Efficient exploitation and conservation of the oceans poses great technological challenges for scientists and engineers who must develop materials, structures and equipment for use in harsh environment of the oceans. For the applications of materials in marine environment, knowledge of the corrosion properties is essential for selection purposes. Presently, effort is being devoted to exploit deep-sea mineral resources. Deterioration of materials in the deep sea is due to the cumulative effect hydrostatic pressure, temperature, pH, dissolved oxygen, salinity and sea current. For the first time, in-situ corrosion measurements on the effect of deep sea environment on some metallic and composite materials were carried out at depths of 500,1200,3500, and 5100 m for 168,174 and 174 days of exposure in the Indian Ocean. Corrosion rate was obtained from weight loss measurements (mm/year) and surface morphology of as-exposed and cleaned specimens of the above materials was studied under scanning electron microscope and ED AX. Galvanic coupling of steel with zinc, magnesium and aluminium were also studied.. Tensile on metal and alloys and tensile, compressive, flexure and ILSS tests on carbon fibre reinforced composite specimen were performed on exposed specimens. XRD studies were conducted on the corrosion product of materials. In order to correlate the performance of materials in deep-sea environment, seawater current and temperature data were also collected at same period Results reveal that the corrosion behaviour of steels is controlled by dissolved oxygen prevailing and corrosion rate corresponds to dissolved oxygen available at these depth levels. This is due to the fact that oxygen acts as a cathodic deploarizer during corrosion reaction of steels in seawater. Corrosion rate of aluminium increases as the depth increases. This is due to the effect of hydrostatic pressure, which reduces the ionic radii of chlorine ions and facilitates easy penetration of these ions into surface layer. Titanium, titanium alloy (Ti-6A1-4V) and stainless steels did not show any deterioration at all depths studied. Morphology of as exposed and corroded coupons reveal different features. EDS analyses on exposed specimens are analyzed in light of seawater parameters. Carbon fibre reinforced composite did not show any change in properties like tensile, compression flexural and ILSS compared to control (unexposed) specimens. The deposition of calcium carbonate on galvanically coupled mild steel with zinc, aluminium and magnesium corresponds to availability of calcium in the deep ocean. EDS analyses on exposed coupons did not reveal calcium element below the calcium carbonate compensation depth (CCD) at 3800 m in Indian Ocean. Potentiodynamic polarization studies on some metals and alloys indicate that the behaviour of materials in deep-sea environment is a cumulative effect of all oceanographic parameters. Tensile test results on stainless steels SS-304 & SS-316L), titanium and titanium alloy (exposed) specimens did not show any significant change in their tensile properties and is again attributed to the passive film formed on its surface and nearly zero corrosion rate observed. Microbiological investigations on the exposed materials indicate that except carbon fibre reinforced composite all other metals and alloys harboured bacterial colonies. Results have been used to recommend structural materials suitable for the deep-sea applications.

Slope-channels act as conduits that transport sediments from the shelf staging area to the basin floor. The Pliocene-Pleistocene section of the Columbus Basin in the deep-water slope offshore eastern Trinidad provides an opportunity to study slope-channel morphology and evolution, as well as any association between deep-water deposits, palaeo-seafloor bathymetry, shelf sediment feeder mechanism and changes in sediment supply types and volumes. Approximately 3250 km2 of 3D seismic data allow imaging and interpretation of channels within an interval between two regional surfaces termed P30 and P40. Observations of seismic cross-sections and stratal slices reveal a number of features including channels, mud diapirs, mass transport deposits (MTDs), and faulted anticlinal ridges. Channels appear leveed and unleveed, and alternate with MTDs in a cyclic vertical succession. Nineteen channels were mapped and divided into two groups based on their degree of levee development and stratigraphic position relative to MTDs. Group 1 channels, positioned below MTDs near the base of the interval, are shallowly incised, and show limited levee development. Group 2 channels, situated above MTDs, are relatively deeply incised, and have comparatively larger, well-developed levees throughout their lengths. Morphometric data from these channel groups reveal significant variability in channel width, channel depth, meander belt width, and sinuosity downslope. This variability is associated with influences of temporally equivalent local features and regional sea-floor slope changes. Increased slope gradient causes a marked increase in sinuosity. Diapirs and anticlinal ridges confine channel paths, divert their flow, and cause post-depositional deformation of both levees and channels. Levee height decreases downslope while levee width shows considerable asymmetry, which is related to occurrences of mud diapirism and MTDs. Irregularities on the upper surface of MTDs create accommodation space that confines turbidity flows, enabling ponding of sediments and volumetrically large levee construction. This accounts for dispersion of turbidity flows below the MTD which creates a series of small channels spread over a wide area, and comparatively fewer, confined channels above the MTDs with large levees. / text

