Macroinfaunal structure and effects of thermal discharges in a mesohaline habitat of Chesapeake Bay,near a Nuclear Power Plant

The soft-bottom macroinfauna of the Chesapeake Bay near the Calvert Cliffs Nuclear Power Plant, Maryland, USA, was studied quarterly in 1977. A total of 42,900 organisms distributed among 55 taxa was taken in 180 Smith-McIntyre grabs. Two communities and an ecotone between these two communities were identified in association with three sediment types: sand, sand-clay, and clay. Reproductive activities of 8 numerically dominant species are described. The macroinfauna at Calvert Cliffs was largely seasonal; species richness and organism abundances were lowest in late summer. The polychaetes Scolecolepides viridis and Heteromastus filiformis and the bivalves Macoma balthica and Mya arenaria were dominant in March-June. In September-December, the polychaetes Neanthes succinea, Paraprionospio pinnata, and Glycinde solitaria and the bivalve Gemma gemma became dominant. There were clear indications of differences associated with sediment types in total number of species, total number of individuals, and abundances of the dominant species. The shallower and intermediate habitats had higher sand-clay ratios, lower organic carbon contents, and larger numbers of organisms than the deeper clay habitat. Within each depth, no apparent detrimental effects caused by the thermal discharges on total number of species, total number of individuals, abundances of the dominant species, species diversity or evenness were found. Increased abundance was observed at the discharge stations for a few species, especially for Mya arenaria and N. succinea.     

Up-beat motion in swinging limbs: new insights into assessing movement in free-living aquatic vertebrates

A new system is presented for assessing the movement of animal limbs including, after suitable calibration, quantification of limb stroke frequency and amplitude, which may be used to derive limb angular velocity and acceleration. The system is based on use of an archival unit logging data from a Hall sensor, itself set to sense magnetic-field strength at frequencies of up to 30 Hz. Typically, the Hall sensor is placed on the animal body adjacent to the limb being monitored, while a small magnet is glued to the limb. Changes in limb position result in variation of the magnetic-field strength perceived by the sensor. Captive trials were successfully performed on a harbour seal (Phoca vitulina), an Australian sea lion (Neophoca cinerea) and a hawksbill turtle (Eretmochelys imbricata), as well as on 18 free-living Magellanic penguins (Spheniscus magellanicus). The unit performed well in almost all cases, illustrating that stroke frequency was relatively invariant in any species tending, however, to be higher in smaller animals and showing that the primary variance was manifest in stroke amplitude. As an example of the utility of the system, the importance of buoyancy was demonstrated in the penguins, which had longer glide phases and lower flipper beat amplitudes at greater depths, because body air was compressed, which reduced upthrust. The small size of the system (ca. 25 g in air) makes it suitable for a wide range of marine vertebrates. Potential problems of system sensitivity, the suitability of particular recording frequencies and the value of appropriate calibration are discussed.     

Pollution in the upland environment

As part of a study on the effects of pollutants on forests, a long-term monitoring programme has been operating at two sites (602 and 275 m above sea level (a.s.l.)) in Glentress Forest, south-east Scotland, since June 1987. At these sites, equipment has been recording 20-min data for weather parameters, and cloud and rain event frequency, duration and intensity. The chemical composition of bulk cloud and rainwater has been measured. Cloudwater detection and collection has been made using passive 'Harp wire' gauges (with a cross-sectional area of 0.047 m2) strung with polypropylene filament and having a typical collection efficiency of 29% when compared with independent measurements of windspeed and liquid water content. During 1988, the annual rainfall at the upper site was 1213 mm, occurring over 1776 h. The equivalent cloudwater deposition to a forest with a drag coefficient of 0.06 was estimated to be 375 mm over 1936 h. A 'typical cloud event' lasted 4.5 h and would deposit to forests at a rate of 0.2 mm h(-1). There were significantly higher loadings of suspended particulate material (> 0.2 microm) in cloudwater (mean 18.42, max. 94.5 mg litre(-1)) compared with rainwater (mean 2.6, max. 25.6 mg litre(-1)). There were similar differences in ion concentrations, e.g. for H+ in cloudwater (mean 163, max. 1259 microm) and in rainwater (mean 33, max. 262 microM). It is concluded that cloudwater deposition represents a major pathway for pollutant transfer to the upland environment, especially where the surface vegetation is efficient at capturing cloudwater, i.e. forests. The consequences of this increased pollutant loading to forests and water catchments are yet to be assessed.     

