Marine Micropaleontology最新文献

{"title":"Two new ceratioid cornucavate dinoflagellate cysts from the Upper Cretaceous, Gulf of Suez, Egypt","authors":"Ali Soliman ,&nbsp;Hamid Slimani ,&nbsp;Somia Said","doi":"10.1016/j.marmicro.2024.102338","DOIUrl":"10.1016/j.marmicro.2024.102338","url":null,"abstract":"<div><p><span>Diverse and well-preserved assemblages of organic-walled dinoflagellate cysts have been recovered from the Matulla Formation (Coniacian – Santonian), Gulf of Suez, Egypt. Among the abundant dinoflagellate cyst assemblages, the new species </span><em>Odontochitina elbeialyi</em> sp. nov. and <em>Odontochitina ornata</em> sp. nov. (Family Ceratiaceae) are described. The two new species are unique by having a granulate periphragm and three prominent horns. The horns are truncated distally and devoid of striae, ridges and perforations. <em>Odontochitina elbeialyi</em><span> sp. nov. is characterized by a weakly expressed tabulation on the pericyst indicated by the occasional presence of sutural lines or low ridges indicating the cingulum (two transverse ridges), at plate boundaries. </span><em>Odontochitina ornata</em> sp. nov. differs from the former, particularly by its clear tabulation, which is corniform gonyaulacoid and more strongly expressed by sutural ridges, and by rare short (rudimentary) sutural (mostly gonal) nipple-like, to truncated processes. Based on the current material, <em>Odontochitina elbeialyi</em> sp. nov. and <em>Odontochitina ornata</em><span> sp. nov. have short stratigraphic ranges and may therefore be considered as stratigraphic markers for the late Santonian (Late Cretaceous). Their comparison with all formally published species of the genus </span><em>Odontochitina</em> is presented and discussed, and the associated relevant dinoflagellate cyst taxa are also indicated. The paleoenvironmental significance of the <em>Odontochitina elbeialyi</em> sp. nov. and <em>Odontochitina ornata</em> sp. nov. is discussed.</p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"187 ","pages":"Article 102338"},"PeriodicalIF":1.9,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139398314","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":"Integrated biostratigraphy of Upper Cretaceous deposits from an exceptional continental vertebrate-bearing marine section (Transylvanian Basin, Romania) provides new constraints on the advent of ‘dwarf dinosaur’ faunas in Eastern Europe","authors":"R. Bălc ,&nbsp;R. Bindiu-Haitonic ,&nbsp;S.-A. Kövecsi ,&nbsp;M. Vremir ,&nbsp;M. Ducea ,&nbsp;Z. Csiki-Sava ,&nbsp;D. Ţabără ,&nbsp;Ș. Vasile","doi":"10.1016/j.marmicro.2023.102328","DOIUrl":"10.1016/j.marmicro.2023.102328","url":null,"abstract":"<div><p><span>The present paper outlines the results of a detailed study of calcareous nannofossils<span><span> and small foraminifera made on Campanian<span> marine deposits from the southwestern part of the Transylvanian Basin, Romania, part of the marine-to-continental transitional Petrești succession that yielded the oldest temporally well-constrained continental vertebrate remains in this area. These results are integrated with new and previously published palynostratigraphic information as well as with novel detrital zircon geochronometry data. All three groups of </span></span>fossils<span> (calcareous nannofossils, small foraminifera, and palynomorphs) convergently indicate an early to middle Late Campanian age for the marine part of the Petrești section. Based on detrital zircon analyses, the most likely maximum depositional age of the studied deposits is 76 ± 1.7 Ma, thus confirming the age supported by microfossil<span> assemblages. Palaeoenvironmental interpretation of the fossil assemblages<span> recovered from the marine part of the Petrești section suggests that despite their flysch-like facies, these beds were deposited in a continental shelf setting, under </span></span></span></span></span>suboxic conditions<span><span> and frequent fluctuations in nutrient supply to the seafloor, but quite stable environmental conditions within the water column. The synthesis of all currently available biostratigraphic and geochronologic data from the Petrești succession suggests a middle-late Late Campanian start for the expansion of the emergent land areas that made up the latest Cretaceous Hațeg Island, earlier than previously accepted dates (Maastrichtian) for this event. Furthermore, it documents the establishment of a diversified continental vertebrate faunal assemblage by the second half of the Late Campanian on these emergent lands while also providing further evidence for a later, post-Campanian arrival of certain iconic Hațeg Island dinosaur groups such as titanosaurs and hadrosauroids. Finally, our data show that kogaionid multituberculate mammals were already members of the earliest known Hațeg Island faunas, extending the fossil record of this group from the </span>Maastrichtian into the later part of the middle Late Campanian.