Changes in Pelagic Bacteria Communities Due to Leaf Litter Addition

Abstract

In many limnetic systems, the input of allochthonous organic matter, e.g., leaf litter, is a substantial source of dissolved organic carbon (DOC) for pelagic bacteria, especially in fall and winter when autochthonous DOC production is low. However, relatively little is known about community changes of pelagic lake bacteria due to leaf litter input which includes both the release of leaf leachates and microorganisms from the leaf litter into the surrounding water. Therefore, we have experimentally studied the effects of different types of leaf litter (Betula pendula, Fagus silvatica, and Pinus silvestris) on the pelagic bacterial community composition by adding leaves to different treatments of epilimnic water samples (unfiltered, 0.2 µm and 5.0 µm-pre-filtered) from humic Lake Grosse Fuchskuhle (Northeastern Germany). The addition of leaf litter led to a significant increase in DOC concentration in lake water, and each leaf litter type produced significantly different amounts of DOC (p = <0.001) as well as of specific DOC fractions (p = <0.001), except of polysaccharides. DGGE banding patterns varied over time, between types of leaf litter, and among treatments. Bacteria belonging to known bacterial phylotypes in the southwest basin of Lake Grosse Fuchskuhle were frequently found and even persisted after leaf litter additions. Upon leaf litter addition, α-proteobacteria (Azospirillum, Novosphingobium, and Sphingopyxis) as well as β-proteobacteria (Curvibacter and Polynucleobacter) were enriched. Our results indicate that supply of leaf litter DOM shifted the bacterial community in the surrounding water towards specific phylotypes including species capable of assimilating the more recalcitrant DOC pools. Statistical analyses, however, show that DGGE banding patterns are not only affected by DOC pools but also by treatment. This indicates that biological factors such as source community and grazing may be also important for shifts in bacterial community structure following leaf litter input into different lakes.

Co-habiting amphibian species harbor unique skin bacterial communities in wild populations

“…This was by far the most abundant phylotype across all species in all sites. This genus and its close relatives are commonly found in a wide variety of natural aquatic systems (Shaw et al , 2008; Mueller-Spitz et al , 2009; Hutalle-Schmelzer et al , 2010) and they appear to be primarily freshwater organisms with a wide range of temperature tolerance (9–40 °C) and pH tolerance (5.5–8.5) for growth (Ding and Yokota, 2004). Due to the lack of comparable studies, we do not know if members of this genus are commonly associated with other species of amphibians found at other locations.…”

Microbial diversity and metaproteomic analysis of activated sludge responses to naphthalene and anthracene exposure

“…Sphingomonadales species have been isolated and studied in recent years for their potential removal of PAH, especially for individual physiological characteristics and highly efficient metabolic activity. [34][35][36][37] However, current research remains mainly focused on the isolation and identication of Sphingomonadales populations and the related research on the PAH degradation pathway, degrading enzyme system, and associated encoding genes in Sphingomonadales remains limited.…”

Microbial communities in an ephemeral stream system and the implications of saline mine discharge

“…Microbial community structure differed between Middle Creek (with high organic matter) and the Bacteroidetes have previously been associated with high organic matter loads (Eiler et al 2003, Hutalle-Schmelzer et al 2010, Newton et al 2011. Further higher abundances of potential sporeforming and phototrophic members such as Chloroflexi and Firmicutes Frigaard 2006, Paredes-Sabja et al 2011) were detected in Middle Creek.…”

“…These two microbial groups have been reported to be associated with high organic matter loads in lakes (Eiler et al 2003, Hutalle-Schmelzer et al 2010, Newton et al 2011) and streams ). This may explain their relative lower abundance in the Upper Isaac Catchment, as a result of low carbon and nutrient conditions experienced in these sediments.…”

“…These conditions were considered likely to select for microbial communities with competitive advantages in utilising nutrient and carbon sources. For example, Bacteroidetes have been reported to occur in higher abundances in lakes with high organic matter loads (Eiler et al 2003, Hutalle-Schmelzer et al 2010. In contrast microbial groups such as Actinobacteria, Alphaproteobacteria and Acidobacteria contain members generally associated with low nutrient concentrations in freshwater ecosystems (Eiler et al 2003, Haukka et al 2006, Newton et al 2011).…”