Species Of Foraminifera Research Articles

Influence of Bottom Water Parameters on the Distribution of Benthic Foraminifera from the Gulf of Mannar, Off Tiruchendur, Southeast Coast of India

Foraminifera are found in all marine environments, but they are very particular about the congenial environment for their reproduction, diversity and abundance. To understand the influence of bottom water parameters on the distribution of foraminifera from the shallow shelf region of Bay of Bengal, off Tiruchendur, Southeast Coast of Tamil Nadu, sediment and bottom water samples were collected at 27 stations, along three traverses viz. from off Veerapandianpattinam, off Tiruchendur and from off Alandurai, ranging in depths from 1.6m to 18.5m. The samples were collected during three seasons representing, summer (May 2016), pre monsoon (October 2016) and winter (January 2017) and thus the total samples amounted to 81. A total of 105 species of foraminifera have been identified from 47 genera, 32 families, 16 superfamilies and 4suborders. Among these 105 foraminiferal species, five were found to be widespread and abundant viz. Ammonia beccarii, A. tepida, Asterorotalia inflata, Nonioniodes boueanum and Quinqueloculina seminulam. Various bottom water parameters such as temperature, salinity, dissolved oxygen and pH were determined and correlated with the foraminiferal population. Temporally, higher temperature, salinity, dissolved oxygen and pH of bottom water observed during summer (May 2016) were congenial for higher population in the study area. Optimum conditions for the higher population and abundance of foraminifera are: Temperature: > 32.0°C, Dissolved oxygen: >6.0 mg/l, Salinity: >32 ppt and pH>8.1.

Diversity and flexibility of algal symbiont community in globally distributed larger benthic foraminifera of the genus Amphistegina

BackgroundUnderstanding the specificity and flexibility of the algal symbiosis-host association is fundamental for predicting how species occupy a diverse range of habitats. Here we assessed the algal symbiosis diversity of three species of larger benthic foraminifera from the genus Amphistegina and investigated the role of habitat and species identity in shaping the associated algal community.ResultsWe used next-generation sequencing to identify the associated algal community, and DNA barcoding to identify the diatom endosymbionts associated with species of A. lobifera, A. lessonii, and A. radiata, collected from shallow habitats (< 15 m) in 16 sites, ranging from the Mediterranean Sea to French Polynesia. Next-generation sequencing results showed the consistent presence of Ochrophyta as the main algal phylum associated with all species and sites analysed. A significant proportion of phylotypes were classified as Chlorophyta and Myzozoa. We uncovered unprecedented diversity of algal phylotypes found in low abundance, especially of the class Bacillariophyta (i.e., diatoms). We found a significant influence of sites rather than host identity in shaping algal communities in all species. DNA barcoding revealed the consistent presence of phylotypes classified within the order Fragilariales as the diatoms associated with A. lobifera and A. lessonii, while A. radiata specimens host predominately diatoms of the order Triceratiales.ConclusionsWe show that local habitat is the main factor influencing the overall composition of the algal symbiont community. However, host identity and the phylogenetic relationship among hosts is relevant in shaping the specific endosymbiont diatom community, suggesting that the relationship between diatom endosymbiont and hosts plays a crucial role in the evolutionary history of the genus Amphistegina. The capacity of Amphistegina species to associate with a diverse array of diatoms, and possibly other algal groups, likely underpins the ecological success of these crucial calcifying organisms across their extensive geographic range.

Evaluation of the relationship between biomass of living (stained) benthic foraminifera and particulate organic matter vertical flux in an oligotrophic region, Campos Basin, southeastern Brazilian continental margin

This study investigates the relationship between the vertical flux of particulate organic matter (POM) and the biomass of living benthic foraminifera in a region at the continental slope of the Campos Basin (between 400 and 3000 m). Vertical POM fluxes to the seafloor were modeled as a function of remote sensing chlorophyll-a concentration, sea surface temperature, and derived products such as primary production rates and estimates of dominant phytoplankton size. Measurements of biovolume predicted the biomass of benthic foraminifera. The mean calculated vertical POM fluxes (24.2 ± 17.3 mgCm−2.day−1) were consistent with observations from other oligotrophic environments and correlated positively with the total organic carbon (TOC) content in the sediments. The total biomass of benthic foraminifera, and the biomasses of 14 individual foraminifera species also showed significant correlations with the estimated vertical POM fluxes. The spatial distribution of these fluxes, sediment carbon, and foraminifera biomass in Campos Basin depicted the expected decrease with local depth but our data suggested that the foraminifera communities were influenced by mesoscale eddies associated with the Brazil Current System.

