COS 57-10
Influence of disturbance regimes on the metabolic activity and diversity of benthic bacterial communities
Disturbances play a significant role in shaping the community structure, influence the patterns of species richness and diversity, and affect ecosystem functioning. Their influence on biodiversity has captivated ecologists for several decades. Disturbances can be quantified in two ways: intensity and frequency. Because in many locations, these disturbance regimes can change rapidly and have strong impacts on ecosystems, understanding how they influence natural communities is an important issue in ecology.
Bacterial communities are useful and convenient biological tools to approach general ecological questions, such as disturbance ecology, because they have a high growth rate and high diversity. We investigated the influence of the disturbance intensity and frequency by testing how the metabolic activity and diversity of benthic bacterial communities are affected by addition of organic matter via the supply of mussel biodeposits (metabolic diversity is defined as the number of carbon sources utilized). We performed a microcosm experiment that exposed bacterial communities to these different disturbance regimes. We used Biolog EcoPlates to characterize the influence of these regimes on the Community Level Physiological Profiling (CLPP) of benthic bacterial communities.
Results/Conclusions
Interestingly, our results showed that disturbance frequency and instantaneous intensity have no significant influence on bacterial metabolic activity and diversity. However, the accumulated intensity of disturbance significantly increased the functional activity of benthic bacterial communities. Above a certain tipping point (19g d-1 m-2), organic matter additions significantly increased the bacterial metabolic activity and diversity. While the accumulated intensity of disturbance has rarely been taken into account in most of previous studies, these results indicate that it is necessary to consider this disturbance regime to better understand response of communities and disturbance ecology.