We investigated benthic foraminiferal species as tracers for carbon export flux in the Indo-Pacific warm pool (International Ocean Discovery Program Expedition 363). In core tops, the distribution of lower bathyal and upper abyssal species can be separated into two distinct groups. Foraminifera belonging to the high carbon flux (>3.5 g C m−2 year−1), ‘warm’ (>3.5°C) group are Bolivina robusta, Bulimina aculeata, Globobulimina pacifica, Hoeglundina elegans, Laticarinina pauperata, and Cibicidoides pachyderma. The lower carbon flux, ‘cold’ group includes Oridorsalis umbontus, Uvigerina bifurcata, and Planulina wuellerstorfi. An index based on the percent ‘warm’ assemblage with respect to the total ‘warm’ plus ‘cold’ species in core-top samples correlates significantly with carbon flux (r = 0.91, P = 0.0007) and modern bottom water temperatures (r = 0.94, P = 0.0002). When applied to down-core species abundances based on core catchers spanning the late Miocene through Pleistocene, we observed that sites from the northwestern Australian margin show marked changes in the ‘warm’ index, suggesting a large paleoenvironmental signal in this dynamic region. At Papua New Guinea, down-core abundances of the ‘warm’ group are highest (>80%), consistent with high organic matter input via the Sepik River. At the deeper of the two sites, down-slope movement in this tectonically unstable region may have contributed to organic matter input. At Manus Basin, the ‘warm’ species abundances are also relatively high and covary with the percent abundance of Uvigerina proboscidea, providing further evidence for the use of this index as a tracer for carbon flux. Overall, this study contributes evidence for the relationship between benthic foraminiferal assemblages and carbon export flux in the Indo-Pacific warm pool, suggesting that the ‘warm’ index can be used as a tracer for paleoproductivity.
我们调查了海底有孔虫物种作为印度洋-太平洋暖池中碳出口通量的示踪剂（国际海洋发现计划远征363）。在岩心顶部，下深海和上深海物种的分布可以分为两组。属于高碳通量（>3.5 g C m−2 year−1）、“温暖”（>3.5°C）组的有孔虫是Bolivina robusta、Bulimina acureata、Globobulimina pacifica、Hoeglundina elegans、Laticarina pauperata和厚壳虫Cibicidoides pachyderma。碳通量较低的“冷”组包括脐黄背藻、分叉乌维捷琳娜和乌埃勒斯托菲螺旋藻。基于岩芯顶部样本中“温暖”+“寒冷”物种总数的“温暖”组合百分比的指数与碳通量（r=0.91，P=0.0007）和现代底层水温（r=0.94，P=0.0002）显著相关。当应用于基于中新世晚期至更新世岩芯捕集器的岩芯下物种丰度时，我们观察到，澳大利亚西北部边缘的遗址显示出“温暖”指数的显著变化，这表明在这个动态区域有一个大的古环境信号。在巴布亚新几内亚，“温暖”组的岩心丰度最高（>80%），这与通过Sepik河输入的高有机物一致。在这两个地点的深处，这个构造不稳定区域的下坡运动可能有助于有机物的输入。在马努斯盆地，“温暖”物种的丰度也相对较高，与长鼻乌维捷琳娜的丰度百分比一致，为使用该指数作为碳通量示踪剂提供了进一步的证据。总的来说，这项研究为印度洋-太平洋暖池中底栖有孔虫组合与碳输出通量之间的关系提供了证据，表明“温暖”指数可以用作古生产力的示踪剂。
