NITROGEN AND PHOSPHORUS IN SURFACE WATERS OF THE UPPER COLORADO RWER BASIN1

ABSTRACT: As part of a basinwide water-quality study, nitrogen and phosphorus data for the Upper Colorado River Basin from the Colorado-Utah State line to the Continental Divide were analyzed for spatial distributions, concentrations associated with various land uses, and temporal trends. Nitrogen and phosphorus concentrations generally increased in a downstream direction. Some nutrient concentrations were elevated at some sites in the upper parts of the basin in areas influenced by increasing urbanization. Sites were grouped according to land use and site type, and median nutrient concentrations were compared among groups. Sites within the agricultural areas of the basin generally had the highest concentrations of nitrogen and phosphorus; concentrations for main-stem, tributary, and urbanization sites were slightly lower than for the agricultural sites. Background sites, or sites with minimal land-use impacts, had very low median nutrient concentrations. Several sites with long-term data were analyzed for temporal trends in concentrations. Several statistically significant downward trends of low and moderate magnitude were observed for nitrogen and phosphorus species. No upward trends were observed in the data at any site.     

Eusociality has evolved independently in two genera of bathyergid mole-rats — but occurs in no other subterranean mammal

Summary Extensive field and laboratory studies show that Damaraland mole-rats, like naked mole-rats, have an extreme form of vertebrate sociality. Colonies usually contain 2 reproductives and up to 39 non-breeding siblings, 90% of whom live a socially-induced lifetime of sterility; they remain in the natal colony, forage for food, defend the colony and care for successive litters. Although there is heightened dispersal following good rainfall, the majority of adult non-reproductives remain in their natal colony and failure to disperse is not directly attributable to habitat saturation or unfavourable soil conditions. A major dispersal event follows the death of a reproductive. Differences in colony cohesion, ethology and the hormonal profiles of non-reproductive animals suggests that eusociality evolved along different pathways in these two phylogenetically divergent genera of the Bathyergidae.     

Accumulation of Biophilic Elements in the Needles of Picea Species in Natural and Urbanized Ecosystems of Siberia and Central Asia in Relation to the Assessment of Environmental Quality

Variation in the content of N, P, K, Ca, Mg, Na, Cu, Zn, Mn, and Fe has been analyzed in the needles of 19 spruce species growing in the natural and urbanized ecosystems of Siberia and Central Asia. The results have shown that similarity in the content of biophilic elements in one-year-old needles of different species is conditioned by biochemical processes, which confirms the status of these species as passive bioindicators of environmental quality. The contents of trace elements in perennial needles, except color variations of chlorophyll, deserve further study as prospective indicators of environmental quality.     

Scotch Pine Pollen under Conditions of Environmental Stress

Environmental conditions causing stress have a significant effect on the generative organs of Scotch pine. The parameters characterizing pine pollen are subject to significant interannual variations and are closely connected with weather and climatic conditions in the period of pollen formation. Airborne pollutants affect the quality of pine pollen, which is especially apparent in the years favorable for the formation of microspores. The ability of Scotch pine pollen to germinate and form pollen tubes in the regions with different technogenic loads proved to be significantly lower than in tree stands of the background areas.     

Scenarios for integrated river catchment and coastal zone management

The European Water Framework Directive requires EU Member States to introduce water quality objectives for all water bodies, including coastal waters. Measures will have to be introduced if these objectives are not met, given predictions based on current trends. In this context, the estimation of future fluxes of nutrients and contaminants in the catchment, and the evaluation of policies to improve water quality in coastal zones are an essential part of river basin management plans. This paper investigates the use of scenarios for integrated catchment/coastal zone management in the Humber Estuary in the U.K. The context of this ongoing research is a European research project which aims to assist the implementation of integrated catchment and coastal zone management by analysing the response of the coastal sea to changes in fluxes of nutrients and contaminants from the catchments. The example of the Humber illustrates how scenarios focusing on water quality improvement can provide a useful tool to investigate future fluxes and evaluate policy options for a more integrated coastal/catchment management strategy.     

