Preliminary Examination of How Human-driven Freshwater Flow Alteration Affects Trophic Ecology of Juvenile Snook (<Emphasis Type="Italic">Centropomus undecimalis</Emphasis>) in Estuarine Creeks

Maintaining proper freshwater and marine inputs is essential for estuarine function. Alteration of freshwater flows into small tributaries that traverse the upland-estuarine margin may be especially problematic, e.g., by impacting the nursery areas for juvenile finfish and shellfish. We used stomach contents and stable isotope analysis (δ¹³C, δ¹⁵N) to examine effects of freshwater flow alterations on the trophic ecology of juvenile common snook (Centropomus undecimalis) in four mangrove creeks with different freshwater flow regimes. Diet diversity in less degraded creeks was greater than in more degraded creeks, and the importance (by % mass) of the top three preys was disproportionately higher in the more degraded creeks. Stable isotope measures of trophic diversity corroborate these trends, suggesting higher intraspecific trophic diversity in less degraded creeks. The difference in diet diversity of juvenile snook may be an indicator of an overall change in ecosystem function and these shifts in food web structure may affect the rate that juveniles of this and other species with similar habitat requirements successfully join the adult population.     

Thermal equilibrium and hydrostatic equilibrium for excited states in planetary atmospheres

Thermal equilibrium and hydrostatic equilibrium are mutually exclusive for any particular quantum state of an atmospheric constituent in a non-isothermal atmosphere. As a result, there is a flux of rotationally, vibrationally, and electronically excited atoms and molecules down the temperature gradient, balanced by an up-gradient transport of ground-state atoms and molecules, resulting in a net transport of excitation energy, but with no net mass transport. The energy flux is first formulated as a molecular process and applied to vibrationally excited molecular nitrogen and rotationally excited atomic oxygen in the Earth's lower thermosphere, then reformulated as a bulk process and applied to the Venusian atmosphere, where it is shown that the CO₂ vibrational flux is a significant contribution to the total eddy energy flux in the 0–60 km region.     

A strategy for modeling ground water rebound in abandoned deep mine systems

Discharges of polluted water from abandoned mines are a major cause of degradation of water resources worldwide. Pollution arises after abandoned workings flood up to surface level, by the process termed ground water rebound. As flow in large, open mine voids is often turbulent, standard techniques for modeling ground water flow (which assume laminar flow) are inappropriate for predicting ground water rebound. More physically realistic models are therefore desirable, yet these are often expensive to apply to all but the smallest of systems. An overall strategy for ground water rebound modeling is proposed, with models of decreasing complexity applied as the temporal and spatial scales of the systems under analysis increase. For relatively modest systems (area < 200 km2), a physically based modeling approach has been developed, in which 3-D pipe networks (representing major mine roadways, etc.) are routed through a variably saturated, 3-D porous medium (representing the country rock). For systems extending more than 100 to 3000 km2, a semidistributed model (GRAM) has been developed, which conceptualizes extensively interconnected volumes of workings as ponds, which are connected to other ponds only at discrete overflow points, such as major inter-mine roadways, through which flow can be efficiently modeled using the Prandtl-Nikuradse pipe-flow formulation. At the very largest scales, simple water-balance calculations are probably as useful as any other approach, and a variety of proprietary codes may be used for the purpose.     

Economic Implications of Potential ENSO Frequency and Strength Shifts

Some argue that global climate change may alter the frequency and strength of extreme events. This paper examines the economic damages in the agricultural sector arising from a shift in El Niño Southern Oscillation (ENSO) event frequency and strength. The assumptions about the frequency of ENSO shift are motivated by an article by Timmermann etal. (1999). The damage estimates reported here are in the context of the global agricultural system. Annual damages in the 3 to 4 hundred million U.S. dollar range are found if only the frequency of ENSO events changes. However, annual damages rise to over $1 billion if the events also intensify in strength. Event anticipation and crop mix adaption on the part of farmers can help offset the damages but cannot fully alleviate them.     

