Elevated atmospheric concentrations of carbon dioxide (CO₂), partly driven by anthropogenic activity, are decreasing the pH of the oceans. This thesis aimed to assess the biological response of foraminifera to ocean acidification. Foraminifera are single-celled organisms that form the dominant component of many marine communities. A series of laboratory experiments were carried out on benthic intertidal foraminifera from the Eden and Ythan estuaries, NE Scotland, to assess the impacts of ocean acidification. The responses of two dominant intertidal species of foraminifera (Haynesina germanica and Elphidium williamsoni) to ocean acidification were initially investigated in a short-term (6 week) experiment. Multiple species and multiple stressors (seasonal temperature regime and elevated CO₂) were then incorporated in a long-term (18 month) mesocosm study to investigate the physiological consequences (e.g. survival, growth) of ocean acidification. Survival of both Haynesina germanica and Elphidium williamsoni was significantly reduced under low pH conditions. Live specimens of both these calcareous species were however recorded at low pH, in reduced numbers. Following long-term exposure to ocean acidification, foraminiferal populations were still dominated by calcareous forms. Agglutinated foraminifera were recorded throughout the long-term incubations but their numbers were not high enough in the initial sediment collections to allow them to contribute significantly to the populations. Overall, survival of all foraminifera was greatly reduced in elevated CO₂ treatments. Temperature effects were observed on foraminiferal survival and diversity with the largest CO₂ effects recorded under the seasonally varying temperature regime. Foraminiferal test damage for all live species was also highest under elevated CO₂ conditions. Test dissolution was particularly evident in Haynesina germanica with important morphological features, such as functional ornamentation, becoming reduced or completely absent under elevated CO₂ conditions. A reduction in functionally important ornamentation could lead to a reduction in feeding efficiency with consequent impacts on this organism's survival and fitness. In addition, changes in the relative abundance and activities of these important species could affect biological interactions (e.g. food web function) and habitat quality.

The West Antarctic Ice Sheet (WAIS) is currently thinning and retreating because shifting oceanic currents are transporting warmer waters to the ice margin, which could lead to a collapse of the ice sheet and global sea level rise. International Ocean Discovery Program (IODP) Expedition 374 sailed to the Ross Sea in 2018 to study the history of the WAIS over the last 20 million years. Previous geologic drilling projects into Ross Sea sediments that record the history of the WAIS (DSDP Leg 28, RISP, MSSTS, Cape Roberts Drilling Project, ANDRILL), as well as modeling studies, show considerable variability of ice-sheet extent during the Neogene and Quaternary including ice sheet collapse during times of extreme warmth. The purpose of this study is to reconstruct paleoenvironments on the Ross Sea and confirm modeling studies that show warming waters in the Southern Ocean led to the loss of Antarctic ice in the past. Site U1523 is a key site as it is located close to the shelf break and therefore sensitive to warm water incursions from modified Circumpolar Deep Water (mCDW) onto the Ross Sea continental shelf as the Antarctic Slope Current weakens with a changing climate. Shelf sites U1522 and U1521 provide perspective for what was happening closer to the Ross Ice Shelf. Multiple incursions of subpolar or temperate planktic foraminifera taxa occurred during the latest Pliocene and early Pleistocene prior to ~1.8 Ma at Site U1523 indicating times of warmer than present conditions and less ice in the Ross Sea. Especially high abundances of foraminifera are recorded in the late Pleistocene associated with Marine Isotope Stage (MIS) 31, MIS 11, and MIS 5e might also indicate reduced ice and relatively warmer conditions. The interval of abundant foraminifera around MIS 31 (MIS 37 to 21) suggests multiple warmer interglacials during the Mid-Pleistocene Transition (MPT). A change in benthic foraminiferal assemblages and a large increase in foraminiferal fragments after the MPT (~800 ka) indicate stronger currents at the seafloor and perhaps corrosive waters, suggesting a major change in water masses entering (mCDW) or exiting the Ross Sea (AABW) since the MPT.

