In situ velocity profiles in gassy sediments: Kiel Bay

Acoustic behavior of gas-bearing sediments is significantly different from that of gas-free sediments. In situ velocity profiles and acoustic signal characteristics in gas-bearing sediments of the upper several meters of the sea floor in Kiel Bay are presented in this study. Observed velocities in gas-bearing sediments are both higher and lower than those of the gas-free sediments. Small amounts of gas appear to cause signal reverberation without much attenuation. whereas large amounts of gas cause substantial attenuation.     

Variability of the O2−H2S zone structure in the Black Sea: ‘Dramatic’ or mesoscale?

This paper discusses the conclusion derived during a joint U.S—Turkey expedition on the R/VKrorr on the dramatic variations of the O₂–H₂S zone in the Black Sea observed over the last 20 years. This conclusion is shown to be invalid since it was based on a comparison of data obtained at two stations only (in 1969 and 1988) that was made in various regions and in different seasons. Examples are provided for the inter-seasonal and mesoscale variations of hydrophysical and hydrochemical characteristics in the O₂–H₂S zone which, as to their scales, are comparable to or even exceed the variations registered during the expedition ofKrorr.Translated by Mikhail M. Trufanov.     

Numerical experiments on the four-dimensional assimilation of the observation data derived in the Black Sea in June 1984 on the basis of a numerical energy-balanced model

A procedure for the four-dimensional (4D) analysis of the hydrophysical fields in the Black Sea with an assimilation of the temperature and salinity (T, S) data was realized on the basis of a numerical model which involves the primitive equations of motion, and the heat and salt advection equations. Two experiments were carried out which differed by the observation data assimilation procedure. Analysis has shown that the observation data assimilation procedure realized using the energy-balanced model allows the reproduction of some synoptic features of the circulation in the Black Sea. A comparison of two computations demonstrates the efficiency of assimilating the measurement data on the basis of the 4D analysis as compared with the sequential objective analysis.Translated by Mikhail M. Trufanov.     

Contaminant concentrations and toxicity of sea-surface microlayer near Los Angeles, California

Sea-surface microlayer samples were collected from six nearshore areas receiving different amounts of anthropogenic inputs. The samples were analyzed for selected trace metals, chlorinated hydrocarbons, and polycyclic aromatic hydrocarbons. The relative toxicities of the samples were determined with fish embryo bioassays.Contaminant concentrations generally increased from offshore to the inshore stations. Contaminant concentrations were several orders of magnitude higher in microlayer samples from the highly industrialized Los Angeles and Long Beach harbors compared to samples from a site 15km offshore. Microlayer samples from the inshore stations were significantly more toxic, and induced significantly more developmental abnormalities and chromosome aberrations, than samples from the offshore stations.     

Serum biochemical and cellular responses to experimental cupric ion challenge in mussels

Our intent has been to develop rapid and sensitive bioassay procedures for laboratory and field applications based on hemolymph factors in animals such as the bay mussel, Mytilus edulis. We found that mussel hemolymph could be easily and repeatedly sampled from individual animals in sufficient amounts to allow analyses for lysozyme, proteolytic activity, total protein and hemocyte counts. In static tests there seemed to be graded responses indicating release of increasing amounts of the above factors into the hemolymph in roughly direct proportion to Cu²⁺ concentration at lethal and sublethal levels. We interpreted this to be evidence for increased lysosomal and cellular disruption as cupric ion exposure was increased or prolonged. At the same time, Cu²⁺ concentrations in the mussel hemolymph increased up to an order of magnitude above ambient in the range of 26 to 267 ppb. We felt that this was evidence for the release of Cu-binding proteins into the mussel hemolymph. Simultaneously with the above events the serum granulocytes increased in numbers above control values by factors of 3 or 4 in response to copper challenge while macrophage (terminology of Moore & Lowe, 1977) counts, including controls, declined precipitously.