Correa Araneda, Francisco

Temuco (Chile) is one of the most polluted cities in Chile and Latin America. Although the fine fraction of particulate matter (PM2.5) has been extensively studied and monitored due to its negative impact on public health, its microbiological components remain unknown. We explored, the airborne bacterial community in PM2.5 under good, moderate, alert, pre-emergency and emergency indices of air quality (AQIs) established by the Chilean government. Bacterial community relationship with environmental factors (PM2.5, PM10, carbon monoxide, among others), was also evaluated. Significant differences in PM2.5 bacterial community composition associated with AQIs were revealed, using 16S rRNA target sequences of denaturing gradient gel electrophoresis (DGGE) bands. Bacterial communities in PM2.5 were mainly clustered (80%) into emergency and pre-emergency samples. The dominant phylum was Proteobacteria and most abundant genus was Novosphingobium, traditionally related to opportunistic respiratory diseases. The main factors associated with community structure were PM2.5, PM10 and carbon monoxide concentrations. This study exposed that bacterial community composition in Temuco varies according to AQIs, with the occurrence of potential opportunistic bacteria on heavily polluted days.

The tiger crab Aegla concepcionensis Schmitt, 1942 (Decapoda, Aeglidae) is a threatened freshwater decapod, endemic of Chile, with significant gaps in knowledge about its biology and ecology. The aim of this work was to contribute to the knowledge of the ecology of A. concepcionensis, through the extension of its known distribution range, recorded in a new type of ecosystem, and the description of the physicochemistry, vegetation and benthic macroinvertebrate and microalgal communities of those sites, which provides information about habitat use of the species. Our results show the presence of A. concepcionensis until 270 km south of the previously described range and reveal that the species inhabits streams and lakes. A. concepcionensis is associated to environments with cold and temperate waters, well oxygenated, with neutral pH and low conductivity, and characterized by low anthropic intervention, which is reflected in the high proportion of native riverine plant species and the high diversity of macroinvertebrate and microalgal benthic communities. We conclude that the previously restricted known distribution range of this species was mainly due to low sampling effort or misidentifications. Our results indicate that anthropic intervention should be avoided or minimized in the distribution area of A. concepcionensis, especially in those areas associated with urban expansion and touristic activities in streams and lakes.