Dissolved and labile concentrations of Cd, Cu, Pb, and Zn in the South Fork Coeur d’Alene River, Idaho: Comparisons among chemical equilibrium models and implications for biotic ligand models

In order to evaluate thermodynamic speciation calculations inherent in biotic ligand models, the speciation of dissolved Cd, Cu, Pb, and Zn in aquatic systems influenced by historical mining activities is examined using equilibrium computer models and the diffusive gradients in thin films (DGT) technique. Several metal/organic-matter complexation models, including WHAM VI, NICA-Donnan, and Stockholm Humic model (SHM), are used in combination with inorganic speciation models to calculate the thermodynamic speciation of dissolved metals and concentrations of metal associated with biotic ligands (e.g., fish gills). Maximum dynamic metal concentrations, determined from total dissolved metal concentrations and thermodynamic speciation calculations, are compared with labile metal concentrations measured by DGT to assess which metal/organic-matter complexation model best describes metal speciation and, thereby, biotic ligand speciation, in the studied systems. Results indicate that the choice of model that defines metal/organic-matter interactions does not affect calculated concentrations of Cd and Zn associated with biotic ligands for geochemical conditions in the study area, whereas concentrations of Cu and Pb associated with biotic ligands depend on whether the speciation calculations use WHAM VI, NICA-Donnan, or SHM. Agreement between labile metal concentrations and dynamic metal concentrations occurs when WHAM VI is used to calculate Cu speciation and SHM is used to calculate Pb speciation. Additional work in systems that contain wide ranges in concentrations of multiple metals should incorporate analytical speciation methods, such as DGT, to constrain the speciation component of biotic ligand models.     

Acoustic-gravity wave propagation in an atmosphere with two sound channels

Summary In order to interpret the observed features of pressure records produced by waves from large explosions in the earth's atmosphere, the writers have obtained numerical solutions of the homogeneous equations governing acoustic-gravity wave propagation in a stratified compressible fluid. Theoretical dispersion curves and variations of perturbation kinetic energy with altitude are presented for 11 normal modes. It is shown that the step-like character of the phase velocity curves in the velocity-period plane can be interpreted as being the result of interference between two families of normal modes-«quasi-horizontal modes» representing energy propagation in the lower atmosphere (below the ozonosphere) and «quasi-vertical modes» representing energy propagation in the upper atmosphere (above the ozonosphere). The theoretical prediction that several normal modes contribute to the observed barogram traces is verified by Fourier analysis of a number of wave records.Lamont Geological Observatory Contribution No. 611. — This research was supported by National Science Foundation Grant NSF-G-11997, Office of Naval Research Contract Nonr 266 (70), and National Science Foundation Grant NSF-GP-550. — Part of this research was done at the NASA Institute for Space Studies, New York, N. Y.     

Basalt from Louisiana continental shelf

A basalt outcrop was discovered on Alderdice Bank on the outer Louisiana continental shelf. The basalt shows an age of 76.8 ± 3.3 × 10⁶ years. Textural, mineralogical, and chemical characteristics indicate that it is an alkali basalt of shallow intrusive origin. It was probably brought to the seafloor by salt tectonics and exposed due to salt dissolution.An accurate account of the Mesozoic geologic history of the Gulf of Mexico must consider the apparent consanguinity of all magmatic rocks of the region, including the Alderdice Bank basalt, and the apparent basinward decrease in age of magmatic activities.     

Characterization of bacterial community structure in vestimentiferan tubeworm Ridgeia piscesae trophosomes

Terminal‐restriction fragment length polymorphisms (T‐RFLPs) were used to address the question whether there are multiple phylotypes of bacteria within the trophosome of the vestimentiferan tubeworm Ridgeia piscesae in addition to the known endosymbiont. Clone libraries were constructed to aid in the identification of the additional bacterial phylotypes. Individual R. piscesae specimens were collected from Juan de Fuca Ridge, Axial Caldera and Explorer Ridge, Magic Mountain. Clone library analyses revealed only one bacterial phylotype (expected R. piscesae endosymbiont) within the Explorer Ridge trophosomes. However, the Axial Caldera clone library revealed five operational taxonomic units (OTUs). Three of the resulting phylotypes detected (designated RAE) were putative thioautotrophic symbionts within the γ‐Proteobacteria which belonged to the anticipated endosymbiont group (RAE OTU 1), the Maorithyas hadalis symbiont II group (RAE OTU 3), and the Halothiobacillus group (RAE OTU 4). The remaining two phylotypes were most likely opportunistically derived. RAE OTU 5 was an α‐Proteobacterium within the Roseobacter group and RAE OTU 2 was within the Cytophaga–Flavobacterium–Bacteroidetes. T‐RFLP analyses revealed that all 15 trophosomes evaluated contained at least RAE OTUs 1 and 4. Five of the 15 trophosomes contained at least RAE OTUs 1, 3, and 4 and two of the trophosomes contained at least five RAE OTUs. Cluster analysis of the T‐RFLP data revealed three distinct clusters. The number of taxa within the trophosome may be an indication of the general health of the tubeworm. This study strongly suggests that we have discovered and identified more than one bacterial phylotype within the trophosome of vestimentiferan R. piscesae.     

