Effects of FPOM size and quality on aquatic heterotrophic bacteria |
| |
| Institution: | 1. University of Gothenburg, Department of Biological and Environmental Sciences, Box 463, 40530 Gothenburg, Sweden;2. Leibniz-Institute of Freshwater Ecology and Inland Fisheries (IGB), Alte Fischerhütte 2, 16775 Stechlin, Koenigin-Luise-Str. 6–8, 14195 Berlin, Germany;3. Leibniz-Institute for Baltic Sea Research (IOW), Seestrasse 15, 18119 Rostock, Germany;4. Department of Biology, Mt. Allison University, Sackville, NB, E4 L 1G7, Canada |
| |
| Abstract: | Mechanical and biological processing in aquatic systems converts coarse particulate organic matter (CPOM) into fine particulate organic matter (FPOM). Other sources of particles with different size classes include flocculated dissolved matter, algae and soil particles. The relative magnitudes of these inputs are influenced by the degree of allochthony of a lake or stream. The size-reactivity hypothesis, formulated for dissolved organic matter, postulates that bacterial degradation rates are higher with high-molecular-weight fractions than with low-molecular-weight fractions. In this study, we investigated the effect of particle size on degradation of POM and on freshwater bacterial communities. We generated leaf-derived particle size classes of the same age (same diagenesis status) but differing in quality (maple and beech leaves). Contrary to our expectations, we found a strong effect of particle size and no significant effect of substrate quality on community respiration which decreased at smaller particle size, on C:N ratios which declined with particle size, and on δ15 N which showed a decreasing trend (though not significant) at smaller particle size in beech leaves. By contrast, bacterial community structure and ?13C values responded mainly to particle quality. Bacterial biomass, estimated by qPCR, was affected by complex interactions between particle size and quality. These findings open an unanticipated perspective on the size-reactivity hypothesis for particulate organic matter. |
| |
| Keywords: | Size-reactivity Aquatic bacteria FPOM Carbon turnover DGGE Freshwater |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
