This study examined the foraminifera and the ecologic conditions of the benthic environment of the Oregon shelf and the uppermost slope (75-550 m depth) between 143°45' N and 144°40' N. Seasonal collections monitored the near-bottom marine environment and the sedimentary substrate at 16 stations. The foraminiferal benthic fauna was examined from eight seasonal stations and two additional stations. Use of a multiple corer provided randomly selected subsarnples of the sediment for ecologic and faunal analyses. Use of water bottles that triggered upon bottom impact provided measurements of the water as close to the bottom as 0. 6 m. Computerized data processing and statistical analyses aided the ecologic and faunal evaluations. The environmental study showed the existence of considerable variation in the hydrography of near-bottom waters, especially between summer and winter (upwelling and non-upwelling) collections at the same station. Upwelling conditions directly affect the benthic Redacted for Privacy environment. In addition, the water at any one place, at least dciring upwelling, was so well mixed that vertical stratification did not exist between 0.6 and 5.0 m off the bottom. Statistically significant sea-. sorial variations in surface sediments at the same station were not observed. The living benthic foraminiferal fauna exhibited considerable within-station variation both in species composition and in specimen size of selected species. The percent abundance of individual dominant species varied in adjacent cores (subsamples) by amounts up to 46%. Living specimens of a single species were found that were three times as large as the smallest living specimen from the same sample, yet there was no evidence of a multimodal size distribution resulting from age classes. The author suggests that the dominant species are aggregated and that the aggregations are colonies of asexually produced siblings. Lack of fit of species-frequency curves to the lognormal distribution indicated that relatively few species are fit to reproduce in a particular environment; most juvenile specimens that enter a particular environment belong to species that will not thrive there and either die or simply maintain growth with little chance of reproductive success. The existence of colonial aggregations of individuals is considered to provide the best explanation of the observed variations between adjacent samples. However, the observed variations could be due to sampling error or to substrate microheterogeneity. A possible natural community of 15 dominant species has been determined for those species that form a consistent part of each other's biologic environment. The community crossed the depth and substrate boundaries upon which the stations were selected and appeared to be a general community for the Oregon outer shelf. The limits of the community appear to be determined mostly by water depth, with approximate boundaries at 75-100 m and somewhere between 200-500 m. Regression analyses to determine the ecologic control on the foraminiferal fauna did not indicate a close correspondence between faunal parameters and environmental variables. Regression analyses to determine the ecologic control on mdividual species indicated that most species depended upon a set of two to four environmental variables rather than upon one single limiting factor. The set for each species was different. Temperature. phosphate concentration and oxygen concentrations were common hydrographic members of sets; percent silt, percent sand, percent clay, organic carbon content and organic nitrogen were common sedimentary members of sets. / Graduation date: 1972

The shell weight and abundance of planktonic foraminifera, together with seawater parameters, collected from area off the Southern Taiwan were analyzed in this study. Plankton tows were conducted between April 2006 and December 2011 at water depths of 50, 100, 150, and 200 m. In addition, five sediment trap moorings and one box core were sampled at the same area. Globigerinoides sacculifer was picked for counting numbers and measuring weight from towed samples and core sediments. For seawater samples, dissolved inorganic carbon was analyzed. The age model of sediment core was determined based on the excess lead-210. The seasonal variation of planktonic foraminifera abundance is not obvious in the Gao-ping submarine canyon regime. The shell abundance decreases as the depth increases. Furthermore, the relationship between shell abundance and lunar cycle can be observed from the sediment trap moorings. Shell abundance reaches its maximum before full moon. The sea surface is dominated with larger shells at night than daytime. Shell abundance and size are closely related with the optima growth environmental parameters than anything else. The foraminiferal shell weight is not so different between winter, summer, and autumn. But in spring the shell weight is the lightest among all. Based on the foraminiferal shell weight and the corresponding seawater carbonate ion concentration obtained from this study, it is not easy to explain the relationship between both. Shell weight in downcore record was lighter after A.D. 1890, which probably was caused by the acidification of seawater resulted from the increase of CO2 in the atmosphere.

