The Importance Of Bioturbation

In bioturbation literature, it is often assumed that microbially-mediated processes have been affected by bioturbation, with no analysis of the microbial community (Kristensen, 1984, Kristensen, 1985, Kristensen and Blackburn, 1987, Gilbert et al., 1998, Christensen et al., 2000, Michaud et al., 2006, Bonaglia et al., 2014). For example, variations in microbial nutrient remineralisation (Renz and Forster, 2013), and declines in sediment functioning under reduced pH conditions (Widdicombe and Needham, 2007), have been attributed to changes in bacterial communities due to macrofaunal bioturbation activity. Generally, these assumptions are appropriate because they are based on previous research that supports this microbial link between bioturbation and biogeochemical cycling. Yet, overall, it has lessened the amount of microbial data available to assess the …show more content…
Cell abundance is usually determined using epifluorescent microscopy and has demonstrated that bioturbation stimulates microbial proliferation (Table. 1). Cell counts alone, however, provide no information on the presence, growth, or activity of key functional groups that mediate biogeochemical processes. Therefore, various culture-based methods to assess abundances of specific microbial groups, such as sulphate-reducing bacteria (SRB), have been developed (Table. 1). Yet, these culture-dependent techniques are biased by the presence of uncultivatable bacteria (Teske et al., 1996, Naslund et al., 2010), with typically only 1-10% of the total community being assessed (Jenkins and Kemp, 1984, Katayama et al., 2003, Lucas et al., 2003). Overreliance on these abundance-based techniques will limit the amount of data available to understand bioturbation effects on microbially mediated processes (Nicolaisen and Ramsing,