Resilience and susceptibility to algal blooms

1. Resilience and susceptibility to algal blooms • An aquatic ecosystem will have varying degrees of resilience and susceptibility to a disturbance. • Quantification of this is important to determine the risk of problems forming at different times of the year, or under differing antecedent conditions. • The same disturbance at different times may results in different responses. • Quantification of both the “disturbance”, the “ecosystem resilience” and the “response” is an ongoing line of research at CWR.

2. Disturbance and Response • Nothing particular unusual about the size of the “disturbance”, 1 in 2 yr ARI, but something very unusual about the size of the response. • Subsequent upwelling and warming explains why conditions favourable for algal growth, but why Microcystis and not something else? • Clearly the susceptibility of the system to a Microcystis bloom was very high, compared to all other periods of the historical record.

3. Research questions • What controls the resilience or susceptibility to algal blooms? • In particular, what controls the susceptibility to Microcystis? • How do we quantify disturbances at a fundamental level? {Burragorang was actually a “serial” disturbance – an inflow, followed by upwelling}