</span></p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"187 ","pages":"Article 102328"},"PeriodicalIF":1.9,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139374584","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":"Foraminifera associated with macroalgae on tropical coastal sandstone reefs","authors":"Davy Barbosa Bérgamo ,&nbsp;David Holanda de Oliveira ,&nbsp;Edson Régis Tavares Pessoa Pinho de Vasconcelos ,&nbsp;Nykon Craveiro ,&nbsp;José Souto Rosa Filho","doi":"10.1016/j.marmicro.2023.102325","DOIUrl":"10.1016/j.marmicro.2023.102325","url":null,"abstract":"<div><p><span>While they are extremely abundant and ecologically important, the epiphytic foraminifera of tropical reefs are still poorly known. The present study describes the foraminiferal assemblages associated with macroalgae on tropical reefs of the Brazilian coast. Samples of four species of macroalgae, two foliose (</span><em>Padina antillarum</em> and <em>Ulva lactuca</em>) and two corticated (<em>Palisada perforata</em> and <em>Gelidiella acerosa</em>), were collected from intertidal sandstone reefs at Pina, Enseada dos Corais, and Toquinho (Northeastern Brazil). Overall, only 13.3% of the 708,754 foraminifera specimens were alive, belonging to 37 species, with dominance of <em>Rosalina anglica</em>. Most tests were hyaline-perforate and conical in shape, and most species were permanently or temporarily sessile. The majority of living foraminifera were attached to the surface of <em>Palisada</em> and <em>Gelidiella</em>, and no attached specimens were found in either <em>Padina</em> or <em>Ulva</em>. The species richness and abundance of the living foraminifera varied significantly among the macroalgae, occurring the high values in <em>P. perforata</em>. The assemblages varied significantly between the two species of corticated macroalgae, and between the corticated and foliose species, but not between the two foliose algae. Some of the specimens of <em>Glabratella</em> and <em>Rosalina</em> were reproducing, and had juveniles attached to the parental test. This is the first study to focus on the ecological interactions of the epiphytic foraminifera of the tropical southern Atlantic Ocean, and its results indicate that the characteristics of the epiphytic assemblages can be used as a proxy for the understanding of the structure and function of microbenthic communities on tropical reefs.</p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"186 ","pages":"Article 102325"},"PeriodicalIF":1.9,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139028059","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":"Corrigendum to “An endemic conodont fauna of Darriwilian (Middle Ordovician) age from the Santa Gertrudis Formation, southwestern Gondwanan margin and its paleobiogeographic relationships” [Marine Micropalaeontology volume 181 (2023) 1–21/Article Number 102241]","authors":"Guillermo L. Albanesi ,&nbsp;C. Rubén Monaldi ,&nbsp;Christopher R. Barnes ,&nbsp;Fernando J. Zeballo ,&nbsp;Gladys Ortega","doi":"10.1016/j.marmicro.2023.102327","DOIUrl":"https://doi.org/10.1016/j.marmicro.2023.102327","url":null,"abstract":"","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"186 ","pages":"Article 102327"},"PeriodicalIF":1.9,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0377839823001263/pdfft?md5=45389c5545cfad1618f6f0600450b5da&pid=1-s2.0-S0377839823001263-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139090117","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":"A new methodology for foraminifera extraction from cemented calcareous shelf sediments","authors":"Anna Arrigoni,&nbsp;Werner E. Piller,&nbsp;Gerald Auer","doi":"10.1016/j.marmicro.2023.102324","DOIUrl":"10.1016/j.marmicro.2023.102324","url":null,"abstract":"<div><p><span>Choosing the most conservative technique to extract unequivocally identifiable foraminiferal tests is crucial to avoid biases in sedimentary sequence<span><span> dating and paleoenvironmental interpretations. However, for problematic samples containing heavily encrusted specimens, the concentration and isolation of microfossils might be challenging. In this work, we analyzed Early-Middle Pleistocene samples from the International Ocean Discovery Program (IODP) Site