title: The effects of elevated CO2on the growth and toxicity of field populations and cultures of the saxitoxin-producing dinoflagellate,Alexandrium fundyense.
abstract: The effects of coastal acidification on the growth and toxicity of the saxitoxin-producing dinoflagellateAlexandrium fundyensewere examined in culture and ecosystem studies. In culture experiments,Alexandriumstrains isolated from Northport Bay NY, USA, and the Bay of Fundy, Canada, grew significantly faster (16 -190%;p<0.05) when exposed to elevated levels of pCO2(~ 800- 1900μatm) compared to lower levels (~390μatm). Exposure to higher levels of pCO2 also resulted in significant increases (71 - 81%) in total cellular toxicity (fg STX eq. cell-1) in the Northport Bay strain, while no changes in toxicity were detected in the Bay of Fundy strain. The positive relationship between pCO2enhancement and elevated growth was reproducible using natural populations from Northport;Alexandriumdensities were significantly and consistently enhanced when natural populations were incubated at 1500 μatm pCO2, a value at the upper range of those recorded in Northport Bay, 390 - 1500 µatm. During naturalAlexandriumblooms in Northport Bay, pCO2concentrations increased over the course of a bloom to more than 1700μatm and were highest in regions with the greatestAlexandriumabundances, suggestingAlexandriummay be further exacerbating acidification or be especially adapted to these extreme, acidified conditions. The co-occurrence ofAlexandriumblooms and elevated pCO2represents a previously unrecognized, compounding environmental threat to coastal ecosystems. The ability of elevated pCO2to enhance the growth and toxicity ofAlexandriumindicates that acidification promoted by eutrophication or climate change can intensify these, and perhaps other, harmful algal blooms.
authors.affiliation: Stony Brook University, School of Marine and Atmospheric Sciences, Southampton, NY 11968, USA.
authors.forename: Theresa K
authors.initials: TK
authors.lastname: Hattenrath-Lehmann
authors.affiliation: Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA.
authors.forename: Juliette L
authors.initials: JL
authors.lastname: Smith
authors.affiliation: Stony Brook University, School of Marine and Atmospheric Sciences, Southampton, NY 11968, USA.
authors.forename: Ryan B
authors.initials: RB
authors.lastname: Wallace
authors.affiliation: Stony Brook University, School of Marine and Atmospheric Sciences, Southampton, NY 11968, USA.
authors.forename: Lucas
authors.initials: L
authors.lastname: Merlo
authors.affiliation: Stony Brook University, School of Marine and Atmospheric Sciences, Southampton, NY 11968, USA.
authors.forename: Florian
authors.initials: F
authors.lastname: Koch
authors.affiliation: Stony Brook University, School of Marine and Atmospheric Sciences, Southampton, NY 11968, USA.
authors.forename: Heidi
authors.initials: H
authors.lastname: Mittelsdorf
authors.affiliation: Stony Brook University, School of Marine and Atmospheric Sciences, Southampton, NY 11968, USA.
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Goleski
authors.affiliation: Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA.
authors.forename: Donald M
authors.initials: DM
authors.lastname: Anderson
authors.affiliation: Stony Brook University, School of Marine and Atmospheric Sciences, Southampton, NY 11968, USA.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Gobler