Evaluating the Adaptation of a Predictive Model

An ecologist models the sudden collapse of a fish population after a certain level of river pollution is reached. They base their model on an economic concept originally used to describe a situation where a small change in market sentiment triggers a rapid, self-reinforcing crash in asset prices. In this adaptation, what does the 'river pollution level' that triggers the collapse correspond to in the original economic model?

Adapting Economic Models to Public Health

An economist's model for a speculative market bubble, which describes a rapid, unsustainable increase in asset prices followed by a sudden collapse, is being adapted to explain a sudden algal bloom in a lake. Match the key component from the economic model (Term) with its analogous component in the new environmental model (Definition).