U1460, located on the southwestern Australian shelf platform, characterized by extensive early marine </span>diagenesis. At this site, foraminiferal preservation varies between the glacial and interglacial phases. In particular, tests are highly encrusted in samples representing sea-level lowstands of glacials while exhibiting better preservation in samples corresponding to interglacials. As the application of previously established, very conservative preparation techniques (e.g., sieving technique, soaking in H</span></span>₂O₂ solution and gentle sonication) did not produce satisfactory results, it was necessary to set up a new procedure for foraminifera isolation specifically for the cautious cleaning of cemented benthic and planktic foraminiferal tests. This new methodology combines the use of a freeze-dryer with repeated soakings in highly-diluted H₂O₂<span> solution to disaggregate the material. To evaluate the efficiency of our technique objectively, we considered the improvements obtained with our procedure on the worst-preserved samples of our record (corresponding to glacials) and the best-preserved (associated with interglacials). Despite being more time-consuming than other preparation techniques, this newly developed procedure produces excellent results in samples exhibiting a high level of encrustation for reliable quantitative studies and isotope analysis on foraminiferal assemblages. Our new methodology is highly conservative and thus preserving even delicate taxa.</span></p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"187 ","pages":"Article 102324"},"PeriodicalIF":1.9,"publicationDate":"2023-12-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139067805","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":"Biodiversity and evolutionary phases of Lochkovian (Lower Devonian) conodonts in the Pyrenees: A comparative study","authors":"José Ignacio Valenzuela-Ríos ,&nbsp;Jau-Chyn Liao","doi":"10.1016/j.marmicro.2023.102326","DOIUrl":"10.1016/j.marmicro.2023.102326","url":null,"abstract":"<div><p><span>This paper aims to evaluate the zone-by-zone changes in Lochkovian<span> conodont biodiversity in the Pyrenees region and compare the results with previous studies. Additionally, the paper seeks to identify evolutionary phases within the Lochkovian. We analyse the stratigraphic range data from eight classical Pyrenean Lochkovian sections. A total of 48 taxa at the species level, primarily confined to the Lochkovian, are included in the analysis. We employ both qualitative and quantitative approaches, including Clark's method for the conodont evolution index and Foote's parameters for measuring taxonomic diversity and rates. The zonal scheme employed in this study follows the global three-fold subdivision of the Lochkovian stage, with additional subdivisions based on local records. The zone-by-zone analysis of stratigraphically well-controlled successions contributes to our understanding of the conodont diversity dynamics in this region. The results are consistent with previous studies, but also highlight the unique aspects of the Pyrenean conodont record. Their highest diversity occurs in the middle Lochkovian within the </span></span><em>kutscheri</em>-<em>pandora</em><span> beta Zone, succeeded by an extinction event towards the end of this interval. Following a brief proliferation of species at the onset of the upper Lochkovian, another extinction event concludes this Stage. Results from all different rate measurements applied to Pyrenean Lochkovian conodonts are in disagreement with the prevailing perspective suggesting an escalation in the proportion of singletons and a concomitant decline in per-taxon rates with an increase in interval length. Comparative analysis of conodont records across various regions (Carnic Alps, Prague Synform, Central Nevada, and the Pyrenees) during the Lochkovian reveals significant differences in biodiversity, taxonomic composition, and zonal distribution.