>Magister Scientiae - MSc / Durban Basin located on the eastern coast of South Africa has been a focus of interest for Petroleum Exploration for the last few decades. Only four exploratory wells have been drilled in this offshore basin without success. During the initial stage of its creation, the basin suffered major tectonic disturbance as evident from the presence extensional faults followed by intense igneous activities. This was followed by marine sedimentation in the late Mesozoic (late Jurassic-early Cretaceous). An attempt has been made in this work to understand the distribution of the rock in space and time for the early Cretaceous sediments considered most prospective for hydrocarbon exploration in Southern Africa. Temporal distribution of planktonic foraminifera helps in identification of the three early Cretaceous (Barremian to Albian) stages within the drilled intervals. Foraminiferal biostratigraphic studies integrated with sedimentology, log motif analysis and seismic data analysis helps to predict paleodepth and depositional environment during early Cretaceous in this research. / 2022-04-30

An almost complete sequence of middle and upper marine strata, informally designated in this study as the "Strata of Cascade Head", has yielded 334 species and varieties of fossil Foraminifera. The Foraminifera were collected from 38 localities in four stratigraphic sections measured along the Salmon River, Neskowin Creek, Cascade Head Road, and near the town of Three Rocks in the central Oregon Coast Range.

No description available.

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1979. / Microfiche copy available in Archives and Science. / Bibliography: p. 110-119. / by Jonathan Erez. / Ph.D.

The biostratigraphy and isotope stratigraphy of the upper Aptian to lower Cenomanian interval including oceanic anoxic events OAE1b, 1c and 1d are investigated in ODP Site 763, drilled on the Exmouth Plateau offshore northwest Australia. Benthic foraminifera suggest that Site 763 was situated in outer neritic to upper bathyal water depths (~150-600 m). OAEs of the Atlantic basin and Tethys are typically associated with organic carbon-rich black shales and δ13C excursions. However, OAEs at this high latitude site correlate with ocean acidification and/or pyrite formation under anoxic conditions rather than black shales. Ocean acidification maybe responsible for sporadic low abundances of planktic foraminifera compared to radiolarians and benthic foraminifera associated with increased volcanogenic CO2 production during the formation of the Southern and Central Kerguelen Plateaus. Sea surface temperature may have cooled to 11°C in the late Aptian but increased gradually during the Albian. The Aptian/Albian boundary is placed at a negative carbon isotope excursion associated with the lowest occurrence of Microhedbergella renilaevis, typically found within the Niveau Kilian black shale of OAE1b. Third-order sea level cycles, particularly in the middle Albian, produced cyclic changes in the abundance of inoceramid prisms that increased during inferred times of falling sea level. The late Albian OAE1c and OAE1d coincide with horizons of intense pyritization and the absence of all biocomponents suggesting the development of euxinia. Warm Tethyan waters reached the Exmouth Plateau during the latest Albian based on the presence of thermocline dwelling keeled planktic foraminifera including Planomalina buxtorfi.

Benthic foraminifera inhabiting the mudflats of the Eden Estuary, NE Scotland, exhibited a single annual peak in abundance at both high (270 individuals 10 cm⁻²) and low shore (210 individuals 10 cm⁻²) intertidal sampling stations during June 2000. The increased total abundance coincided with reproduction in the two dominant foraminiferal species Elphidium williamsoni (May) and Haynesina germanica (June) at both sites. Benthic diatom biomass, measured as chlorophyll c, peaked at the high intertidal site during March and April 2001 (36 and 37 mg m cm⁻², respectively) and at the low intertidal site in June2000 (45 mg m cm⁻²). The high intertidal foraminiferal populations appeared to display a lagged response to increases in chlorophyll c. Multivariate statistics suggest that abiotic factors control the abundance of foraminifera at the high intertidal site. At the low intertidal site, total foraminiferal abundance demonstrated an almost immediate response to increased chlorophyll c and multivariate statistics suggested biotic factors are more important in controlling foraminiferal species abundance here. Ingestion rates of ¹³C-Iabelled benthic diatoms over a five-day experimental period were high (e.g. enrichment values for Elphidium were recorded as 687 ± 121 % after 1 day) in intertidal benthic foraminifera. Laboratory observations of E. williamsoni demonstrated rapid asexual reproduction (within 3 days) and growth rates of up to 14 µm day⁻¹ were estimated. Three benthic foraminiferal species E. williamsoni, H germanica and E. oceanensis ingest motile benthic diatoms as a food resource on the intertidal mudflats of the Eden Estuary. Novel application of natural abundance stable isotope (δ¹³C and δ¹⁵N) techniques demonstrated the trophic position of intertidal benthic foraminifera, confirming that they largely ingest and assimilate organic matter derived from benthic diatoms. Foraminifera have largely been overlooked in meiofaunal studies, but play a significant role in the rapid transfer of autotrophic carbon to higher trophic levels within benthic marine food webs.

