The Early Jurassic was a time of rapidly rising sea-level associated with the extensive spread of anoxic bottom waters. Sea-level rise across the Pliensbachian - Toarcian boundary culminated in the falciferum Zone of the Toarcian and is one of the best authenticated eustatic events in the Jurassic. This major transgressive pulse was marked by deepw ater marine sequencesa nd was associatedw ith the deposition of organic-rich shales. The development of anoxia coincides with a notable period of mass extinction of the marine fauna. High resolution sampling and study of the microfaunast hrough sequencesin N. W. Europe confirm that benthic foraminiferal. faunas were similarly affected by an early Toarcianfalciferum Zone event. Samples were analysed from Pliensbachian - Toarcian mudstone,c lay and shale sequenceso f the south Dorset Coast,t he Midlands, the Yorkshire Coast, southern France and southwest Germany. The sections studied show distinct changes in assemblagesa cross the Pliensbachian - Toarcian boundary and in the basal zones of the Toarcian. Evidence for a foraminiferal extinction event in the Pliensbachian - Toarcian includes the elimination of the important Lower Jurassic Lingulina tenera, Frondicularia terquem! and Marginulina prima plexus groups, initiating a significant period of turnover of the microfauna. The foraminiferal extinction event recorded in the Lower Toarcian sections of north west Europe is only significant at species level. No extinctions at the family-level occurred. A marked changea lso occurred in the charactero f associatedn odosariid assemblagest:h e uniserial forms of Nodosaria, Frondicularia and Lingulina, dominating the Pliensbachian assemblagesw, ere largely replacedb y coiled Lenticulina in the early Toarcian. A reduction in test size and a decline in species diversity, compared with Hettangian to Sinemurian foraminiferal assemblagesr,e flect the developmento f low oxygen conditions followed by a subsequenrte newal of the microfauna in the Middle Toarcian. The foraminiferal data show no evidence of progressive displacement of older by younger faunas. Instead certain species only expanded their populations and diversity significantly after the extinction of similar niche-occupying species. The Pliensbachian - Toarcian (Lower Jurassic) sediments of the north Yorkshire coast contain highly organic-rich shales where the sequence stratigraphic significance is somewhat obscure. Benthic foraminiferal species distribution (as a function of organic flux and oxygenation) allowed palaeobathymetry to be determined on quantitative assemblage characteristics. In parallel with this methodology, a suite of trace elements (including Mn, Ca, Fe, and Al) have been analysed following nitric and hydrofluoric acid digestion. Maxima of Ca and Mn occur at the base of the falcifierum Subzone (falcifierum Zone). It is suggested that these maxima are an artefact of condensation of carbonate fossiliferous material due to sediment starvation and correspond to published estimates of a maximum flooding surface. Interpretations of the benthic foraminiferal assemblages surrounding this event provide further support for a transgressive event -associated with the development of low oxygen conditions and the deposition of organic-rich shales. Additional Lower Jurassic,H ettangiant o lower Pliensbachian,s equencesw ere investigated for the purposes of establishing their foraminiferal correlation potential as candidate Global Stratotype Sections and Points for the basal Sinemurian and basal Pliensbachian.

The samples for this study were adopted from the drilling cores for the slope-stability monitoring project inside the campus of NSYSU. Stratigraphically the strata belongs to the Gutingken Formation and is lain below the Kaohsiung Limestone. Two cores were selected for this research, one is W-2 (N: 2504008.088; E: 174168.943, 60m in length) and the other is S-4 (N: 2503968.458; E: 174009.179, 55m in length). The thickness of the Gutingken Mudstone in cores W2 and S4 is 38.7m and 21.8m, respectively. Each sample was obtained at every 10 cm interval for W2 and 30~40 cm for S4 with an average weight of 40 g. This study mainly contains two parts: analyzing the planktonic foraminifera for their carbon and oxygen stable isotopic compositions and dating the downcore records by correlating with the nannobiostratigraphy. Particular is the stable isotopic compositions of planktonic foraminifera in these terrestrial sedimentary sequences which has not been done in Taiwan before. Overall the mudstone analyzed in this study falls in the biostratigraphic range of small Gephyrocapsa Subchron, which spreads within 1.242 Ma~1.031 Ma. according to previous report. The age range is further constrained at about 1.186~1.065 Ma based on the oxygen isotope record and thus can be regarded as a high-resolution isotopic stratigraphy within the small Gephyrocapsa subchron. The average sedimentation rate inferred by the best age model from these cores is about 31cm/ky. It shows a progressive decrease in sedimentation rates: the younger the strata, the lower the sedimentation rate. On the contrary, the sedimentation rate varies dramatically at the lower part of the record. The turbidity current might be a potential factor responsible for the change. In addition, the spectral analysis of £_18O data presents a comparatively significant cycle of about 2.5ky through out the record. It might indicate a periodic forcing which influenced the environment during sediment depositation. The £_13C record obtained from this study fail to reflect the high productivity during the glacials. The mechanism that might affect the productivity in the area is not clear and still needs advanced research.

