Spatial heterogeneity of biogeochemical parameters in a subtropical lake

Spatial variability in aquatic ecosystems is caused by physical (upwelling, fronts, seiches, turbulence, inflows, etc.), chemical (e.g. unequal nutrient loads), biological processes (grazing, migration, etc.), and their interactions (Reynolds, 1984; Kalikhman et al., 1995; Knauer et al., 2000). Boundary processes can generate intense resuspension, turbulent mixing, and upward fluxes of nutrients (Imboden and Wuest, 1995; Ostrovsky et al., 1996; Macintyre et al., 1999). Presently the role of various phenomena in formation of spatial variability of suspended particles and chemical fluxes is poorly understood. The visualization of the complex spatial organization of an aquatic ecosystem is an essential step toward the identification of the processes responsible for its formation. Analysis of such information can help to reveal mechanisms that control eutrophication and determine local importance of internal and external loading of nutrients. Revelation of seasonal aspects of spatial heterogeneity can be also useful for verification of the existing complex three-dimensional mathematical models (e.g. Hodges et al., 2000) of aquatic ecosystems.