Search

Concern for the maintenance of water quality of the lakes on K'gari-Fraser Island has attracted research attention but the impact of beach camping on beach freshwater has been poorly considered. The assumption has been that the natural assimilative capacity of the foredune ecosystem is sufficient to dissipate any negative environmental impact. An exploratory study of nutrients, faecal coliforms and faecal sterols in the watertable and beach flows associated with camping and non-camping zones reveals concerning differences between sample sites. The study suggests nutrient levels in the watertable are enriched in camping zones and that, in some areas, faecal coliforms persist in beach flows. The link to a human cause is supported by the presence of strong faecal sterol signals in soil samples from the watertable interface. The risk implications for human health are significant although the biological impact implications remain unexplored.

In response to the absence of monitoring data, the Air Pollution Model (TAPM), a 3D prognostic model that predicts both meteorology and air pollution concentrations, was used to investigate the transport of ammonia across part of the Sunshine Coast region (South East Queensland, Australia), following its emission to the atmosphere from 41 poultry farms (egg and broiler) in the district, which cumulatively house approximately 9.8 million fowl. The study estimated the total amount of ammonia that is deposited directly into the Pumicestone Passage waterbody (63 km 2 ) and onto the surrounding catchment (1184 km 2 ), through both wet and dry deposition processes over a twelve-month period. The results indicate that wet deposition is the dominant deposition process into the waterbody (89%) and catchment area (94%). Most of the ammonia deposition is predicted to occur within a relatively short distance from the farms, due to higher concentrations at these locations. In the base case simulation, the estimated 1823 tonnes of annual ammonia emissions were predicted to result in the direct deposition of approximately 2.3 tonnes of ammonia into the Pumicestone Passage waterbody and approximately 53.5 tonnes onto the Pumicestone Passage catchment land surface, where there was potential for its subsequent run-off into the waterbody. This annual loading into the waterbody is not insignificant and is likely to contribute to the formation of algal blooms. The fate of the remaining 91% of the ammonia estimated to be emitted from the farms was not accounted for in the deposition totals. This ammonia most likely remains suspended in the atmosphere and is transported outside of the simulation study area.

The wet deposition of iron and peroxides was monitored during an intense rain squall in the equatorial Pacific Ocean. Iron and hydrogen peroxide were determined at sea using adsorptive cathodic stripping voltammetry (ACSV) and an enzyme-catalyzed flourometric technique, respectively. The equatorial rainwater was enriched in ACSV reactive iron (average 2.7 nmol Fe kg−1) and hydrogen peroxide (average 8.5 μmol kg−1) relative to the concentrations found in surface seawater (0.05–0.07 nmol Fe kg−1; 40–70 nmol peroxides kg−1). Wet depositional fluxes during the squall varied from 70 to 105 nmol Fe m−2 h−1 and from 56 to 880 μmol peroxide m−2 h−1. The input of rainwater into the surface layer was documented by using hydrogen peroxide and iron signals as well as the depression in surface salinity as tracers. The squall created a patch of lower-salinity surface seawater that was relatively enriched in ACSV reactive iron (0.2–0.3 nmol Fe kg−1) and peroxides (200–300 nmol kg−1). The observed concentrations of iron and peroxides in rainwater, their wet-depositional fluxes, and their initial sea surface enrichments, were quantitatively consistent with independent predictions based on applicable iron aerosol and gas-phase peroxide scavenging models for the region.

Marine aerosol particles from the Equatorial Pacific were studied using transmission electron microscopy. Sea-salt aggregates consist largely of NaCl and Na-Ca sulfate crystals. Variations in the composition of sea-salt aggregates occur, and these may reflect the effects of relative humidity. There are several species of submicron, S-bearing particles, presumably including ammonium sulfate and strong acids. Diatom fragments are common, and sparse kaolinite and rutile crystals are the mineral component of this marine aerosol. The samples we studied appeared to be free of obvious anthropogenic effects.

As part of the Asian Dust Inputs to the Ocean System (ADIOS) project, atmospheric dust fluxes and primary productivity were monitored during the dusty season (spring) of 1986 at 26°N, 155°W, in the North Pacific Ocean. The arrival of major pulses of dust from Asia was followed by major increases in primary production. Extensive chemical analyses of the atmospheric particles showed that they were iron-rich (10-15%) and, further, that if only a small proportion (e.g. 10%) of this iron dissolved in the euphotic zone, it would be sufficient to support the increases in carbon production at this location. The systematic increases in production noted with increasing depth and time may result from a continual release of iron from the settling particles in the euphotic zone. At all depths, systematic decreases in production followed the initial surge in production, indicating that the phytoplankton may have evolved from being iron-limited to being nitrogen-limited. Comparison of particle concentrations calculated by a particle settling model with primary productivity profiles indicated that mineral particles with settling velocities equivalent to those of 14 to 18-μm-diameter spherical quartz particles were the most likely source for the iron stimulating the increases in primary production.