Reestablishment of the Perdido Key Beach Mouse (Peromyscus polionotus trissyllepsis) on Gulf Islands National Seashore

Abstract: In April 1986, the endangered Perdido Key beach mouse (Peromyscus polionotus trissyllepsis) existed only as a small population of less than 30 animals on the western end of Perdido Key at Gulf State Park, Alabama This population was vulnerable to extinction from a variety of causes. Fifteen pairs of mice from Alabama were moved approximately 20 km on the same island to Gulf Islands National Seashore Florida between November 1986 and April 1988. The Alabama population was surveyed by live-trapping before each removal and showed a large increase during this study. Eleven pairs of mice were released into enclosures to stimulate burrowing and reduce dispersal at the release site. The last four pairs w e released unrestricted into the dune habitat Trapping in July 1988 revealed that virtually all available dune habitat (11,000 linear m; approximately 160 ha) had been occupied by the mice. Fifty-five individuals were captured including four of the released mice. Exchanges between the populations are recommended to prevent loss of genetic diversity. Future research should investigate demographics, dispersal pattern, and the application of DNA fingerprinting techniques to determine rates of gene flow in the population. The Perdido Key beach mouse provides an excellent model for studying the effects of a population bottleneck on genetic diversity and testing the predictions of population viability analysis.     

Concurrent Chemical and Histological Analyses: Are They Compatible?

Bivalves are often used as sentinel organisms in monitoring programmes for trace organic contaminants. the animal's physiological state may be important in interpreting trends in contaminant body burden. Simultaneous evaluation of physiological state and organic contaminant concentration in bivalves typically involves removal of a lipid-rich cross-section of the body mass for histopathological and/or gonadal analysis.

In this study, the bias introduced by this technique in the final trace organic concentrations, e.g. of polynuclear aromatic hydrocarbons, chlorinated pesticides and polychlorinated biphenyls, are evaluated on five different size groups of oysters. As a test case, we evaluated the use of this method in the NOAA's Status & Trends Mussel Watch (NS&T) Programme. the average biases introduced by this technique in the final trace organic concentrations in Gulf of Mexico oysters have been increasing since 1986 as a consequence of a continuous decrease in the size of the individuals sampled.     

An approach to preimplantation diagnosis of β-thalassaemia

Using the polymerase chain reaction (PCR), it was possible to amplify a single copy fragment of the β-globin gene from 2–32 human embryonic cells obtained from arrested preimplantation embryos. For the detection of β-thalassaemia mutations, allele specific priming of the PCR using nested primers was employed using approximately 10 pg of DN A from individuals known to carry these mutations. This approach was successful in detecting the presence or absence of five Asian Indian β-thalassaemia mutations that were selected for this study. In spite of meticulous precautions against contamination, false-positive amplification was observed, a problem that will have to be overcome before this approach can be used in clinical practice.     

Winter-spring essential reorganization of cell proliferation in the digestive tract epithelia in the mussel Crenomytilus grayanus

A study of the seasonal dynamics of cell proliferation in the digestive tract epithelia of the mussel Crenomytilus grayanus (Bivalvia) collected in the Sea of Japan between 1971 and 1984 revealed two opposite states so far unknown for marine molluscan tissues: proliferative resting in winter and a following outburst of cell division in spring. In winter and early spring (at water temperatures below or near 0°C), mitotic figures in the lining epithelia of labial palps and intestine strongly reduced in number and later almost disappeared (February-March); DNA-synthesizing cells in these epithelia on thymidine radioautographs became sparse and only a restricted number of new cells entered the cell cycle. A proliferation block was relieved at the beginning of April (at a temperature of 2 to 4°C): an initiation of a many-fold increase in the mitotic index and some increase in the ³H-T-labelled nuclei index and their advance to the maximum in late April to May (up to more than 0.2 and 5 to 6%, accordingly) were found. In late spring (at temperatures of 5 to 10°C), a striking rise in the number of cells entering the cell cycle was observed with a probable acceleration of the cycle proper. Both seasonal states of cell proliferation — a deep depression and outburst, established in the winter-spring period are interpreted as essential events in the life cycle of the mussel studied.