This study investigates the use of larger foraminifera in determining the biostratigraphy of the Avon Park Formation and the Ocala Limestone in central Florida. Sedimentary rocks of the Avon Park Formation are the oldest exposed deposits in the state of Florida, and together with the Ocala Limestone comprise a part of the confining unit of the Floridan Aquifer, a major source of Florida’s water supply. Material from the ROMP 29A core collected by the U. S. Geological Survey was evaluated and compared to previous studies of the biostratigraphy of the formations. The larger foraminifera of the Avon Park Formation were examined in thin section, and those of the Ocala Limestone were free specimens. The larger foraminifera from both units were described and identified, and the biostratigraphy determined. The morphological features of the larger foraminifera of the Ocala Limestone were measured and analyzed at various depths within the ROMP 29A core. The Avon Park Formation contains predominantly the shallow-water, conical foraminifera Fallotella cookei, Fallotella floridana, Pseudochrysalidina floridana, Coleiconus christianaensis, Coleiconus sp. A, Coskinolina sp. A, Coskinolina sp. B, Fallotella sp. A, Fallotella sp. B, Fabularia vaughani and larger miliolids. The Ocala Limestone contains a different, deeper water assemblage that included the larger foraminifera Heterostegina ocalana, Lepidocyclina ocalana varieties, Lepidocyclina chaperi, Lepidocyclina pustulosa, Nummulites willcoxi, Nummulites striatoreticulatus, Nummulites floridensis and Pseudophragmina spp. A, B, and C. The age of the Avon Park Formation was corroborated by the occurrence of the biomarker echinoid Neolaganum dalli as Eocene, and the Ocala Limestone also contained Eocene larger foraminifera with Eocene to possibly Oligocene calcareous nannofossils. The distribution of the larger foraminifera of the Avon Park Formation was correlated with the subtidal and peritidal zones of the continental shelf. Analyses of variance showed that the changes in measurements of the morphology in Heterostegina ocalana, Lepidocyclina spp. and Nummulites spp. were correlated with change in the depositional environments.

Holocene sediments from intertidal and shallow subtidal zones in Bahia la Choya, Mexico exhibit significant differences based on their mineralogical content, constituent composition, textural parameters, and foraminiferal assemblages. The intertidal sediments are characterized by low calcium carbonate content, being dominated by quartz, and are moderately well sorted and coarse skewed with a fine mean grain size {Mz = 2.73 phi}. Total numbers {living and dead} of benthonic Foraminifera per ml of sediment are relatively low (12/ml) in the intertidal zones. In contrast, the subtidal sediments are characterized by high calcium carbonate content, being dominated by molluscan shell fragments, and are poorly sorted and nearly symmetrically skewed with a medium mean grain size {Mz = 1.41 phi}. Total numbers of benthonic Foraminifera per ml of sediment are relatively high (52/ml) in the subtidal zone. The analysis of bioerosion intensity indicates that differences in susceptibility to bioerosion exist not only at the subordinal level but also at the generic level of Foraminifera. Overall rates of test destruction are rapid, apparently due to the combination of biological, chemical, and physical processes. The experimental determination of test characteristics which correlate with settling or entrainment enables the delineation of foraminiferal morphotypes which are most likely to be transported. Test settling velocity is mostly affected by test size and weight. Movement threshold velocity is, also, mostly affected by test size, weight, and shape, in addition to the nature of the substrates and initial test orientation. Foraminifera from siliciclastic environments exhibit relatively low settling and movement threshold velocities. Thus, taxa from siliciclastic settings are more likely to be transported by currents than are those from carbonate environments, which show a wide range of settling and movement threshold velocities. Such information may be utilized to distinguish between autochthonous and allochthonous microfossil assemblages in the stratigraphic record.

