The role of women in artisanal fisheries along the Lower Benue River

A questionnaire survey was carried out to assess the role of women in the artisanal fisheries of fish markets sector along the Lower Benue River. Four (4) fishing settlement communities of fish markets along the Lower Benue were selected. They are namely North Bank, Wadata, Abinse and Gbajimba . Structure and unstructured questionnaire were administered to cover areas of personal data, fish production activities, processing and marketing among others. The study revealed that women along the Lower Benue River participate activity in the artisanal fisheries sub-sector. However, the major role played by the women was in the area of processing and preservation, marketing and distribution. These accounted 52 and 42% respectively. The distribution of the women was not tribally based however, Jukun women accounted for 66.20% followed by Agatu women 13.00%. The age bracket of the women mostly involved in fisheries activities was between 31-40 years. About 86% of them was married. The initial capital base was low and mostly by personal saving accounting for 52%. Need for government assistance was the highlight in this study. About 86% sought for Federal Government intervention from the National Poverty Eradication Programme. This they felt will be a welcome development to boost women participation in the Artisanal fisheries sub-sector along the Lower Benue River

Survey of the shrimp stocks of the Sierra Leone inshore shelf : a summary report outlining objectives, observations and recommendations on the status of the Sierra Leone shrimp fishery

This report gives the species and catch-rates per hour of some commercial shrimp species caught in the course of a short survey of inshore shelf fishing grounds. Species seen in significant quantities were: Parapenneopsis atlantica, Parapenaeus longirostris, Penaeus kerathurus and Penaeus duorarum notialis

Time for a Sea Change: a Study of the Effectiveness of Biodiversity Conservation Measures and Marine Protected Areas Along Southern Thailand’s Andaman Sea Coastline

This study examines how Thailand’s biodiversity conservation measures affect fishing communities, especially in the marine protected areas (MPAs) on the Andaman Sea coastline. It documents the various efforts of the local fishing communities to protect the resources in the area. Also included are recommendations for government agencies, civil society and the international community. [PDF contains 94 pages]

Seismic structure along transitions from flat to normal subduction: central Mexico, southern Peru, and southwest Japan

The fine-scale seismic structure of the central Mexico, southern Peru, and southwest Japan subduction zones is studied using intraslab earthquakes recorded by temporary and permanent regional seismic arrays. The morphology of the transition from flat to normal subduction is explored in central Mexico and southern Peru, while in southwest Japan the spatial coincidence of a thin ultra-slow velocity layer (USL) atop the flat slab with locations of slow slip events (SSEs) is explored. This USL is also observed in central Mexico and southern Peru, where its lateral extent is used as one constraint on the nature of the flat-to-normal transitions.

In western central Mexico, I find an edge to this USL which is coincident with the western boundary of the projected Orozco Fracture Zone (OFZ) region. Forward modeling of the 2D structure of the subducted Cocos plate using a finite-difference algorithm provides constraints on the velocity and geometry of the slab’s seismic structure in this region and confirms the location of the USL edge. I propose that the Cocos slab is currently fragmenting into a North Cocos plate and a South Cocos plate along the projection of the OFZ, by a process analogous to that which occurred when the Rivera plate separated from the proto-Cocos plate 10 Ma.

In eastern central Mexico, observations of a sharp transition in slab dip near the abrupt end of the Trans Mexican Volcanic Belt (TMVB) suggest a possible slab tear located within the subducted South Cocos plate. The eastern lateral extent of the USL is found to be coincident with these features and with the western boundary of a zone of decreased seismicity, indicating a change in structure which I interpret as evidence of a possible tear. Analysis of intraslab seismicity patterns and focal mechanism orientations and faulting types provides further support for a possible tear in the South Cocos slab. This potential tear, together with the tear along the projection of the OFZ to the northwest, indicates a slab rollback mechanism in which separate slab segments move independently, allowing for mantle flow between the segments.

