Monday, December 10, 2012

Global change and the future of harmful algal blooms in the ocean

Mar Ecol Prog Ser

Vol. 470: 207–233, 2012
doi: 10.3354/meps10047
Published December 6, 2012

Global change and the future of harmful algal blooms in the ocean

Fei Xue Fu*, Avery O. Tatters, David A. Hutchins

*The University of Southern California, Department of Biological Sciences, 3616 Trousdale Parkway, Los Angeles, California 90089, USA

ABSTRACT: The frequency and intensity of harmful algal blooms (HABs) and phytoplankton
community shifts toward toxic species have increased worldwide. Although most research has
focused on eutrophication as the cause of this trend, many other global- and regional-scale
anthropogenic influences may also play a role. Ocean acidification (high pCO2/low pH), greenhouse
warming, shifts in nutrient availability, ratios, and speciation, changing exposure to solar
irradiance, and altered salinity all have the potential to profoundly affect the growth and toxicity
of these phytoplankton. Except for ocean acidification, the effects of these individual factors on
harmful algae have been studied extensively. In this review, we summarize our understanding of
the influence of each of these single factors on the physiological properties of important marine
HAB groups. We then examine the much more limited literature on how rising CO2 together with
these other concurrent environmental changes may affect these organisms, including what is possibly
the most critical property of many species: toxin production. New work with several diatom
and dinoflagellate species suggests that ocean acidification combined with nutrient limitation or
temperature changes may dramatically increase the toxicity of some harmful groups. This observation
underscores the need for more in-depth consideration of poorly understood interactions
between multiple global change variables on HAB physiology and ecology. A key limitation of
global change experiments is that they typically span only a few algal generations, making it
difficult to predict whether they reflect likely future decadal- or century-scale trends. We conclude
by calling for thoughtfully designed experiments and observations that include adequate
consideration of complex multivariate interactive effects on the long-term responses of HABs to a
rapidly changing future marine environment.

KEY WORDS: Climate change · CO2 · Ocean acidification · Temperature · Stratification · Nutrient
limitation · HAB · Algal toxins · Phycotoxins

No comments: