Global change impacts on cyanobacterial bloom toxicity

Introduction

Harmful cyanobacterial blooms produce toxins that are a major threat to water quality and human health. Blooms increase with eutrophication and are expected to be amplified by climate change. Yet, we lack a mechanistic understanding of the toxicity of blooms and their response to the complex interplay of multiple global change factors.

Mechanisms of Bloom Toxicity

Bloom toxicity is determined by a combination of mechanisms acting at different ecological scales, including:

1. Cyanobacterial biomass accumulation in the ecosystem.
2. Dominance of toxic species in the community.
3. Contribution of toxic genotypes in the population.
4. Amounts of toxins in cells.

Research Objectives

I will develop a fundamental understanding of bloom toxicity by revealing the combined effects of nutrients, elevated pCO2, and warming at each scale. This will be achieved by integrating these responses using a unique combination of ecological theory, technological advances, and methodological innovations.

Methodological Approach

Specifically, I will use first principles to scale from cellular traits, such as:

• Carbon and nutrient acquisition.
• Cellular toxin synthesis.
• Growth rates.

This will extend to population and community dynamics.

High-Throughput Assessment

To enable rapid assessment of numerous cyanobacterial traits, I will set up a high-throughput flow-cytometry pipeline. Additionally, I will develop a novel lab-on-a-chip experimental platform to allow massive parallel screening of key competitive traits in various phytoplankton species and cyanobacterial genotypes.

Scaling Up Research

To scale from these cellular traits to population and community interactions, I will study genotype selection and interspecific resource competition in state-of-the-art chemostats. Furthermore, I will scale up to natural communities in the field and in large-scale indoor mesocosms to assess global change impacts on the mechanisms underlying toxicity of (near) real-life blooms.

Conclusion

With this unique combination of scaling approaches, I will provide a breakthrough in our mechanistic understanding of the toxicity of cyanobacterial blooms and their response to global change.