Climate Change 2001:
Working Group II: Impacts, Adaptation and Vulnerability
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Figure 5-8: Diagram of complex interactions between climate change, watershed and lake processes, and water clarity of a eutrophic lake [modified from Lathrop (1998) and information in Lathrop et al. (1999)]. The left panel diagrams a warmer, dryer climate with less wind; the right panel diagrams a warmer, windier, and wetter climate with more extreme rain events. In both cases, the altered climate would be expected to change the water quality of the lake, but the complexity of relations leads to uncertain future water clarities. A "+" means an increase and a "-" means a decrease in the condition or process; a "?" means conflicting expectations. Greater blooms of phytoplankton lead to lower water clarity, and reduced blooms lead to greater clarity. Blooms depend on external and internal loading of phosphorus (P). Dryer climates lead to less external loading, whereas wetter climates or more episodic rains lead to more external loading. Warmer climates lead to warmer surface waters and increased vertical stability in the water column, thus less mixing and internal loading. Warmer waters also allow potential invasion by warmer loving, zooplaktivorous fish that can reduce zooplankton species that in turn reduce algal populations. Windier climates result in increased vertical mixing, thus greater internal loading.

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