Nitrate reduction, nitrous oxide formation, and anaerobic ammonia oxidation to nitrite in the gut of soil-feeding termites (Cubitermes and Ophiotermes spp.)
KAUST DepartmentRed Sea Research Center (RSRC)
Online Publication Date2011-11-28
Print Publication Date2012-04
Permanent link to this recordhttp://hdl.handle.net/10754/561931
MetadataShow full item record
AbstractSoil-feeding termites play important roles in the dynamics of carbon and nitrogen in tropical soils. Through the mineralization of nitrogenous humus components, their intestinal tracts accumulate enormous amounts of ammonia, and nitrate and nitrite concentrations are several orders of magnitude above those in the ingested soil. Here, we studied the metabolism of nitrate in the different gut compartments of two Cubitermes and one Ophiotermes species using 15N isotope tracer analysis. Living termites emitted N 2 at rates ranging from 3.8 to 6.8nmolh -1 (g fresh wt.) -1. However, in homogenates of individual gut sections, denitrification was restricted to the posterior hindgut, whereas nitrate ammonification occurred in all gut compartments and was the prevailing process in the anterior gut. Potential rates of nitrate ammonification for the entire intestinal tract were tenfold higher than those of denitrification, implying that ammonification is the major sink for ingested nitrate in the intestinal tract of soil-feeding termites. Because nitrate is efficiently reduced already in the anterior gut, reductive processes in the posterior gut compartments must be fuelled by an endogenous source of oxidized nitrogen species. Quite unexpectedly, we observed an anaerobic oxidation of 15N-labelled ammonia to nitrite, especially in the P4 section, which is presumably driven by ferric iron; nitrification and anammox activities were not detected. Two of the termite species also emitted substantial amounts of N 2O, ranging from 0.4 to 3.9nmolh -1 (g fresh wt.) -1, providing direct evidence that soil-feeding termites are a hitherto unrecognized source of this greenhouse gas in tropical soils. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.
- Nitrous Oxide (N2O) Emissions by Termites: Does the Feeding Guild Matter?
- Authors: Brauman A, Majeed MZ, Buatois B, Robert A, Pablo AL, Miambi E
- Issue date: 2015
- Nitrous Oxide Metabolism in Nitrate-Reducing Bacteria: Physiology and Regulatory Mechanisms.
- Authors: Torres MJ, Simon J, Rowley G, Bedmar EJ, Richardson DJ, Gates AJ, Delgado MJ
- Issue date: 2016
- Characterization of N2O emission and associated bacterial communities from the gut of wood-feeding termite Nasutitermes voeltzkowi.
- Authors: Majeed MZ, Miambi E, Riaz MA, Brauman A
- Issue date: 2015 Sep
- Gut-associated denitrification and in vivo emission of nitrous oxide by the earthworm families megascolecidae and lumbricidae in new zealand.
- Authors: Wüst PK, Horn MA, Henderson G, Janssen PH, Rehm BH, Drake HL
- Issue date: 2009 Jun
- N2O-producing microorganisms in the gut of the earthworm Aporrectodea caliginosa are indicative of ingested soil bacteria.
- Authors: Ihssen J, Horn MA, Matthies C, Gössner A, Schramm A, Drake HL
- Issue date: 2003 Mar