title: The effect of oil sands process-affected water and model naphthenic acids on photosynthesis and growth in Emiliania huxleyi and Chlorella vulgaris.
abstract: Naphthenic acids (NAs) are among the most toxic organic pollutants present in oil sands process waters (OSPW) and enter marine and freshwater environments through natural and anthropogenic sources. We investigated the effects of the acid extractable organic (AEO) fraction of OSPW and individual surrogate NAs, on maximum photosynthetic efficiency of photosystem II (PSII) (FV/FM) and cell growth in Emiliania huxleyi and Chlorella vulgaris as representative marine and freshwater phytoplankton. Whilst FV/FM in E. huxleyi and C. vulgaris was not inhibited by AEO, exposure to two surrogate NAs: (4'-n-butylphenyl)-4-butanoic acid (n-BPBA) and (4'-tert-butylphenyl)-4-butanoic acid (tert-BPBA), caused complete inhibition of FV/FM in E. huxleyi (≥10 mg L(-1)n-BPBA; ≥50 mg L(-1)tert-BPBA) but not in C. vulgaris. Growth rates and cell abundances in E. huxleyi were also reduced when exposed to ≥10 mg L(-1)n- and tert-BPBA; however, higher concentrations of n- and tert-BPBA (100 mg L(-1)) were required to reduce cell growth in C. vulgaris. AEO at ≥10 mg L(-1) stimulated E. huxleyi growth rate (p ≤ 0.002), yet had no apparent effect on C. vulgaris. In conclusion, E. huxleyi was generally more sensitive to NAs than C. vulgaris. This report provides a better understanding of the physiological responses of phytoplankton to NAs which will enable improved monitoring of NA pollution in aquatic ecosystems in the future.
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK.
authors.forename: Jessica
authors.initials: J
authors.lastname: Beddow
authors.affiliation: Oil Plus Ltd., Dominion House, Kennet Side, Newbury RG14 5PX, UK.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Johnson
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK.
authors.forename: Tracy
authors.initials: T
authors.lastname: Lawson
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK.
authors.forename: Mark N
authors.initials: MN
authors.lastname: Breckels
authors.affiliation: Institute of Biological, Environmental & Rural Sciences (IBERS), Aberystwyth University, Gogerddan, Aberystwyth, Wales SY23 3EB, UK.
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Webster
authors.affiliation: School of Geography, Earth & Environmental Sciences, University of Plymouth, Plymouth, Devon PL4 8AA, UK.
authors.forename: Ben E
authors.initials: BE
authors.lastname: Smith
authors.affiliation: School of Geography, Earth & Environmental Sciences, University of Plymouth, Plymouth, Devon PL4 8AA, UK.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Rowland
authors.affiliation: School of Biological Sciences, University of Essex, Wivenhoe Park, Colchester, Essex CO4 3SQ, UK. Electronic address: cwhitby@essex.ac.uk.
authors.forename: Corinne
authors.initials: C
authors.lastname: Whitby
mesh_terms: D020418:Algal Proteins / Q000378:metabolism; D002264:Carboxylic Acids / Q000633:toxicity*; D048408:Chlorella vulgaris / Q000187:drug effects* / Q000254:growth & development; D058087:Haptophyta / Q000187:drug effects* / Q000254:growth & development; D000066388:Oil and Gas Industry; D010788:Photosynthesis / Q000187:drug effects*; D045332:Photosystem II Protein Complex / Q000378:metabolism; D010839:Phytoplankton / Q000187:drug effects / Q000254:growth & development; D062065:Wastewater / Q000633:toxicity; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D020418:Algal Proteins; D002264:Carboxylic Acids; D045332:Photosystem II Protein Complex; D062065:Wastewater; D014874:Water Pollutants, Chemical; C046170:naphthenic acid
keywords: Chlorella vulgaris; Emiliania huxleyi; Maximum photosynthetic efficiency; Naphthenic acids; Oil sands process-affected water