Planktonic protozoan population (Ciliates and Dinoflagellates) along the eastern coasts of Qeshm Island, Persian Gulf, Iran

The planktonic protozoa belong to microzooplankton group, which comprise an essential group within the food chains of aquatic ecosystems. In the present work, diversity in planktonic protozoan is explored in the coastal waters of Qeshm Island. Samples were collected using a conical plankton net with a mesh size of 20 μm seasonally during 2017.Physicochemical parameters were measured at the sampling stations. Marine protozoan species were studied using light microscopy, although a few species were also studied using scanning electron microscopy (SEM). In the present work, the diversity of planktonic protozoan is investigated in the coastal waters of Qeshm Island. Microzooplankton samples were collected using a conical plankton net with a mesh size of 20 μm on a seasonal basis and simultaneously the physicochemical properties of the water were recorded. In the laboratory marine protozoan species were identified using light microscopy and for few species scanning electron microscopy (SEM) was employed for better identification. Overall, 54 species were identified (34 species of Dinoflagellates, 19 species of Tintinnida and 1 species of Foraminifera). The most abundant dinoflagellates included the following species: Tripos fusus, Tripos furca , Ornithocercus magnificus, Protoperidinium divergens. Also, the most dominant Tintinnida species were Codonellopsis schabi and Codonellopsis ostenfeldi. The highest Shannon diversity index was 3.58 at Station 1 (inhabited by coral reef), and the lowest was 2.82 at Station 5 (with a muddy substratum). The least similarity values using PCA obtained for stations 1 and 2 most probably due to the influence of environmental factors and the high density of planktonic protozoans. This brought about station separation. Also, the frequency and diversity indices of planktons were higher in the coral reef than in other stations, indicating the influence of the substrate on planktonic protozoan communities.

Recognizing maximum flooding surfaces in shallow-water deposits: An integrated sedimentological and micropaleontological approach (Crotone Basin, southern Italy)

The Pliocene and Pleistocene intervals of the Neogene to Quaternary succession of the Crotone Basin, southern Italy, offer good examples of shallow-marine high-frequency sequences (fourth-order or lower rank stratigraphic frameworks) composing higher-rank units. The analysis of some representative sections from this succession has allowed performing an integrated sedimentological and micropaleontological study aimed at defining new criteria to recognize high-frequency maximum flooding surfaces. In particular, field data have been compared with some parameters derived from the micropaleontological analysis, such as the abundance, diversity and % fragmentation of benthic foraminifera, as well as the ratio between distal and proximal benthic foraminifera species and the plankton/benthos ratio. This integrated study allows to define an uncertainty interval in the high-frequency sequences, in which the maximum flooding surface should lie. This uncertainty interval is usually characterized by lower values of the % fragmentation and higher values of the abundance, diversity and distal/proximal ratio, whereas the peak of the plankton/benthos ratio allows to define a surface of maximum water depth, placed above the maximum flooding surface. Usually, the greater the magnitude of the transgression, the thinner the uncertainty interval. These results highlight the cryptic nature of the maximum flooding surface within condensed sections, even in high-resolution outcrop studies, and allow to refine the criteria based on which the position of such surface can be approximated in the field and in sediment cores.

Atypical, high-diversity assemblages of foraminifera in a mangrove estuary in northern Brazil

Abstract. Mangrove forests are extremely productive ecosystems, are sources and sinks of organic carbon, and provide essential services both to the marine environment and people. We have studied the composition and species richness of modern benthic foraminiferal assemblages from mangrove swamps along the Mamanguape River in Paraíba, northern Brazil. Sampling points for foraminifera were selected to acquire information on the composition of foraminiferal assemblages from dense mangrove stands collected along a river transect. Almost 100 species of benthic foraminifera were identified within the shallow mangrove habitats. The large number of identified mangrove taxa is the highest recorded so far for true mangrove habitats. The high species richness rivals shallow-water assemblages recorded from nearby offshore and reef environments and indicates that a particularly large number of species is capable of growing and flourishing under multiple stressor conditions. Numerical analysis of the faunal assemblages shows that specific taxa, which were previously known to be uncommon in mangrove environments, are abundant in the Mamanguape River estuary. The atypical foraminiferal fauna found in the Mamanguape River estuary resembles shallow-water offshore assemblages, is characterized by high percent abundances of perforate and miliolid taxa, and contains only very few of the otherwise typical and numerically abundant agglutinated mangrove taxa. The unusual structure of the assemblages recorded provides insight into what combination of environmental variables controls their composition and novel perspectives to reconstruct past mangrove environments. Distribution, diversity, and species-specific analysis will provide guidance on the use of Brazilian mangrove foraminifera as indicators for the strength of tidal activity, pollution, and anoxia in coastal waters and sea-level reconstructions.

