An assessment of metal contamination in mangrove sediments and leaves from Punta Mala Bay, Pacific Panama

Due to the growing rate of urbanisation in many tropical coastal areas, there continues to be an increasing concern in relation to the impact of anthropogenic activities on mangrove forests. Punta Mala Bay is located on the Pacific coast of Panama and suffers from intense anthropogenic activities that are potentially harmful to the remaining mangrove forests. Field observations reveal that the mangrove stand within Punta Mala Bay receives high inputs of untreated domestic sewage, storm water run-off and a range of diffuse inputs from shipping activities. Results from analysis of eight metals (Mn, Cu, Zn, Ni, Pb, Fe, Cr, Cd) showed that Fe, Zn and Pb were in concentrations high enough to conclude moderate to serious contamination within the bay, and thus pose the most threat to the regeneration and growth of the mangrove. However, previous biological surveys indicate ongoing mangrove regeneration and domination of stand structure by Laguncularia racemosa, together with high numbers of seedlings and saplings.     

Toxicity of polynuclear aromatic hydrocarbons to the polychaete Neanthes arenaceodentata

The toxicity of ten polynuclear aromatic hydrocarbons (PNAs) to Neanthes arenaceodentata was studied in replicate 96 h bioassays with specific hydrocarbons in solution. Relative solubilities for each PNA were derived in short-term equilibration experiments. Disappearance of representative di-, tri, tetra- and pentacyclic-aromatic hydrocarbons from test solutions was also characterized by ultraviolet spectrophotometry. PNA toxicity and residence time in test solutions were directly related to molecular weight (MW), while relative solubility is inversely related to MW. 96 h TL_m values for the diaromatic PNAs naphthalene, 2,6-dimethylnaphthalene, and 2,3,6-trimethylnaphthalene were 3.8, 2.6 and 2.0 ppm, respectively. Phenanthrene, fluorene and 1-methylphenanthrene (triaromatics) exhibited 96 h TL_m values of 0.6, 1.0 and 0.3 ppm, respectively. None of the tetra- and pentacyclic-aromatics (chrysene, 3,4-benzo(a)pyrene, 1,2,5,6-dibenzanthracene) were toxic up to the highest concentration tested (1 ppm), excepting fluoranthene, with a 96 h TL_m of 0.5 ppm. PNA toxicity appears to be related to both solubility and residence time in test solutions.     

Whither Parity? The Need for a Comprehensive Curriculum in Human‐Environment Geography

If human‐environment geography is central to the discipline, then human‐environment courses should be a sizable segment of the undergraduate curriculum. Undergraduate educational offerings are inadequate, however, meaning that geography departments are shortchanging their majors, missing opportunities to attract and inform the general student body, and failing to meet the needs of future K–12 educators. Unless geography provides satisfactory human‐environment education, it will likely have much less impact on twenty‐first‐century environmental science.     

Observations of complex-terrain flows using acoustic sounders: Experiments,topography, and winds

Acoustic sounders have now been used extensively in a series of noctural drainage flow experiments carried out by the U.S. Department of Energy's Atmospheric Studies in Complex Terrain (ASCOT) program. Doppler acoustic sounders, located in three different valleys during the sequence of experiments, reveal drainage-wind profiles that depend strongly on the ambient meteorological conditions and the elevation of each observing site relative to surrounding terrain. In elevated sites that drain easily, Doppler-sounder derived wind profiles show a simply-structured flow; in lower lying areas, subject to topographic constriction and cold-air pooling, and where Archimedean forces are comparable to those due to synoptic and mesoscale pressure gradients, the wind profiles show considerable vertical and temporal variation. In particular, in the Geysers area of northern California, the seabreeze and the depth of the Pacific Coast marine inversion affect not only the initiation of drainage winds but also their subsequent evolution.     

Wave and turbulence structure in a disturbed nocturnal inversion

Acoustic sounder and tower data obtained at the Boulder Atmospheric Observatory (BAO) are used to examine several features of the wave and turbulence structure associated with a disturbed nocturnal inversion. General features, including mean fields and Richardson number, for the case selected for this study are presented. Spectral analysis of the tower data reveals a separation of energy into wavelike and turbulent fluctuations. Analysis of the heat flux, however, shows upward counter-gradient fluxes in the vicinity of a low-level jet and near the top of the inversion. Cospectral analysis shows that the major contribution to the upward heat flux occurs at frequencies that would normally be considered characteristic of waves. In some cases, the upward flux is associated with a phase shift between vertical velocity w and fluctuating temperature θ different from the quadrature relation that would be expected of internal waves. Time series analysis reveals that these unexpected positive fluxes occur in relatively short bursts. Analysis of time series of θ and w in other cases, as well as inspection of acoustic sounder records, shows that sometimes such upward fluxes can result from a combination of wave motion and horizontal temperature advection. In this case the advection is associated with a shallow cold front.     

