Flooding forested groundwater recharge areas modifies microbial communities from top soil to groundwater table

FEMS Microbiol Ecol. 2009 Jan;67(1):171-82. doi: 10.1111/j.1574-6941.2008.00608.x. Epub 2008 Nov 4.

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 16:1omega5, 16:1omega7, cy17:0 and 18:1omega9t, and the long-chained PLFAs 22:1omega9 and 24:1omega9 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteria* / chemistry
  • Bacteria* / classification
  • Bacteria* / growth & development
  • Bacteria* / metabolism
  • Biomass
  • Ecosystem
  • Fatty Acids / analysis
  • Floods*
  • Fresh Water*
  • Organic Chemicals / metabolism
  • Soil / analysis
  • Soil Microbiology*
  • Trees*

Substances

  • Fatty Acids
  • Organic Chemicals
  • Soil