Abstract
Resource identity and composition structure bacterial community, which in turn determines the magnitude of bacterial processes and ecological services. However, the complex interaction between resource identity and bacterial community composition (BCC) has been poorly understood so far. Using aquatic microcosms, we tested whether and how resource identity interacts with BCC in regulating bacterial respiration and bacterial functional diversity. Different aquatic macrophyte leachates were used as different carbon resources while BCC was manipulated through successional changes of bacterial populations in batch cultures. We observed that the same BCC treatment respired differently on each carbon resource; these resources also supported different amounts of bacterial functional diversity. There was no clear linear pattern of bacterial respiration in relation to time succession of bacterial communities in all leachates, i.e. differences on bacterial respiration between different BCC were rather idiosyncratic. Resource identity regulated the magnitude of respiration of each BCC, e.g. Ultricularia foliosa leachate sustained the greatest bacterial functional diversity and lowest rates of bacterial respiration in all BCC. We conclude that both resource identity and the BCC interact affecting the pattern and the magnitude of bacterial respiration in aquatic ecosystems.
Highlights
Theoretical and empirical evidences have demonstrated that some biological features, such as species community composition, can regulate ecosystem services in a variety of ecosystems (Cardinale et al, 2012)
U. foliosa leachate supported the lowest rate of bacterial respiration (61.75% on average among all bacterial community composition (BCC); Figure 1c)
Bacterial functional diversity (BFD) was similar among bacterial communities from different successional times, i.e. despite the different BCCs showed in the denaturating gradient gel electrophoresis technique (DGGE) analysis, they did not result in marked differences in bacteria functional capacity of decomposing different carbon sources (Figure 2, initial time, P > 0.05, Tukey post-hoc test)
Summary
Theoretical and empirical evidences have demonstrated that some biological features, such as species community composition, can regulate ecosystem services in a variety of ecosystems (Cardinale et al, 2012) These evidences let to establishment of the “biodiversity and ecosystem functioning” paradigm which received a lot of attention in the ecological literature in the last years (see reviews at Balvanera et al, 2006; Caliman et al, 2010). The paradigm of “everything is everywhere and the environment selects” suggests that changes on the structure of bacterial community should occur mainly through time by responding to changes in the local environmental conditions These changes may affect directly the functional traits of bacterial community and, the processes it performs. Functional diversity has been documented as an important community parameter which regulates many ecosystem processes (Hulot et al, 2000), and bacterial communities with greater functional diversity should perform a large number of bacterial processes more efficiently (Leflaive et al, 2008)
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