Recent carbonate sediments from (133-236m) on the northern Jamaican island slope are significantly different from shallower reef zones (l-70m) in grain constituents, textural parameters, and foraminiferal assemblages. The island slope sediment is dominated by coral fragments, calcareous algae, Halimeda plates, and foraminiferal tests. The sediment is characteristically poorly-sorted, nearly-symmetrically skewed, and mesokurtic, with a mean grain size in the fine sand range. Mineralogically, the sediment is predominantly aragonite (66%) and high-Mg calcite (22%), with some calcite (8%), and minor amounts of clays and other insoluble minerals (4%). Q-mode cluster analyses of sediment constituents, textural parameters, and foraminiferal species and larger group abundances were utilized in the delineation of shelf and island slope depositional environments. ineffective for such use. Mineralogy proves No significant differences are observed in sedimentological parameters (textures, constituents, and sedimentation rates) between an island slope traverse located below an area with prominant sill reefs and a traverse below an area lacking well-developed sill reefs. It is suggested that the sill reefs have less effect on off-reef transport than was previously believed. Based on the abundance trends of certain sediment grains and the similarity of sediment grains in island slope and deep fore reef/fore reef slope sediment, it is suggested that the deeper reef zones (>30m) are the source of most sediment transported seaward. Foraminiferal abundances show lateral differences between traverses related to input of shallow water (

Abstract The carbon and oxygen isotopes of planktonic foraminifera, faunal assemblage, and coarse fraction of trap materials were analyzed in this study. The sediment traps were deployed in two lacations. One was in the Kao-ping submarine canyon and the other was in the northern South China Sea. Variations of the individual concentrations from Kao-ping submarine canyon are small throughout the deployment interval except for the period when the Typhoon Chi-Te invaded southern Taiwan in July 2000. The results that benthic foraminifer abundances (#/g) are higher than that of planktonic foraminifera after typhoon invasion reflect the influence of particle settling by lateral transport. In addition, the major planktonic foraminifera found in canyon are Globigerinoides aequilateralis, Globigerinoides ruber, Globigerinoides sacculifer, and Neogloboquadrina dutertrei. At the same time, we also found Globigerina bulloides that usually lives in the high latitudes and cold temperature. It reveals the effect of nutrient supply along coastal region. The coarse fraction contents and foraminiferal abundances collected by the traps in the northern South China Sea are both increasing in January and March. It could be associated with the enhanced surface productivity. The planktonic foraminifera divided into two groups based on their preferrence. The G. bulloides and N. dutertrei live in cold environment while G. aequilateralis, G. ruber, G. sacculifer, and Pulleniatina obliquiloculata preferr warm areas. In this study, G. bulloides and N. dutertrei were found in January whereas G. aequilateralis, G. rubber, G. sacculifer, and P. obliquiloculata were mostly in March. The difference of carbon isotopes of planktonic foraminifera between species are distinct. Orbulina universa is the heaviest and G. ruber was the lightest. Foraminiferal d18O are depleted in October and enriched in January and March. It is suggested that sea surface temperature might be responsible for the variations of planktonic foraminiferal oxygen isotopes. Comparisons of foraminiferal d18O with the hydrographic data provide some informations. The results show that G. ruber lives in shallow water (~10m), G. sacculifer lives in 25m on average, and O. universa lives in deeper water layer (~70m) in northern South China Sea. Moreover, both the carbon isotopes and foraminiferal abundance of G. ruber show a negative correlation with the particles fluxes.