{"title":"Sensitivity of Benthic Foraminifera to Carbon Flux in the Western Tropical Pacific Ocean","authors":"K. Billups, P. Eichler, H. Vital","doi":"10.2113/gsjfr.50.2.235","DOIUrl":"https://doi.org/10.2113/gsjfr.50.2.235","url":null,"abstract":"\u0000 We investigated benthic foraminiferal species as tracers for carbon export flux in the Indo-Pacific warm pool (International Ocean Discovery Program Expedition 363). In core tops, the distribution of lower bathyal and upper abyssal species can be separated into two distinct groups. Foraminifera belonging to the high carbon flux (>3.5 g C m−2 year−1), ‘warm’ (>3.5°C) group are Bolivina robusta, Bulimina aculeata, Globobulimina pacifica, Hoeglundina elegans, Laticarinina pauperata, and Cibicidoides pachyderma. The lower carbon flux, ‘cold’ group includes Oridorsalis umbontus, Uvigerina bifurcata, and Planulina wuellerstorfi. An index based on the percent ‘warm’ assemblage with respect to the total ‘warm’ plus ‘cold’ species in core-top samples correlates significantly with carbon flux (r = 0.91, P = 0.0007) and modern bottom water temperatures (r = 0.94, P = 0.0002). When applied to down-core species abundances based on core catchers spanning the late Miocene through Pleistocene, we observed that sites from the northwestern Australian margin show marked changes in the ‘warm’ index, suggesting a large paleoenvironmental signal in this dynamic region. At Papua New Guinea, down-core abundances of the ‘warm’ group are highest (>80%), consistent with high organic matter input via the Sepik River. At the deeper of the two sites, down-slope movement in this tectonically unstable region may have contributed to organic matter input. At Manus Basin, the ‘warm’ species abundances are also relatively high and covary with the percent abundance of Uvigerina proboscidea, providing further evidence for the use of this index as a tracer for carbon flux. Overall, this study contributes evidence for the relationship between benthic foraminiferal assemblages and carbon export flux in the Indo-Pacific warm pool, suggesting that the ‘warm’ index can be used as a tracer for paleoproductivity.","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"50 1","pages":"235-247"},"PeriodicalIF":1.1,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2113/gsjfr.50.2.235","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48640171","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}
A biostratigraphic and biochronological study from the late Neogene–Quaternary section of Ocean Drilling Program (ODP) Site 807A, located on the Ontong Java Plateau, western equatorial Pacific, revealed 50 planktic foraminiferal events, enabling the identification of eight late Neogene–Quaternary biozones, from the Globorotalia plesiotumida Interval Zone to the Globorotalia truncatulinoides Interval Zone. A significant faunal turnover (17 events) from late Pliocene identified in cores 7 and 8, between 70 and 55 meters below seafloor (mbsf), and spanning 0.67 million years (Myr). This noteworthy turnover may be the result of a shift in oceanographic conditions pertaining to the closure of the Indo–Pacific Seaway, followed by the Northern Hemisphere Glaciation. This study provides a high resolution biostratigraphic and biochronological framework for ODP Site 807A that will aid in correlation and timing the various paleoceanographic changes over the last 6 million years in the western equatorial Pacific.