The structures along the Atwater Fold belt form important deep-water hydrocarbon traps in the northern Gulf of Mexico. The purpose of this study is to map and quantify the morphology, sedimentology and architecture of Plio-Pleistocene basin floor fan systems outboard of the Poseidon Minibasin, located along the Atwater deep-water fold belt (mid-Miocene to Pliocene), and apply that information to determine the temporal and spatial nature of the fill and its implications as a reservoir analog. The data set includes ~2200 km sq. of 3D seismic data, along with information from several wells. Wireline logs show the Tertiary age deposits outboard of the Sigsbee Escarpment to be several hundred feet thick, sharp-based, dominantly coarse-grained (sandy) but fining up cycles composed of sandy basin floor fans, mass transport complexes and leveed channels developed in a confined setting within deep-water “valleys.” The largest valley formed in five main stages: initiating from narrow channel incision, widening through lateral incision and sidewall slumping, straightening, and finally flooding and infilling. The valley system is ~20,000 feet across and ~ 1,400 feet deep, with what look like well-developed levees ranging from 700 to 1300 feet at their thickest point extending ~19000 feet away from the channel. This system is underlain by a ~700 foot thick mass transport complex and overlain by younger, low sinuosity leveed channel systems. Both of these systems appear to have been sourced by large submarine drainages, originating from a shelf edge sediment source system to feed the rugose slope with deep-water channel pathways uninhibited by salt wall inflation at the time of valley deposition. Major phases of salt thrusting along the southern edge of the Atwater were contemporaneous with the formation of these large, through-going valley system, which appear to be associated with the period of sheet thickening and development of monoclinal basinward dip related to rafted mini-basin docking. Well log signatures show evidence for armored clay drapes along the valley margins as well as a flattening of lateral accretion packages toward the distal end of the system. The flattening of these packages seems to signal proximity to the fan terminus, which would serve as an important indicator of spatial extent of plays in deep-water. / text

Although levee deposits make up a significant part of modern and ancient deep-marine slope systems, details of their internal lithological composition and stratal architecture remain poorly documented. At the Castle Creek study area, strata of the Neoproterozoic Isaac Formation (Windermere Supergroup) crop out superbly in a kilometre-scale section through a sinuous deep-water channel-levee system (ICC3). Levee deposits near the outer bend of the channel consist of sandstone-rich (sandstone-to-mudstone ratio of 68:42), medium- to thick-bedded turbidites interstratified with thinly-bedded turbidites. Structureless sandstone (Ta), planar laminated sandstone (Tb), non-climbing ripple cross-stratified sandstone (Tc) and massive and laminated siltstone (Td) are common. Thick beds generally thicken and then thin and fine laterally over about 300 m. Thin-bedded strata, in contrast, thin and fine negligibly over similar distances. In the distal part of the outer-bend levee (up to 700 m laterally away from the channel) strata consist predominantly of thin-bedded Tcd turbidites with a much lower sandstone-to-mudstone ratio (35:65). On the opposite side of the channel, inner-bend levee deposits are mudstone-rich, locally as low as 15:85, and consist mostly of thin-bedded, Tcd turbidites, although thicker-bedded, Ta-d turbidites are more common in the lower part of the section. Lateral thinning and fining of beds is more rapid than their outer-bend counterpart. Levee deposits of ICC3 comprise three stacked decametre-scale upward-thinning and -fining successions. Each is interpreted to record a depositional history consisting of lateral channel migration, levee deposition, channel filling, and distal levee deposition. During the early stage of increasing levee relief it is proposed that the termini of individual beds progressively backstep towards the channel margin resulting in an overall lateral thinning of the stratal profile. This interpretation notably contrasts the common assumption that levee morphology is the result of the vertical stacking of beds that dip. In addition to field studies, laboratory experiments were conducted to determine the depositional threshold of non-climbing ripple cross-stratification, which is common in levee strata of ICC3. It was determined that non-climbing ripples form when bed aggradation rates are less than 0.015 cm/sec, and most probably in flows made up of poorly sorted sediment.

