Spatial distribution of soluble reactive silica (SRSi) in the Tanzanian waters of Lake Victoria and its implications for diatom productivity

Antecedent lake conditions shape resistance and resilience of a shallow lake ecosystem following extreme wind storms

“…Silica concentrations in Müggelsee are primarily driven by seasonal variation, sedimentation and become more bio‐available in the water column through wind driven mixing in spring and fall (Köhler and Nixdorf 1994; Kozerski and Kleeberg 1998; Sommer et al 2012). Concentrations of silica may represent whether the lake was well mixed with cool water temperatures and low diatom biomass (i.e., high concentrations of soluble silica prior to the storm), or when a diatom bloom was present (i.e., low to moderate concentrations of soluble silica) (Saunders et al 2009; Ngupula et al 2014). In our study, we found that mixed conditions (i.e., high concentrations of silica) was linked to storm driven decreases in the resistance and resilience of the lake ecosystem (Fig.…”

“…For example, phycocyanin (i.e., cyanobacteria) may benefit from an increase in other nutrients such as phosphorus or nitrogen as a result of resuspension, which may increase the resilience of the cyanobacteria community following a storm (Shade et al 2012). Similarly, diatom community composition may be leading to different resistance and resilience responses due to functional groups having adaptations related to chemical gradients, uptake of nutrients, position in the water column, or light harvesting, which are all affected by antecedent lake conditions and storms (Saunders et al 2009; Krawiec and Kaufman 2014; Ngupula et al 2014). Saunders et al (2009) found that the two most important predictors of diatom abundance across nutrient and chemical gradients of 50 coastal and inland lakes were conductivity and pH, both of which were found to be relatively important in shaping lake ecosystem resistance and resilience (Figs.…”