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Linking Predation Risk, Herbivore Physiological Stress and Microbial Decomposition of Plant Litter
Published on: March 12, 2013
Changes in pelagic bacteria communities due to leaf litter addition
Kristine Michelle L Hutalle-Schmelzer1, Elke Zwirnmann, Angela Krüger
1Department of Stratified Lakes, Leibniz-Institute of Freshwater Ecology and Inland Fisheries, Alte Fischerhuette 2, 16775 Stechlin, Germany.
Microbial Ecology
|March 4, 2010
Summary
Leaf litter input significantly alters lake bacterial communities by increasing dissolved organic carbon (DOC). Different leaf types selectively enrich specific bacterial groups, influencing community structure and function in aquatic ecosystems.
Area of Science:
- Aquatic Ecology
- Microbial Ecology
- Limnology
Background:
- Allochthonous organic matter, such as leaf litter, is a key source of dissolved organic carbon (DOC) for pelagic bacteria in lakes, particularly during seasons with low autochthonous production.
- The impact of leaf litter leachates and associated microorganisms on the composition of pelagic bacterial communities in lakes remains incompletely understood.
Purpose of the Study:
- To experimentally investigate the effects of different leaf litter types (Betula pendula, Fagus silvatica, Pinus silvestris) on the pelagic bacterial community composition in a humic lake.
- To determine how leaf litter input influences dissolved organic carbon (DOC) concentrations and bacterial community structure in response to varying water filtration treatments.
Main Methods:
- Addition of different leaf litter types to epilimnic water samples from a humic lake.
- Samples were subjected to different pre-filtration treatments (unfiltered, 0.2 µm, 5.0 µm).
- Bacterial community composition was analyzed using Denaturing Gradient Gel Electrophoresis (DGGE), and DOC concentrations were measured.
Main Results:
- Leaf litter addition significantly increased DOC concentrations, with distinct DOC yields and fractions (except polysaccharides) among different leaf litter types.
- DGGE banding patterns showed temporal variations and differences based on leaf litter type and filtration treatment.
- Specific bacterial groups, including α-proteobacteria (e.g., Azospirillum) and β-proteobacteria (e.g., Polynucleobacter), were enriched following leaf litter addition.
Conclusions:
- Leaf litter-derived dissolved organic matter (DOM) shifts pelagic bacterial communities towards phylotypes capable of utilizing recalcitrant DOC pools.
- Bacterial community structure shifts are influenced not only by DOC availability but also by factors such as the initial bacterial source community and grazing pressure.
- The study highlights the complex interplay between allochthonous inputs, DOC characteristics, and biological factors in shaping lake bacterial community dynamics.
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