Present-day and future climate pathways affecting Alexandrium blooms in Puget Sound, WA, USA

Stephanie K. Moore, James A. Johnstone, Neil S. Banas, Eric P. Salathé

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

This study uses a mechanistic modeling approach to evaluate the effects of various climate pathways on the proliferative phase of the toxin-producing dinoflagellate Alexandrium in Puget Sound, WA, USA. Experimentally derived Alexandrium growth responses to temperature and salinity are combined with simulations of the regional climate and Salish Sea hydrology to investigate future changes in the timing, duration, and extent of blooms. Coarse-grid (100-200. km) global climate model ensemble simulations of the SRES A1B emissions scenario were regionally downscaled to a 12-km grid using the Weather Research and Forecasting model for the period 1969-2069. These results were used to: (1) analyze the future potential changes and variability of coastal upwelling winds, and (2) provide forcing fields to a Regional Ocean Model System used to simulate the circulation of the Salish Sea, including Puget Sound, and the coastal ocean. By comparing circa-1990 and circa-2050 climate scenarios for the environmental conditions that promote Alexandrium blooms, we disentangle the effects of three climate pathways: (1) increased local atmospheric heating, (2) changing riverflow magnitude and timing, and (3) changing ocean inputs associated with changes in upwelling-favorable winds. Future warmer sea surface temperatures in Puget Sound from increased local atmospheric heating increase the maximum growth rates that can be attained by Alexandrium during the bloom season as well as the number of days with conditions that are favorable for bloom development. This could lead to 30 more days a year with bloom-favorable conditions by 2050. In contrast, changes in surface salinity arising from changes in the timing of riverflow have a negligible effect on Alexandrium growth rates, and the behavior of the coastal inputs in the simulations suggests that changes in local upwelling will not have major effects on sea surface temperature or salinity or Alexandrium growth rates in Puget Sound.

LanguageEnglish
Pages1-11
Number of pages11
JournalHarmful Algae
Volume48
Early online date13 Jul 2015
DOIs
Publication statusPublished - 1 Sep 2015

Fingerprint

Alexandrium
algal bloom
climate
upwelling
oceans
salinity
ocean
sea surface temperature
surface temperature
heating
simulation
sea surface salinity
heat
growth response
regional climate
dinoflagellate
climate models
toxin
global climate
climate modeling

Keywords

  • Alexandrium
  • climate change
  • HAB
  • harmful algae
  • Puget sound

Cite this

Moore, Stephanie K. ; Johnstone, James A. ; Banas, Neil S. ; Salathé, Eric P. / Present-day and future climate pathways affecting Alexandrium blooms in Puget Sound, WA, USA. In: Harmful Algae. 2015 ; Vol. 48. pp. 1-11.
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Present-day and future climate pathways affecting Alexandrium blooms in Puget Sound, WA, USA. / Moore, Stephanie K.; Johnstone, James A.; Banas, Neil S.; Salathé, Eric P.

In: Harmful Algae, Vol. 48, 01.09.2015, p. 1-11.

Research output: Contribution to journalArticle

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