Historical records suggest that the coastlines of the British Virgin Islands (BVI) and the Sultanate of Oman have been subjected to catastrophic storm and tsunami events throughout recorded history. In 1945, a 7.8 magnitude earthquake -100 km south of Karachi, Pakistan generated a tsunami that impacted the coast of Oman and resulted in over 4000 deaths. Although the 1945 tsunami deposit has been documented, no other paleo-tsunami deposits have been identified despite the fact that historical and paleo-seismic records suggest the contrary. Similarly, the north-eastern islands of the Caribbean, particularly Anegada, BVI, have been subjected to intense hurricane strikes over the past 300 years. Due to its position relative to the Atlantic Ocean and the Puerto Rico Trench, Anegada is a potential recorder of local (e.g. 1690, 1867) and trans-oceanic tsunami events (e.g. 1755 Lisbon) as well. Potential tsunami overwash events at both locations are expected to be intermingled with marine incursions resulting from major storms and Holocene sea level change. Discerning between storm and tsunami overwash is problematic and usually favours a storm interpretation due to their frequency in the geologic record. This bias and lack of properly constrained geologic evidence has hindered the accuracy of tsunami prediction models, and subsequently, the assessment of seismic and tsunami hazards at both locations. Several studies employ the use of foraminifera to distinguish between storm and tsunami deposition; however, they are traditionally conducted in contrasting settings where differences between the terrestrial and marine realms are easily detected. Marine influenced settings lack the same degree of contrast; therefore, microfossil analysis alone is not effective. This dissertation investigates the use of foraminiferal taphonomy as an overwash indicator in two types of coastal settings: 1. a silisiclastic arid system lagoon (Sur, Sultanate of Oman), and 2. semi-tropical carbonate marine ponds (Anegada, British Virgin Islands). Although traditional microfossil taphonomic characteristics have been reported in some overwash studies, no multi-variate investigation into their usefulness as tsunami or storm indicators has previously been conducted. This dissertation shows that the surface condition (e.g. angularity, color, size, fragmentation, etc.) of foraminifera provides important information regarding the origin of overwash deposits and is useful in detecting older deposits at both locations when combined with other proxies. Several important contributions have resulted from this research: 1. Taphofacies analysis helped to constrain sediment provenance and modern nearshore hydrodynamics in an arid system lagoon that could not be achieved with traditional foraminiferal analysis alone. 2. The combined use of foraminiferal provenance and taphonomy was effective in identifying the 1945 Makran Trench tsunami at Sur Lagoon and will be a good indicator of older events at this location; a point which is particularly significant since no geologic evidence of previous tsunami events has ever been recorded. High abundances of predominantly marine taxa coupled with high abundances of large test sizes, fragments and fossil specimens were found to be indicators of tsunami deposition in contrast to lagoon deposition which was characterized by smaller test sizes and less robust lagoon taxa. 3. The preservation of the reefal dwelling Homotrema rubrum, a common encrusting foraminifer in Caribbean reef settings, provided the direction of origin of an overwash event deposited in marine ponds at Anegada and constrained the list of potential overwash candidates. Large and highly preserved Homotrema fragments that are typical of modem reef and storm wrack sediment were found in high abundances within Sand and Shell Sheet in three marine ponds at Anegada. A decrease in the abundance of highly preserved specimens from north to south throughout the ponds, coupled with mollusc taphonomic data strengthens a tsunami interpretation for the deposit. This dissertation shows that taphofacies analysis has broad application to event stratigraphy in a variety of coastal systems. Although the application of taphonomic analysis between the two contrasting environments was widely different, in both cases, taphonomic data provided indicative information regarding the origin of deposition of overwash units at Anegada, BVI and Sur, Sultanate of Oman. / Thesis / Doctor of Philosophy (PhD)

