Superposition of plane strain on an initial sedimentary fabric: an example from Laksefjord, North Norway

Shape fabric determinations in deformed grits, microconglomerates and conglomerates in the Landersfjord region of the Laksefjord Nappe, Finnmark, North Norway, have demonstrated the existence of prolate fabric ellipsoids. The correlation between shape fabric symmetry and the orientation of the principal fabric axes suggests that the fabrics are the result of a tectonic plane strain superimposed roughly coaxially on an initially oblate sedimentary fabric. A plot of the fabric ellipsoids on a three axis diagram allows the effect of the initial fabric to be removed, and the amount of strain to be determined. A contour map of the strain shows it to increase to the north and west. Models are proposed for the origin of the strain.     

Traveltimes for infrasonic waves propagating in a stratified atmosphere

The tau– p method of Buland & Chapman (1983) is reformulated for sound waves propagating in a stratified atmosphere under the influence of a height-dependent wind velocity profile. For a given launch angle along a specified azimuth, the ray parameter is redefined to include the influence of the horizontal wind component along the direction of wave propagation. Under the assumption of negligible horizontal wind shear, the horizontal wind component transverse to the ray propagation does not affect the direction of the wave normal, but displaces the reference frame of the moving wavefront, thus altering the observed incidence azimuth. Expressions are derived for the time, horizontal range, and transverse range of the arriving waves as a function of ray parameter. Algorithms for the location of infrasonic wave sources using the modified tau– p formulation in conjunction with regional atmospheric wind and temperature data are discussed.     

Combined use of aerogammaspectrometry and geochemistry to access sediment sources in a shallow coral site at Armação dos Búzios,Brazil

Coral and reef environments in shallow waters are negatively affected by human activities in several coastal areas worldwide. It has been demonstrated that sediment influx and macronutrient discharges induce decline of coral population structure and diversity. Therefore, efforts to quantify sediment flux, sources and the biological response to sedimentation were conducted by several marine researchers. Herein, we investigated the case study of Armação dos Búzios/Brazil/Western South Atlantic, where coral colonies (mostly Siderastrea stellata) are under stress due to sediment apportionment as a consequence of regional human occupation. Classification of potential sediment source regions was based on a high-resolution aerogammaspectrometry survey for ²³²Th, ²³⁸U and ⁴⁰K in main land near shore, used as primarily tool, in combination with sediment geochemistry. This approach allowed distinguishing three hydrographic basins (Macaé river basin, São João river basin and Una river basin) as potential sources. Hierarchical cluster analysis applied to the set of parameters identified the Macaé River as the most probable sediment contributor to the coralline site.     

Differential gene expression in oyster exposed to sewage

In order to investigate the influence of domestic sewage on the gene expression of Pacific oysters Crassostrea gigas, suppression subtractive hybridization (SSH) method was employed. Oysters were sampled at a farming area and, after 10 days of acclimation in the laboratory, were exposed to untreated domestic sewage diluted 33% for 48 h. Gills of male oysters were excised for total RNA extraction. mRNA was purified and the differential gene expression was analyzed by SSH. We obtained 61 cDNA sequences but only 15 were identified, which includes fatty acid binding protein, multidrug resistance protein, omega glutathione S-transferase, cytochrome P450 isoform CYP356A1, among others. The identified genes are associated with different metabolic functions like biotransformation, membrane transport, aerobic metabolism and translational machinery, evidencing the potential toxic effects elicited by these effluents.     

Reductions in TBT concentrations in UK estuaries following legislation in 1986 and 1987

In 1986 the Government of the United Kingdom (UK) introduced legislation to control the sale of tribytltin (TBT)-based paints. From 1986 to 1989 monitoring was undertaken, whereby samples of water, sediment, oysters (Crassostrea gigas) and mussels (Mytilus edulis) were collected from six estuaries and water samples from five marinas/harbours, and analysed for TBT. In 1989 the concentrations of TBT in water, oysters and mussels were generally only one-third to one-quarter of those observed in 1986. The most marked decrease in concentrations of TBT in oysters and mussels occurred in 1987–1988, following the 1987 ban on the use of TBT-based paints on small boats and mariculture equipment. As the concentrations of TBT in oyster tissues had decreased there has been improvement in oyster growth in terms of both meat production and growth of thin (i.e. normally shaped) shells. Oysters with a normal shell shape can now be grown in five of the six estuaries which were monitored. In contrast to the reduction in concentrations of TBT noted in water and bivalves, changes in concentrations of TBT in sediments showed no clear trend from 1986 to 1989.     

A large marine ecosystem governance framework

A large marine ecosystem (LME) governance framework, developed from a need to effectively address the sustainable management of the shared living marine resources of the Caribbean, is proposed. The framework is based on four propositions and focuses on a linked examination of two well-known components of LME-level governance: the policy cycle process by which decisions are made and the multi-level nature of LMEs. It accommodates the diversity of policy cycles at multiple levels and the linkages among them required for effective governance of LMEs. The framework takes into account of factors such as context, purpose, jurisdictional scale, capacity and complexity and provides a means to identify critical areas for intervention.     

Space-time variability of the Amazon River plume based on satellite ocean color

Satellite ocean color images were used to determine the space-time variability of the Amazon River plume from 2000–2004. The relationship between sea-surface salinity (SSS) and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) absorption coefficient for dissolved and detrital material (a_dg) (r²=0.76, n=30, rmse=0.4) was used to identify the Amazon River plume low-salinity waters (<34 psu). The plume's spatial information was extracted from satellite bi-weekly time series using two metrics: plume area and plume shape. These metrics identified the seasonal variability of plume dimensions and dispersion patterns. During the study period, the plume showed the largest areas from July to August and the smallest from December to January. The mean annual amplitude and the mean, maximum and minimum plume areas were 1020×10³ km², 680×10³ km², 1506×10³ km² and 268×10³ km², respectively. Three main shapes and dispersion pattern periods were identified: (1) flow to the northeastern South American coast, in a narrow band adjacent to the continental shelf, from January to April; (2) flow to the Caribbean region, from April to July; and (3) flow to the Central Equatorial Atlantic Ocean, from August to December. Cross-correlation techniques were used to quantify the relationship between the plume's spatial variability and environmental forcing factors, including Amazon River discharge, wind field and ocean currents. The results showed that (1) river discharge is the main factor influencing plume area variability, (2) the wind field regulates the plume's northwestward flow velocity and residence time near the river mouth, and (3) surface currents have a strong influence over river plume dispersion patterns.