High CO2 and Silicate Limitation Synergistically Increase the Toxicity of Pseudo-nitzschia fraudulenta

Anthropogenic CO2 is progressively acidifying the ocean, but the responses of harmful algal bloom species that produce toxins that can bioaccumulate remain virtually unknown. The neurotoxin domoic acid is produced by the globally-distributed diatom genus Pseudo-nitzschia. This toxin is responsible for amnesic shellfish poisoning, which can result in illness or death in humans and regularly causes mass mortalities of marine mammals and birds. Domoic acid production by Pseudo-nitzschia cells is known to be regulated by nutrient availability, but potential interactions with increasing seawater CO2 concentrations are poorly understood. Here we present experiments measuring domoic acid production by acclimatized cultures of Pseudo-nitzschia fraudulenta that demonstrate a strong synergism between projected future CO2 levels (765 ppm) and silicate-limited growth, which greatly increases cellular toxicity relative to growth under modern atmospheric (360 ppm) or pre-industrial (200 ppm) CO2 conditions. Cellular Si∶C ratios decrease with increasing CO2, in a trend opposite to that seen for domoic acid production. The coastal California upwelling system where this species was isolated currently exhibits rapidly increasing levels of anthropogenic acidification, as well as widespread episodic silicate limitation of diatom growth. Our results suggest that the current ecosystem and human health impacts of toxic Pseudo-nitzschia blooms could be greatly exacerbated by future ocean acidification and ‘carbon fertilization’ of the coastal ocean

Learning about forest futures under climate change through transdisciplinary collaboration across traditional and western knowledge systems

We provide an overview of a transdisciplinary project about sustainable forest management under climate change. Our project is a partnership with members of the Menominee Nation, a Tribal Nation located in northern Wisconsin, United States. We use immersive virtual experiences, translated from ecosystem model outcomes, to elicit human values about future forest conditions under alternative scenarios. Our project combines expertise across the sciences and humanities as well as across cultures and knowledge systems. Our management structure, governance, and leadership behaviors have both fostered and constrained our work and must be continuously responsive to changing group dynamics. Our project presents opportunities for substantial contributions to society, including insights and knowledge about complementary ways of knowing, skills training, and professional development, and opportunities for reflexive learning about effective transdisciplinary, translational, and transformative scientific processes