Articles | Volume 11, issue 7
Biogeosciences, 11, 1727–1741, 2014
Biogeosciences, 11, 1727–1741, 2014

Research article 03 Apr 2014

Research article | 03 Apr 2014

Microbial and metabolic profiling reveal strong influence of water table and land-use patterns on classification of degraded tropical peatlands

S. Mishra1,2,3, W. A. Lee3, A. Hooijer4, S. Reuben3, I. M. Sudiana5, A. Idris6, and S. Swarup1,2,3,7 S. Mishra et al.
  • 1Metabolites Biology Laboratory, Department of Biological Sciences, National University of Singapore (NUS), 117543, Singapore
  • 2NUS Environmental Research Institute, NUS, T-Lab Building, 5A Engineering Drive 1, 117411, Singapore
  • 3Singapore-Delft Water Alliance Block E1, No 1 Engineering Drive 2, NUS, 117576, Singapore
  • 4Deltares, P.O. Box 177, 2600 MH Delft, the Netherlands
  • 5Cibinong Science Center, LIPI, Jl. Raya Bogor Km 46, Cibinong Bogor, 16911, Indonesia
  • 6Faculty of Agriculture, University of Jambi, Jambi, 36122, Indonesia
  • 7Singapore Centre on Environmental Life Sciences Engineering (SCELSE), 60 Nanyang Drive, NTU, 637551, Singapore

Abstract. Tropical peatlands from southeast Asia are undergoing extensive drainage, deforestation and degradation for agriculture and human settlement purposes. This is resulting in biomass loss and subsidence of peat from its oxidation. Molecular profiling approaches were used to understand the relative influences of different land-use patterns, hydrological and physicochemical parameters on the state of degraded tropical peatlands. As microbial communities play a critical role in biogeochemical cascades in the functioning of peatlands, we used microbial and metabolic profiles as surrogates of community structure and functions, respectively. Profiles were generated from 230 bacterial 16 S rDNA fragments and 145 metabolic markers of 46 samples from 10 sites, including those from above and below water table in a contiguous area of 48 km2 covering five land-use types. These were degraded forest, degraded land, oil palm plantation, mixed crop plantation and settlements. Bacterial profiles were most influenced by variations in water table and land-use patterns, followed by age of drainage and peat thickness in that order. Bacterial profiling revealed differences in sites, based on the duration and frequency of water table fluctuations and on oxygen availability. Mixed crop plantations had the most diverse bacterial and metabolic profiles. Metabolic profiling, being closely associated with biogeochemical functions, could distinguish communities not only based on land-use types but also their geographic locations, thus providing a finer resolution than bacterial profiles. Agricultural inputs, such as nitrates, were highly associated with bacterial community structure of oil palm plantations, whereas phosphates and dissolved organic carbon influenced those from mixed crop plantations and settlements. Our results provide a basis for adopting molecular marker-based approaches to classify peatlands and determine relative importance of factors that influence peat functioning. Our findings will be useful in peatland management by providing a basis to focus early efforts on hydrological interventions and improving sustainability of oil palm plantations by adopting mixed cropping practices to increase microbial diversity in the long term.

Final-revised paper