Biozonation and Sequence Stratigraphic Characterization of Sediments in X-well, JV-field Greater Ughelli Depo-belt Niger Delta Basin

Biozonation and sequence stratigraphic characterization of sediments in X-well, JV-Field Greater Ugheli Depo belt Niger Delta Basin were carried out using a total of One hundred and ninety (190) Ditch cutting samples, with the aim of identifying palynological and foraminiferal bio-events such as abundance, zones, paleoenvironment, age and also identify sequence stratigraphic key surfaces such as Maximum Flooding Surfaces (MFS) and Sequence Boundaries (SB) of sediments penetrated by the drill. Diagnostic Palynomorphs such as Praedapollis africanus, Peregrinipollis nigericus, Retibrevitricolporites obodoensis aided in the establishment of three P-zones which are P620, P580, P560 Zones in the well. P620 and P580 Zones were lumped together and occur at depth 4680ft-7620ft while P560 occur at depth 7620-11580ft, species of foraminifera recorded are calcareous and arenaceous benthic Foraminifera species. Planktic Foraminifera specie are generally absent. Species recorded include Sproplectammina wrightii, Florilus atlanticus, Florilus costiferum, Eponides cf eshira, Quinqueloculina rhodiensis, Nonion centrosulcatum, and Alveolophragmium crassum. Foraminiferal zones established are Nonion centrosulcatum (N9), Fursenkoina punctata (N5) planktic and N8-N5 zone. the well records the occurrence of Two maximum flooding surfaces (Mfs) and two sequence boundary(SB) which was establish in P620/P580 zones and one maximum flooding surface which was established in the P560 Zone. The Sequence boundaries, Maximum flooding surfaces and their respective ages in these palynological zones occurred at various depths, P620 and P580 occurred at 26.2Ma Alabamina 1 Mfs at (6397ft) and 28.1Ma BOLIVINA 27Mfs at (7401ft) and the Sequence boundaries occurred at 6750ft at 27.3Ma SB,7553ft at 29.3Ma SB, P560 occurred at depth 31.3Ma UVIGERINELLA 5Mfs at (11200ft).

Biostratigraphy, Paleoecology, Microfacies and Depositional environment of the Asmari formation (Oligocene-Early Miocene) in Karanj oil field, SW Iran

Core data analysis of one well from the Karanj oil field, southwestern Iran, allowed us to precise the biostratigraphy, microfacies and paleoecology of the Asmari Formation. Analysis of thin section from this cored well permitted identification of 28 genera and 20 species of benthic and planktic foraminifera respectively. Subsequently four benthic foraminiferal assemblage biozones were identified, as follows: (1) Lepidocyclina-Operculina-Ditrupa Assemblage zone, (2) Archaias asmaricus-Archaias hensoni-Miogypsinoides complanatus Assemblage zone, (3) Miogypsina-Peneroplis farsensis–Elphidium sp. 14 Assemblage zone and (4) Borelis melo curdica-Borelis melo melo Assemblage zone; indicating an Oligocene (Rupelian-Chattian) to early Miocene (Aquitanian to Early Burdigalian) age for the Asmari Formation. Microfacial study of depositional textures led to characterizing 12 microfacies types, indicating environments in five different settings: restricted lagoon, open lagoon, shoal, slope, and basin mostly in the upper Asmari Formation. These sediments had been deposited under 3 different salinity levels (from 34 to more than 50 psu) in an environment ranging from aphotic to oligophotic and to euphotic zones, and under oligotrophic to eutrophic conditions from the Chattian to the Burdigalian on a carbonate platform (homoclinal ramp). In the studied well, the Asmari Formation had been deposited in a marine environment with normal salinity during the Rupelian-Chattian interval and in a marine environment with high salinity during the Aquitanian to the Burdigalian times.