Wind-tunnel simulation of field dispersion tests (by the U.K. health and safety executive) of water-spray curtains

Field trials of water-spray curtain tests performed by the (British) Health and Safety Executive and designated by HSE 41 and HSE 46 were modeled at a scale ratio of 1:28.9 in an atmospheric boundary-layer wind tunnel. The tests confirmed that dense clouds of carbon dioxide gas were significantly diluted by additional air entrained by the water curtain. Linear and logarithmic scatter diagrams of concentrations measured at equivalent scaled points produced correlations of 0.87 and 0.97, respectively. Results confirm the use of Froude-number modeling of both the dense gas cloud and water spray droplet fluid dynamics.Professor, Colorado State University.Research Associate, Colorado State University.Senior Scientist, Factory Mutual Research Corp., Boston, Mass.     

Complementary use of tracer and pumping tests to characterize a heterogeneous channelized aquifer system in New Zealand

The combined use of pumping and tracer test data enabled the derivation of equivalent average hydraulic conductivities (K_avg) for each test in a heterogeneous channelized alluvial aquifer, whereas K values of the preferential flow paths were two orders of magnitude higher. Greater and earlier drawdown was generally observed along preferential flow lines in a pumping test, within an array of 21 wells. The study aim was to characterize hydraulic properties of a channelized aquifer system in New Zealand by combining tracer and pumping test data. Estimates were able to be made of the percentage of highly permeable channels within the profile (～1.2%), effective porosity that reflected the maximum fraction of highly permeable channels within the aquifer (?_eff–pc ～0.0038), and flows through highly permeable channels (～98%) and the sandy gravel matrix material (～2%). Using ?_eff–pc, a tracer test K_avg value (～93 m/day) was estimated that was equivalent to pumping test values (～100 m/day), but two orders of magnitude smaller than K calculated solely from transport through permeable channels (K_pc ～8,400 m/day). Derived K values of permeable and matrix material were similar to values derived from grain size distribution using the Kozeny-Carman equation.     

The role of money and the financial sector in energy-economy models used for assessing climate and energy policy

This article outlines a critical gap in the assessment methodology used to estimate the macroeconomic costs and benefits of climate and energy policy, which could lead to misleading information being used for policy-making. We show that the Computable General Equilibrium (CGE) models that are typically used for assessing climate policy use assumptions about the financial system that sit at odds with the observed reality. These assumptions lead to ‘crowding out’ of capital and, because of the way the models are constructed, negative economic impacts (in terms of gross domestic product (GDP) and welfare) from climate policy in virtually all cases.

In contrast, macro-econometric models, which follow non-equilibrium economic theory and adopt a more empirical approach, apply a treatment of the financial system that is more consistent with reality. Although these models also have major limitations, they show that green investment need not crowd out investment in other parts of the economy – and may therefore offer an economic stimulus. Our conclusion is that improvements in both modelling approaches should be sought with some urgency – both to provide a better assessment of potential climate and energy policy and to improve understanding of the dynamics of the global financial system more generally.

POLICY RELEVANCE

This article discusses the treatment of the financial system in the macroeconomic models that are used in assessments of climate and energy policy. It shows major limitations in approach that could result in misleading information being provided to policy-makers.     

High resolution scans of Comet Kohoutek in the vicinity of 5015, 5890, and 6563 Å

High resolution scans were made of Comet Kohoutek (1973f) using the McMath solar telescope at Kitt Peak National Observatory. The data were taken on January 1 and 4, 1974 UT, just after the comet perihelion. Hα emission (～4.1 × 10²⁷ photon sec^?1) was observed from the head of the Comet. An upper limit on the He I(5015) radiation was determined to be less than 2% of the observed Hα emission. The Na D1/D2 line intensities on both nights were approximately 0.5, indicating an optically thin emission region.