O revestimento de níquel químico é largamente utilizado na proteção contra a corrosão de equipamentos e estruturas utilizados na exploração de petróleo em águas profundas. Apesar de ser considerado um dos revestimentos mais adequados para esta finalidade, são muitos os casos em que se verificam falhas prematuras do revestimento em serviço. Isto tem sido atribuído às diferenças nas características do revestimento decorrentes das diferenças do processo de aplicação e da natureza e preparação da superfície dos substratos a serem protegidos. Estas diferenças decorrem do fato de não existirem especificações abrangentes que definam as características necessárias do revestimento para uma garantia de qualidade. Diante disto, o presente trabalho teve como objetivo estudar a influência dos principais fatores sobre o desempenho dos revestimentos de níquel químico utilizando ferramentas estatísticas como: planejamento fatorial, seleção dos melhores subconjuntos de regressão, regressão múltipla e curvas de nível. Os fatores considerados neste estudo foram: tipo e estado superficial do substrato, idade do banho, teor de fósforo no revestimento, natureza e teor de contaminantes no revestimento, espessura do revestimento e tipo de tratamento térmico. A caracterização dos revestimentos de níquel químico foi realizada conforme sugerida na norma ISO 4527 e o desempenho dos revestimentos foi verificado por meio dos ensaios de exposição à névoa salina (1 536 h), exposição ao dióxido de enxofre (10 ciclos) e imersão em água do mar sintética (120 dias). Ensaios eletroquímicos (polarização linear e espectroscopia de impedância eletroquímica) foram realizados somente com o intuito de compará-los ao ensaio de exposição à névoa salina e,assim, ter um ensaio capaz de verificar revestimentos de bom desempenho em um período de tempo menor. Dentro dos intervalos estudados, verificou-se que o desempenho do revestimento de níquel químico é influenciado pelo tipo de substrato, pela espessura da camada depositada, pelo teor de fósforo, pela idade do banho, pelo tratamento térmico e pelos teores dos seguintes contaminantes: enxofre, chumbo, magnésio, cobre, ferro e manganês. A metodologia estatística adotada permitiu verificar a interação entre os fatores influenciadores, fato não considerado na literatura consultada. Além disto, foi possível constatar que os ensaios adotados nas normas internacionais atuais são adequados para verificar a qualidade dos revestimentos. Verificou-se também que os ensaios eletroquímicos, apesar de adequados para o estudo da resistência intrínseca à corrosão do revestimento de níquel químico, não se mostraram adequados para detectar a presença de porosidade que é o principal indicativo da qualidade de proteção por barreira de revestimentos catódicos como o níquel químico. Com os resultados obtidos, será possível a elaboração de uma especificação para se obter revestimentos de níquel químico com bom desempenho. / The autocatalytic nickel-phosphorus (NiP) or electroless nickel (EN) coatings are widely used to protect equipment and structures against corrosion and erosion, used in the exploitation of petroleum in deep waters. Even though NiP is considered as the most appropriate coating for this purpose, many premature failures are verified in service. This has been attributed to the differences in the characteristics of the coating due to the differences in the application processes and in the nature and preparation of the substrate surfaces. The lack of broad specifications that define the required characteristics of the good quality coating is responsible for those differences. The present work had as its objective to identify the main factors related to the NiP performance using statistical tools as: factorial design, best subset regression, multiple regression and contour diagram. The considered factors were: substrate type, substrate surface finishing, bath age, phosphorus content, thickness, heat treatment and impurities. The NiP coatings were characterized in agreement with the ISO 4527 and their performance was verified through the salt spray test (1 536 h), the Kesternish test (10 cycles) and the synthetic sea water immersion test (120 days). Electrochemical tests (linear polarization and electrochemical impedance spectroscopy) were conducted in order to compare them to the salt spray test and thus reducing the testing time. In the studied range, it was verified that the NiP performance is influenced by the following factors: substrate type, thickness coating, phosphorus content, bath age (MTO), heat treatment and the impurities: sulfur, lead, magnesium, copper, iron and manganese. It was possible to verify that the types of accelerated corrosion tests adopted in the current international standards are appropriate to verify the quality of the coatings. It was also verified that the electrochemical tests, despite being suitable to indicate the NiP intrinsic corrosion resistance, are not appropriate to verify the NiP porosity (which is the main indication of a cathodic coating quality). With the obtained results, it will be possible to establish a better specification in order to obtain NiP with good quality.