Measurements in a Lewis cell of the kinetics of extraction of copper(II) by 5-nonyl-2-hydroxybenzaldoximes from acidic (hydrogen sulphate buffer) aqueous solution, in the pH range 3.4-2.0, into n-hexane are reported. The effects of changes in the dielectric constant and the viscosity of the organic phase on the rate of extraction have been measured. The effect of the presence of hydroxylic modifiers on kinetics of extraction was also examined. Measurements of the lowering of interfacial tension in these systems were also carried out. The results of all of our experiments agree in showing that, at low initial bulk concentrations of the extractant (less than 1 mol/m3), the rate of extraction is controlled by the interfacial concentration of the extractant and by the rate of diffusion of extractant from the bulk to the interface.

[1] Methyl bromide (CH3Br) was highly supersaturated for over 2 years in the surface coastal seawater off Tasmania. Persistent supersaturations were observed near to shore throughout the year with no evidence of a seasonal cycle. At the same time, a site farther offshore (still under coastal influence) was also predominantly supersaturated but to a lesser extent. Notably, the annual pattern varied over the consecutive years covered in this systematic study. The observed supersaturations are in broad agreement with that which would be predicted by the relationships with the sea surface temperature (SST) derived by Groszko and Moore [1998] and King et al. [2000] for SSTs in the range of 12° to 20°C, although not the seasonal variation predicted by King et al. [2002]. There is much variability, as expected, which is not explained by the SST relationships. The presence of the prymnesiophyte Phaeocystis is found to be related to the seawater concentrations of CH3Br in this work. Our results tentatively indicate that the release of CH3Br into the seawater may be a response to nitrate limiting conditions.

During the Southern Hemispheric spring of 2000 (during the months of November and early December), rain, bulk and size-separated aerosol samples were collected at the Cape Grim Baseline Air Pollution Station located on the island of Tasmania, Australia and analyzed for total organic nitrogen (N), urea, and dissolved free amino acids. Rain and bulk aerosol samples contained organic N at concentrations representing, on average, between 19 and 25% of total N. Urea was not detected in the six rain samples analyzed. However, urea represented ∼24% of the organic N contained in nonbaseline aerosol samples, and ∼2% of the organic N contained within baseline samples. Trajectory analysis combined with meteorological data indicated that high concentrations of urea within aerosols were mainly due to Tasmanian sources, likely animal emissions, although the application of urea fertilizers cannot be dismissed as a source. In nonbaseline samples the highest concentrations of urea were associated with the coarse mode aerosol (greater than 1 μm), although urea was also found in the fine mode aerosol (less than 1 μm), potentially indicating gas-to-particle conversion of urea. Aerosol samples collected in marine air masses contained urea within an intermediate fraction centered at ∼1 μm suggesting the sea surface microlayer as a source. Dissolved free amino acids contributed ∼53% of the organic N in rain, but were not a significant proportion of the total organic N fraction in either nonbaseline or baseline aerosol samples. Due to their presence in rain, amino acids likely exist in aerosols as unhydrolyzed proteins. In cascade impactor samples highly influenced by marine sources, profiles for amino N were inversely related to urea N, possibly indicating live species and the sea surface microlayer as a source for organic N.;

Measurement of the kinetics of extraction of copper(II) by 19 different 5-alkyl-2-hydroxybenzaldoximes (alkyl is C7H15 and C9H19) from acidic (hydrogen sulfate buffer) aqueous solution in the range pH 3.4-2.0, into 20% v/v toluene in n-hexane is reported. The lowering of the interfacial tension has been measured in some cases. The solubility of the extractants in water has been measured spectrophotometrically. A modified Taylor-Aris dispersion technique has been used to measure the diffusion coefficients in n-hexane and Orfom SX7 of some of the extractants and of the copper(II) complexes which they form. At low initial bulk concentrations (10 mol m-3) of the extractants, the rate of extraction is controlled by the rate of diffusion of the extractant from the bulk to the organic-aqueous interface. The diffusion coefficient is related to the steric bulk of the alkyl substituent. At higher initial bulk concentrations (200 mol m-3) of the extractants, when the interface is saturated, the rate of extraction is inversely related to the apparent steric bulk of the alkyl substituent. Copyright 1999 Academic Press.