Heterotrophic bacterial production measured on soil microaggregates sampled using a Biological Laser Printer

Publication date: Available online 8 January 2019Source: Soil Biology and BiochemistryAuthor(s): Michael T. Montgomery, Preston A. Fulmer, Joel D. Gaston, Russell K. Pirlo, Bradley R. RingeisenAbstractAlthough routinely measured in aquatic systems over the last 30 years, heterotrophic bacterial production (3H-leucine method) has only more recently been measured in terrestrial ecosystems to elucidate the role of soil biogeochemical processes in global carbon cycles and climate change. Studying bacterial metabolism at the microaggregate scale (100–300 μm) may unmask important microscale biogeochemical relationships amongst bacterial processes and the surrounding soil. Biological laser printer technology was used to sample soil core sections (ca. one mm thick) into ca. 100–300 μm microaggregates. Bacterial production was measured on collections of five microaggregates each (180 samples over 5 cm depth profile) by suspending microaggregates into filtered rainwater with 3H-leucine and incubating for 4 h. Bacterial production varied by over two orders of magnitude amongst groups of five microaggregates collected over the same millimeter scale core slice. Range for all measurements along the core was below detection (0.005) to 897 fg C aggregate d−1. As expected, variability amongst adjacent (within 2 mm of each other) microaggregates groups generally decreased with depth along with the total magnitude of bacterial production rate. Variation in bacterial produc...

Source: Soil Biology and Biochemistry - January 8, 2019 Category: Biology Source Type: research