The prospects of finding exploitable geothermal reservoirs

Summary The existing interest in the prospect of geothermal power has been stimulated by the recent revision in the relative costs of the various sources of energy that can be efficiently converted to electrical energy for easy distribution. One may erroneously conclude that the energy sources that are alternates to fossil fuels have simply been ignored. In fact, there are very strong reasons, based on physical or engineering considerations, why solar, wind, and tidal power have not been productively developed throughout the world. There are also valid physical and geological reasons why geothermal reserves have never attracted much investment relative to alternative energy sources. This article sets forth some of those reasons.A geothermal target is defined in terms of present germane technology and economic conditions. Geothermal targets are observed to be rare at the present geological time; this can be explained by a model of a geothermal reservoir due to a short-lived intrusion. It dissipates the heat by conduction and convection within a few tens of thousands of years. Geothermal targets are rare in space because they are only likely to occur where curreent tectonic activity is high. Geothermal development is rare in practice because the technology is not widespread for economically handling the corrosive brines or high water-content of natural steams. Environmental pollution from geothermal developments is often far worse than anticipated. Any geothermal reservoir is a depletable resource, assuming current technology.Investment in the development of drilling holes an order of magnitude deeper than at present and in the use of hot rock or magma is most appropriate for the long-term development of geothermal power. In the immediate future, petroleum must be used while nuclear power plants are constructed. There will not be any physical shortage of petroleum within a hundred years; but much of it happens to be in the other guy's backyard.A geothermal summary of high-temperature geothermal reserves, exclusive of the USA, is given.HIG Contribution Number 752     

The New Zealand seismograph network

The New Zealand seismograph network is one of the oldest established and most extensive in the world. From the installation of a Milne seismograph in 1900, it has now grown to consist of 36 permanent stations and two telemetered arrays. The network's stations provide for the recording of world earthquakes over an area that extends from the Pacific Islands to Antarctica, but its main emphasis is given to the study of local seismicity in New Zealand. Instrumentation varies from very low magnification instruments capable of recording the strongest earthquakes, to modern high-magnification networks, and a digitally recording Seismic Research Observatory. A set of portable recorders is also available for field studies. Present analysis procedures are being revised to take account of lateral variations in seismic velocity and attenuation.     

Potentiometric Determination of Silver Thiolate Formation Constants Using a Ag2S Electrode

Formation constants for silver thiolates were obtained by titration of the ligand in a constant temperature, ionic strength and pH medium and measuring the potential change at a Ag2S electrode. A non-linear equation was derived from which the first and second silver formation constants, 1 and 2, and the sulfide group acid dissociation constant, Ka, were determined. An overall estimate of the uncertainty in the derived parameters was obtained using a Monte Carlo approach. The procedure was compared to a previous work on AgHS°. Log 1, log 2 and - log Ka results were obtained for cysteine (11.9 ± 0.5, 15.2 ± 0.4, 7.8 ± 0.1), glutathione (12.3 ± 0.3, 14.3 ± 0.8, 8.8 ± 0.3) and 3-mercaptopropanoic acid (12.0± 0.4, 14.0 ± 0.4, 10.5 ± 0.3) at 20 °C and 0.01 m ionic strength.     

The Haicheng,China, earthquake of 4 February 1975; the first successfully predicted major earthquake

The earthquake of magnitude 7.3 that occurred near the town of Haicheng in north-east China on 4 February 1975 was the first major earthquake anywhere in the world known to have been predicted with enough certainty for people to have been warned, and measures taken for civil protection. These steps were successful in keeping the number of casualties small. This paper describes a visit to the affected area seven and a half months after the earthquake, and discussions with Chinese scientists about their successful prediction methods. The prediction resulted from the synthesis of many types of investigation, but the main methods used for long-, mid- and short-term prediction appear to have been based on studies of seismicity, deformation and foreshocks respectively.