In southern Peru, observations of a gradual increase in slab dip coupled with a lack of any gaps or vertical offsets in the intraslab seismicity suggest a smooth contortion of the slab. Concentrations of focal mechanisms at orientations which are indicative of slab bending are also observed along the change in slab geometry. The lateral extent of the USL atop the horizontal Nazca slab is found to be coincident with the margin of the projected linear continuation of the subducting Nazca Ridge, implying a causal relationship, but not a slab tear. Waveform modeling of the 2D structure in southern Peru provides constraints on the velocity and geometry of the slab’s seismic structure and confirms the absence of any tears in the slab.

In southwest Japan, I estimate the location of a possible USL along the Philippine Sea slab surface and find this region of low velocity to be coincident with locations of SSEs that have occurred in this region. I interpret the source of the possible USL in this region as fluids dehydrated from the subducting plate, forming a high pore-fluid pressure layer, which would be expected to decrease the coupling on the plate interface and promote SSEs.

Structural and clumped-isotope constraints on the mechanisms of displacement along low-angle detachments

Despite years of research on low-angle detachments, much about them remains enigmatic. This thesis addresses some of the uncertainty regarding two particular detachments, the Mormon Peak detachment in Nevada and the Heart Mountain detachment in Wyoming and Montana.

Constraints on the geometry and kinematics of emplacement of the Mormon Peak detachment are provided by detailed geologic mapping of the Meadow Valley Mountains, along with an analysis of structural data within the allochthon in the Mormon Mountains. Identifiable structures well suited to constrain the kinematics of the detachment include a newly mapped, Sevier-age monoclinal flexure in the hanging wall of the detachment. This flexure, including the syncline at its base and the anticline at its top, can be readily matched to the base and top of the frontal Sevier thrust ramp, which is exposed in the footwall of the detachment to the east in the Mormon Mountains and Tule Springs Hills. The ~12 km of offset of these structural markers precludes the radial sliding hypothesis for emplacement of the allochthon.

The role of fluids in the slip along faults is a widely investigated topic, but the use of carbonate clumped-isotope thermometry to investigate these fluids is new. Faults rocks from within ~1 m of the Mormon Peak detachment, including veins, breccias, gouges, and host rocks, were analyzed for carbon, oxygen, and clumped-isotope measurements. The data indicate that much of the carbonate breccia and gouge material along the detachment is comminuted host rock, as expected. Measurements in vein material indicate that the fluid system is dominated by meteoric water, whose temperature indicates circulation to substantial depths (c. 4 km) in the upper crust near the fault zone.

Slip along the subhorizontal Heart Mountain detachment is particularly enigmatic, and many different mechanisms for failure have been proposed, predominantly involving catastrophic failure. Textural evidence of multiple slip events is abundant, and include multiple brecciation events and cross-cutting clastic dikes. Footwall deformation is observed in numerous exposures of the detachment. Stylolitic surfaces and alteration textures within and around “banded grains” previously interpreted to be an indicator of high-temperature fluidization along the fault suggest their formation instead via low-temperature dissolution and alteration processes. There is abundant textural evidence of the significant role of fluids along the detachment via pressure solution. The process of pressure solution creep may be responsible for enabling multiple slip events on the low-angle detachment, via a local rotation of the stress field.

Clumped-isotope thermometry of fault rocks associated with the Heart Mountain detachment indicates that despite its location on the flanks of a volcano that was active during slip, the majority of carbonate along the Heart Mountain detachment does not record significant heating above ambient temperatures (c. 40-70°C). Instead, cold meteoric fluids infiltrated the detachment breccia, and carbonate precipitated under ambient temperatures controlled by structural depth. Locally, fault gouge does preserve hot temperatures (>200°C), as is observed in both the Mormon Peak detachment and Heart Mountain detachment areas. Samples with very hot temperatures attributable to frictional shear heating are present but rare. They appear to be best preserved in hanging wall structures related to the detachment, rather than along the main detachment.

Evidence is presented for the prevalence of relatively cold, meteoric fluids along both shallow crustal detachments studied, and for protracted histories of slip along both detachments. Frictional heating is evident from both areas, but is a minor component of the preserved fault rock record. Pressure solution is evident, and might play a role in initiating slip on the Heart Mountain fault, and possibly other low-angle detachments.

