Experimental insights into the importance of aquatic bacterial community composition to the degradation of dissolved organic matter

Abstract

Bacteria play a central role in the cycling of carbon, yet our understanding of the relationship between the taxonomic composition and the degradation of dissolved organic matter (DOM) is still poor. In this experimental study, we were able to demonstrate a direct link between community composition and ecosystem functioning in that differently structured aquatic bacterial communities differed in their degradation of terrestrially derived DOM. Although the same amount of carbon was processed, both the temporal pattern of degradation and the compounds degraded differed among communities. We, moreover, uncovered that low-molecular-weight carbon was available to all communities for utilisation, whereas the ability to degrade carbon of greater molecular weight was a trait less widely distributed. Finally, whereas the degradation of either low- or high-molecular-weight carbon was not restricted to a single phylogenetic clade, our results illustrate that bacterial taxa of similar phylogenetic classification differed substantially in their association with the degradation of DOM compounds. Applying techniques that capture the diversity and complexity of both bacterial communities and DOM, our study provides new insight into how the structure of bacterial communities may affect processes of biogeochemical significance.

Microbial community changes induced by Managed Aquifer Recharge activities: Linking hydrogeological and biological processes

“…In addition, many sequenced phylotypes, such as Nitrospira sp, Stenotrophomonas sp and Methylobac-5 terium sp have been associated with degradation capabilities (Cycoń et al, 2017;Daims et al, 2001;Wang et al, 2015). In short, the MAR microbial ecosystem studied in this work presents many more phylotypes than previous studies reported in groundwater systems (Logue et al, 2015), and thus, MAR can be considered an efficient remediation system.…”

Climate‐related changes of soil characteristics affect bacterial community composition and function of high altitude and latitude lakes

“…S3), indicated that soil extract additions selected for copiotrophic bacteria, rare under oligotrophic conditions, but preponderant during periods of high allochthonous loadings. This agrees with previous observations from field (Crump et al ., 2003; Roiha et al ., 2011) and laboratory experiments (Logue et al ., 2016) showing that rapid shifts in community composition take place upon soil organic matter input. The loss and prevalence of the taxa determined in our study may be explained by their different functional adaptability, including differences in resource affinities (Cottrell & Kirchman, 2000; Salcher et al ., 2011; Heinrich et al ., 2013), physiological characteristics (Hahn & Pöckl, 2005; Šimek et al ., 2006) and genetic composition (Bauer et al ., 2006; Gómez‐Pereira et al ., 2012; Teeling et al ., 2012; Tveit et al ., 2013).…”

“…The loss and prevalence of the taxa determined in our study may be explained by their different functional adaptability, including differences in resource affinities (Cottrell & Kirchman, 2000; Salcher et al ., 2011; Heinrich et al ., 2013), physiological characteristics (Hahn & Pöckl, 2005; Šimek et al ., 2006) and genetic composition (Bauer et al ., 2006; Gómez‐Pereira et al ., 2012; Teeling et al ., 2012; Tveit et al ., 2013). Further, changes in lake bacterial community composition have been attributed not only to the differential response of individual bacterial taxa to DOM inputs, but also to the introduction of soil bacteria with allochthonous sources or to incubation effects (Crump et al ., 2003; Logue et al ., 2016). In our experiments, however, the addition of soil‐borne bacteria with the soil extracts was not confirmed when using staining techniques and microscopy.…”

“…Nevertheless, the degree of response clearly differed between locations (SAA vs. GKS) and soil treatments (local vs. foreign soil treatment in SAA). The patterns observed in substrate uptake rates were most likely the result of differences in initial bacterioplankton community composition (Logue et al ., 2016), DOC lability (Kalbitz et al ., 2003; Berggren et al ., 2009) and nutrient (or rather P) availability (Moran & Hodson, 1990; Olsen et al ., 2002). For instance, total dissolved phosphorus concentrations were three times lower in the local and in the foreign soil treatments in GKS than in SAA (Table S1).…”

Dissolved Compounds Excreted by Copepods Reshape the Active Marine Bacterioplankton Community Composition

“…These groups are considered to be opportunistic bacteria in surface waters, and they responded rapidly to the enrichment derived from copepod excretion. Several studies have suggested that enrichment experiments tend to enhance the abundance of microorganisms rarely found in nature, but that have opportunistic and copiotrophic qualities that allow them to rapidly adapt to changes in environmental conditions, outcompeting abundant groups in the field (Nelson and Wear, 2014;Pedler et al, 2014;Logue et al, 2016). Lauro et al (2009) argued that copiotroph bacteria have a higher genetic potential to sense and rapidly respond to a sudden nutrient influx, compared to the more widely distributed oligotrophic bacteria.…”