Effects of exotic fish farms on bird communities in lake and marine ecosystems

Salmon farming is a widespread activity around the world, also known to promote diverse environmental effects on aquatic ecosystems. However, information regarding the impact of salmon farming on bird assemblages is notably scarce. We hypothesize that salmon farming, by providing food subsidies and physical structures to birds, will change their local community structure. To test this hypothesis, we conducted a seasonal monitoring of bird richness, abundance, and composition at paired salmon pen and control plots in two marine and two lake sites in southern Chile, from fall 2002 to summer 2004. Overall, salmon farming had no significant effects on species richness, but bird abundance was significantly and noticeably higher in salmon pens than in controls. Such aggregation was mainly accounted for by the trophic guilds of omnivores, diving piscivores, carrion eaters, and perching piscivores, but not by invertebrate feeders, herbivores, and surface feeders. Species composition was also significantly and persistently different between salmon pens and controls within each lake or marine locality. The patterns described above remained consistent across environment types and seasons indicating that salmon farming is changing the community structure of birds in both lake and marine habitats by promoting functional and aggregation responses, particularly by favoring species with broader niches. Such local patterns may thus anticipate potential threats from the ongoing expansion of the salmon industry to neighboring areas in Chile, resulting in regional changes of bird communities, toward a less diverse one and dominated by opportunistic, common, and generalist species such as gulls, vultures, and cormorants.     

Paying for International Environmental Public Goods

Supply of international environmental public goods must meet certain conditions to be socially efficient, and several reasons explain why they are currently undersupplied. Diagnosis of the public goods failure associated with particular ecosystem services is critical to the development of the appropriate international response. There are two categories of international environmental public goods that are most likely to be undersupplied. One has an additive supply technology and the other has a weakest link supply technology. The degree to which the collective response should be targeted depends on the importance of supply from any one country. In principle, the solution for the undersupply lies in payments designed to compensate local providers for the additional costs they incur in meeting global demand. Targeted support may take the form of direct investment in supply (the Global Environment Facility model) or of payments for the benefits of supply (the Payments for Ecosystem Services model).     

Pilot-scale application of a single-stage hybrid airlift BioCAST bioreactor for treatment of ammonium from nitrite-limited wastewater by a partial nitrification/anammox process

Environmental Science and Pollution Research - This paper presents the treatment of a nitrite-limited wastewater by partial nitrification/anammox process under different dissolved oxygen (DO)...     

Interactions of Trametes versicolor, Coriolopsis rigida and the arbuscular mycorrhizal fungus Glomus deserticola on the copper tolerance of Eucalyptus globulus

The presence of high levels of Cu in soil decreases the shoot and root dry weights of Eucalyptus globulus. However, higher plant tolerance of Cu has been observed in the presence of the arbuscular mycorrhizal (AM) fungus Glomus deserticola. The hyphal length of G. deserticola was sensitive to low Cu concentrations, and the percentage of AM root colonisation and the metabolic activity of the AM fungus were also decreased by Cu. Therefore, a direct effect of Cu on the development of the AM fungus inside and outside the root cannot be ruled out. E. globulus colonised by G. deserticola had higher metal concentrations in the roots and shoots than do non-mycorrhizal plants; however, the absence of a higher root to shoot metal ratio in the mycorrhizal plants (1.70 ± 0.11) indicated that G. deserticola did not play a filtering/sequestering role against Cu. The saprobe fungi Coriolopsis rigida and Trametes versicolor were able to remove Cu ions from the asparagine–glucose growth media. However, plants inoculated with C. rigida and T. versicolor did not accumulate more Cu than non-inoculated controls, and the growth of the plant was not increased in the presence of these fungi. However, C. rigida increased the shoot dry weight, AM root length colonisation, and metabolic mycelial activity of plants colonised with G. deserticola in the presence of Cu; only this saprobe-AM fungus combination increased the tolerance of E. globulus to Cu. Inoculation with G. deserticola and C. rigida increased the E. globulus Cu uptake to levels reached by hyperaccumulative plants.     

Changes in the sorption, desorption, distribution, and availability of copper, induced by application of sewage sludge on Chilean soils contaminated by mine tailings

The effect of mine tailings and sewage sludge was evaluated on sorption, desorption, availability and distribution of copper in two soils, one high (sandy soil) and one low in copper (clay soil). In both soils contaminated by mine tailings the copper sorption capacity and the affinity of the substrate for the metal decreased substantially compared to the uncontaminated soils, however, the sorption remained always high in the clay soil substrates. In the substrates with sandy soil, the high Cu content and lower clay content were determining factors in the lower magnitude of the sorption. Similarly, metal desorption was closely related to these two parameters, and it was higher in clay soil with lower pH. In general, the application of sewage sludge favored the sorption of Cu in soils contaminated and uncontaminated with mine tailings, and in all cases desorption decreased, an effect that remained for at least 30 days. Simple extraction of Cu with CaCl2 and diethylenetriaminepentaacetic acid gave contradictory results, so a careful choice of the procedure is required, depending on the level of metal in the soil and on the acting principle of the extracting agent. In that relation, more complete information on the changes in the metal forms was obtained by application of the sequential extraction procedure proposed by the European Community Bureau of Reference.     

Beneficial effect of saprobe and arbuscular mycorrhizal fungi on growth of Eucalyptus globulus co-cultured with Glycine max in soil contaminated with heavy metals

The effects of saprobe and arbuscular mycorrhizal (AM) fungi on growth, chlorophyll and N, P and K content of Eucalyptus globulus Labill. growing in soil contaminated by heavy metals in the presence or absence of Glycine max were investigated. Glomus mosseae and Glomus deserticola increased dry weight, shoot length, total N, P and K concentration and the quantity of chlorophyll in E. globulus shoots. The protection of Eucalyptus by AM fungi against the action of the heavy metals was more evident when this plant grew as an intercrop with soybean than as a monoculture. The presence of the saprobe fungi Fusarium concolor and Trichoderma koningii further enhanced shoot dry weight, N, P and K content of AM Eucalyptus. The co-inoculation of Eucalyptus with Glomus deserticola and T. koningii was more effective for Cd uptake. In addition, Glomus deserticola enhanced the amount of Pb absorbed by Eucalyptus plants. We showed that it is important to select the most efficient AM and saprobe fungi to stimulate plant growth in heavy-metal-contaminated soil and that the combination of both plays an important role in metal tolerance of Eucalyptus plants.