</span></p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"187 ","pages":"Article 102326"},"PeriodicalIF":1.9,"publicationDate":"2023-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139072242","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":"Origins and paleoclimatic and paleoceanographic significance of laminated sediments of middle Pleistocene age from the southern Bering Sea","authors":"Jonaotaro Onodera ,&nbsp;Alan E.S. Kemp ,&nbsp;Richard B. Pearce ,&nbsp;Keiji Horikawa ,&nbsp;Kozo Takahashi","doi":"10.1016/j.marmicro.2023.102323","DOIUrl":"10.1016/j.marmicro.2023.102323","url":null,"abstract":"<div><p>Laminated diatomaceous sediments occur intermittently in the Bering Sea over the past 5 million years. A varve (annually deposited) origin for the laminae has been suggested, but there is currently no consensus. Here, we report results of a study of two laminated intervals dating from ∼528 ka and ∼ 782 ka from IODP Site U1340 on the Bowers Ridge. We combine conventional micropaleontological methods with scanning electron microscope analysis that resolves the seasonal cycle of flux events recorded and demonstrates an annual origin for the laminae. Resting spores of <em>Chaetoceros</em> spp., and more rarely of <em>Thalassiosira antarctica</em> represent early spring blooms with the latter likely due to increased meltwater input. Diatom laminae containing concentrations of <em>Shionodiscus trifultus</em>, <em>Thalassiosira</em> spp., <em>Actinocyclus curvulatus</em>, and <em>Neodenticula seminae</em>, represent flux from the main spring-summer bloom episodes, with the latter indicating influx of seed populations from the North Pacific Alaskan Stream. Concentrations of <em>Coscinodiscus</em> spp. in the uppermost part of the diatom laminae represent “Fall Dump” sedimentation of these stratified-adapted diatoms in response to break down of summer stratification in autumn/early-winter storms. The lithogenic laminae represent mainly winter deposition and rare earth element analysis suggests provenance from the southern Bering Sea shelf and the Aleutian Arc. Productivity was high in the studied intervals with total mass fluxes around 5 times higher than modern values. Variation in lamina thickness and diatom composition contain periodicities of 2–8 years, as well as a bi-decadal variability likely related to influence of the Pacific Decadal Oscillation.</p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"186 ","pages":"Article 102323"},"PeriodicalIF":1.9,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0377839823001226/pdfft?md5=61d648afd2a9e5ec3ec40ecca98ceee3&pid=1-s2.0-S0377839823001226-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138682558","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":"Calcification depth of pteropods in the Coral Sea using stable oxygen isotopes","authors":"Zirong Huang ,&nbsp;Anran Chen ,&nbsp;Horng-Sheng Mii ,&nbsp;Mahyar Mohtadi ,&nbsp;Stephan Steinke","doi":"10.1016/j.marmicro.2023.102322","DOIUrl":"10.1016/j.marmicro.2023.102322","url":null,"abstract":"<div><p><span><span>Pteropods are marine holoplanktonic gastropods inhabiting epipelagic and mesopelagic waters with a wide distribution from tropical to polar regions. However, their </span>ontogeny<span> and calcification depth/habitat depth are not well understood. To this end, we analyzed the stable oxygen isotopic composition of five pteropod species (</span></span><em>Diacavolinia angulata</em>, <em>Diacavolinia longirostris</em>, <em>Heliconoides inflatus</em>, <em>Limacina bulimoides</em> and <em>Telodiacria quadridentata</em>) from two multicores recovered offshore north-eastern Australia between 15°S and 26°S in the Coral Sea. We applied the <em>Limacina</em><span><span> dissolution index (LDX) to evaluate the preservation status of the pteropods, which revealed very good to moderate aragonite preservation at both locations. Comparison of the pteropod shell oxygen isotopic composition with predicted aragonite equilibrium </span>oxygen isotope values implies calcification depths of 50 ± 20 m for </span><em>D. longirostris</em> and 75 ± 30 m for <em>D. angulata</em>, suggesting that they predominantly calcify in the mixed layer during austral summer. The apparent calcification depths of <em>T. quadridentata</em> and <em>H. inflatus</em><span> at 90 ± 30 m and 120 ± 30 m at both sites indicate a year-round, lower mixed layer and upper thermocline habitat depth, respectively, while </span><em>T. quadridentata</em> appear to calcify at temperatures above 22 °C. The calcification depth of <em>L. bulimoides</em> is deeper (100 ± 15 m) at the northern station and shallower (75 ± 30 m) at the southern station that might also hint to a temperature control. The relative narrow calcification depth ranges of the investigated pteropod species in the Coral Sea bolster their potential for reconstructing past ocean conditions at the mixed layer and thermocline.