There is emerging evidence that Climate Change (CC) already is impacting coastal and offshore marine phytoplankton communities, and that future trends may include increases in the frequency and severity of Harmful Algal Blooms (HABs). But the projections of CC:HAB effects remain largely speculative. Some fundamental linkages are clearly anticipated; for example, the projected increases in surface water stratification that in principle will favour many cyanobacteria and toxic dinoflagellates. But these and other expected linkages are founded on limited and often conflicting experimental data. Given our poor success in predicting present-day HAB outbreaks, it is reasonable to believe that unexpected linkages will also emerge. So, scientific debate at this time cannot reliably inform on connections between HABs and CC, or how severe any effects on HABs may be in the future.
HAB research over the past few decades has largely centered on three broad areas:
identification of HAB organisms and determining their optimal growth conditions,
detection and characterization of algal toxins, and
investigating HAB species distributions and their ecophysiology in coastal waters.
These research thrusts are not well suited to inform on purported CC:HAB linkages. A new focus is needed in HAB research to build understanding of how the competition among HAB and non-HAB species may change with climate. Our current insights about conditions favoring initiation and maintenance of different HABs must be put into the context of long-term alterations in coastal environments. This shift in research priority will not be straightforward, and the path forward is not clear. It is critical that HAB scientists identify the research issues of greatest importance over the next decade to determine what fundamental parameters and research infrastructure are needed to forecast HAB patterns in a changing climate.
Bring together algal physiologists, ecologists, oceanographers, modellers and climate change specialists to develop a consensus on the priority research directions for future HAB/CC funding.
Develop “proactive” research strategies that build rigorous, testable hypotheses to guide scientists, managers and the public on what environmental and HAB changes are projected.
Design funding-realistic observing infrastructures (combining research studies, detection schemes, observing systems) to capture the critical datasets needed to assess HAB patterns in relation to measurable indicators of climate change.