{"title":"Late Neogene–Quaternary Planktic Foraminiferal Biostratigraphy and Biochronology from ODP Site 807A, Ontong Java Plateau, Western Equatorial Pacific","authors":"Tushar Kaushik, A. Singh, D. K. Sinha","doi":"10.2113/gsjfr.50.2.111","DOIUrl":"https://doi.org/10.2113/gsjfr.50.2.111","url":null,"abstract":"\u0000 A biostratigraphic and biochronological study from the late Neogene–Quaternary section of Ocean Drilling Program (ODP) Site 807A, located on the Ontong Java Plateau, western equatorial Pacific, revealed 50 planktic foraminiferal events, enabling the identification of eight late Neogene–Quaternary biozones, from the Globorotalia plesiotumida Interval Zone to the Globorotalia truncatulinoides Interval Zone. A significant faunal turnover (17 events) from late Pliocene identified in cores 7 and 8, between 70 and 55 meters below seafloor (mbsf), and spanning 0.67 million years (Myr). This noteworthy turnover may be the result of a shift in oceanographic conditions pertaining to the closure of the Indo–Pacific Seaway, followed by the Northern Hemisphere Glaciation. This study provides a high resolution biostratigraphic and biochronological framework for ODP Site 807A that will aid in correlation and timing the various paleoceanographic changes over the last 6 million years in the western equatorial Pacific.","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"50 1","pages":"111-127"},"PeriodicalIF":1.1,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2113/gsjfr.50.2.111","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45033404","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}
C. V. Davis, J. Fehrenbacher, C. Benitez‐Nelson, R. Thunell
The trace element composition of planktic foraminifera shells is influenced by both environmental and biological factors (‘vital effects’). As trace elements in individual foraminifera shells are increasingly used as paleoceanographic tools, understanding how trace element ratios vary between individuals, among species, and in response to high frequency environmental variability is of critical importance. Here, we present a three-year plankton tow record (2010–2012) of individual shell trace element (Mg, Sr, Ba, and Mn) to Ca ratios in the planktic species Globigerina ruber (pink), Orbulina universa, and Globorotalia menardii collected throughout the upper 100 m of Cariaco Basin. Plankton tows were paired with in situ measurements of water column chemistry and hydrography. The Mg/Ca ratio reflects different calcification temperatures in all three species when calculated using species-specific temperature relationships from single-species averages of Mg/Ca. However, individual shell Mg/Ca often results in unrealistic temperate estimates. The Sr/Ca ratios are relatively constant among the four species. Ratios of Mn/Ca and Ba/Ca are highest in G. menardii and are not reflective of elemental concentrations in open waters. The Mn/Ca ratio is elevated in all species during upwelling conditions, and a similar trend is demonstrated in Neogloboquadrina incompta shells from the California margin collected during upwelling periods. Together this suggests that elevated shell Mn/Ca may act as a tracer for upwelling of deeper water masses. Our results emphasize the large degree of trace element variability present among and within species living within a limited depth habitat and the roles of biology, calcification environment, and physical mixing in mediating how trace element geochemistry reflects environmental variability in the surface ocean.
{"title":"Trace Element Heterogeneity Across Individual Planktic Foraminifera from the Modern Cariaco Basin","authors":"C. V. Davis, J. Fehrenbacher, C. Benitez‐Nelson, R. Thunell","doi":"10.2113/gsjfr.50.2.204","DOIUrl":"https://doi.org/10.2113/gsjfr.50.2.204","url":null,"abstract":"\u0000 The trace element composition of planktic foraminifera shells is influenced by both environmental and biological factors (‘vital effects’). As trace elements in individual foraminifera shells are increasingly used as paleoceanographic tools, understanding how trace element ratios vary between individuals, among species, and in response to high frequency environmental variability is of critical importance. Here, we present a three-year plankton tow record (2010–2012) of individual shell trace element (Mg, Sr, Ba, and Mn) to Ca ratios in the planktic species Globigerina ruber (pink), Orbulina universa, and Globorotalia menardii collected throughout the upper 100 m of Cariaco Basin. Plankton tows were paired with in situ measurements of water column chemistry and hydrography. The Mg/Ca ratio reflects different calcification temperatures in all three species when calculated using species-specific temperature relationships from single-species averages of Mg/Ca. However, individual shell Mg/Ca often results in unrealistic temperate estimates. The Sr/Ca ratios are relatively constant among the four species. Ratios of Mn/Ca and Ba/Ca are highest in G. menardii and are not reflective of elemental concentrations in open waters. The Mn/Ca ratio is elevated in all species during upwelling conditions, and a similar trend is demonstrated in Neogloboquadrina incompta shells from the California margin collected during upwelling periods. Together this suggests that elevated shell Mn/Ca may act as a tracer for upwelling of deeper water masses. Our results emphasize the large degree of trace element variability present among and within species living within a limited depth habitat and the roles of biology, calcification environment, and physical mixing in mediating how trace element geochemistry reflects environmental variability in the surface ocean.","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"50 1","pages":"204-218"},"PeriodicalIF":1.1,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2113/gsjfr.50.2.204","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43220091","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}
The study of the test morphology of type specimens and newly collected foraminiferal material of the family Lasiodiscidae Reitlinger, 1956, from the Carboniferous (Visean Stage, Mississippian Subsystem) to Permian (Roadian Stage, Guadalupian Series) beds of Russia (East European Platform and Urals), Turkey, and Tajikistan (Darvaz) allowed a revision of the species composition of the genera Howchinia, Monotaxinoides, Eolasiodiscus, Turrispiroides, and Mesolasiodiscus. A new genus, Postmonotaxinoides, is described. The species Monotaxinoides transitorius, M. subplanus, M. gracilis, Eolasiodiscus donbassicus, E. galinae, Mesolasiodiscus tenuis, M. nigrans, Postmonotaxinoides horridus, P. costiferus, and P. grandis are redescribed based on new data of their test morphology. Their taxonomy is revised and new phylogenetic reconstructions for the species are proposed.
{"title":"Taxonomy and Evolution of Visean–Roadian (Late Mississippian–Guadalupian) Lasiodiscidae","authors":"E. Kulagina, T. Filimonova","doi":"10.2113/gsjfr.50.2.141","DOIUrl":"https://doi.org/10.2113/gsjfr.50.2.141","url":null,"abstract":"\u0000 The study of the test morphology of type specimens and newly collected foraminiferal material of the family Lasiodiscidae Reitlinger, 1956, from the Carboniferous (Visean Stage, Mississippian Subsystem) to Permian (Roadian Stage, Guadalupian Series) beds of Russia (East European Platform and Urals), Turkey, and Tajikistan (Darvaz) allowed a revision of the species composition of the genera Howchinia, Monotaxinoides, Eolasiodiscus, Turrispiroides, and Mesolasiodiscus. A new genus, Postmonotaxinoides, is described. The species Monotaxinoides transitorius, M. subplanus, M. gracilis, Eolasiodiscus donbassicus, E. galinae, Mesolasiodiscus tenuis, M. nigrans, Postmonotaxinoides horridus, P. costiferus, and P. grandis are redescribed based on new data of their test morphology. Their taxonomy is revised and new phylogenetic reconstructions for the species are proposed.","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"50 1","pages":"141-173"},"PeriodicalIF":1.1,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2113/gsjfr.50.2.141","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42053492","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}
Eastern Myanmar is an indispensable part of the Cimmerian Continent with Gondwana provenance. Fusulinids from Eastern Myanmar remain poorly known despite their biochronological and paleogeographical significance. This paper describes Rugososchwagerina (Xiaoxinzhaiella) subrotunda sp. nov. and Chusenella quasidouvillei of Murgabian age (Middle Permian) from the Thitsipin Formation at the Pindaya in the Shan Plateau, Eastern Myanmar. Taxonomic analysis of this new collection and of Rugososchwagerina (s.l.) in the literature leads us to suppress Xiaoxinzhaiella Shi, Yang & Jin, 2005 as a subgenus of RugososchwagerinaMiklukho-Maklay, 1959. This subgenus is diagnosed with much tighter coiling and reduced septal folding in juvenarium as well as relatively smaller test diameter throughout the ontogeny, compared with Rugososchwagerina (s.s.) which is typified by R. yabeiSkinner & Wilde, 1966. Furthermore, our comprehensive review reveals that the known occurrences of R. (Xiaoxinzhaiella) are strictly confined within blocks that previously constituted the Cimmerian Continent during the Permian period, and they were even more widespread than Rugososchwagerina (s.s.) among these blocks. Therefore, the previous understanding that Rugososchwagerina (s.l.) is characteristic for the Middle Permian Cimmerian region can be refined. We propose that R. (Xiaoxinzhaiella) is more appropriate as the truly endemic foraminiferal index signifying Cimmerian affinity.
{"title":"Permian Fusulinid Rugososchwagerina (Xiaoxinzhaiella) from the Shan Plateau, Myanmar: Systematics and Paleogeography","authors":"Hao Huang, Xiaochi Jin, Yukun Shi","doi":"10.2113/gsjfr.50.1.11","DOIUrl":"https://doi.org/10.2113/gsjfr.50.1.11","url":null,"abstract":"Eastern Myanmar is an indispensable part of the Cimmerian Continent with Gondwana provenance. Fusulinids from Eastern Myanmar remain poorly known despite their biochronological and paleogeographical significance. This paper describes Rugososchwagerina (Xiaoxinzhaiella) subrotunda sp. nov. and Chusenella quasidouvillei of Murgabian age (Middle Permian) from the Thitsipin Formation at the Pindaya in the Shan Plateau, Eastern Myanmar. Taxonomic analysis of this new collection and of Rugososchwagerina (s.l.) in the literature leads us to suppress Xiaoxinzhaiella Shi, Yang & Jin, 2005 as a subgenus of RugososchwagerinaMiklukho-Maklay, 1959. This subgenus is diagnosed with much tighter coiling and reduced septal folding in juvenarium as well as relatively smaller test diameter throughout the ontogeny, compared with Rugososchwagerina (s.s.) which is typified by R. yabeiSkinner & Wilde, 1966. Furthermore, our comprehensive review reveals that the known occurrences of R. (Xiaoxinzhaiella) are strictly confined within blocks that previously constituted the Cimmerian Continent during the Permian period, and they were even more widespread than Rugososchwagerina (s.s.) among these blocks. Therefore, the previous understanding that Rugososchwagerina (s.l.) is characteristic for the Middle Permian Cimmerian region can be refined. We propose that R. (Xiaoxinzhaiella) is more appropriate as the truly endemic foraminiferal index signifying Cimmerian affinity.","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"16 1","pages":"11-24"},"PeriodicalIF":1.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2113/gsjfr.50.1.11","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68293193","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":"2019 Joseph A. Cushman Award to Valeria (Alla) Mikhalevich","authors":"M. Kaminski","doi":"10.2113/gsjfr.50.1.1","DOIUrl":"https://doi.org/10.2113/gsjfr.50.1.1","url":null,"abstract":"","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"50 1","pages":"1-2"},"PeriodicalIF":1.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2113/gsjfr.50.1.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68293170","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}
This paper provides the first record of isolated foraminiferal assemblages from the continuous Aalenian–lower Bajocian succession from the pelagic region of the Neotethys. The studied Tűzkövesárok section B of Bakonycsernye (Hungary) has been well dated by ammonites and consists of Ammonitico Rosso type limestones. The foraminiferal fauna extracted by glacial acetic acid yielded 49 benthic taxa (species and subspecies); protoglobigerinids also occurred. Most specimens belonged to the suborder Spirillinina, followed by the suborder Lagenina and Rotaliina; agglutinated forms were subordinate and miliolids were absent. The majority of the species have wide stratigraphic ranges; moreover, the distributions of 11 species changed based on their appearances in this section. Nevertheless, the Aalenian and Bajocian parts of the section could be distinguished based upon the stratigraphic distributions of some species.
