title: Differential effects of crude oil on denitrification and anammox, and the impact on N2O production.
abstract: Denitrification and anammox are key processes for reducing the external nitrogen loads delivered to coastal ecosystems, and these processes can be affected by pollutants. In this study, we investigated the effect of crude oil on denitrification and anammox. Controlled laboratory experiments were performed using sediment slurries from the Lima Estuary (NW Portugal). Anammox and denitrification rates were measured using (15)N-labeled NO3(-), and the production of (29)N2 and (30)N2 quantified by membrane inlet mass spectrometry. Results revealed that while denitrification rates were stimulated between 10 and 25 000 times after crude oil amendment, anammox activity was partially (between 2 and 5 times) or completely inhibited by the addition of crude oil when comparing to rates in unamended controls. Similar results were observed across four estuarine sediment types, despite their different physical-chemical characteristics. Moreover, N2O production was reduced by 2-36 times following crude oil addition. Further work is required to fully understand the mechanism(s) of the observed reduction in N2O production. This study represents one of the first contributions to the understanding of the impact of crude oil pollution on denitrification and anammox, with profound implications for the management of aquatic ecosystems regarding eutrophication (N-removal).
authors.affiliation: CIMAR/CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal. Electronic address: hribeiro@ciimar.up.pt.
authors.forename: Hugo
authors.initials: H
authors.lastname: Ribeiro
authors.affiliation: CIMAR/CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal.
authors.forename: Ana P
authors.initials: AP
authors.lastname: Mucha
authors.affiliation: CIMAR/CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Azevedo
authors.affiliation: CIMAR/CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal; ICBAS - Instituto de Ciências Biomédicas de Abel Salazar (ICBAS-UP), Universidade do Porto, Porto, Portugal.
authors.forename: Paula
authors.initials: P
authors.lastname: Salgado
authors.affiliation: CIMAR/CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal; ICBAS - Instituto de Ciências Biomédicas de Abel Salazar (ICBAS-UP), Universidade do Porto, Porto, Portugal.
authors.forename: Catarina
authors.initials: C
authors.lastname: Teixeira
authors.affiliation: CIMAR/CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal.
authors.forename: C Marisa R
authors.initials: CMR
authors.lastname: Almeida
authors.affiliation: Department of Marine Sciences, University of Georgia, Athens, GA, 30602, USA.
authors.forename: Samantha B
authors.initials: SB
authors.lastname: Joye
authors.affiliation: CIMAR/CIIMAR - Centro Interdisciplinar de Investigação Marinha e Ambiental, Universidade do Porto, Rua dos Bragas, 289, 4050-123 Porto, Portugal.
authors.forename: Catarina
authors.initials: C
authors.lastname: Magalhães
mesh_terms: D064751:Ammonium Compounds / Q000737:chemistry; D000693:Anaerobiosis; D058440:Denitrification; D017753:Ecosystem; D063366:Estuaries; D009584:Nitrogen / Q000737:chemistry*; D009609:Nitrous Oxide / Q000378:metabolism*; D010084:Oxidation-Reduction; D010578:Petroleum / Q000633:toxicity*; D011174:Portugal
chemical_list: D064751:Ammonium Compounds; D010578:Petroleum; D009609:Nitrous Oxide; D009584:Nitrogen
keywords: Anammox; Denitrification; N cycle; Nitrous oxide; Oil spills