Hypoxia, with dissolved oxygen levels < 1.4 ml L-1, is a recurring summer feature of Louisiana shelf bottom waters. Stable isotope characterization (delta^18O and delta D) of surface waters over the hypoxic zone shows a shift of dominant river influence from the Mississippi River during April to the Atchafalaya in July. Carbon isotopes of dissolved inorganic carbon (δ13CDIC) in bottom waters reveal the respiration of terrestrial organic carbon (OC) at inshore localities of 10 m depth and the respiration of marine OC at depths equal to and greater than 20 m. delat^18O and delta^13C profiles of Louisiana shelf Conus shells collected in 1972 show no evidence for summer hypoxia. Comparison with modern Conus records reveal a delta^13CDIC reduction during the last four decades associated with intrusion of ^13C-depleted fossil fuel CO2. Summer delta^13C reductions in Texas shelf Pteria shells may imply dissolved oxygen (DO) was reduced by ≈0.7 ml L-1, although this may be attributed to influence of Brazos River discharge on shell delta^18O and delta^13C. Foraminifera fauna measured in age-calibrated sediments from the Texas shelf reveal a low oxygen conditions on between 1960 and modern sediments. From 1950 to 1960, fauna indicate oxygenated bottom waters. Contemporaneous increases of foraminifera delta^13Cand delta^18O suggest this event is associated with severe drought (the Little Dust Bowl). The synchronicity of these data suggests a link between Brazos River discharge and shelf hypoxia.

The subject of this study was to provide the link between benthic foraminiferal assemblages and the surrounding environments. Stained sediment samples were collected from northeast and southwest South China Sea. In addition to the faunal census, cluster analysis and the stable isotope of benthic foraminiferal shells were measured. The results were compared with other parameters, such as %TOC, %CaCO3, and coarse fraction in the sediment. The spatial distribution of stained and total benthic foraminifera seems not to be related with either TOC contents in sediment or the sampling water depth. This is probably because of the TOC contents may not reflect the food supply directly. Cluster analysis of the faunal assemblages in Kaoping submarine canyon shows that all species in this study could be divided into three main groups. The first group is the shallow-intermediate infauna. It distributes in the inner shelf and the proportion decreases as the water depth increased. The second group is those species live in the shallow water. The third group is infauna along the outer shelf and slope. The cluster analysis of the faunal assemblages in the Sunda Shelf can be also divided into three groups. The first group is infaunal taxa. The second is epifauna- shallow infauna and disseminates in the shallow water. The third group is epifaunal taxa. The result of stable isotope of benthic foraminiferal shells in Kaoping submarine canyon does not show any clear relationship between oxygen and carbon isotopes. It is possibly because the selected species is not suitable for isotope analysis or the specimens are not sufficient. But the isotope measurements obtained from the Sunda Shelf reveal the great consistence with the variation of temperature and salinity in bottom water. Some species found in the Sunda Shelf even have great potential in paleoceanography study.

Thesis (M.S.)--University of Missouri, School of Mines and Metallurgy, 1931. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed December 14, 2009) Includes bibliographical references (p. 75).

