title: Are changes in the structure of nematode assemblages reliable indicators of moderate petroleum contamination?
abstract: This study assesses through a multiple before-after-control-impact (MBACI) design the effects of diesel oil on the structure of nematode assemblages in unvegetated tidal flats of a subtropical estuary. Oil-exposed treatments were contrasted with controls for a duration of four successive days before and after an experimental spill in three distinct areas of the Paranaguá Estuarine Complex (Southern Brazil). No significant differences were observed in nematode total density, number of taxa and the overall assemblage structure between the control and impact treatments from before to after the experimental spill. This reinforces the idea that, despite being good indicators of environmental stress, free-living marine nematodes are able to tolerate low concentrations of hydrocarbons and to survive in moderately contaminated areas. We also show that robust experimental designs are useful to avoid confounding expected natural variability with the effects of a mild impact.
authors.affiliation: Centro de Estudos do Mar, Universidade Federal do Paraná, Av. Beira Mar s/n, PO Box 61, CEP 83255-976 Pontal do Paraná, Paraná, Brazil. Electronic address: silvaleite.daniel@gmail.com.
authors.forename: Daniel Silva
authors.initials: DS
authors.lastname: Leite
authors.affiliation: Centro de Estudos do Mar, Universidade Federal do Paraná, Av. Beira Mar s/n, PO Box 61, CEP 83255-976 Pontal do Paraná, Paraná, Brazil. Electronic address: leonardosandrini@gmail.com.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Sandrini-Neto
authors.affiliation: Centro de Estudos do Mar, Universidade Federal do Paraná, Av. Beira Mar s/n, PO Box 61, CEP 83255-976 Pontal do Paraná, Paraná, Brazil. Electronic address: manuelazeglin@gmail.com.
authors.forename: Manuela Zeglin
authors.initials: MZ
authors.lastname: Camargo
authors.affiliation: Universidade do Estado de Santa Catarina, Av. Madre Benvenuta 2007, CEP 88035-001 Florianópolis, Santa Catarina, Brazil. Electronic address: michelict@gmail.com.
authors.forename: Micheli Cristina
authors.initials: MC
authors.lastname: Thomas
authors.affiliation: Centro de Estudos do Mar, Universidade Federal do Paraná, Av. Beira Mar s/n, PO Box 61, CEP 83255-976 Pontal do Paraná, Paraná, Brazil. Electronic address: lana@ufpr.br.
authors.forename: Paulo C
authors.initials: PC
authors.lastname: Lana
mesh_terms: D000818:Animals; D044822:Biodiversity; D001938:Brazil; D004784:Environmental Monitoring; D063366:Estuaries; D005742:Gasoline / Q000009:adverse effects*; D006838:Hydrocarbons / Q000009:adverse effects / Q000032:analysis; D009348:Nematoda / Q000187:drug effects*; D059392:Petroleum Pollution / Q000009:adverse effects*; D010860:Pigments, Biological / Q000032:analysis; D011156:Population Density; D014874:Water Pollutants, Chemical / Q000009:adverse effects*
chemical_list: D005742:Gasoline; D006838:Hydrocarbons; D010860:Pigments, Biological; D014874:Water Pollutants, Chemical
keywords: Diesel; Experimental oil spill; MBACI; Nematodes; Paranaguá Bay