Although levee deposits make up a significant part of modern and ancient deep-marine slope systems, details of their internal lithological composition and stratal architecture remain poorly documented. At the Castle Creek study area, strata of the Neoproterozoic Isaac Formation (Windermere Supergroup) crop out superbly in a kilometre-scale section through a sinuous deep-water channel-levee system (ICC3). Levee deposits near the outer bend of the channel consist of sandstone-rich (sandstone-to-mudstone ratio of 68:42), medium- to thick-bedded turbidites interstratified with thinly-bedded turbidites. Structureless sandstone (Ta), planar laminated sandstone (Tb), non-climbing ripple cross-stratified sandstone (Tc) and massive and laminated siltstone (Td) are common. Thick beds generally thicken and then thin and fine laterally over about 300 m. Thin-bedded strata, in contrast, thin and fine negligibly over similar distances. In the distal part of the outer-bend levee (up to 700 m laterally away from the channel) strata consist predominantly of thin-bedded Tcd turbidites with a much lower sandstone-to-mudstone ratio (35:65). On the opposite side of the channel, inner-bend levee deposits are mudstone-rich, locally as low as 15:85, and consist mostly of thin-bedded, Tcd turbidites, although thicker-bedded, Ta-d turbidites are more common in the lower part of the section. Lateral thinning and fining of beds is more rapid than their outer-bend counterpart. Levee deposits of ICC3 comprise three stacked decametre-scale upward-thinning and -fining successions. Each is interpreted to record a depositional history consisting of lateral channel migration, levee deposition, channel filling, and distal levee deposition. During the early stage of increasing levee relief it is proposed that the termini of individual beds progressively backstep towards the channel margin resulting in an overall lateral thinning of the stratal profile. This interpretation notably contrasts the common assumption that levee morphology is the result of the vertical stacking of beds that dip. In addition to field studies, laboratory experiments were conducted to determine the depositional threshold of non-climbing ripple cross-stratification, which is common in levee strata of ICC3. It was determined that non-climbing ripples form when bed aggradation rates are less than 0.015 cm/sec, and most probably in flows made up of poorly sorted sediment.

Twenty-five piston cores 6 to 12 feet long were obtained from the deepwater sediments of Bear Lake, Utah-Idaho. Analyses of these cores revealed that the deep-water sediments of the lake are divided into two major S('f]Uflnces: a younger sequence rich in carbonate minerals, here called the carbonate sequence, and an older sequence rich in silicate minerals, referred to in this paper as the silt sequence. The carbonate sequence is composed of clay-sized quartz, aragonite, calcite, dolomite, montmorillonite, illite, kaolinite, chlorite, and amorphous material. The silt sequence consists of both silt- sized and claysized particles of quartz, calc ite, dolomite, montmorillonite, illite, kaolinite, chlorite, and amorphous material. Aragonite is absent in the silt sequence. The carbo nate sequence is rich in ostracod exoskeletons and pollen grains. Small quantities of woody material and dark, organic-rich wnes occur within the silt sequence. Chemical analyses for Mg, Ca, Fe, Mn, K, Zn, Na , and Sr were reformed on the sediments. Unusually high concentrations of Fe (8.25 percent) were found in the silt sequence, and of Sr (0 .110 percent), in the carbonate sequence. Isotopic analyses for o18 and c13 in the lake sediments indicate that formation of the authigenic carbonate minerals occurred under normal lake-bottom conditions. From the data collected, the following conclusions or inferences are made. The carbonate sequence was deposited in water depths similar to, or grea ter than, those of the present. Within this sequence, aragonite is precipitating at present from solution in such quantities that it is responsible for the inversion of the average Ca/ Mg mole ratio of inflowing water of 2:1 to a Ca/ Mg mole ratio of 1:5 in the lake water. The high concentration of Mg +2 and possible high concentration of Sr+2 in the lake water have resulted in conditions favorable for development of protodolomite. Atypical X-ray diffraction patterns for calcite and dolomite, and the relative abundances of aragonite, calc ite, and dolomite reveal that protodolomite probably is, or has been, forming in Bear Lake. The silt sequence was deposited in water shallow enough for rooted plants to establish themselves . In this shallow environment detrital sediments rich in kaolinitic clay derived from the· Bear Lake Plateau were altered to sediments rich in montmorillonitic clay and amorphous materials. The sharp contact between the silt sequence and the overlying carbonate sequence apparently represents abrupt termination of widespread swampy depositional conditions in the Bear Lake graben, caused by flooding, which possibly resulted from the most recent major episode of downfaulting of Bear Lake Valley.

