Bioturbation: impact on the marine nitrogen cycle

Laverock, Bonnie, Gilbert, Jack A., Tait, Karen , Osborn, A. Mark and Widdicombe, Steve (2011) Bioturbation: impact on the marine nitrogen cycle. Biochemical Society Transactions, 39 (1). pp. 315-320. ISSN 0300-5127

Full content URL: http://dx.doi.org/10.1042/BST0390315

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Item Type:Article
Item Status:Live Archive

Abstract

Sediments play a key role in the marine nitrogen cycle and can act either as a source or a sink of biologically available (fixed) nitrogen. This cycling is driven by a number of microbial remineralization reactions, many of which occur across the oxic/anoxic interface near the sediment surface. The presence and activity of large burrowing macrofauna (bioturbators) in the sediment can significantly affect these microbial processes by altering the physicochemical properties of the sediment. For example, the building and irrigation of burrows by bioturbators introduces fresh oxygenated water into deeper sediment layers and allows the exchange of solutes between the sediment and water column. Burrows can effectively extend the oxic/anoxic interface into deeper sediment layers, thus providing a unique environment for nitrogen-cycling microbial communities. Recent studies have shown that the abundance and diversity of micro-organisms can be far greater in burrow wall sediment than in the surrounding surface or subsurface sediment; meanwhile, bioturbated sediment supports higher rates of coupled nitrification–denitrification reactions and increased fluxes of ammonium to the water column. In the present paper we discuss the potential for bioturbation to significantly affect marine nitrogen cycling, as well as the molecular techniques used to study microbial nitrogen cycling communities and directions for future study.

Keywords:bioturbation, microbial community structure, nitrogen cycle, nutrient flux, oxic/anoxic interface
Subjects:C Biological Sciences > C180 Ecology
F Physical Sciences > F700 Ocean Sciences
C Biological Sciences > C500 Microbiology
Divisions:College of Science > School of Life Sciences
ID Code:6737
Deposited On:31 Oct 2012 17:50

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