Paléoécologie des foraminifères benthiques de nouvelles coupes de basse latitude du passage Crétacé-Paléogène : Coupes de l’Oued Es Smara et de l’Oued Abiod (région de Téjerouine, NW Tunisie)

Due to an impact of a bolide at the K/Pg boundary, the planktonic foraminifera have suffered sever mass extinction. However, no small Benthic Foraminifera species have documented mass extinction at the K/Pg boundary. Nevertheless, many species showed disturbance. The Maastrichtian assemblages may be different from those of the lower Paleogene by their species content, diversity and frequencies. At Oued Es Smara and Oued Abiod sections, the small benthic foraminifera indicate lower bathyal environment, and manifest significant faunal turnover. Until the uppermost Maastrichtian, their assemblages are highly diversified, with 77 species and 76 species respectively at Oued Es Smara and Oued Abiod sections. These are dominated by endobenthic morphotypes. At the K/Pg boundary, although 33 species (42,85%) (Oued Es Smara section) and 27 species (35,52%) (Oued Abiod section) of them seem to disappear, but only few species have really extinct such as Arenobulimina obesa. Nevertheless, the majority of species persist elsewhere at the Danian (e.g., Pseudoglandulina manifesta, Cibicioides proprius, Clavulinoides amorpha, Coryphostoma plaitum, Pullenia coryelli). At the lower Danian, the survivor Maastrichtian species are of 58% (Oued Es Smara) and 65% (Oued Abiod). Throughout the Parasubbotina pseudobulloides subzone, 4 others species were progressively disappeared. They are oligotrophic and low oxygen tolerant. About the Masstrichtian species, at the two studied sections (e.g. Gaudryina inflata and Tritaxia midwayensis) they seem to be more trophic exigent. Consequently, the benthic Foraminifera did not suffer massive extinction at the K/Pg boundary, but their assemblages underwent a significant faunal turnover which reflects important environmental changes. These changes are compatible with the catastrophic scenario induced by the large asteroid impact.

Development of a Training Set of Contemporary Salt-Marsh Foraminifera for Late Holocene Sea- Level Reconstructions in southeastern Australia

We collected contemporary foraminiferal training sets from two salt marshes to enable more precise and accurate proxy historical sea-level reconstructions from southeastern Australia. Combined with an existing training set from Tasmania, this new regional set consists of 112 samples and 16 species of foraminifera, of which 13 are agglutinated. Cluster analyses group the regional training set into a high–elevation cluster, dominated by Trochamminita salsa, a mid–elevation cluster, dominated by Entzia macrescens and Trochammina inflata, and a mid–low elevation cluster dominated by Miliammina fusca and tidal-flat species. We develop transfer functions using local and regional training sets and assess their performance. Our resulting site-specific and chosen regional models are capable of predicting sea level with decimetre-scale precision (95% confidence intervals of 0.12–0.22 m). These results are comparable to other examples from around the world. When developing regional training sets, we advocate that the similarity in the environmental settings (particularly salinity) should be assessed as an alternative way of grouping sites, rather than simply using spatial proximity. We compare our findings with global results and conclude that salt marshes along microtidal coasts yield models with the lowest vertical uncertainties. Studies with the lowest uncertainties are located in the western Pacific and the western Atlantic, whereas those from the eastern Atlantic generally have larger tidal ranges and carry larger vertical uncertainties. Our models expand the existing region available for sea-level reconstruction and can be used to generate new late Holocene sea-level reconstructions across southeastern Australia.

Biostratigraphy, microfacies and sedimentary model of the Qom Formation in the Posht- Darband section, northwest of Hamadan

In order to determination of biozones, facies types and sedimentary model, the Posht Darband stratigraphic section of the Qom Formation with thickness of 330 meters located in the northwest of Hamedan, structural zone of the Sanandaj- Sirjan, has been considered. On the basis of field observations, Qom Formation is composed of medium to thick-bedded limestone (Member a) and alternation of sandy limestone, sandstone and green marl (Member b). According to paleontological study, seventeen genera and nine species of benthic foraminifera and other skeletal components are introduced from the Posht Darband section and consequently, Lepidocyclina - Operculina - Ditrupa Assemblage zone has been recognized in the Qom Formation. Facies analysis (Variety in fauna features, fabrics, and sedimentary textures) has produced eight microfacies related to the four facies belts of tidal flat, reef, slope and open marine. Base on abundance in reef facies deposits including coral boundstone, algae and bryozoan, an open shelf is proposed for the Qom Formation. The vertical distribution column of the facies types (without considering the possible erosion phenomenon) suggests that the facies changes in member a are gradual, but in member b they were rapidly, with facies retrogradation and progradation.

