the demonstrated limited proxy potential in these parts of the Aegean Sea, we suggest that it is possible to employ Ba/Ca of infaunal benthic species in order to reconstruct export productivity in deep-sea areas with a less complex linkage between primary productivity and nutrient distribution in bottom waters.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"194 ","pages":"Article 102431"},"PeriodicalIF":1.5,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143095753","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":"Evolutionary, paleoecological and taphonomic aspects of new agglutinated foraminifer Devonodendron scopulum from the Frasnian of Holy Cross Mts, Poland","authors":"Grzegorz Racki","doi":"10.1016/j.marmicro.2024.102434","DOIUrl":"10.1016/j.marmicro.2024.102434","url":null,"abstract":"<div><div>Regularly bifurcated tubiform (tree-like) microfossils, although illustrated three decades ago from the Frasnian of the Holy Cross Mts (southern Poland), have not been studied in detail until now. In this paper, the distinctive microproblematic is interpreted as a calcite-cemented agglutinated foraminifer belonging to <em>Devonodendron scopulum</em> sp. et gen. nov., appearing in a major radiation after the Givetian Revolution. Based on the study of isolated three-dimensional specimens, this Devonian species is the best documented of the early branching foraminifera. It resembles living arborescent representatives of the family Schizamminidae (such as <em>Schizammina arborescens</em> and <em>S. andamana</em>), but also the family Dendrophryidae (<em>Psammatodendron arborescens</em>), which has already been reported in the fossil record (Cretaceous; questionable Silurian). However, in light of genetic studies of modern monothalamids, phylogenetic inferences based on such simple morphology are risky. The tree-like branching system of this species suggests erect attached and filter feeding life habit. <em>Devonodendron scopulum</em> shows a pronounced microhabitat selectivity, being dominantly restricted to mid-slope metazoan-microbial mud-mounds. The buildups provided microniches for flourishing a very abundant and diverse calcareous microbiota, including taxa with known (<em>Nanicell</em>a) and presumed (<em>Eifeliflabellum</em>) foraminiferal affinities. The environment was characterized by a specific diagenetic setting for the fossilization of micritic-organic tubular tests due to rapid microbially mediated lithification and overwhelming recrystallization processes. As a result, microfossils are largely preserved as stacked homogeneous rhomboidal calcite plates. Many specimens in some sites are actually just coalesced sparry calcite ‘pseudomorphs’ mimicking the original test morphology.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"195 ","pages":"Article 102434"},"PeriodicalIF":1.5,"publicationDate":"2024-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349454","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":"Eocene to Early Miocene dinoflagellate cysts from the southern Gulf of Mexico","authors":"Alessandro-Cesare Bruno,&nbsp;Javier Helenes","doi":"10.1016/j.marmicro.2024.102422","DOIUrl":"10.1016/j.marmicro.2024.102422","url":null,"abstract":"<div><div>This paper documents the Eocene to Miocene dinoflagellate cyst assemblages found at Site 94 in the southern part of the Gulf of Mexico. Four unique dinoflagellate cyst assemblages representing depositional periods from the Early Eocene to the Early Miocene are defined in this study. The Early to Middle Eocene assemblage presents the highest average concentrations of dinoflagellate cysts, is dominated by <em>Operculodinium</em>, and contains few heterotrophic taxa. The Early Oligocene assemblage has medium concentration and is dominated by <em>Deflandrea</em>. The Late Oligocene also has high average concentrations of dinoflagellate cysts, is dominated by <em>Homotryblium</em>, and contains few heterotrophic taxa. The Early Miocene assemblage has lower average concentrations of dinoflagellate cysts, is dominated by <em>Pyxidinopsis</em>, and lacks heterotrophic taxa. Our palynological data is related to significant regional paleogeographic and paleoceanographic changes. Namely, the Early to Middle Eocene free flow of tropical water masses from the south and the Late Eocene restriction of this flow by a land bridge connecting northern South America to Cuba in the north. The Oligocene gradual return of the tropical water masses and finally, the Early Miocene emergence of the Florida Platform when the Gulf of Mexico reached modern oceanographic conditions. The stratigraphic ranges of selected dinoflagellate cysts fit in age with previous microfossil data from the site and allowed us to define the Early Oligocene - Late Oligocene transition. The presence of well-preserved dinoflagellate cysts allowed the identification of 60 species and the discovery of three new species: <em>Achomosphaera psilata</em> sp. nov., <em>Carpatella reticulata</em> sp. nov., and <em>Hystrichosphaeropsis gulficum</em> sp. nov.</div></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"193 ","pages":"Article 102422"},"PeriodicalIF":1.5,"publicationDate":"2024-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142744016","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":"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}