Flooding forested groundwater recharge areas modifies microbial communities from top soil to groundwater table |
| |
Authors: | Kirsten Schütz Peter Nagel Walter Vetter Ellen Kandeler & Liliane Ruess |
| |
Institution: | Department of Environmental Sciences, Institute of Biogeography, University of Basel, Basel, Switzerland;;Institute of Food Chemistry, University of Hohenheim, Stuttgart, Germany;;Institute of Soil Science, University of Hohenheim, Stuttgart, Germany;and;Institute of Zoology, Darmstadt University of Technology, Darmstadt, Germany |
| |
Abstract: | Subsurface microorganisms are crucial for contaminant degradation and maintenance of groundwater quality. This study investigates the microbial biomass and community composition by phospholipid fatty acids (PLFAs)], as well as physical and chemical soil characteristics at woodland flooding sites of an artificial groundwater recharge system used for drinking water production. Vertical soil profiles to c . 4 m at two watered and one nonwatered site were analyzed. The microbial biomass was equal in watered and nonwatered sites, and considerable fractions (25–42%) were located in 40–340 cm depth. The microbial community structure differed significantly between watered and nonwatered sites, predominantly below 100 cm depth. Proportions of the bacterial PLFAs 16:1ω5, 16:1ω7, cy17:0 and 18:1ω9t, and the long-chained PLFAs 22:1ω9 and 24:1ω9 were more prominent at the watered sites, whereas branched, saturated PLFAs (iso/anteiso) dominated at the nonwatered site. PLFA community indices indicated stress response ( trans / cis ratio), higher nutrient availability (unsaturation index) and changes in membrane fluidity (iso/anteiso ratio) due to flooding. In conclusion, water recharge processes led to nutrient input and altered environmental conditions, which resulted in a highly active and adapted microbial community residing in the vadose zone that effectively degraded organic compounds. |
| |
Keywords: | flooding groundwater recharge fatty acids microorganisms vadose zone PLFA indices |
|
|