Recent scientific investigations of sub-millennial paleoceanographic variability have attempted to use the population statistics of single planktic foraminiferal δ18O in an attempt to characterize the variability of high-frequency signals such as the El Niño Southern Oscillation (ENSO). However, this approach is complicated by the relatively short lifespan of individual foraminifera (~2-4 weeks) compared to the time represented by a sediment sample of a marine core (decades to millennia). The resolving ability of individual foraminiferal analyses (IFA) is investigated through simulations on an idealized virtual sediment sample. We focus on ENSO-related sea-surface temperatures (SST) anomalies in the tropical Pacific Ocean (Niño3.4 region). We constrain uncertainties on the range and standard deviation associated with the IFA technique using a bootstrap Monte Carlo approach. Sensitivity to changes in ENSO amplitude and frequency and the influence of the seasonal cycle on IFA are investigated through the construction of synthetic time series containing different characteristics of variability. We find that the standard deviation and range of the population of individual foraminiferal δ18O may be used to detect ENSO amplitude changes at particular thresholds (though the uncertainty in range is much larger than in standard deviation); however, it is highly improbable that IFA can resolve changes in ENSO frequency. We also determine that the main driver of the IFA signal is ENSO amplitude as opposed to changes in the seasonal cycle although this is specific to Niño3.4 where the SST response to ENSO is maximal. Our results suggest that rigorous uncertainty analysis is crucial to the proper interpretation of IFA data and should become a standard in individual foraminiferal studies. / text

Ο κύριος στόχος της παρούσας εργασίας είναι να μελετηθεί η μικροπανιδική κατανομή στα επιφανειακά ιζήματα του Αμβρακικού κόλπου και να συνδυαστούν μικροπαλαιοντολογικά και ιζηματολογικά δεδομένα σαν μια πρώτη προσπάθεια να κατανοηθούν τα ιζηματογενή μοτίβα και η μικροπανιδική κατανομή στον κόλπο καθώς και να εντοπιστούν οι μεταβολές στις παλιοωκεανογραφικές συνθήκες / -

The analyses of benthonic foraminifera in surface sediments for two-years (Oct. 2007-August 2009) and cores from Halifax Harbour (HH) were essential for short-term monitoring, and reference environment reconstruction for the remediation that started in 2008. The distribution of foraminifera in the surface sediments indicates a lateral environmental variation and positive correlation to the pollution rate in HH as the environmental purity increases seawards. The treated area, Inner Harbour, recorded a rapid environmental recovery during treatment period (2008), and reverted to its former characteristics after treatment stopped (early 2009). This recovery represented by an increase in both diversity (from <12 to >20 species) and abundance (from 120–880 to 1350-1750 individuals). Additionally, the assemblage during that period witnessed a decrease in opportunistic species (<50%), shell deformities (<11%), and inner linings (17%), and a significant increase in calcareous species. The assemblage in pre-impact environment, as inferred from cores, has a high diversity (>30 species) and abundance (>4000 individuals), a dominant calcareous record (>60%), and lower deformities (3-4%). The gradual environmental degradation due to organic enrichment in the harbour caused an increasing foraminiferal decimation to reach dramatic levels with the huge growth of Halifax city since late 1950s. This decimation led to dominance of opportunistic species (e.g., agglutinated forms such as Eggerella advena, and Reophax scottii), abundance of shell deformities, and complete absence of calcareous tests, leaving only their inner linings. Analysis of benthonic foraminifera in two cores from Sydney Harbour (SH) helped to compare contamination types in both areas (domestic in HH vs. industrial in SH). The domestic pollution in HH developed an agglutinated assemblage with low diversity, low abundance, and high ratios of inner linings. In SH the assemblage showed higher diversity (>22 species) and abundance (>4000 individuals), dominant calcareous record (>50%), and low inner linings (<10%) together with some species that had never been observed in such cold waters in Nova Scotia (Ammonia beccarii).

Glacioeustatic control of a late-middle Eocene oxygen isotope record is evident from the comparison of such a record with an independent proxy for sea-level. The data, δ18O and planktonic:benthic foraminifera ratios, were determined from samples of the Mossy Grove Core, Hinds County, Mississippi. The temporal order of magnitude for the glacioeustatic cycles, while smaller than two other orders of sea level change identified from this sedimentary package, is comparable to those associated with Milankovitch cycles. Refinement of the sample interval’s sequence statigraphy recognizes a Healing Phase Unit and allowed for identification of the time stratigraphic condensed section. Identification of the condensed section allows for the correlation of this sequence to other sections in the Gulf Coast. / Department of Geology

276 leaves : plates, maps / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Geology, 1961