Authors: Gbemisola O Sanni Frédéric Coulon Terry J McGenity
Publish Date: 2015/04/14
Volume: 22, Issue: 20, Pages: 15230-15247
Abstract
Mudflats are ecologically important habitats that are susceptible to oil pollution but intervention is difficult in these finegrained sediments and so cleanup usually relies on natural attenuation Therefore we investigated the impact of crude oil on the bacterial diatom and archaeal communities within the upper parts of the diatomdominated sediment and the biofilm that detached from the surface at high tide Biodegradation of petroleum hydrocarbons was rapid with a 50 decrease in concentration in the 0–2mm section of sediment by 3 days indicating the presence of a primed hydrocarbondegrading community The biggest oilinduced change was in the biofilm that detached from the sediment with increased relative abundance of several types of diatom and of the obligately hydrocarbonoclastic Oleibacter sp which constituted 5 of the pyrosequences in the oiled floating biofilm on day 3 compared to 06 in the nonoiled biofilm Differences in bacterial community composition between oiled and nonoiled samples from the 0–2mm section of sediment were only significant at days 12 to 28 and the 2–4mmsediment bacterial communities were not significantly affected by oil However specific members of the Chromatiales were detected 1 of sequences in the 2–4mm section only in the oiled sediment supporting other work that implicates them in anaerobic hydrocarbon degradation Unlike the Bacteria the archaeal communities were not significantly affected by oil In fact changes in community composition over time perhaps caused by decreased nutrient concentration and changes in grazing pressure overshadowed the effect of oil for both Bacteria and Archaea Many obligate hydrocarbonoclastic and generalist oildegrading bacteria were isolated and there was little correspondence between the isolates and the main taxa detected by pyrosequencing of sedimentextracted DNA except for Alcanivorax Thalassolituus Cycloclasticus and Roseobacter spp which were detected by both methodsWe thank Anne Fahy and Farid Benyahia for technical advice and assistance and Boyd McKew for his assistance in designing the mesocosms We also acknowledge John Green for helping to set up the mesocosms We are grateful for PhD scholarship funds for GOS from the Petroleum Technology Development Fund PTDF Nigeria
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