Foraminifera-derived carbon contribution to sedimentary inorganic carbon pool: A case study from three Norwegian fjords.

Norwegian fjords have been recently recognized as hot spots for carbon burial due to the large amounts of terrestrial organic matter delivered to fjord sediments, as well as the high sediment accumulation rates. Here, we present the first data on the contribution of benthic foraminiferal inorganic carbon to the sediments of three Norwegian fjords. Our study shows that calcareous foraminifera, which are among the most abundant calcifying organisms in the modern global oceans, can constitute between 15% and 33% of inorganic carbon accumulated in the sediments of the two studied southern Norwegian fjords (Raunefjorden and Hjeltefjorden). In a northern Norwegian fjord (Balsfjorden), the contribution of calcareous foraminifera to the inorganic carbon pool is smaller (<1%) than the one observed in southern fjords. We also found that the amount of foraminifera-derived carbon is primarily dependent on the species composition of the foraminifera community. Large calcareous foraminifera species, despite a lower number of individuals, constitute, on average, 13%-29% of the inorganic carbon in the two southern Norwegian fjords, while the contribution of small, highly abundant species does not exceed 4% of the inorganic carbon pools in the sediments. Calcareous foraminifera species that are indicative of dysoxic conditions have been found to have low inorganic carbon contents per specimen compared to other analysed similar-sized calcareous foraminifera species. This relationship most likely exists due to the thin test walls of these foraminifera species, which may facilitate gas exchange. The results of our case study suggest that the climate-driven formation of near-bottom low-oxygen zones may lead to the dominance of foraminifera associated with dysoxic conditions and, in consequence, to the decrease of foraminifera-derived inorganic carbon. However, to properly analyse the contribution of carbon from thin-walled foraminifera to the sedimentary carbon pool, further studies analysing a broader range of these species is needed.

COMMENTS ON “STRATIGRAPHIC DISTRIBUTION OF SHALLOW-WATER BENTHIC FORAMINIFERA FROM THE LOWER CRETACEOUS TAFT FORMATION, CENTRAL IRAN (YAZD BLOCK), WITH EVIDENCE FOR THE IMPORTANCE OF HIATUSES” BY GHEIASVAND, M. ET AL. [ANNALES DE PALÉONTOLOGIE, 2020, 154 (3), 102399] AND RELATED PAPERS

Gheiasvand et al. (2020) use the two larger benthic foraminifera species Simplorbitolina manasi Ciry &amp; Rat and Mesorbitolina parva (Douglass) (Orbitolinidae) as upper Aptian “potential index fossils” for parts of the Taft Formation in Central Iran. This age assignment is accompanied by changes to well-established orbitolinid biozona-tions (e.g. occurrence of Praeorbitolina in the late Aptian) with far-reaching implications. These data were also used in a later “multidisciplinary study” (Gheiasvand et al., 2021) for isotopic correlations (e.g., location of OAE`s), delimitation of palaeobiogeographic faunal provinces and related migration patterns. It is shown herein that the taxa identified as S. manasi and M. parva belong to Iraqia simplex Henson and Palorbitolina lenticularis (Blumenbach) respectively documenting a lower and not an upper Aptian age. This revised age and the different taxononomic inventory do not question all results obtained by Gheiasvand et al. (2020, 2021), but provide a revised basis interpretation.

Planktonic Foraminiferal biostratigraphy of Jaddala Formation in well (K-152), Northern Iraq

Many species of planktonic foraminifera were identified from the Jaddala Formation from well (K-152)of depth (1010-900 m.) northern Iraq. The recorded planktonic foraminifera assemblages permits the recognition of four biozones these are (from top to bottom):Globigerinatheka subconglobata biozone (p11), Acarinina bullbrooki biozone (p10), Acarinina Pentacamerata biozone (p9) 1- Morozovell aragonensi biozone (p8) and On the basis of biocorrelation with previous works Early to Middle Eocene age confirmed for the Jaddala Formation at the studied section.

