## 4 Discussion
Taking into account that bulk TN:TP resources often vastly overestimates the corresponding bioavailable resources [105], in this study, we found similar in-lake and inflow river nutrient ratios, suggesting that lake water chemistry was highly influenced by nutrient loadings from the surrounding catchment, as observed in other studies [100]. In contrast, following Storm Hector, there was a decoupling period of TN:TP patterns of in-lake and inflowing streams lasting for 2 months (from mid-June to mid-August), with higher TN:TP values recorded in the lake compared with the inflowing rivers. Previous studies have concluded that, in general, TN:TP ratios are relatively higher in lakes than in their inflow streams, in part likely owing to enhanced water column primary production and microbial activity [106]. In addition, [PERSON] and [PERSON] (2012) reported a disproportionally larger increase in nitrate loading during an extreme rain event, causing a substantial increase of in-lake dissolved inorganic nitrogen:total phosphorus ratio (DIN:TP) [46]. Another study suggested that storm events disproportionately mobilize P compared to N, contributing to reduction in N:P loading to the receiving water bodies [19]. Nevertheless, as Storm Hector in Feeagh mainly influenced the stratification pattern, instead of being characterised by an event that increased catchment nutrient runoff, the enhanced difference between inflow and in-lake total nutrient ratios seemed to be driven by internal biological dynamics accentuated, in turn, by the loss of lake stability, as suggested by [PERSON] et al. (2018) [106]. Phytoplankton community composition appeared to follow the natural seasonal succession expected for a dystrophic low-productivity lake such as Feeagh [65]. However, while cyanobacteria blooms have previously been linked to increases in water temperature and high stability [107; 108; 109; 110], directly associated with extreme weather events [111; 31], and associated with the depletion of available nitrogen [111; 112; 113; 114], the higher cyanobacteria biomass that we found has rarely been seen before in Feeagh [10]. _Woronichinia neegeliana_ appeared to take advantage of post-storm warm and calm conditions in Lough Feeagh. This cyanobacteria species is one of the most commonly associated with toxic cyanobacteria blooms [115]. It is not capable of fixing atmospheric nitrogen, but it is very efficient at taking up other dissolved fractions, with cells usually taking advantage when N concentrations are limiting to other algae [116]. A decrease in turbulent diffusion was shown to be the dominant environmental parameter determining the timing of phytoplankton development, together with an increase in water temperatures when light is limited (e.g., brown lakes such as Feeagh) [25]. Therefore, despite storm events disrupting the stability of the systems, if the persistent calm conditions of this study occur more frequently [4], a quick return to thermal stratification will potentially increase cyanobacteria biomass, even in lakes with low inorganic nutrient concentrations and high water colour [117]. In addition to cyanobacterial increases, a wide range of effects on phytoplankton community composition after physico-chemical lake changes driven by episodic meteorological events have been reported [118]. In accordance with our study, [PERSON] et al. (2011) observed that, unlike previous documented effects of hurricanes, where increased N inputs stimulated primary productivity, a substantial reduction in phytoplankton biomass occurred, coinciding with a large decline in mean irradiance in the mixed layer and increases in phytoplankton grazers [55]. In this study, an increase in the biomass of grazers also simultaneously occurred with a decrease in phytoplankton biomass at different depths, particularly the Cryptophyta group, which is considered a high-quality food for primary consumers [119; 120], and is highly selected by copepods [121].