{"title":"Aalenian–Lower Bajocian Foraminiferal Fauna from the Ammonitico Rosso Series of Bakonycsernye (Hungary). Part 1: Taxonomy and Biostratigraphy","authors":"Gábor Zsiborás, Á. Görög","doi":"10.2113/GSJFR.50.1.41","DOIUrl":"https://doi.org/10.2113/GSJFR.50.1.41","url":null,"abstract":"This paper provides the first record of isolated foraminiferal assemblages from the continuous Aalenian–lower Bajocian succession from the pelagic region of the Neotethys. The studied Tűzkövesárok section B of Bakonycsernye (Hungary) has been well dated by ammonites and consists of Ammonitico Rosso type limestones. The foraminiferal fauna extracted by glacial acetic acid yielded 49 benthic taxa (species and subspecies); protoglobigerinids also occurred. Most specimens belonged to the suborder Spirillinina, followed by the suborder Lagenina and Rotaliina; agglutinated forms were subordinate and miliolids were absent. The majority of the species have wide stratigraphic ranges; moreover, the distributions of 11 species changed based on their appearances in this section. Nevertheless, the Aalenian and Bajocian parts of the section could be distinguished based upon the stratigraphic distributions of some species.","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"22 1","pages":"41-72"},"PeriodicalIF":1.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2113/GSJFR.50.1.41","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68292758","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}
Nazihah Azmi, Fatin Izzati Minhat, S. S. Hasan, Omar Abdul Rahman Abdul Manaf, Aishah Norashikin Abdul A’ziz, Wan Nurzalia Wan Saelan, H. Shaari, Azzyyati Abdul Aziz, S. Suratman
We investigated the distribution of modern benthic foraminifera from Kelantan waters in the western part of the Sunda Shelf, South China Sea. Twenty-nine benthic foraminiferal species were identified from seven samples collected along a ∼250 km-long transect perpendicular to the Kelantan coastline. Calcareous hyaline species made up 57% of the overall assemblages collected in the study area, followed by calcareous porcelaneous (23%) and agglutinated (20%) species. Cluster analysis recognised two distinctive groups. Group A represented the shallow inner-shelf area (19–35 m water depth) with a coarse sand-dominated substrate where Amphistegina papillosa (13.37%) and Assilina ammonoides (11.04%) were highly abundant. Group A had lowest diversity with no agglutinated species. Group B, occurred at 40–60 m water depth, had higher foraminiferal diversity and was characterised by a very fine sand substrate. The foraminiferal assemblages here were dominated by calcareous hyaline species in group B followed by calcareous porcelaneous and agglutinated species. Group B was characterised by Assilina ammoinodes (11.04%), Heterolepa dutemplei (10.29%), and Discorbinella bertheloti (10.03%). The dominant agglutinated species in Group B were Textularia agglutinans (4.93%) and Cylindroclavulina bradyi (3.55%). Shallow-water species, such as Amphistegina spp., were absent from Group B. Our study shows that the distribution of benthic foraminiferal assemblages from the western Sunda shelf off Kelantan, is closely associated with changes in seafloor sediment, distance from the shore, and water depth.
{"title":"Distribution of Benthic Foraminifera off Kelantan, Peninsular Malaysia, South China Sea","authors":"Nazihah Azmi, Fatin Izzati Minhat, S. S. Hasan, Omar Abdul Rahman Abdul Manaf, Aishah Norashikin Abdul A’ziz, Wan Nurzalia Wan Saelan, H. Shaari, Azzyyati Abdul Aziz, S. Suratman","doi":"10.2113/GSJFR.50.1.89","DOIUrl":"https://doi.org/10.2113/GSJFR.50.1.89","url":null,"abstract":"We investigated the distribution of modern benthic foraminifera from Kelantan waters in the western part of the Sunda Shelf, South China Sea. Twenty-nine benthic foraminiferal species were identified from seven samples collected along a ∼250 km-long transect perpendicular to the Kelantan coastline. Calcareous hyaline species made up 57% of the overall