Unravelling the evolution of extraordinary long-range planktonic foraminifera species based on image processing analysis

The recent growing interest in Late Cretaceous biserial planktonic foraminifera (heterohelicids) has greatly enhanced their use as paleoceanographic and biostratigraphic markers. Pseudotextularia nuttalli, one of the most common cosmopolitan planktonic foraminifera, has an exceptionally long evolutionary range (Turonian-Maastrichtian). The image processing procedure we developed in this study enabled us to document changes in the growth pattern of Ps. nuttalli over time and between different oceanic provinces, and to identify possible speciation events within this lineage. The analysis was complemented by morphometric measurements of the penultimate chamber and test.The morphometric analyses do not indicate an early speciation event within this lineage, and thus, do not support splitting to Planoheterohelix praenuttalli (Turonian-Coniacian) and Pseudotextularia nuttalli (Coniacian-Maastrichtian). Our results indicate a gradual phyletic increase in mean test size from the Santonian through the Maastrichtian, along with increasing morphological diversification. This trend seems to coincide with the global cooling that culminated in the Late Cretaceous.Comparing between Ps. nuttalli from different oceanic provinces reveals that the Southern Tethys specimens are significantly less developed than their counterparts from the two tropical oceanic localities. This adaptive responsiveness suggests a negative correlation between test size and high productivity conditions in the upper water column.The case of Ps. nuttalli lineage exemplifies how extraordinary long-range species (>30 My) can evolutionarily change over time from “primitive” to “developed” forms, without showing a morphological gap. Such species may also show adaptive morphological diversification in response to different environments and, thus, are valuable for palaeoceanographic and paleoecologic reconstructions.

Biostratigraphy of Yamama Formation in Faihaa Oil Field, Southern Iraq

The Yamama Formation was studied in three wells (Fh-1, Fh-2, and Fh-3) within Faihaa oil field, south Iraq. Thin sections were studied by using the polarizing microscope examination in order to determine microfossils and biozone. Thirty-five species of benthic foraminifera were recognized, including four index species. In addition, twelve species of calcareous green algae were recognized, including two index species. Other fossils that were recognized in Yamama Formation include Gastropoda, Bryozoa, Coral, Rudist, and Pelecypoda.&#x0D; Six biozones were observed, which are Charentia cuvillieri sp. (Range Zone of Berriasian age), Psudochryalidina infracretacea sp. (Range Zone of Berriasian age), Pseudocyclammina Lituus sp. (Range Zone of Valanginian age), Nezzazata Perforate sp.andChoffatella sp.(Assemblage Zoneof Berriasian-Valanginian age), Desycladales Green Algae- Cylindroporella sp. (Range Zone of Early Cretaceous- Berriasian age), and Desycladales Green Algae- Salpingoporella cf. circassa sp. (Range Zone of Valanginian age). According to these biozones, the age of Yamama Formation was distinguished to be the Berriasian-Valanginian.

Sedimentary signatures of the abrupt deglacial rise in sea level from the East China Sea inner shelf

Understanding the link between deglacial sea-level jumps and abrupt climate change may provide crucial insights into future ice-climate feedbacks. However, much ambiguity remains surrounding many of the last deglacial meltwater pulses. Here, we present a complete sedimentary succession from the inner shelf of the East China Sea, which has clearly documented multiple abrupt rises in the deglacial sea level. The results suggest that the postglacial sedimentary sequence, resting on a late Pleistocene basement of stiff clay, formed during a three-stage process marked by characteristic lithology and foraminiferal fauna. The abrupt shifts in the sedimentary facies indicate that seawater firstly intruded into the inner shelf just before the onset of the slowdown in sea-level rise caused by the Younger Dryas cooling event and changed the inner shelf into a tidal flat environment, as demonstrated by the sudden appearance of both planktonic foraminifera and typical brackish-water species of benthic foraminifera. Meltwater pulse 1B (MWP-1B) is depicted by a sharp upward transition to a nearshore subtidal environment at 11.62 kyr. This episode of sea-level rise induced the initial flooding of the inner shelf, which is well documented by the sudden reduction in brackish-water foraminifera species and evident increase in inner-shelf benthic species. The prominent sea-level rise at approximately 7.54 kyr was responsible for the shift to stable inner shelf conditions and resulted in the maximum flooding of the inner shelf area, initiating subsequent formation of the alongshore mud wedge. Additionally, obvious peaks in both the benthic foraminifer abundance and the marine algae concentration at approximately 8.13 kyr confirm the previously identified sea-level jump at approximately 8.2 kyr, which coincides with the weakening of the Asian monsoon demonstrated by the peak grain size in our record, further indicating its apparent connection to the 8.2 kyr climatic reversal.

