Much of what scientists think about soil metabolism might be wrong. New evidence from Northern Arizona University suggests that microbes in different soils use different biochemical methods to process nutrients, respire, and grow. The study, published last month inPlant and Soil, addresses long-held assumptions in the field of soil ecology and calls for more research and high-resolution methods to be applied to the area.
According to Paul Dijkstra, a research professor of biology at the Center for Ecosystem Science and Societyat NAU and the lead author of the study, soil metabolism differs from soil to soil. We were the first to see that.
We have learned that biochemistry is more about the metabolic pathways that the soil microbiota choosesmatters, and it matters a lot, according to the co-author. Michaela Dippold, a professor of geo-biosphere interactions at the University of Tubingen in Germany. Our field urgently needs to develop experimental approaches that can measure maintenance energy demand and underlying respiration in a robust way. It''s a challenge to which future soil ecology research will have to respond.
Dijkstra developed a basic and applied microbiology that allows for a single microbial species to model metabolism in laboratory conditions. By adding that labeled glucose to a soil sample, scientists can retrace how much CO2 was produced from each carbonatom in the molecule. In the manner in which a single letter in the gameshowWheel of Fortune may indicate an entire phrase, the position-specific CO2is a clue to the biochemical pathway taken.
Dijkstra said that when we developed this technique in 2011 to discern among metabolic pathways in soil, we essentially had a reply to a question no one had yet asked.
The villagers of the region discovered that most CO2 was obtained from the third C-atom in one soil, but from the first C-atom in the other two soils, suggesting that the soil microbial community in each was using a different biological method to process the sugar.
The first measurements for Dijkstra resulted in a kind of eureka moment. It was a Friday at 4 oh, and I was slummed. I quickly made a mix of these carbon isotopes, injected them into the soil, and measured the result of CO2. After 40 minutes, I pulled everything away, without believing I was seeing anything.
While the researchers do not know why soil communities use different pathways, one example is that some pathways provide protection against oxygen stress in certain situations.
The team''s proposal has significant implications for future soil research and management. As such, a small portion of the soil microbiome is highly active and effective in metabolizing and mobilizing nutrients, and it''s vital for researchers to know who those microbes are, according to Dippold. It''s important to learn more about the trophic dynamics of different soils to identify management goals.
This study suggests that these placeholder assumptions may hamper the fields'' ability to utilize what it knows about soils to combat climate warming.
Soil ecology cannot be compared in a simple proxy. We must be focused on soil microbial metabolism, and we need more extensive and more powerful tools to do sono matter how difficult such research might be. If not, we will again and again end up with inconclusive conclusions whose underlying processes aren''t well understood. That, according to Dippold, will limit our ability to manipulate soil microbial processes in order to reduce greenhouse gases emissions and reduce greenhouse impacts on soil health.