Les changements paléoenvironnementaux se produisant pendant le Sarmatien dans la Paratéthys Centrale ont été reconstitués par l’étude des foraminifères (36 espèces) et des ostracodes (28 espèces) de deux forages, combinée à une analyse géochimique de leurs squelettes calcitiques, des coquilles aragonitiques de gastéropodes et des dents phosphatiques de rongeurs.La composition de la microfaune indique que la connexion entre la Paratéthys et la Méditerranée est interrompue ou réduite à la base du Sarmatien mais qu’un bras de mer persiste entre Paratéthys Centrale et Paratéthys Orientale jusqu’à la fin du Sarmatien. Le Sarmatien inférieur est caractérisé par des eaux saumâtres peu profondes (maximum 80 m), bien ventilées, des températures stables (~ 15°C), un riche couvert végétal (algues et/ou phanérogames) et des efflorescences phytoplanctoniques périodiques. Un événement transgressif y est observé (TST de 3ème ordre; TB 2.6 du cycle global). Les changements faunistiques qui se produisent à la limite entre Sarmatien inférieur et moyen sont expliqués par un évènement de type HST accompagné de conditions dysoxiques. A la fin du Sarmatien moyen, une baisse du niveau marin relatif d’environ 50 m se produit et des eaux tempérées chaudes, plus saumâtres (17-23‰) et bien ventilées se mettent en place. Après un court épisode régressif, une connexion est rétablie entre la Paratéthys et la Méditerranée au début du Sarmatien supérieur. Des eaux chaudes (15-21° C), bien ventilées, correspondant à des lagunes marines et des marécages avec de fortes variations de la salinité (15-43 ‰) s’installent alors avant un isolement ultime de la Paratéthys qui se produit à la fin du Sarmatien. / Palaeoenvironmental changes in the Sarmatian Central Paratethys were reconstructed by studying foraminifers (36 species) and ostracods (28 species) from two boreholes coupled with geochemical analyses of their calcite skeletons and of aragonite gastropod shells and phosphate rodent teeth.The composition of the microfauna suggests that the connection between the Central Paratethys and the Mediterranean was interrupted or limited at the base of the Sarmatian, but that a seaway between the Eastern and Central Paratethys existed until the end of the Sarmatian. The early Sarmatian is characterized by brackish littoral seawater (maximum 80 m), well ventilated, stable temperatures (~ 15°C), with rich algae and/or seagrass vegetation and periodic phytoplankton blooms. A transgressive event can be observed as part of a 3rd order transgressive systems tract (TST) corresponding roughly to the TB 2.6 global cycle. The faunal changes occurring at the boundary between the lower and the middle Sarmatian can be explained by a sea-level highstand with dysoxic conditions. A relative sea-level fall with a maximum depth of about 50 m, and well ventilated, warm temperate and more brackish (17-23‰) conditions is documented at the end of the middle Sarmatian. After a short regressive event, a marine connection between the Paratethys and the Mediterranean was established at the beginning of the upper Sarmatian. Warm (15-21°C), well-ventilated, corresponding to marine shallow lagoon and marsh environments with high fluctuations in salinity (15-43 ‰) then prevailed before a final isolation of the Central Paratethys that occurred at the end of the Sarmatian.

