Effects of pulp bleach plant effluents on hepatic xenobiotic biotransformation enzymes in fish: Laboratory and field studies

The present preliminary report on studies of the influence of pulp bleach plant effluents on hepatic biotransformation enzymes in fish is a part of a major characterisation of biochemical and physiological effects of effluents from pulp industries in Sweden. Our studies on the xenobiotic biotransformation enzymes demonstrate, so far, that the pulp effluents have the potential to strongly induce 7-ethoxyresorufin-O-deethylase activity (EROD) in fish liver and that fish living in the receiving water of an effluent from a pulp bleach plant have induced hepatic EROD activities as well as higher hepatic UDP glucuronyltransferase activities than those living in an unpolluted area. It is thus apparent that measures of induction of biotransformation enzymes in fish liver may be a useful approach in monitoring the presence of potential hazardous compounds released from pulp industries.     

Tectonic control over topography and channel sedimentation across the forearc slope of the southern Kurile Trench

A high-resolution seismic survey covering more than 2,000 km² has revealed the processes responsible for the slope morphology and channel sedimentation across the forearc slope-basin of the Kurile Arc–NE Japan Arc collision zone, offshore from Tokachi (Hokkaido, Japan). The dominant slope contours parallel the trench but, in the middle and lower reaches of the southern slope, contours are convex-shaped with an offshore trend. This sector of the slope is traversed diagonally by the Hiroo submarine channel. The offshore-trending convex contours and the channel course have developed through the interplay of tectonic and sedimentary processes, including the development of anticlines, anticline-induced lobe sedimentation and channel avulsion. In its upper reaches, the channel is restricted by a topographic low associated with NNW–SSE-trending anticlines which developed within the upper and middle slope sectors during late Miocene uplift. The uplift timing and trend of these anticlines indicate that they resulted from collision, the channel sedimentology and slope morphology of the middle and lower slopes having been influenced by Pliocene uplift of NE–SW-trending anticlines. The trends of these anticlines parallel those of the Kurile Trench. The Pliocene and early Pleistocene strata of the middle and lower slopes consist of ponded lobe sediments deposited along the palaeo-Hiroo submarine channel on the landward side of the anticlines. As a lobe pile accumulated, the channel thalweg shifted to the north of the stack, allowing the channel to bypass the topographic high formed by the growing stack. Thick levee deposits built up along the channel course during the late Pleistocene and Holocene. These levees, along with the Pliocene and early Pleistocene lobes, are reflected in the present-day sigmoid-shaped, convex offshore-trending contours. Thus, the interplay of subduction- and collision-related anticlines, tectonic-related channel ponding, and avulsion has contributed to the slope morphology of the southern Kurile Trench.     

Digital underwater acoustic voice communications

This paper describes the design of an underwater acoustic diver communication system controlled by a digital signal processor. The speech signal transmission rate is compressed by using linear predictive coding (LPC) and the extracted parameters are transmitted through the water to a synchronized receiver by employing digital pulse position modulation (DPPM). The pulse position in each time frame is estimated by an energy detection and decision algorithm which enables the received LPC parameters to be recovered and used to synthesize the speech signal     

Seasonal course of theT,S-characteristics in the north-eastern Tropical Atlantic

The problem of the seasonal variations of temperature and salinity in the intermediate zone located between the West African and the Gulf of Guinea upwellings is considered. The vertical distribution of the phase-amplitude characteristics of the annual and semi-annual variations is examined in good detail and their parameters are defined from the monthly means using the least-squares fit technique. The contribution of isopycnic advection to the formation of seasonal thermohaline variations is studied.Translated by Vladimir A. Puchkin.     

Characterization of interface roughness of rippled sand off Fort Walton Beach, Florida

As part of the environmental characterization to model acoustic bottom scattering during the high-frequency sediment acoustics experiment (SAX99), fine-scale sediment roughness of a medium sand was successfully measured within a 600 /spl times/ 600-m area by two methods: stereo photography and a technique using a conductivity system. Areal coverage of the two methods, representing approximately 0.16 m/sup 2/ of the sea floor, was comparable, resulting in the depiction and quantification of half-meter wavelength sand ripples. Photogrammetric results were restricted to profiles digitized at 1-mm intervals; sediment conductivity results generated gridded micro-bathymetric measurements with 1- to 2-cm node spacing. Roughness power spectra give similar results in the low-spatial-frequency domains where the spectra estimated from both approaches overlap. However, spectra derived from higher resolution photogrammetric results appear to exhibit a multiple-power-law fit. Roughness measurements also indicate that spectrum changes as a function of time. Application of statistical confidence bounds on the power spectra indicates that roughness measurements separated by only 1-2 m may be spatially nonstationary.     

The petroleum evaluation of a tectonically complex area: The western margin of the Southeast Basin (France)

The Southeast Basin of France is the thickest onshore French sedimentary basin which contains locally as much as 10 km of Mesozoic-Cenozoic sediment. Basin development occurred in several stages between late Carboniferous and late Cretaceous times. Partial tectonic inversion took place during two compressive events, the so-called ‘Pyrenean’ and ‘Alpine’ phases of late Cretaceous-early Tertiary and late Tertiary ages respectively. They are separated by an intervening stretching event of Oligocene age, which further south resulted in the opening of the western Mediterranean oceanic basin. As a result of this complex tectonic history, structural traps were difficult to image on the seismic data shot during the first phase of exploration prior to 1980. Oil and gas natural seeps, and shows in several wells, indicate that some petroleum systems are, or have been active, at least in some places.The present erosional western margin of the basin is more or less superimposed on the initial Triassic-Jurassic margin. Margin subsidence and Tertiary inversion are discussed using regional sections on which the polyphase history of the entire basin is well shown. These sections are located on three major segments where the Mesozoic margin is either partly preserved (Ardèche), or has been partly inverted in late Tertiary times (Vercors-Chartreuse), or has been completely inverted in early Tertiary times (Corbières-eastern Pyrenees). 1-D ‘Genex’ basin modelling on the Ardèche segment, and 2-D ‘Thrustpack’ structural-maturity modelling in the Vercors-Chartreuse segment are used to further assess the remaining petroleum plays.     

Remote estimation of surficial seafloor properties through the application Angular Range Analysis to multibeam sonar data

The variation of the backscatter strength with the angle of incidence is an intrinsic property of the seafloor, which can be used in methods for acoustic seafloor characterization. Although multibeam sonars acquire backscatter over a wide range of incidence angles, the angular information is normally neglected during standard backscatter processing and mosaicking. An approach called Angular Range Analysis has been developed to preserve the backscatter angular information, and use it for remote estimation of seafloor properties. Angular Range Analysis starts with the beam-by-beam time-series of acoustic backscatter provided by the multibeam sonar and then corrects the backscatter for seafloor slope, beam pattern, time varying and angle varying gains, and area of insonification. Subsequently a series of parameters are calculated from the stacking of consecutive time series over a spatial scale that approximates half of the swath width. Based on these calculated parameters and the inversion of an acoustic backscatter model, we estimate the acoustic impedance and the roughness of the insonified area on the seafloor. In the process of this inversion, the behavior of the model parameters is constrained by established inter-property relationships. The approach has been tested using a 300 kHz Simrad EM3000 multibeam sonar in Little Bay, NH. Impedance estimates are compared to in situ measurements of sound speed. The comparison shows a very good correlation, indicating the potential of this approach for robust seafloor characterization.