assemblages collected in the study area, followed by calcareous porcelaneous (23%) and agglutinated (20%) species. Cluster analysis recognised two distinctive groups. Group A represented the shallow inner-shelf area (19–35 m water depth) with a coarse sand-dominated substrate where Amphistegina papillosa (13.37%) and Assilina ammonoides (11.04%) were highly abundant. Group A had lowest diversity with no agglutinated species. Group B, occurred at 40–60 m water depth, had higher foraminiferal diversity and was characterised by a very fine sand substrate. The foraminiferal assemblages here were dominated by calcareous hyaline species in group B followed by calcareous porcelaneous and agglutinated species. Group B was characterised by Assilina ammoinodes (11.04%), Heterolepa dutemplei (10.29%), and Discorbinella bertheloti (10.03%). The dominant agglutinated species in Group B were Textularia agglutinans (4.93%) and Cylindroclavulina bradyi (3.55%). Shallow-water species, such as Amphistegina spp., were absent from Group B. Our study shows that the distribution of benthic foraminiferal assemblages from the western Sunda shelf off Kelantan, is closely associated with changes in seafloor sediment, distance from the shore, and water depth.","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"50 1","pages":"89-96"},"PeriodicalIF":1.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2113/GSJFR.50.1.89","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68293521","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}
M. Rostami, F. Frontalini, R. Leckie, R. Coccioni, E. Font, B. Balmaki
Extinction patterns, paleobathymetric inferences, and paleoenvironmental changes based on benthic foraminifera were investigated across the Cretaceous/Paleogene (K/Pg) boundary at the Galanderud section (Northern Alborz, Iran), which contains one of the most continuous and expanded K/Pg transitions in the eastern Tethys. On the basis of benthic foraminiferal taxa abundance and distribution, an outer neritic to uppermost bathyal paleo-depositional setting is inferred. In addition, benthic foraminiferal assemblages and planktic/benthic ratios do not indicate any major change in relative sea level during latest Maastrichtian-early Danian time. Changes in benthic foraminiferal assemblages, morphotypes, diversity, heterogeneity, and benthic foraminiferal oxygen index, coupled with statistical analyses, define three intervals. In the first interval (uppermost Maastrichtian Plummerita hantkeninoides Zone), benthic foraminiferal assemblages are moderately to well preserved and highly diverse, with a combination of epibenthic and endobenthic taxa indicating stable, mesotrophic to weakly eutrophic, normal marine conditions. A major change in benthic foraminiferal assemblages at the K/Pg boundary defines a second interval (basal Danian Guembelitria cretacea and lower part of Parvularugoglobigerina eugubina Zones) that is marked by a decrease in the endobenthic morphogroups as well as a decrease in diversity, heterogeneity, genus and species richness. This second interval denotes highly oligotrophic conditions and a collapse in productivity and food availability due to the extinction of some primary producers, with the exception of the three chalk beds representing short-lived blooms of calcareous dinoflagellates. Benthic foraminifera do not show significant extinction at the end of the Cretaceous at this section with only about an 8% loss of species. Additionally, the abundance of some opportunistic species, including Cibicidoides pseudoacutus and Tappanina selmensis, may reflect instability in the benthic foraminiferal assemblages. The third interval (middle-upper part of the Pv. eugubina Zone) is characterized by the dominance of epibenthic morphogroups (up to 70% of the assemblages) with a partial recovery of endobenthic groups. The characteristics of the benthic foraminiferal assemblages indicate that the flux of food to the benthos had not fully recovered during the early Danian.
