# Investigating the Impact of Wildfires on Lake Water Quality Using Earth Observation Satellites
## 5 Conclusions  
This study intended to contribute to the global study of the effects of wildfires on lake water quality, including a large number of lakes in many regions worldwide and covering different lake types and ecological settings. To this aim, the satellite derived Lakes_cci and Fire_cci datasets were used and the SPR approach was applied to identify lakes most influenced by their catchment and likely to be more impacted by wildfires via a terrestrial pathway. Satellite derived Chl-a and turbidity variables were considered as indicators of changes in water quality induced by wildfires. The lakes affected by the biggest wildfires, in terms of burned areas extension, were located in the African continent and were characterized by regular annual fires. Lake morphology was important in determining lake responses, as among a large number of hydro-morphological lake characteristics, lake depth was found to be significant in determining Chl-a concentration peaks, with higher peaks in shallower than in deeper lakes. The standardized precipitation index was a candidate parameter for determining maximum turbidity peaks, with the probability of developing higher peaks in wetter conditions. When analyzing globally the entire set of lakes, it was a challenging task to identify significant relationships between fires and lake water responses in terms of Chl-a and turbidity changes. When focusing on a restricted group of lakes (regular burning, in the African region) we found more significant relationships; therefore, partitioning lakes by location and wildfire frequency and intensity may aid in the understanding of relationships that are distinct globally. We finally found that during a six-month period after a major fire, lake Chl-a and turbidity either increased or decreased in a similar number of lakes, suggesting that lake specific ecological and hydro-morphological context is important to interpret potential responses to fires. Our findings are in agreement with previous local studies on the effect of fires on lakes, since comparison of pre- and post-fire lake water quality variables detected either changes or stability in lake conditions. Defining lake responses to fires at global scale and generalizing findings proved to be difficult because of the many interactions among the variables involved, resulting in complex hydrological and ecological dynamics in lakes, eventually translated into water quality condition changes. Moreover, lake biological responses to fires are extremely complex and inconsistent among relevant studies, likely because organisms respond to opposing factors that can simultaneously enhance or inhibit primary productivity. Nutrients flushing from soils in burned areas through runoff have the potential to promote primary production in a lake, while a reduction in light availability by increased turbidity can reduce phytoplankton growth. Ideally, future studies should incorporate information on seasonal nutrient dynamics over a long timeframe so that loads derived from wildfires and other sources can be partitioned and related with greater confidence to in-lake responses in Chl-a and turbidity. Moreover, future works should combine remote sensing data with hydrological modelling to better quantify the role of precipitation, soil type, and runoff in explaining water quality changes due to fire effects. There exists an opportunity to pair with local authorities and practitioners to help further understand relationships. The incidence and intensity of wildfires is increasing globally, which together with increasing pressure on water quantity and quality in lakes is threatening many global communities who depend on them. This study underlines that the responses within lakes are dependent on factors such as lake depth and trophic conditions, as well as the timing and magnitude of the drought-fire-precipitation cycle.