O presente estudo compreendeu a caracterização dos estuários de Santos/São Vicente e Cananéia quanto aos processos naturais e antrópicos; e o estudo de traçadores biológicos - foraminíferos. Estas regiões foram escolhidas, sobretudo devido ao antagonismo no que tange o impacto antrópico e, ainda, à sua complexidade ambiental. Os resultados hidrogeoquímicos, nutrientes e concentração de metais confirmaram a maior influência humana no estuário de Santos/São Vicente, principalmente na área mais interna do sistema, em comparação com a baixa influência antropogênica do estuário de Cananéia. A distribuição dos foraminíferos bentônicos como traçadores do gradiente de tensão ecológica (natural e antrópica) foi discutida a partir da análise de amostras coletadas nos sedimentos superficiais dos estuários, comparando-se a fauna, porém, sem desconsiderar as divergências espaciais das áreas em questão. Amostras foram coletadas para realização de análise qualitativa e quantitativa, além da análise micrométrica das testas dos foraminíferos. Os resultados obtidos revelaram que a distribuição das associações de foraminíferos refletiu o padrão natural em Cananéia, no que diz respeito tanto a abundância quanto ao tamanho específico. Os dados biométricos revelaram que a região de Cananéia concentra os maiores diâmetros médios, que estão sempre associados com as campanhas de inverno. Tal fato evidencia que a matéria orgânica elevada no verão contribui para o aumento da população e não de tamanho médio de organismos. Isso demonstra um esforço reprodutivo que provavelmente visa aproveitar a disponibilidade de alimento do verão. Outros resultados pertinentes foram: estabelecimento das espécies Buliminella elegantissima e Pararotalia cananeiaensis em locais que não são correspondentes no que diz respeito às características ambientais, denotando a plasticidade destas espécies em traçar uma rota de transporte e estabelecimento, que geralmente está relacionado à deposição da matéria orgânica. A partir dos dados obtidos pode-se concluir que os foraminíferos se comportam de maneira singular, de acordo com o tensor que está regendo seu estabelecimento, e através da análise de sua distribuição, foi possível inferir se um tensor antrópico ou ambiental influenciou o estabelecimento de espécies de foraminíferos nos estuários de Santos e Cananéia. / This study had as a goal to characterize two estuaries, Santos/São Vicente and Cananéia, regarding to natural and anthropogenic parameters. Besides that, the biological trace elements - foraminiferal assemblage. The study has been held along the two estuarine areas, and both of them have shown bio-geographical patternal patches. These study areas were chosen in accordance with their antagonist impact approach and their environmental complexity. Among the advantages on developing studies that uses bioindicators to evaluate na environmental quality patterns, it is evident the large amount of experiments on the water and sediments that these areas are constantly under over than three decades. The hydrochemical results, organic content and heavy metal confirm the human influence at Santos estuary, mainly in the internal áreas, in comparison with the low rate anthropogenic influence from Cananéia estuary. Foraminiferal distribution as a ecológical tracer, both natural and human made, was discussed from sediment samples from both áreas, but always concerning about the oceanographic differences. Samples were picked up aldo to biometric analysis on the foraminiferal shells. Results show that foraminiferal distribution follows the natural patterns as the first way, both relating to abundance and size. Biometric data revealed that the largest diameter average was always associated with the winter samples. It is such evidence that the high level of organic matter contributes incrising the population, but no longer raising its diameter size. This is a sight for a reproductive effort in order to not miss out food availability during the summer. Another relevant result is: Buliminella elegantissima and Pararotalia cananeiaensis establishment in areas where they wouldnt normally settle down, denoting they do not correspond with the same variable in both study areas. This fact evidences the plasticity of these species on fitting different environment characteristic in order to establish and to reproduce. This is generally associated with organic matter deposition and makes foraminiferal distribution a singular pattern that allows determining a natural or an anthropogenic influence.