O presente estudo teve por objetivo analisar a influência da disposição oceânica de esgotos domésticos e petroquímicos na coluna d\'água, nos sedimentos e nas associações de foraminíferos bentônicos. Para atingir tal objetivo foram coletadas amostras próximo aos emissários do Araçá, do Saco da Capela e do Terminal Petrolífero Almirante Barroso (TEBAR), em 2005 e 2006. Coletou-se também 10 amostras ao longo do Canal de São Sebastião, SP, em 2008. Em cada ponto amostral foram obtidos dados físico-químicos da coluna d\'água, sedimentológicos (granulometria, Cot, N, P e S) e das associações de foraminíferos. As biocenoses e tanatocenoses foram estudadas separadamente. Os resultados das análises hidrogeoquímicas não demonstraram alterações de origem antrópica. Os valores de todos os parâmetros analisados estiveram dentro dos limites estabelecidos pelo CONAMA. Os resultados das análises granulométricas e geoquímicas indicaram dois setores distintos no Canal de São Sebastião, um na região norte, com sedimentos arenosos e teores baixos de Cot, N, P e S e outro na região central, com predominância de sedimentos finos e teores elevados Cot, N, P e S. Na região central verificou-se abundância significativa de espécies euribiontes. Segundo os resultados granulométricos e geoquímicos obtidos para a região do Saco da Capela, o estresse ambiental decorrente do esgoto disposto ocorre de forma pontual, i.e. na saída do emissário submarino. As associações de foraminíferos são compostas predominantemente por espécies típicas de ambientes bem oxigenados. O emissário do Araçá está posicionado em região com circulação de fundo oscilando entre moderada e fraca. Os resultados geoquímicos indicaram enriquecimento orgânico, decorrente do efluente disposto, na região nordeste. Nesta região foram obtidas as maiores abundâncias de espécies euribiontes, com declínio de espécies estenobióticas. Pelas tanatocenoses de Setembro de 2006, constatou-se grau elevado de estresse na saída do emissário (estação Ar1), onde ocorreu dominância de foraminíf eros aglutinantes, sendo observados sinais de dissolução em espécimes hialinos. A região circundante ao emissário do TEBAR é a que apresenta maior nível de degradação ambiental. Nesta região os sedimentos são predominantemente lamosos, com elevados teores de Cot, N, P e S. As condições redutoras dos sedimentos de fundo são observadas pelos valores negativos de Eh, pelo valor levemente ácido de pH e pelos valores baixos das razões C/S. As associações de foraminíferos são compostas dominantemente por espécies bioindicadoras de ambientes hipóxicos. Os estudos comparativos (NMDS, MANOVA e teste t) evidenciaram diferenças significativas nas estruturas composicionais quando as biocenoses e tanatocenoses são comparadas entre si, bem como quando as biocenoses são comparadas com as tanatocenoses. Pelos resultados obtidos verificou-se que as interpretações seriam diferentes das obtidas, caso os estudos de avaliação ambiental fossem realizados com a associação total de foraminíferos (vivos + mortos). Palavras-chave: emissário submarino, esgotos domésticos, esgotos petroquímico / The influence of oceanic disposal of domestic and petrochemical effluents on physicochemical parameters of the water column, geochemistry of sediments and foraminiferal assemblages was assessed in this study. Water and sediment samples were collected near Araçá, Saco da Capela and Almirante Barroso Terminal Petroliferous (TEBAR) outfalls, in the São Sebastião Channel, São Paulo, Brazil, in 2005 and 2006. Ten other samples distributed along the channel were collected in 2008. For each water sample physicochemistry analyses were carried out. In the sediments, grain size, geochemistry (TOC, N, P and S) and foraminiferal co mposition were analyzed. Live and dead benthic foraminiferal composition and distribution were studied separately. The water column analyses did not demonstrate human-induced changes. The values of almost all parameters were within the National Environmental Council (CONAMA) limits. Grain size analysis and geochemistry results indicated two different morphosedimentary sectors in the São Sebastião Channel, one in the north with sandy sediments and low TOC, N, P and S, and the other in the central region wit h predominantly fine sediments, significant nutrient, TOC and S values. The Saco da Capela submarine outfall is positioned in high hydrodynamic environment. Geochemical results indicated that the environmental stress occurs only at the outfall end (station Ar1). The foraminiferal assemblage is composed of species typical of well-oxygenated bottom waters and low organic content. The Araçá submarine outfall is located in an area with moderate to weak bottom circulation. Organic enrichment due the domestic effluent disposal was observed in the southeast and northeast area, mainly by P and S and, to a lesser extent, by TOC values. In these regions opportunistic foraminiferal species dominate and stenobiotic species are absent or present in diminished values. The highest level of environmental degradation was registered in September, 2006, when dominance of agglutinated shells and signals of dissolution in hyaline shells were observed in the thanatocenosis. The area around TEBAR diffusers presents high levels of environmental stress. In this area, characterized by muddy sediments, the highest TOC, N, P and S contents were registered in all the periods were found. Reducing conditions in the region are demonstrated by values of Eh, acid pH and low C/S ratios. In the foraminiferal assemblage, environmental degradation was inferred by the dominance hypoxic species. Comparative studies (NMDS, MANOVA and t test) indicated significant differences in foraminiferal composition among biocenosis, among thanatocenosis and between biocenosis and thanatocenosis. These results demonstrate that biocenosis and thanatocenosis must be studied separately.