Strong atom-light interactions along nanostructures: Transition from free-space to nanophotonic interfaces

An exciting frontier in quantum information science is the integration of otherwise "simple'' quantum elements into complex quantum networks. The laboratory realization of even small quantum networks enables the exploration of physical systems that have not heretofore existed in the natural world. Within this context, there is active research to achieve nanoscale quantum optical circuits, for which atoms are trapped near nano-scopic dielectric structures and "wired'' together by photons propagating through the circuit elements. Single atoms and atomic ensembles endow quantum functionality for otherwise linear optical circuits and thereby enable the capability of building quantum networks component by component. Toward these goals, we have experimentally investigated three different systems, from conventional to rather exotic systems : free-space atomic ensembles, optical nano fibers, and photonics crystal waveguides. First, we demonstrate measurement-induced quadripartite entanglement among four quantum memories. Next, following the landmark realization of a nanofiber trap, we demonstrate the implementation of a state-insensitive, compensated nanofiber trap. Finally, we reach more exotic systems based on photonics crystal devices. Beyond conventional topologies of resonators and waveguides, new opportunities emerge from the powerful capabilities of dispersion and modal engineering in photonic crystal waveguides. We have implemented an integrated optical circuit with a photonics crystal waveguide capable of both trapping and interfacing atoms with guided photons, and have observed the collective effect, superradiance, mediated by the guided photons. These advances provide an important capability for engineered light-matter interactions, enabling explorations of novel quantum transport and quantum many-body phenomena.

Observação do transporte de sedimentos em suspensão ao longo do Canal Norte do rio Amazonas durante condições de baixa descarga (outubro 2008)

The Amazon river, located in northernBrazil, discharges between 80,000 and 250,000 m3s-1 of water onto the adjacent shelf, creating a plume of brackish water that extends hundreds of kilometers away from the river mouth. This river also carries a large amount of fine sediments to the ocean where fluid mud has been found in the topset and upper foreset layers of the subaqueous delta formed on the mid-shelf. One of the main goals of this dissertation is to describe how turbulence and suspended sediment concentration vary along the Northern Channel of the Amazon river. Water column measurements were carried out in October 2008 at six anchor stations (P1, P3, P5, P6, P8 e P9) located seaward of the river mouth; P1 and P9 were 125 km apart. Each station was occupied during 13 hours during which current speed and direction were continuously sampled with a 600 kHz Teledyne-RDI ADCP; hourly profiles of temperature, salinity, turbidity and depth were also obtained. Water samples were collected for determination of Suspended Particulate Matter (SPM) concentration and calibration of the turbidity sensor. Current speed reached values above 1.5 m s1 in the along-channel direction (NE-SW); a remarkable ebb-flood asymmetry was observed and flows were strongly ebb-dominated. Throughout the water column, SPM concentration at stations P1 and P3 varied between 100 and 300 mg L1 in association with the presence of freshwater. In contrast, a strong salinity gradient was observed between stations P6 and P9, coinciding with the occurrence of concentrations of SPM above 10 g L-1 (fluid mud). At stations P3, P5 and P6, interface between freshwater from the Amazon river and salt water from the continental shelf, shear stresses wereestimated through four diferents methods: Reynolds, Turbulent Kinetic Energy (TKE), modified TKE and Quadratic Law; in the nearbed region (3 mab) the computed values varied between 0 and 3 Pa. At the three stations (P3, P5 and P6) the lowest and the highest shear stress values were obtained through, respectively, the Reynolds and the TKE methods. Over the whole water column turbulence intensity was estimated through the standard deviation of the turbulent component of the along-channel current velocity (root-mean square of u); from these values, it was estimated the turbulent dissipation of energy (G), whose values at 3 mab varied between zero and 20 s1.

