title: Ocean acidification with (de)eutrophication will alter future phytoplankton growth and succession.
abstract: Human activity causes ocean acidification (OA) though the dissolution of anthropogenically generated CO2 into seawater, and eutrophication through the addition of inorganic nutrients. Eutrophication increases the phytoplankton biomass that can be supported during a bloom, and the resultant uptake of dissolved inorganic carbon during photosynthesis increases water-column pH (bloom-induced basification). This increased pH can adversely affect plankton growth. With OA, basification commences at a lower pH. Using experimental analyses of the growth of three contrasting phytoplankton under different pH scenarios, coupled with mathematical models describing growth and death as functions of pH and nutrient status, we show how different conditions of pH modify the scope for competitive interactions between phytoplankton species. We then use the models previously configured against experimental data to explore how the commencement of bloom-induced basification at lower pH with OA, and operating against a background of changing patterns in nutrient loads, may modify phytoplankton growth and competition. We conclude that OA and changed nutrient supply into shelf seas with eutrophication or de-eutrophication (the latter owing to pollution control) has clear scope to alter phytoplankton succession, thus affecting future trophic dynamics and impacting both biogeochemical cycling and fisheries.
authors.affiliation: Centre for Sustainable Aquatic Research, Swansea University, Swansea SA2 8PP, UK k.j.flynn@swansea.ac.uk.
authors.forename: Kevin J
authors.identifier: http://orcid.org/0000-0001-6913-5884
authors.initials: KJ
authors.lastname: Flynn
authors.affiliation: Plymouth Marine Laboratory, Prospect Place, Plymouth PL1 3DH, UK.
authors.forename: Darren R
authors.initials: DR
authors.lastname: Clark
authors.affiliation: Centre for Sustainable Aquatic Research, Swansea University, Swansea SA2 8PP, UK.
authors.forename: Aditee
authors.initials: A
authors.lastname: Mitra
authors.affiliation: Centre for Sustainable Aquatic Research, Swansea University, Swansea SA2 8PP, UK.
authors.forename: Heiner
authors.initials: H
authors.lastname: Fabian
authors.affiliation: Marine Biological Section, University of Copenhagen, Strandpromenaden 5, 3000 Helsingør, Denmark.
authors.forename: Per J
authors.identifier: http://orcid.org/0000-0003-0228-9621
authors.initials: PJ
authors.lastname: Hansen
authors.affiliation: University of Maryland Center for Environmental Science, Horn Point Laboratory, PO Box 775, Cambridge, MD 21613, USA.
authors.forename: Patricia M
authors.initials: PM
authors.lastname: Glibert
authors.affiliation: Plymouth Marine Laboratory, Prospect Place, Plymouth PL1 3DH, UK Marine Biological Association, Citadel Hill, Plymouth PL1 2PB, UK.
authors.forename: Glen L
authors.initials: GL
authors.lastname: Wheeler
authors.affiliation: University of Maryland Center for Environmental Science, Horn Point Laboratory, PO Box 775, Cambridge, MD 21613, USA.
authors.forename: Diane K
authors.initials: DK
authors.lastname: Stoecker
authors.affiliation: Plymouth Marine Laboratory, Prospect Place, Plymouth PL1 3DH, UK.
authors.forename: Jerry C
authors.initials: JC
authors.lastname: Blackford
authors.affiliation: Marine Biological Association, Citadel Hill, Plymouth PL1 2PB, UK.
authors.forename: Colin
authors.initials: C
authors.lastname: Brownlee
mesh_terms: D044822:Biodiversity; D002254:Carbonates / Q000737:chemistry; D005068:Eutrophication; D006863:Hydrogen-Ion Concentration; D008962:Models, Theoretical; D010839:Phytoplankton / Q000254:growth & development / Q000502:physiology*; D012623:Seawater / Q000737:chemistry*
chemical_list: D002254:Carbonates
keywords: eutrophication; food security; ocean acidification; plankton succession; primary production