Disturbance Increases Microbial Community Diversity and Production in Marine Sediments.

Katell Guizien,Sonja K Fagervold,Pierre E Galand,Sabrina Lucas,Erwan Peru,Audrey M Pruski,Christine Dupuy,Gilles Vétion

doi:10.3389/fmicb.2016.01950

Abstract

Disturbance strongly impacts patterns of community diversity, yet the shape of the diversity-disturbance relationship remains a matter of debate. The topic has been of interest in theoretical ecology for decades as it has practical implications for the understanding of ecosystem services in nature. One of these processes is the remineralization of organic matter by microorganisms in coastal marine sediments, which are periodically impacted by disturbances across the sediment-water interface. Here we set up an experiment to test the hypothesis that disturbance impacts microbial diversity and function during the anaerobic degradation of organic matter in coastal sediments. We show that during the first 3 weeks of the experiment, disturbance increased both microbial production, derived from the increase in microbial abundance, and diversity of the active fraction of the community. Both community diversity and phylogenetic diversity increased, which suggests that disturbance promoted the cohabitation of ecologically different microorganisms. Metagenome analysis also showed that disturbance increased the relative abundance of genes diagnostic of metabolism associated with the sequential anaerobic degradation of organic matter. However, community composition was not impacted in a systematic way and changed over time. In nature, we can hypothesize that moderate storm disturbances, which impact coastal sediments, promote diverse, and productive communities. These events, rather than altering the decomposition of organic matter, may increase the substrate turnover and, ultimately, remineralization rates.

Highlights

One of the key features of microbial communities in most natural ecosystems is that they harbor a tremendous diversity (Keller and Zengler, 2004)
Soil experiments showed that diversity declined with increasing disturbance frequencies, (Kim et al, 2013) and a negative diversity-disturbance relationship was observed in natural marine sediments (Boer et al, 2009)
We showed that disturbance had a positive effect on sediment microbial communities by increasing their production and both their community and phylogenetic diversity during the first 3 weeks of the experiment

Summary

Introduction

One of the key features of microbial communities in most natural ecosystems is that they harbor a tremendous diversity (Keller and Zengler, 2004). Disturbance Increases Microbial Community Diversity to disturbance has been a central interest in ecology studies for decades. Investigations have aimed to resolve how disturbances in an ecosystem influence the diversity of the communities (Sousa, 1984). In this respect, the intermediate disturbance hypothesis (IDH; Grime, 1973; Connell, 1978) suggests that the relationship between diversity and disturbance can be represented graphically as a unimodal distribution. Community diversity is low when disturbance levels are low and increases with disturbance frequency or strength. Recent studies have refuted the idea of a positive relationship between disturbance and community diversity. Soil experiments showed that diversity declined with increasing disturbance frequencies, (Kim et al, 2013) and a negative diversity-disturbance relationship was observed in natural marine sediments (Boer et al, 2009)

Methods

Results

Discussion

Conclusion