Lipídios como indicadores de processos biogeoquímicos em sedimentos da margem continental do Estado do Rio de Janeiro

Este estudo constitui parte do Projeto Habitats Heterogeneidade Ambiental da Bacia de Campos coordenado pelo CENPES/Petrobras, um projeto multidisciplinar de caracterização ambiental que considera as diferentes feições e habitats da margem continental do sudeste brasileiro. O objetivo desta tese foi investigar os processos relacionados com a origem, o transporte e o acúmulo de matéria orgânica (MO) em sedimentos da margem continental da Bacia de Campos (RJ). Para isso, foram determinados a composição elementar da matéria orgânica (carbono e nitrogênio) por combustão a seco e os lipídios (esteróis, álcoois e ácidos graxos) por CG-MS e CG-DIC. Foram analisadas 215 amostras de sedimento superficial (0-2 cm de profundidade), coletadas em duas amostragens (períodos seco e chuvoso de 2008/2009), distribuídas sobre 12 isóbatas (de 25 a 3000 m) ao longo de 9 transectos de norte a sul da bacia. Além disto, foram ainda consideradas as isóbatas de 400 a 1900 m em dois cânions submarinos no norte da bacia (Almirante Câmara e Grussaí). Com base nos resultados obtidos, a MO sedimentar na plataforma e talude da bacia revelou-se essencialmente autóctone, derivada de produtores primários e secundários. Com isto, a MO contém uma fração reativa significativa e, portanto, é potencialmente biodisponível para os organismos bentônicos. No entanto, foram observados gradientes espaciais significativos na qualidade e na quantidade da MO sedimentar. Na plataforma continental (25 m a 150 m de profundidade) as concentrações de lipídios foram intermediárias e houve predomínio de MO sedimentar lábil. Exceções foram as áreas influenciadas por ressurgência costeira e/ou intrusão sub-superficial (próximo à Cabo Frio, Cabo de São Tomé e no limite norte da bacia), onde as concentrações foram altas. No talude superior e médio (400 a 1300 m) as concentrações de MO foram notadamente mais elevadas, mas com maior influência de processos bacterianos de alteração de sua composição original. E no talude inferior (1900 a 3000 m) as concentrações de MO estiveram muito baixas e apenas os lipídios mais resistentes à degradação bacteriana foram encontrados em concentrações mensuráveis. Isto sugeriu a exportação de materiais da plataforma ao longo do gradiente batimétrico, possivelmente decorrente da ação de meandros e vórtices da Corrente do Brasil e das correntes de fundo atuantes na região. Além disto, por ser lábil e biodisponível, a MO no sedimento apresenta uma fração biodisponível que pode ter uma influência na ecologia das comunidades bentônicas, particularmente aquelas localizadas no talude superior. Os cânions Grussaí e Almirante Câmara se revelaram regiões de acúmulo de MO e importantes no transporte da MO com valor nutritivo para comunidades bentônicas do talude médio e inferior.

Variabilidade espacial e temporal da distribuição do material particulado em suspensão nas proximidades do canal de navegação da baía de Sepetiba (RJ)

Este estudo teve como objetivo principal caracterizar os padrões de distribuição do material particulado em suspensão ao longo da baía de Sepetiba, associando as variabilidades espaciais e temporais com ciclos de maré. Além disso, o estudo também avalia a utilização de equipamentos acústicos como ferramentas à estimativa das concentrações de material particulado em suspensão. A aquisição de dados foi realizada num total de sete campanhas realizadas entre novembro de 2010 e dezembro de 2011. Sete estações foram posicionadas nas proximidades do canal principal de acesso à baía, ao longo de um transecto que se estende do seu interior até sua desembocadura. As sete campanhas amostrais se distribuem em duas séries longas, de 13 e 25 horas, de aquisição em um ponto fixo, e cinco amostragens ao longo das estações. A aquisição de dados envolve: coleta de amostras de água, utilizadas nas estimativas das concentrações de material particulado; coleta de sedimentos de fundo para caracterização granulométrica das estações amostradas; perfis de parâmetros físico-químicos; dados de correntômetria adquiridos junto ao fundo. O processamento das amostras de água e sedimentos foi realizado no laboratório de Geologia Marinha da Faculdade de Oceanografia da Universidade do Estado do Rio de Janeiro. As concentrações de material particulado em suspensão foram utilizadas na calibração de sensores acústicos e óticos, permitindo uma avaliação espaço-temporal mais detalhada dos padrões de distribuição junto ao fundo e ao longo da coluna dágua. Os dados observados permitiram identificar que as maiores concentrações de material particulado em suspensão ocorrem em condições de maré enchente, e estão associadas à assimetria de maré. A baía pode ser dividida em dois setores: um na porção mais interna, onde se observou maior influência do aporte fluvial, onde as concentrações de material particulado em suspensão respondem à propagação da pluma do canal de São Francisco; e outro que se estende da porção central até sua desembocadura, onde predomina o domínio marinho, com influência de eventos oriundos da plataforma continental. Também pode ser identificada a influência do fenômeno La Niña, que provavelmente foi responsável por: altas salinidades encontradas no interior da baía e ocorrência da Água Central do Atlântico Sul à baixas profundidades. Quanto à utilização de equipamentos acústicos nas estimativas das concentrações de material particulado, os dados se demonstraram ricos em detalhes, que permitiram avaliar o comportamento do material particulado junto ao fundo frente a diferentes condições de maré, turbulência e incidência de oscilações.

