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.     

Mass flux and undertow in a surf zone

The mass of water carried shoreward by the breaking waves in a surf zone will, in a two-dimensional situation, be compensated by a seaward return flow, the undertow. It is shown that the undertow is driven by the local difference between radiation stress and the set-up pressure gradient which only balance each other in average over the depth. Turbulent shear stresses are required to maintain a steady situation. Comparison with measurements confirms the theoretical results.     

Application of cluster analysis to study the relationship between the fine stratification and the background hydrological conditions in the ocean

Cluster analysis is discussed in the context of its application to map various test areas in the sea. By analysing the correspondence of the identified categories to areas with specific hydrological conditions, an attempt is made to relate the types of fine structure to diverse background conditions. With two test areas mapped, a conclusion is made as to the possible application of cluster analysis to this end.Translated by Vladimir A. Puchkin.     

Evaluation of drift current parameters using an analytical model

The paper is concerned with the evaluation of the drift current parameters derived through the use of an analytical model. In this model, effective when stratification is stable and indifferent, the vertical turbulence coefficient profile is prescribed by the power function, and hydrodynamic quantities are prescribed using the external parameters of the problem (wind stress, the Coriolis parameter, and the dimensionless stratification parameter). Model data are compared with the observations of the upper mixed layer in the vicinity of the oceanic Station C, conducted during one year. It is shown that, under the spring-summer-time warming conditions, the model at issue is capable of adequately simulating the upper ocean layer dynamics. Translated by Vladimir A. Puchkin.     

Formation of pockmarks by pore-water escape

During the course of a North Sea rig site investigation, a number of seabed depressions were observed on side-scan sonar records, some of which may be identified as pockmarks. Others are described as pits. A pockmark evolutionary series is proposed on the basis of all these features with a suggested mechanism which would favor release of pore water, but does not exclude gas escape. Acoustic voids are considered to be a related phenomenon.     

A note on significant wave height

In this note conservative bounds for significant crest height and amplitude obtained from the crossing intensity of a sea are presented. For Gaussian models of a sea level, the Rayleigh approximation for the distributions of amplitude and crest height is proved to provide conservative values for the expected significant wave characteristics. The results are illustrated by examples in which both Gaussian and non-Gaussian models for a sea are considered.