{"title":"Benthic Foraminifera Across the Cretaceous/Paleogene Boundary in the Eastern Tethys (Northern Alborz, Galanderud Section): Extinction Pattern and Paleoenvironmental Reconstruction","authors":"M. Rostami, F. Frontalini, R. Leckie, R. Coccioni, E. Font, B. Balmaki","doi":"10.2113/gsjfr.50.1.25","DOIUrl":"https://doi.org/10.2113/gsjfr.50.1.25","url":null,"abstract":"Extinction patterns, paleobathymetric inferences, and paleoenvironmental changes based on benthic foraminifera were investigated across the Cretaceous/Paleogene (K/Pg) boundary at the Galanderud section (Northern Alborz, Iran), which contains one of the most continuous and expanded K/Pg transitions in the eastern Tethys. On the basis of benthic foraminiferal taxa abundance and distribution, an outer neritic to uppermost bathyal paleo-depositional setting is inferred. In addition, benthic foraminiferal assemblages and planktic/benthic ratios do not indicate any major change in relative sea level during latest Maastrichtian-early Danian time. Changes in benthic foraminiferal assemblages, morphotypes, diversity, heterogeneity, and benthic foraminiferal oxygen index, coupled with statistical analyses, define three intervals. In the first interval (uppermost Maastrichtian Plummerita hantkeninoides Zone), benthic foraminiferal assemblages are moderately to well preserved and highly diverse, with a combination of epibenthic and endobenthic taxa indicating stable, mesotrophic to weakly eutrophic, normal marine conditions. A major change in benthic foraminiferal assemblages at the K/Pg boundary defines a second interval (basal Danian Guembelitria cretacea and lower part of Parvularugoglobigerina eugubina Zones) that is marked by a decrease in the endobenthic morphogroups as well as a decrease in diversity, heterogeneity, genus and species richness. This second interval denotes highly oligotrophic conditions and a collapse in productivity and food availability due to the extinction of some primary producers, with the exception of the three chalk beds representing short-lived blooms of calcareous dinoflagellates. Benthic foraminifera do not show significant extinction at the end of the Cretaceous at this section with only about an 8% loss of species. Additionally, the abundance of some opportunistic species, including Cibicidoides pseudoacutus and Tappanina selmensis, may reflect instability in the benthic foraminiferal assemblages. The third interval (middle-upper part of the Pv. eugubina Zone) is characterized by the dominance of epibenthic morphogroups (up to 70% of the assemblages) with a partial recovery of endobenthic groups. The characteristics of the benthic foraminiferal assemblages indicate that the flux of food to the benthos had not fully recovered during the early Danian.","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"50 1","pages":"25-40"},"PeriodicalIF":1.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2113/gsjfr.50.1.25","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68292730","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}
Sediment surface death assemblages of recent testate amoebae (Arcellacea) are reported from nine sites in Lake Superior and Lake Michigan. These are the first profundal sediment-water interface samples of testate amoebae described from either of the Great Lakes which provide valuable insight on deep-water, large-lake assemblages. Centropixid strains were present to abundant in shallower, nearshore sites (up to 66 m water depth). Assemblages at depths >40 m were dominated by Difflugia oblonga “tenuis.” The shallowest sample (26 m) was dominated by Centropyxis aculeata “discoides” and Difflugia oblonga “tenuis.” Over 100 tests per sample were observed from >100 m. Density of tests appears to be constrained by lithology rather than water depth. The deepest site (325 m) yielded low foraminiferal abundances. This pilot study provides a first step towards documenting the distribution of testate amoebae in the Great Lakes.
{"title":"Profundal Testate Amoebae (Arcellacea) of Lake Superior and Lake Michigan","authors":"Krystyna Kornecki, M. Katz","doi":"10.2113/GSJFR.50.1.3","DOIUrl":"https://doi.org/10.2113/GSJFR.50.1.3","url":null,"abstract":"Sediment surface death assemblages of recent testate amoebae (Arcellacea) are reported from nine sites in Lake Superior and Lake Michigan. These are the first profundal sediment-water interface samples of testate amoebae described from either of the Great Lakes which provide valuable insight on deep-water, large-lake assemblages. Centropixid strains were present to abundant in shallower, nearshore sites (up to 66 m water depth). Assemblages at depths >40 m were dominated by Difflugia oblonga “tenuis.” The shallowest sample (26 m) was dominated by Centropyxis aculeata “discoides” and Difflugia oblonga “tenuis.” Over 100 tests per sample were observed from >100 m. Density of tests appears to be constrained by lithology rather than water depth. The deepest site (325 m) yielded low foraminiferal abundances. This pilot study provides a first step towards documenting the distribution of testate amoebae in the Great Lakes.","PeriodicalId":54832,"journal":{"name":"Journal of Foraminiferal Research","volume":"14 1","pages":"3-10"},"PeriodicalIF":1.1,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2113/GSJFR.50.1.3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68292750","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}
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