Hypoxic and low pH water in the nearshore marine environments of Monterey Bay, California: characterizing a decade of oxygen and pH, and drivers of variability.

A decade-long time series recorded in southern Monterey Bay, California demonstrates that the shallow, near-shore environment (17 m depth) is regularly inundated with pulses of cold, hypoxic and low pH water. During these episodes, oxygen can drop to biologically threatening levels, and pH levels were lower than expected. Weekly water chemistry monitoring revealed that the saturation state of aragonite (the more soluble form of calcium carbonate) was often below saturation and had a moderate positive relationship with pH, however, analytical and human error could be high. Pulses of hypoxia and low pH water with the greatest intensity arise at the onset of the spring upwelling season, and fluctuations are strongly semidurnal (tidal) and diurnal. Arrival of cold, hypoxic water on the inner shelf typically occurs 3 days after the arrival of a strong upwelling event and appears to be driven by upwelling modulated by internal tidal fluctuations. I found no relationship between the timing of low-oxygen events and the diel solar cycle nor with terrestrial nutrient input. These observations are consistent with advection of hypoxic water from the deep, offshore environment where water masses experience a general decline of temperature, oxygen and pH with depth, and inconsistent with biochemical forcing. Comparisons with concurrent temperature and oxygen time series taken ~20 km away at the head of the Monterey Canyon show similar patterns but even more intense hypoxic events due to stronger semidiurnal forcing there. Analysis of the durations of exposure to low oxygen levels establishes a framework for assessing the ecological relevance of these events. Increasing oceanic hypoxia and acidification of both surface and deep waters may increase the number, intensity, duration and spatial extent of future intrusions along the Pacific coast. Evaluation of the resiliency of nearshore ecosystems such as kelp forests, rocky reefs and sandy habitats, will require consideration of these events.

Variation saisonniere des structures hydrologique et dynamique du plateau continental ivoirien (VASPI I, II, III)

This data report contains all the meteorological, hydrological and dynamic data gathered during the VASPI cruises (I : from December 8th to December 13th 1982, II : from March 5th to March 9th 1983, and III : from October 6th to October 10th 1983) carried out along the continental shelf of Ivory Coast by the oceanographic ship "Andre NIZERY". These cruises, which represent a part of a coastal programme, are included in the more general scientific program FOCAL, whose main scientific objective is the study of the thermal context of the intertropical atlantic area.

Contribution à l'écologie de quelques taxons du zooplancton de Côte d'Ivoire. 4 - Euphausiaces

Euphausiids vertical distribution on the Côte d'Ivoire continental shelf during different seasons, average zonal distrubution, mean distance to the shore, and seasonal variations in abundance computed for five years, suggest that the appearance, and the shifting of euphausiids across and along the shelf are related with the variations of the distance from the shore of the ivorian under-current. The author reports that Nyctiphanes capensis has not been found in the region.

Religion, emotions and social transformation along migratory processes. The cases of African church leaders in Spain and South Africa

221 p.