A LAND-USE POLICY BASED ON WATER SUPPLY1

ABSTRACT: Santa Fe Country, New Mexico, has adopted a land-use policy in which zoning densities provide a balance between the water use on a parcel of land and the water supply available bencath that land. In two of four mapped hydrologic zones, ground water in storage will be allowed to be mined to exhaustion in 100 years (40 years in urban areas). Elsewhere, the policy is for a steady state with use balanced by recharge. Equations to determine storage or recharge can be solved using site specific data or regional estimates of hydrologic conditions. Substantial reductions in the lot size requirements are allowed if water conservation convenants are adopted. Public acceptance indicates that the policy successfully integrates technical and political concerns. It is simple to administer, yet reflects widely expressed public goals and values.     

DEVELOPMENT AND EVALUATION OF A DIMENSIONLESS UNIT HYDROGRAPH1

ABSTRACT: A generalized unit hydrograph method is developed and evaluated for ungaged watersheds. A key component in this method is the value of a dimensionless storage coefficient. Procedures to estimate this coefficient are given using calibrated values from 142 rainfall-runoff events gaged in watershed located mainly in the Eastern US. Only limited success was obtained in predicting this storage coefficient. Thirty-seven, independent rainfall-runoff events were used to test the proposed technique. The generalized unit hydrograph predicted the observed runoff hydrographs fairly well with considerable improvement in accuracy over the SCS dimensionless unit hydrograph. Approximately one-half of test storms had percent errors in predicted peak flow rates that were less than 34 percent compared to percent error of 88 percent with the SCS method.     

The influence of mycorrhizal symbiosis and fertilizer amendments on establishment of vegetation in heavy metal mine spoil

Biomass production of Andropogon gerardii and Festuca arundinacea was assessed in mine tailings (chat), a material containing high levels of zinc. The effects of organic and inorganic fertilizer amendments, the addition of an expanded clay material, and mycorrhizal fungi on the revegetation of chat were assessed. Plant growth in chat was best with mycorrhizal inoculation combined with nitrogen (either organic or inorganic) and phosphorus fertilization. Plant growth was also achieved if the chat material was amended with expanded clay and N and P fertilizer. However, the biomass produced in contaminated soil did not equal that of similarly fertilized uncontaminated soil. Regression analysis and canonical discriminate analysis revealed significant differences in the responses of the two plant species to the various chat amendments. Although F. arundinacea generally produced greater biomass than A. gerardii, it tended to accumulate more zinc in the shoots than A. gerardii. Therefore, if plant cover is to be used as forage or if wind-blown plant dry matter is of concern, A. gerardii may be more appropriate than F. arundinacea for revegetation of these toxic sites. Alternatively, if maximum plant cover is of primary importance to reduce wind or water erosion from contaminated soils, F. arundinacea may be the species of choice.     

SO2-induced growth reductions and sulphur accumulation in wheat

Ten open-top chambers were used to obtain SO(2) concentration-response relationships for growth in wheat cv. Banks, and to study the associated sulphur accumulation. Two-week-old seedlings were exposed to 0.004, 0.042, 0.121, 0.256 or 0.517 microl litre(-1) SO(2) for 79 days, 4 h per day. Response variables measured included height, shoot weight, development stage, tiller number, ear weight per plant, average ear weight, total ear number and shoot sulphur concentration. All growth parameters were significantly negatively affected by SO(2) concentrations above and including 0.042 microl litre(-1). A highly significant positive correlation existed between shoot sulphur concentration and ambient SO(2) concentration.     

PCBs and other organochlorines in human tissue samples from the Welsh population: I--Adipose

The general exposure of humans to polychlorinated biphenyls (PCBs) and SigmaDDT (i.e., p,p'-DDT + p,p'DDE = p,p'-DDD) in Wales (UK) was determined through the analysis of adipose tissue samples collected from 75 individuals during post-mortem examinations in 1990-1991. Fifty PCB congeners were screened, of which 29 were identified in most of the samples. Congener IUPAC numbers 138, 153 and 180 were the most abundant compounds, accounting for an average of 55% of the SigmaPCB congeners analysed. SigmaPCB concentrations varied between 0.2 and 1.8 microg g(-1) of adipose tissue and were positively correlated with the donors age and negatively associated with the percentage of lipid in the adipose tissue. A progressive change in the congener pattern was noted with increasing subject age. Tissue from older individuals generally contained a relatively high proportion of the more persistent and higher chlorinated congeners. SigmaDDT concentrations ranged from 0.11 to 5.6 microg g(-1) adipose tissue, with p,p'-DDE contributing 96% towards the SigmaDDT concentration. SigmaDDT levels were also positively correlated with age. No significant differences in the SigmaPCB and SigmaDDT concentrations were noted between males and females, between people living in rural and urban locations or with the subjects' body weight at the time of their death.