Partitioning of polycyclic aromatic hydrocarbons between water and particles compared to bioaccumulation in mussels: a harbour case

Water and particles from three sites located in Halifax Harbour, near and further away from combined municipal sewage effluents (CMSE) were analysed for parental and alkylated polycyclic aromatic hydrocarbons (par and alkPAH). Bioavailability of PAH was compared for inter-tidal mussels collected at the same sites in April and November. The PAH fingerprint determined over 9 sampling times covering a period of 19 months differed more between phases (water and particles) and seasons, than between sites. In the spring, more alkPAH associated with diesel and gasoline were detected in the soluble phase, along with more bioaccumulation of alkPAH in inter-tidal mussels. A broader number of parPAH were detected in mussels collected in the fall. The mean sum of dissolved alkPAH concentrations was higher in water at the site closer to raw CMSE than at the other two sites and particles of that site. However, lowest bioconcentration factors (BCF) were determined in mussels of this more contaminated site. Similar biota-particle accumulation factors (BPAF) were determined for parPAH in mussels from the three sites, all lower than the BCF of alkPAH. The study indicates that sewage treatment plants will reduce the amount of parPAH especially larger than fluoranthene and pyrene from being deposited in the harbour; that alk naphthalenes and fluorenes present in water will continue to be discharged; that the disturbance of sediments can make particle-bound PAH available to mussels.     

Turnover of hepatic hemoproteins in rainbow trout

The hepatic mixed function oxidase system in the fish differs from that in mammals in its responses to the two classic mammalian inducers. The cytochrome P-448-type inducers (polycyclic aromatic hydrocarbons) stimulate monooxygenase activity, but phenobarbital, a P-450-type inducer, does not.¹ We have compared the effects of phenobarbital (PB) and polychlorinated biphenyls (PCB) on the turnover of hepatic microsomal hemoproteins in trout (PCB's are P-448- and P-450-type inducers in mammals, which in fish induce only cytochrome P-448). We show here that neither PCB nor PB treatment changed the turnover rate. However, both the rates of synthesis and degradation were much slower than in the rat.     

The sea-surface microlayer of puget sound: Part I. Toxic effects on fish eggs and larvae

The sea surface is an important habitat for the developmental stages (eggs and larvae) of many fish and invertebrates; it is also a concentration point for anthropogenic contaminants entering the sea. Studies were conducted to determine the extent to which the sea surface of Puget Sound was toxic to the early life history stages of fish. Three urban bays with suspected contamination, a rural reference bay, and a Central Sound site were compared. Surface-dwelling eggs and organisms (zooneuston) were collected with a surface-skimming neuston net and their densities enumerated. Sand sole (Psettichthys melanostictus) embryos were exposed in the field and laboratory to the sea-surface microlayer. To develop a useful year-round approach to monitoring sea-surface toxicity, larval development of anchovies, kelp bass, and sea urchins was also evaluated as an indication of sea-surface microlayer toxicity.During the spawning season (February and March), urban boys in Puget Sound had lower concentrations of sand sole eggs and neustonic organisms on the sea surface than did the rural bayor Central Sound reference sites. Compared to the reference sites, laboratory exposure to surface microlayer samples collected from urban bay sites generally resulted in more chromsomal aberrations in developing sole embryos, reduced hatching success of sole larvae, and reduced growth in trout cell cultures. In situ hatching success of sole eggs was reduced by half or more in urban bays compared to reference sites.Toxicity was associated with visible surface slicks and, in urban bays, increased with increasing surface pressure (dynes cm⁻¹). Results to be reported separately (Part II) indicate that toxicity is strongly correlated with the presence of high concentrations of polycyclic aromatic hydrocarbons and metals in the sea-surface microlayer. The toxicity of SMIC samples was similar when evaluated by sole, anchovy, kelp bass, or sea urchin tests. A sea-surface monitoring program could use sea urchin embryos to evaluate site-specific sea-surface toxicity throughout the year.     

An experimental facility for testing loaded structures in a high hydrostatic pressure environment and an application to axially loaded columns

An experimental facility is described for the testing of structures under a combined axial load and hydrostatic pressure load. This facility was used to determine the effects of hydrostatic pressure (up to 6000 psi) on the load-carrying capacity of slender metal columns. There appeared to be no significant effect in this case.