Problem
1. The trophic state of a lake may be of importance not only for ecological considerations but also because you may want to use it for commercial goals. Imagine a company wants to establish a lucrative fish farm over the four lakes (now assuming they are all oligotrophic). They have hired you as geo-consultant to establish if this project is feasible, given that they want to grow a highly sensitive Asian fish species that needs very stable environmental conditions to thrive. Let us further assume that there is a coal-fired power plant in the vicinity of the lakes (bummer!). What are your first investigative steps, why? Hint: Ask yourself if AR can be kept in check and if so, how? Why does AR differ regionally and even locally? Prioritise your approach, i.e. give only the most important initial steps.
2. Would there be a difference qualitatively in the oxygen state in the hypolimnion if the lake had contained 550 ppb nitrogen rather than phosphorous (don't assume that P is now the limiting factor, concentrate on N instead). What two factors does that depend on?