Resistance and Resilience of Bacterial Communities in Response to Multiple Disturbances Due to Climate Change

Abstract

Global warming and eutrophication are becoming very common phenomena. In the climate change scenario this will be a very regular problem in aquatic ecosystems. Aquatic ecosystems are exposed to high temperature and nutrient loads, which may change the equilibrium state for bacterial communities. Previous studies have shown that bacterial communities are sensitive to disturbances and not immediately resilient after the disturbance regardless the breadth of taxonomic groups or type of disturbances. As we are experiencing increase of temperature and heavy nutrient loads in many aquatic ecosystems, it is important to know how bacterial communities respond (in terms of resistance and resilience) to multiple disturbances. This study therefore aimed to test how two disturbances (temperature and nutrient increase) affect bacterial communities when applied individually or in combination. Bacterial abundance, bacterial carbon production and respiration were measured to investigate the effects of those disturbances on processes related to ecosystem services. Changes in bacterial community composition in response to the disturbances were analyzed by a molecular fingerprinting method. The study found that bacterial community function was more sensitive to combined disturbances than to individual ones. The composition of the bacterial community, however, showed resistance to the applied disturbances. The results indicate that the modeling of bacterial communities for ecosystem management will be challenging given the multidimensional aspect of disturbances in changing climate context.