Dissolved oxygen (DO) depletion in a water body is governed by two primary mechanisms: biological oxygen demand (BOD) from the water column, and sediment oxygen demand (SOD) from sediments. SOD is the dominant oxygen sink in many water bodies; measurements show as much as 95% of oxygen consumption as attributable to SOD (Truax, Shindala, & Sartain, 1996). Measuring SOD in surface water impoundments is an essential component in evaluating and an important input for modeling the health of a water body. Traditional SOD measurement methods are difficult in deeper waters, such as in reservoirs or lakes, because traditional SOD measurement chambers require direct placement. The goal of this research was to modify an existing SOD chamber design to support deployment and recovery in depths in excess of 5ft, typically from a boat or other floating platform. The design required accurate DO measurements, taken unattended and recorded for several hours to several days, for SOD calculations and other parameters such as cation releases under anaerobic conditions. Using a previously designed chamber, I developed tools and methods to meet these requirements. DO data logger probes were purchased so that DO calculations could be taken without the need of surface support. To mount the chambers inside the previously designed chambers, a new mounting mechanism was designed and installed onto the chamber lids. Deployment and recovery methods and design were developed to ensure the chambers would be recoverable from a boat in deep waters. Previously, the unmodified chambers could not be deployed unattended because of the required power and data link with the surface. Here I present an easily replicated chamber design that allows for remote chamber placement and measurement of SOD in deep waters without the need of SCUBA or other specialized equipment that is traditionally required. The chamber design allows water to circulate through the chambers until they are placed and closed on the sediment bed, at which time the measurements start, ensuring correct initial conditions. During deployment, the data logger will log DO concentrations at predetermined intervals for several hours or days at a time. To recover the chambers, the researcher must only find the buoy attached to the rope and hoist the units back to the surface. Modifications and methods were tested and revised over the course of several months and dozens of tests. Experiments were conducted at various depths, ranging from 12–50ft, which showed the versatility of the chambers. Using this design, other researchers will be able to generate substantial amounts of SOD data at depths that will allow accurate SOD behavior to be included in models of water impoundments.