O presente estudo teve por objetivo analisar a influência da disposição oceânica de esgotos domésticos e petroquímicos na coluna d\'água, nos sedimentos e nas associações de foraminíferos bentônicos. Para atingir tal objetivo foram coletadas amostras próximo aos emissários do Araçá, do Saco da Capela e do Terminal Petrolífero Almirante Barroso (TEBAR), em 2005 e 2006. Coletou-se também 10 amostras ao longo do Canal de São Sebastião, SP, em 2008. Em cada ponto amostral foram obtidos dados físico-químicos da coluna d\'água, sedimentológicos (granulometria, Cot, N, P e S) e das associações de foraminíferos. As biocenoses e tanatocenoses foram estudadas separadamente. Os resultados das análises hidrogeoquímicas não demonstraram alterações de origem antrópica. Os valores de todos os parâmetros analisados estiveram dentro dos limites estabelecidos pelo CONAMA. Os resultados das análises granulométricas e geoquímicas indicaram dois setores distintos no Canal de São Sebastião, um na região norte, com sedimentos arenosos e teores baixos de Cot, N, P e S e outro na região central, com predominância de sedimentos finos e teores elevados Cot, N, P e S. Na região central verificou-se abundância significativa de espécies euribiontes. Segundo os resultados granulométricos e geoquímicos obtidos para a região do Saco da Capela, o estresse ambiental decorrente do esgoto disposto ocorre de forma pontual, i.e. na saída do emissário submarino. As associações de foraminíferos são compostas predominantemente por espécies típicas de ambientes bem oxigenados. O emissário do Araçá está posicionado em região com circulação de fundo oscilando entre moderada e fraca. Os resultados geoquímicos indicaram enriquecimento orgânico, decorrente do efluente disposto, na região nordeste. Nesta região foram obtidas as maiores abundâncias de espécies euribiontes, com declínio de espécies estenobióticas. Pelas tanatocenoses de Setembro de 2006, constatou-se grau elevado de estresse na saída do emissário (estação Ar1), onde ocorreu dominância de foraminíf eros aglutinantes, sendo observados sinais de dissolução em espécimes hialinos. A região circundante ao emissário do TEBAR é a que apresenta maior nível de degradação ambiental. Nesta região os sedimentos são predominantemente lamosos, com elevados teores de Cot, N, P e S. As condições redutoras dos sedimentos de fundo são observadas pelos valores negativos de Eh, pelo valor levemente ácido de pH e pelos valores baixos das razões C/S. As associações de foraminíferos são compostas dominantemente por espécies bioindicadoras de ambientes hipóxicos. Os estudos comparativos (NMDS, MANOVA e teste t) evidenciaram diferenças significativas nas estruturas composicionais quando as biocenoses e tanatocenoses são comparadas entre si, bem como quando as biocenoses são comparadas com as tanatocenoses. Pelos resultados obtidos verificou-se que as interpretações seriam diferentes das obtidas, caso os estudos de avaliação ambiental fossem realizados com a associação total de foraminíferos (vivos + mortos). Palavras-chave: emissário submarino, esgotos domésticos, esgotos petroquímico / The influence of oceanic disposal of domestic and petrochemical effluents on physicochemical parameters of the water column, geochemistry of sediments and foraminiferal assemblages was assessed in this study. Water and sediment samples were collected near Araçá, Saco da Capela and Almirante Barroso Terminal Petroliferous (TEBAR) outfalls, in the São Sebastião Channel, São Paulo, Brazil, in 2005 and 2006. Ten other samples distributed along the channel were collected in 2008. For each water sample physicochemistry analyses were carried out. In the sediments, grain size, geochemistry (TOC, N, P and S) and foraminiferal co mposition were analyzed. Live and dead benthic foraminiferal composition and distribution were studied separately. The water column analyses did not demonstrate human-induced changes. The values of almost all parameters were within the National Environmental Council (CONAMA) limits. Grain size analysis and geochemistry results indicated two different morphosedimentary sectors in the São Sebastião Channel, one in the north with sandy sediments and low TOC, N, P and S, and the other in the central region wit h predominantly fine sediments, significant nutrient, TOC and S values. The Saco da Capela submarine outfall is positioned in high hydrodynamic environment. Geochemical results indicated that the environmental stress occurs only at the outfall end (station Ar1). The foraminiferal assemblage is composed of species typical of well-oxygenated bottom waters and low organic content. The Araçá submarine outfall is located in an area with moderate to weak bottom circulation. Organic enrichment due the domestic effluent disposal was observed in the southeast and northeast area, mainly by P and S and, to a lesser extent, by TOC values. In these regions opportunistic foraminiferal species dominate and stenobiotic species are absent or present in diminished values. The highest level of environmental degradation was registered in September, 2006, when dominance of agglutinated shells and signals of dissolution in hyaline shells were observed in the thanatocenosis. The area around TEBAR diffusers presents high levels of environmental stress. In this area, characterized by muddy sediments, the highest TOC, N, P and S contents were registered in all the periods were found. Reducing conditions in the region are demonstrated by values of Eh, acid pH and low C/S ratios. In the foraminiferal assemblage, environmental degradation was inferred by the dominance hypoxic species. Comparative studies (NMDS, MANOVA and t test) indicated significant differences in foraminiferal composition among biocenosis, among thanatocenosis and between biocenosis and thanatocenosis. These results demonstrate that biocenosis and thanatocenosis must be studied separately.

No description available.