Biozonation and paleobathymetry of the Gurpi Formation in the Dasht-e Arjan section , Zagros area , based on foraminifera

In this research the Gurpi Formation in the Zagros Basin outcropping in the Dasht-e Arjan section, Shiraz province ,for the purpose of biozonational and Paleobathymetric studies were investigated. The thickness of these sediments is about 130 m and consists of Limestones and Shales.To determine the palaeobathymetry of the Gurpi Formation, Planktonic and benthic foraminifera were investigated . A depth of about 270m to 510m was determined for these sediments based on the ratio of planktonic foraminifera to the total assemblages of foraminifera after omitting infaunal benthic foraminifera (%P*) by using the equation D = e (3.58718+(0.03534 × %P* )).In this study sixty-two species of planktonic foraminifera belonging to eighteen genera were recognised .According to the studied planktonic foraminifera the Upper Cretaceous deposits in this area were divided into nine biozones as following :biozone1- Dicarinella concavata Interval Zone. Biozone2- Dicarinella asymetrica Total Range Zone. Biozone3- Globotruncanita elevata Partial range zone .Biozone4- Globotruncana ventricosa Interval Zone. Biozone5- Radotruncana calcarata Interval zone. Biozone 6- Globotruncanella havanensis Partial Range Zone. Biozone7- Globotruncana aegyptiaca Interval Zone. Biozone 8- Gansserina gansseri Interval Zone. Biozone 9- Contusotruncana contusa Interval Zone Based on the studied planktonic foraminifera the Early Santonian to Maastrichtian ages were determined for the sediments .

Reef foraminifera as bioindicators of coral reef health in southern South China Sea

Pulau Tioman is a famous tourist island off Peninsular Malaysia with beautiful coral reefs. This study aims to assess the health of the coral reefs surrounding Pulau Tioman based on the application of the Foraminifera in Reef Assessment and Monitoring Index (FI). Ten sampling sites around Pulau Tioman were studied with a total of 30 samples. Eight orders, 41 families, 80 genera, and 161 species of benthic foraminifera were identified. The agglutinated type of foraminifera constituted 2–8% of the total assemblages. Calcareous hyaline and porcelaneous groups represented 79% and 19% of the total assemblages, respectively. Symbiont-bearing taxa were the most common foraminifera. The results indicate that most of the sampling sites are conducive for coral reef growth with good recoverability from future stress to the ecosystem. However, several areas with higher coastal development and tourism have reduced water and sediment quality. Therefore, the limit on the number of visitors and tourists should be revised to enable coral growth and health. The FI values in this study showed a positive correlation with good water qualities and a negative correlation with organic matter enrichment. The FI is a good measure to assess the health of a coral reef and can be applied to other reef ecosystems around Malaysia.

The Occurrence and Distribution of Benthic Foraminifera in Tropical Waters Along the Strait of Malacca

Foraminifera are shelled single-celled protists that are found in all marine environments. Benthic foraminifera either live in sediments or attach to surfaces on the seafloor. Understanding the distribution and ecological response of benthic foraminifera is crucial, as they can indicate past and current ocean conditions. However, the benthic foraminifera distribution along the busy Strait of Malacca, which connects the Indian Ocean (north) to the Java Sea (south), is undersampled. In this study, we collected 24 surface samples from the northern Strait of Malacca to understand the distribution of foraminifera assemblages in shallow tropical waters. A total of 49 species of benthic foraminifera were identified. Calcareous hyaline species dominated the assemblages, with an extremely low occurrence of calcareous porcelaneous species. The common calcareous hyaline taxa were Asterorotalia pulchella, Pseudorotalia schroeteriana, Discorbinella bertheloti, Ammonia tepida, and Heterolepa praecincta. Cluster analysis categorised the foraminiferal assemblages into three major groups. The first cluster (Group A) consisted of a more diverse assemblage of hyaline and agglutinated species that inhabited a mean water depth of 45 m. The second cluster represented a population that inhabited deeper water environments (average water depth of 59 m). Finally, the third cluster (Group C) consisted of a foraminifera assemblage that inhabited shallow coastal environments (average depth of 22 m) with higher organic matter enrichment. The multivariate canonical correspondence analysis (CCA) showed that the foraminiferal assemblages reflected the shallow to deep water transition in the Malacca Strait. Water depth, which defines the depositional environment, had a greater influence on foraminifera distribution here than organic matter and salinity.