title: Multitaxon activity profiling reveals differential microbial response to reduced seawater pH and oil pollution.
abstract: There is growing concern that predicted changes to global ocean chemistry will interact with anthropogenic pollution to significantly alter marine microbial composition and function. However, knowledge of the compounding effects of climate change stressors and anthropogenic pollution is limited. Here, we used 16S and 18S rRNA (cDNA)-based activity profiling to investigate the differential responses of selected microbial taxa to ocean acidification and oil hydrocarbon contamination under controlled laboratory conditions. Our results revealed that a lower relative abundance of sulphate-reducing bacteria (Desulfosarcina/Desulfococcus clade) due to an adverse effect of seawater acidification and oil hydrocarbon contamination (reduced pH-oil treatment) may be coupled to changes in sediment archaeal communities. In particular, we observed a pronounced compositional shift and marked reduction in the prevalence of otherwise abundant operational taxonomic units (OTUs) belonging to the archaeal Marine Benthic Group B and Marine Hydrothermal Vent Group (MHVG) in the reduced pH-oil treatment. Conversely, the abundance of several putative hydrocarbonoclastic fungal OTUs was higher in the reduced pH-oil treatment. Sediment hydrocarbon profiling, furthermore, revealed higher concentrations of several alkanes in the reduced pH-oil treatment, corroborating the functional implications of the structural changes to microbial community composition. Collectively, our results advance the understanding of the response of a complex microbial community to the interaction between reduced pH and anthropogenic pollution. In future acidified marine environments, oil hydrocarbon contamination may alter the typical mixotrophic and k-/r-strategist composition of surface sediment microbiomes towards a more heterotrophic state with lower doubling rates, thereby impairing the ability of the ecosystem to recover from acute oil contamination events.
authors.affiliation: Department of Biology & CESAM, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Francisco J R C
authors.initials: FJ
authors.lastname: Coelho
authors.affiliation: Department of Biology & CESAM, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Daniel F R
authors.initials: DF
authors.lastname: Cleary
authors.affiliation: Centre of Marine Sciences (CCMAR), University of Algarve, Faro, 8005-139, Algarve, Portugal.|Institute for Bioengineering and Biosciences, Department of Bioengineering, Instituto Superior Técnico, Universidade de Lisboa, 1049-001, Lisbon, Portugal.
authors.forename: Rodrigo
authors.identifier: 0000-0002-5932-4101
authors.initials: R
authors.lastname: Costa
authors.affiliation: Department of Biology & CESAM, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Marina
authors.initials: M
authors.lastname: Ferreira
authors.affiliation: Department of Biology & CESAM, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Ana R M
authors.initials: AR
authors.lastname: Polónia
authors.affiliation: Department of Chemistry & QOPNA, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal.
authors.forename: Artur M S
authors.initials: AM
authors.lastname: Silva
authors.affiliation: Department of Chemistry & QOPNA, University of Aveiro, Campus Universitário de Santiago, Aveiro, Portugal.
authors.forename: Mário M Q
authors.initials: MM
authors.lastname: Simões
authors.affiliation: Department of Biology & CESAM, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Oliveira
authors.affiliation: Department of Biology & CESAM, University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal. gomesncm@ua.pt, gomesncm@hotmail.com.
authors.forename: Newton C M
authors.initials: NC
authors.lastname: Gomes
mesh_terms: D001105:Archaea / Q000145:classification*; D057231:Climate Change; D006863:Hydrogen-Ion Concentration; D059392:Petroleum Pollution; D012623:Seawater / Q000737:chemistry*; D016999:Sulfur-Reducing Bacteria / Q000145:classification*; D014874:Water Pollutants, Chemical / Q000009:adverse effects*
chemical_list: D014874:Water Pollutants, Chemical
keywords: climate change interactions; microbial ecology; ocean acidification; oil pollution