17:15 〜 19:15
[MIS03-P03] Soil microbial functional diversity distribution from a past crop area to peatland transect.
キーワード：Komado wetland, mountain mire, human activities
Komado wetland is a mountain peatland in the Fukushima prefecture and consists of 3 distinct peatlands (Oyachi, Shirakabayachi and Mizunashiyachi). In the past, the primary beech forest around those peatlands was converted into crop areas, mainly for radish (Daikon) cultivation. In 2000 the whole catchment became a natural conservation area after finding out that effluxes from the surrounding crops were affecting the peatland ecosystem. Nowadays, those past crop areas are still visible from satellite images as scarce vegetation spots and on-site observations show that the vegetation struggles to take back the land in a now sandy/clayey reddish soil terrain. While past agricultural activities have undeniably altered the soil’s constitution in those areas, the high exposure to runoff of bare soils after crop usage is expected to still impact the lower elevation peatland by carrying mineral constituents into the marsh and possibly triggering the microbial diversity of peat soils.
To determine if those 20th-century agricultural practices still impact the Komado peat soils, we decided to study the functional diversity of the soil microbial community, along with some other physicochemical parameters (pH, carbon, nitrogen, iron, and aluminum contents) of surface and deep soil along a transect going from the past crop area to the center of the Oyachi peatland.
Results show that the 6 soil profiles can be sorted into 3 groups depending on their physicochemical parameters and the functional diversity of their aerobic microbial community. The first group includes the 2 peat profiles exhibiting high microbial functional diversity, strong acidic conditions, and a higher carbon, nitrogen, and iron concentration at the surface than in deep soils, while aluminum is more concentrated in deep soils. The second group includes the soil profile at the edge of the past crop area and the soil profile in the past crop area with growing vegetation. This group is characterized by mildly acidic conditions, medium microbial functional diversity, high iron, and aluminum concentrations, and medium carbon and low nitrogen concentrations. The 3rd group includes the soil profile at the transition between the past crop area and the peatland, and the profile from the non-vegetated past crop area. This last group is characterized by poor microbial functional diversity and mildly acidic conditions, it is also poor in carbon and nitrogen but rich in iron and aluminum. At the same time, the microbial communities from the first group are more diverse but also more adapted to degrade highly resistant organic matter such as polymers, while the second group seems to be able to efficiently degrade more simple organic matters like amine and amino-acid. Finally, one interesting behavior is the absence of aerobic microbial functional diversity from deep soils of the transitional profile (group 3), this might indicate a fully anaerobic microbial community in this soil layer.
Overall, the microbial functional diversity of peat soils does not seem to be directly impacted by the past crop areas, Further investigations in Shirakabayachi and Mizunashiyachi peatlands need and will be conducted in the future to enlighten the present results. It is also noteworthy to indicate that the past crop area vegetated surface soils exhibit a quite strong microbial functional diversity (equivalent to the less impact edge of past crop area soils) compared to the non-vegetated soil, which highlights the resilience of the soil microbial community under a plant cover.
To determine if those 20th-century agricultural practices still impact the Komado peat soils, we decided to study the functional diversity of the soil microbial community, along with some other physicochemical parameters (pH, carbon, nitrogen, iron, and aluminum contents) of surface and deep soil along a transect going from the past crop area to the center of the Oyachi peatland.
Results show that the 6 soil profiles can be sorted into 3 groups depending on their physicochemical parameters and the functional diversity of their aerobic microbial community. The first group includes the 2 peat profiles exhibiting high microbial functional diversity, strong acidic conditions, and a higher carbon, nitrogen, and iron concentration at the surface than in deep soils, while aluminum is more concentrated in deep soils. The second group includes the soil profile at the edge of the past crop area and the soil profile in the past crop area with growing vegetation. This group is characterized by mildly acidic conditions, medium microbial functional diversity, high iron, and aluminum concentrations, and medium carbon and low nitrogen concentrations. The 3rd group includes the soil profile at the transition between the past crop area and the peatland, and the profile from the non-vegetated past crop area. This last group is characterized by poor microbial functional diversity and mildly acidic conditions, it is also poor in carbon and nitrogen but rich in iron and aluminum. At the same time, the microbial communities from the first group are more diverse but also more adapted to degrade highly resistant organic matter such as polymers, while the second group seems to be able to efficiently degrade more simple organic matters like amine and amino-acid. Finally, one interesting behavior is the absence of aerobic microbial functional diversity from deep soils of the transitional profile (group 3), this might indicate a fully anaerobic microbial community in this soil layer.
Overall, the microbial functional diversity of peat soils does not seem to be directly impacted by the past crop areas, Further investigations in Shirakabayachi and Mizunashiyachi peatlands need and will be conducted in the future to enlighten the present results. It is also noteworthy to indicate that the past crop area vegetated surface soils exhibit a quite strong microbial functional diversity (equivalent to the less impact edge of past crop area soils) compared to the non-vegetated soil, which highlights the resilience of the soil microbial community under a plant cover.