RESUMO
Habitat fragmentation in urban environments concentrates bird populations that have managed to adapt to these newly developed areas. Consequently, the roosts of these birds are potentially creating environments conducive to fungal growth and dissemination. Airborne fungi derived from these environments are relatively unstudied, as is the potential health risk arising from these fungi. This study documented the diversity of culturable airborne fungal propagules associated with forty urban bird roosts. Environmental variables from each site were recorded to allow us to analyse the correspondence between different bird species, the substrate they occupy and airborne fungal propagules. Associations were established between Rhodotorula and Pacific black ducks, wood ducks, myna birds and miner birds when in the presence of bare soil as a substrate. Further associations were established between Penicillium, Scopulariopsis and Cunninghamella and pigeons, sparrows and swallows living in areas with hard surfaces such as bitumen and rocks.
Assuntos
Aerossóis , Microbiologia do Ar , Aves , Fungos/classificação , Fungos/isolamento & purificação , AnimaisRESUMO
There is uncertainty as to the rates of coal fly ash needed for optimum physiological processes and growth. In the current study we tested the hypothesis that photosynthetic pigments concentrations and CO(2) assimilation (A) are more sensitive than dry weights in plants grown on media amended with coal fly ash. We applied the Terrestrial Plant Growth Test (Guideline 208) protocols of the Organization for Economic Cooperation and Development (OECD) to monocots [barley (Hordeum vulgare) and ryegrass (Secale cereale)] and dicots [canola (Brasica napus), radish (Raphanus sativus), field peas (Pisum sativum), and lucerne (Medicago sativa)] on media amended with fly ashes derived from semi-bituminous (gray ash) or lignite (red ash) coals at rates of 0, 2.5, 5.0, 10, or 20 Mg ha(-1). The red ash had higher elemental concentrations and salinity than the gray ash. Fly ash addition had no significant effect on germination by any of the six species. At moderate rates (= 10 Mg ha(-1)) both ashes increased (p < 0.05) growth rates and concentrations of chlorophylls a and b, but reduced carotenoid concentrations. Addition of either ash increased A in radish and transpiration in barley. Growth rates and final dry weights were reduced for all of the six test species when addition rates exceeded 10 Mg ha(-1) for gray ash and 5 Mg ha(-1) for red ash. We concluded that plant dry weights, rather than pigment concentrations and/or instantaneous rates of photosynthesis, are more consistent for assessing subsequent growth in plants supplied with fly ash.
Assuntos
Carbono , Carvão Mineral , Produtos Agrícolas/crescimento & desenvolvimento , Material Particulado , Fotossíntese , Pigmentos Biológicos/análise , Cinza de Carvão , GerminaçãoRESUMO
An examination was made of the genetic variation with age in mangrove populations in two estuaries in south-east Australia, one contaminated, the other uncontaminated. Sediment nutrient and metal levels, and isozyme/allozyme complements were measured in three age-classes in four stands in each estuary, to identify site and intergenerational genetic composition, and influences of sediment contamination. Within each river, there were greater genetic distances among the age-classes than among sampling sites. A downstream gradient of genetic distance was found in the uncontaminated river, but not the contaminated one, where genetic distances seemed to reflect site-specific factors, though apparently not the present sediment metal or nutrient levels. It appears that genetic distances in the polluted river may reflect past fluctuations in pollution pressures. In both rivers, genetic distances indicate that the mangroves within one estuary form one population, with 'neighbourhood' differentiation.
Assuntos
Avicennia/genética , Variação Genética , Poluentes da Água/intoxicação , Avicennia/crescimento & desenvolvimento , Sedimentos Geológicos/química , Dinâmica Populacional , RiosRESUMO
In order to ensure conservation of mangroves, genetic diversity in remaining populations must be explored. Both morphological and isozyme analyses were used and compared in investigating the intra- and inter-estuarine variation in Avicennia marina in Sydney, the most urbanised area in Australia. Sediment characteristics, metal levels, tree attributes, leaf morphology and isozyme/allozyme analyses were conducted. Tree characteristics did not prove to be adequate genetic markers, but leaf morphology may be of use in this species. Isozyme/allozyme analyses indicated that genetic distance corresponded with geographic distance, although habitat metal levels may indicate local selection pressures. High levels of heterozygote deficiencies were displayed in each estuary, which could threaten future viability. The results hold implications for management as periodic isozyme analysis may be useful in indicating management needs. The identification of metal-tolerant types may also be useful. Transplantation among estuaries may assist in increasing genetic diversity, if considered desirable. Whatever the management aims, isozyme/allozyme analyses are shown to be useful for revealing genetic diversity in this species.