</p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"186 ","pages":"Article 102322"},"PeriodicalIF":1.9,"publicationDate":"2023-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138580551","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":"Reconstruction of the sedimentary environment of Nayband Bay during the last 1600 years; implications for relative sea level and climate change in Northern Persian Gulf","authors":"Mohammad Ali Hamzeh,&nbsp;Abdolmajid Naderi Beni,&nbsp;Hamid A.K. Lahijani,&nbsp;Ali Mehdinia,&nbsp;Vahid Aghadadashi,&nbsp;Emad Koochaknejad","doi":"10.1016/j.marmicro.2023.102321","DOIUrl":"10.1016/j.marmicro.2023.102321","url":null,"abstract":"<div><p><span><span>This paper reconstructs the relative sea level (RSL) and palaeoclimate of the northern coasts of the </span>Persian Gulf<span> (PG) during the last 16 centuries using physiochemical and ecological proxies from a radiocarbon-dated sediment core from the Nayband Bay (NB) estuary. The results show that between 1600 and 1150 cal yr BP, the NB was a marine lagoon with high river discharge, indicated by low organic matter content sandy silt sediments, high foraminiferal abundance (7900 tests per 10 cm</span></span>³<span><span>), and balanced agglutinated and hyaline taxa. During the Medieval Warm Period, the NB became a shallow lagoon, and consequently, a playa with high eolian input and low river discharge formed in the studied site that extended until 500 cal. yr BP. This condition is indicated by sediment finning trend, elevated </span>magnetic susceptibility<span> in sandy mud sediments, and low foraminiferal frequency dominated by hyaline taxa (mainly opportunist </span></span><em>Ammonia beccarii</em><span><span>). During the stillstand condition corresponding to 500–250 cal yr BP, the evolution of tidal channels in the area provided a platform for developing the upcoming mangrove habitat. In the last 250 years, RSL in the north of NB dropped enough to create a low-energy intertidal flat sheltered by a sandbar, which allowed mangrove growth. We conclude that the ecological and sedimentological evolution of the shallow marginal NB is mainly driven by eustatic RSL decline superimposed by local uplift. We suggest that the current orbitally-induced increasing insolation trend, enhanced by human-induced </span>global warming, could increase aridity in the PG and the southern Zagros.</span></p></div>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"186 ","pages":"Article 102321"},"PeriodicalIF":1.9,"publicationDate":"2023-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138556672","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":"Holocene paleo-redox conditions in a microbial dolomitic lake using benthic foraminifera as bioindicators","authors":"Daniel François, Camila Areias, Nayara Dornelas, Luiz G.R. Sá-Valle, Anna Paula Soares Cruz, José Carlos Sícoli Seoane, Crisógono Vasconcelos, Nicolás M. Stríkis, Daniel Souza dos Santos, Adina Paytan, Cátia F. Barbosa","doi":"10.1016/j.marmicro.2023.102319","DOIUrl":"https://doi.org/10.1016/j.marmicro.2023.102319","url":null,"abstract":"<p>Brejo do Espinho coastal lake (LBE) is one of the few places in the world where dolomite [CaMg(CO3)2] is precipitating in the modern environment under microbially induced processes and low oxygen conditions. We use pore morphometry of the foraminifera <em>Ammonia</em> cf. <em>A. veneta</em> to evaluate paleo-O2 dynamics during the dolomitic depositional phase that took place at LBE in the late Holocene. Foraminiferal community structure was also investigated, and results were compared to bulk isotopic composition of carbonates, total organic carbon (TOC), and X-ray Diffraction of sediments (XRD). The correlation matrix (Spearman method) showed that <em>Ammonia</em> test pores morphometric parameters displayed significant correlations with overall biotic and geochemical data, with pore area presenting a relatively higher association. Surface pores were primarily controlled by the degradation of organic matter (Pore area-TOC, <em>r =</em> −0.84), and foraminifera density appeared to be influenced by oxygen changes, with a higher abundance in the highest porosity intervals (Area-N, <em>r =</em> 0.82), indicating a direct effect of oxygen penetration on species dominance. These data also reveal a tolerant behavior of the low-O2 bioindicator species <em>Quinqueloculina laevigata</em> and <em>A. veneta</em>. Understanding microbe-mineral interactions is critical for interpreting paleo records, and our data provide strong support for coupling assemblage and pores analysis as paleo-O2 bioindicators for paleo-redox coastal settings.</p>","PeriodicalId":49881,"journal":{"name":"Marine Micropaleontology","volume":"3 1","pages":""},"PeriodicalIF":1.9,"publicationDate":"2023-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138539809","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}