Maps 1-4 are inserts within the thesis back cover / The Cambro-Ordovician sequence at St. Simon, Québec, was divided informally into ten horizons by Mathey (1970). The most prominent lithologies within the horizons are pelites, feldspathic sandstones and petromict conglomerates. One horizon 50 metres thick of feldspathic sandstones and conglomerates, described in this study, consists of three large fining upward sequences·. The fining upward sequences are defined by the occurrence of five facies. These facies are: poorly sorted coarse conglomerates, well sorted coarse conglomerates, medium conglomerates with scattered pebbles and boulders, fine conglomerate with scattered pebbles and boulders and coarse sandstones. The base of each sequence is characterized by the occurrence of coarse conglomerates; the top is characterized by the occurrence of fine conglomerates and coarse sandstones. Rarely do the coarse conglomerates grade into thick developments of medium and fine conglomerates. The fine conglomerates grade in places into coarse sandstones, although generally the coarse sandstones have sharp bases. The conglomerates display sharp bases, normal and inverse grading, grain imbrication and orientation. The long axes of the grains, which define the orientation are parallel to, and not transverse to the flow direction suggested by the imbrication. To produce these features it is suggested that turbulence and dispersive pressures were operative within the flow. If the pebbles had moved as bed load material, they would have come to rest with their long axes transverse and not parallel to the flow direction suggested by the imbrication. The term "fluxoturbidite" (Dzulynski et al., 1959) has been applied to some coarse grained deposits in geosynclinal sequences. The characteristic features of "fluxoturbidites" are their unusually coarse grain size, thick irregular bedding with associated slump structures and poorly developed grading. The differences between the conglomerates described in this study and the typical "fluxoturbidite" preclude the use of this term to describe the deposits described by the author. It is suggested that the conglomerates were deposited upon a submarine fan complex by currents which flowed parallel to the present tectonic axes. / Thesis / Master of Science (MSc)

With a strong demand for aquatic products, seaweed is a promising application in a wide range of areas, such as food, medicine and energy. Kenya is seen as a country with great potential of expanding its seaweed industry, and by inspiration from the widespread production of algaes at Zanzibar, improvements and adaptations can be made to fit Kenya. One of the places with proper environmental conditions is Shimoni, situated in the south coast of Kenya, and the purpose of this report is to assist on the expansion of seaweed farming in Shimoni, by assessing the possibilities of deep-water cultivations at site, and mediate strengths, weaknesses, opportunities and threats with the technique. In addition, another purpose is also to map out important stakeholders for starting up and expanding the system. The methods SWOT-analysis and stakeholder mapping have been carried out by literature studies and interviews with local scientists. Results have shown that deep-water techniques are less demanding on the environment than cultivations in the intertidal area and may support the local environment if proper conditions are provided for. Seaweed cultivations have large potential as an additional livelihood opportunity in coastal communities, given that adjustments to changes in market prices and environmental conditions can be met. However, deep water methods require larger initial costs than the ones carried out in the intertidal, hence political and technical support may be crucial for launching the system. These processes may be implemented iteratively as business opportunities arise. In conclusion, field research covering non-expected local aspects is further recommended. / Den globala efterfrågan av havsbaserade produkter ökar, och tycks inte mattas av. Algindustrin ses som ett lovande område att kunna bemöta detta behov på grund av sitt breda användningsområde. Mat, medicin och energi är bara några exempel på vad råvaran kan användas till. Kenya ses som ett land med stor potential att expandera sin nuvarande algindustri. Med inspiration av den närliggande storproducenten Zanzibar kan förbättringar och anpassningar göras för att passa in i Kenya. Ett område med bra miljöförutsättningar är Shimoni, beläget i södra Kenya, vilket är området denna rapport fokuserar på. Syftet med rapporten är att utvärdera möjligheterna för att utvidga algodlingar i området genom att studera potentialen hos djupvattenodling. Detta genom att analysera styrkor, svagheter, möjligheter och hot med den specifika tekniken. Syftet är vidare att kartlägga viktiga aktörer som kan ha betydelse vid en uppstart och expandering av odlingarna. Metoderna SWOT-analys och aktörskartläggning har gjorts med litteraturstudier och intervjuer med lokala forskare, som grund. Resultat har visat att djupvattentekniker är mindre påfrestande på miljön än odlingar belägna närmare strandkanten, och kan vara uppbyggande för den lokala miljön om rätt tekniker används. Algodling har en stor potential som en kompletterande sysselsättning i kustområden, om marknadspriset på råvaran höjs och att en viss miljöstandard upprätthålls. Dock så kräver djupvattenodlingar större initiala kostnader än tekniker som placeras vid lägre vattenstånd, vilket gör att politiskt och tekniskt stöd är avgörande för en möjlig uppbyggnad. Detta kan ske stegvis i takt med att nya affärsmöjligheter uppdagas. Slutligen rekommenderas fältstudier för att studera lokala aspekter som kan förekomma, vilka skiljer sig från litteraturen.