## 1 Introduction
However, little is known about shifts in N\(\cdot\)P ratios in aquatic ecosystems due to extreme climatic events [19; 20]. Differences in nutrient mobilization in peatland catchments [21] can disentangle relationships between loadings and in-lake N\(\cdot\)P dynamics during extreme weather events. On the other hand, internal lake processes such as changes in microbial and primary producer nutrient uptake may drive a shift in lake N\(\cdot\)P seasonal pattern [22], in turn impacting higher trophic levels [23]. Phytoplankton community composition can be strongly affected by episodic weather events through changes in lake water column stability which, in turn, effects light and nutrient availability [24; 25; 26; 27; 28]. Previous studies have found evidence of effects on phytoplankton communities following nutrient pulses as a consequence of episodic events [29; 30; 31]. In addition, in temperate stratified lakes, the seasonal pattern of primary production is linked to the development of thermal stratification [32]. According to the 'critical depth hypothesis', the initiation of the spring phytoplankton bloom occurs when the depth of surface mixing is shallower than the base of the euphotic depth [33; 34]. For this reason, buoyant cyanobacteria generally dominate in lakes during calm and warm conditions [35] where, in contrast, deeper mixed layers favour taxa which are less sensitive to large fluctuations in light levels, such as certain Chlorophyta and diatom species [35; 36]. Fast-sinking algae, like heavy and non-motile diatoms, take advantage of higher turbulence to remain in the mixed layer longer [37; 38]. Cryptobytes, Chrysophytes and Dinophytes, which are often very motile and can have mixotrophic feeding strategies [39; 40; 41], can also have competitive advantages when mixed layer depths are deeper and relatively high-turbulence conditions dominate, because of their low light:nutrient requirements [42]. Quantifying changes in gross primary production (GPP), respiration (R) and net ecosystem productivity (NEP) (where NEP = GPP-R), can be used to assess the impact of episodic events on lake ecosystems, by changing the metabolic balance between R and GPP, and hence NEP [10; 43; 44]. Ecosystem metabolism and biomass dynamics are tightly coupled [45], and an increase in the biomass of the heterotrophic planktonic community is linked with an increase in ecosystem R [46; 47]. In addition, R is strongly coupled to GPP, as R is constrained by the availability of labile carbon exudates through photosynthesis from primary producers (NEP) [48]. Consequently, shifts at the base of aquatic food webs (e.g., from heterotrophic to autotrophic production) have an effect on metabolism estimates, thus providing a general picture of whole-lake ecosystem impacts driven by meteorological extreme events [30; 49]. However, the net effect of extreme climatic events on ecosystem metabolism is not straightforward, as metabolic rates differ at species level [50]. Therefore, new evidence may help to explain discrepancies between observations [43; 51; 52]. A number of studies have assessed the response of zooplankton community composition and biomass altered by extreme weather-related events increasing lake turbulence and deepening the thermocline [53; 54; 55; 56; 57; 58; 59]. Almost all authors who have studied zooplankton dynamics following storms have reported a relative increase in the biomass of omnivorous and predatory copepods during storm-induced mixing, which could be accompanied by changes in the biomass of the strictly herbivous groups such as cladocerans [58]. Diet selection by calanoid copepods is strongly influenced by both particle quality and abundance of food available [60]. Therefore, changes in zooplankton community composition after meteorological-induced episodic events may be, in part, explained by the indirect effects to changes in their food source. New tools are increasingly available which allow food quality changes for primary consumers to be assessed.