Growth rates and skeletal density of the scleractinian cold-water coral Desmophyllum dianthus at Isla Liliguapi (Fjord Comau, southern Chile)

It has been hypothesized that endolithic photo-autotrophs inside the skeleton of cold-water corals may have a mutualistic relationship with the coral host positively affecting coral calcification. This study investigated the effect of endolithic photo-autotrophs on the apical septal extension of the cold-water coral Desmophyllum dianthus at Fjord Comau, southern Chile (42.41° - 42.15°S, 72.5°W). The fluorescent staining agent calcein was used to document the linear apical extension of septae for a period of one and a half years between 2006 and 2007. The results showed a severe reduction in extension rates associated with the presence of endolithic photo-autotrophs. Infested individuals grew about half as fast as non-infested polyps with a median value of 1.18 µm/day compared to 2.76 µm/day. Contrary to the initial hypothesis, these results point toward a parasitic relationship between D. dianthus and its endolithic photo-autotrophs potentially impairing coral fitness. However, further data on physiological parameters and other aspects of the calcification process are necessary to confirm these findings.

Comunidad, conectividad y movimiento regional en la Patagonia: evolución del capital social en la Región de Aysén, Chile

Las pequeñas comunidades rurales de la Región de Aysén, Chile, evidencian una variedad de formas y tipos de capital social. La forma específica de capital social que predomina ha evolucionado según cambios en el contexto nacional y la progresiva integración comunicacional. Tras haber sido ejemplo de cooperación comunitaria, las comunidades rurales enfrentaron el desafío de relacionarse con actores sociales de mayor poder, en el escenario ampliado de la sociedad civil regional. En muchos casos, este cambio conllevó una menor autonomía y la captura de facciones comunitarias en cadenas de clientelismo. Sin embargo, en 2012 emergió el movimiento “Tu problema es mi problema” para enfrentar la marginación percibida en sus relaciones asimétricas con el gobierno central. Este evento masivo de desobediencia civil se basó en tres formas de capital social y marcó la emergencia de una ciudadanía de alcance regional, cumpliendo una de las condiciones para una descentralización plenamente democrática.

Sedimentological and pollen records from the fjord region of southern Chile

The position and intensity of the southern westerly wind belt varies seasonally as a consequence of changes in sea surface temperature. During the austral winter, the belt expands northward and the wind intensity in the core decreases. Conversely, during the summer, the belt contracts, and the intensity within the core is strengthened. Reconstructions of the westerly winds since the last glacial maximum, however, have suggested that changes at a single site reflected shifts throughout the entire southern wind belt. Here we use sedimentological and pollen records to reconstruct precipitation patterns over the past 12,500 yr from sites along the windward side of the Andes. Precipitation at the sites, located in the present core and northern margin of the westerlies, is driven almost entirely by the wind belt, and can be used to reconstruct its intensity. Rather than varying coherently throughout the Holocene epoch, we find a distinct anti-phasing of wind strength between the core and northern margin over multi-millennial timescales. During the early Holocene, the core westerlies were strong whereas the northern margin westerlies were weak. We observe the opposite pattern in the late Holocene. As this variation resembles modern seasonal variability, we suggest that our observed changes in westerly wind strength can best be explained by variations in sea surface temperature in the eastern South Pacific Ocean.