GEISHA | Global Evaluation of the Impacts of Storms on freshwater Habitat and structure of phytoplankton Assemblages

Phytoplankton abundance and composition are sensitive to water column conditions which are strongly influenced by weather (e.g., wind and rain) and climate change. The FRB-CESAB GEISHA project was framed in support to the GLEON Stormblitz project to gather and analyse time-series through collaborative efforts to assess the impacts of storms on phytoplankton. The project includes more than 80 researchers from governmental institutes and universities. GEISHA was, among others, able to:

• gather and standardize existing long-term datasets,
• assess the impact of storms on nutrients, light, water column stability and subsequent impacts on the structure of phytoplankton communities,
• perform meta-analyses to evaluate the sensitivity of aquatic ecosystems to extreme weather events, and
• highlight that biological consequences of storms on phytoplankton are fundamental to the dynamics of lakes and yet are still poorly understood. There is a real need for scientific collaboration to understand the impact of extreme weather events on lakes.

This document summarizes, in just a few pages, the project’s context and objectives, the methods and approaches used, the main findings, and the implications for science, society, and both public and private decision-making.