This workshop demystifies cyanobacteria and the blooms they form. It includes a technical examination of how a handful of cyanobacteria use unique adaptations to take full advantage of the structure of lakes, thereby becoming a co-conspirator in the eutrophication process, inevitably leading to formation of surface blooms. The workshop begins by briefly outlining the three different groups of cyanobacteria, explaining how the specific adaptation of buoyancy regulation separates them from other phytoplankton. Buoyancy will be covered in detail, including the initial discovery and subsequent experimentation leading to our understanding of vacuoles, vesicles, formation triggers, and collapse curves. Buoyancy will be demonstrated as the primary adaptation enabling an organism to exert control over its environment.
Lake structure is explored next, through the lens of a lake as an environment for phytoplankton, including the specific aspects of thermal dynamics that cyanobacteria take advantage of. This section begins with a review of properties of water, including density, viscosity, redox, pH, light, oxygen, dissolved gases, and carbonate. It will then explore how the dynamics of heat and light are the pivotal structural aspects that regulate distribution and succession of all plankton. The density anomaly is considered specifically to illustrate its role as the master variable that regulates distribution of just about everything in lakes. The distribution of heat in lakes, including convection, turbulent flow, and density gradients, will be discussed to illustrate how wind and light stratify a lake by establishing an epilimnion. This section concludes with a review of community phytoplankton ecology, including law of the minimum, paradox of the plankton, competitive exclusion principal, Reynolds numbers, niche space, photosynthetic efficiency, r- vs K- selection, nutrient uptake rates, and predation.
The final section of the workshop will return to buoyancy and how cyanobacteria use it to regulate their position in the water column to maximize uptake of nutrients and light. Through the mechanism of buoyancy, cyanobacteria have the capacity to transform the elevated phosphorus levels associated with cultural eutrophication into the characteristic conditions observed in eutrophic lakes. This section of the workshop will present theoretical models for both the seasonal succession of phytoplankton in lakes and the theoretical bloom space models for predicting habitats suitable for cyanobacteria dominance. The different types of blooms will be discussed, along with the inevitability of shore scum, and how global warming is making it certain that there will be more blooms, that will last longer.
The workshop ends with a brief discussion of lake management alternatives used to mitigate cyanobacteria blooms. Concepts behind methods such as Alum, aeration, circulation, and algaecides will be discussed in the context of short-circuiting cyanobacteria growth.
Presenter
George W. Knoecklein started his limnological education at Unity College in Unity Maine, where he took part in one of the first studies of Unity Pond. George continued his education at Michigan State University where he earned a Master of Science in limnology while working on US EPA Clean Lakes projects at Lake Lansing, Michigan, and Skinner Lake, Indiana. George moved back to Connecticut in 1985 to pursue a career in lake management working for Ecosystem Consulting Service until earning a PhD in limnology from Peter Rich at the University of Connecticut. That year he founded Northeast Aquatic Research, a consulting firm that works specializing in assisting lake stakeholders understand and manage the threats of invasive aquatic plants and cyanobacteria.