Climate Effects on Wetland Soils Create the “Perfect Storm” for Toxic Cyanobacteria Blooms: Fresh Perspectives on an Old Problem.

A grand challenge for the 21^st century will be better management of lands to ensure the provision of safe and reliable water supplies.  Watersheds and their wetlands are filters for nutrient loading to surface waters.  Recent reports show that the frequency and intensity algal blooms in surface waters are increasing, particularly cyanobacteria, which can produce potent toxins.  What has historically been a problem for nutrient-rich (eutrophic) waters is starting to occur in nutrient-poor (oligotrophic) waters without the obvious triggers of major phosphorus sources.  Competing paradigms have led to contentious debates. Our focus has turned to the role of wetlands as bioreactors and controllers on the loading of macro and micronutrients that limit the growth of cyanobacteria. Our research explores how climate affects the variable redox areas of wetlands by changing the timing, magnitude, and organization of reducing conditions, which in turn changes the fates of macronutrients (N removal, P release) and releases essential micronutrients that can be accessed by cyanobacteria through an iron-scavenging system. All of these factors create a perfect storm for the promotion of cyanobacterial blooms.