The ecological effects of floating photovoltaic systems vary with panel coverage and lake trophic status: an experimental approach

Freshwater ecosystems face increasing human pressures, including techno-engineering interventions like floating photovoltaic systems (FPVs), which are rapidly expanding, outpacing research on their potential ecological impacts. We experimentally tested how different levels of FPV coverage (0%, 25%, 45%, 65%) influence water physical properties, biodiversity, and ecosystem functioning, and whether these effects interact with nutrient enrichment (lake trophic status). Increasing FPV cover reduced water temperature and evaporation independently of nutrients. Regarding biodiversity, the zooplankton community was affected by FPV and nutrient enrichment, with higher abundance at 45% FPV, no effects on species richness, and lower diversity at intermediate FPV covers under enrichment. Zooplankton composition changed with coverage and nutrients, through modifications in dominant taxa (Ceriodaphnia setosa, Simocephalus vetulus, and Polyarthra). Macroinvertebrate richness and diversity declined with increasing FPV cover, particularly in enriched mesocosms. Community composition changed with FPV and nutrient interactions, with Asellidae dominating 65% FPV treatments and Chironomidae dominating non-enriched uncovered treatments. Gross primary production and respiration decreased with increased FPV coverage, while decomposition and CO₂ were affected only by nutrients. FPVs can thus alter freshwater physical conditions, biodiversity, and ecosystem functioning, with context-dependent effects, highlighting the need to consider local ecological characteristics in FPV deployment.

Presentation Preference: Standard Oral (12 Minutes)

Primary Presenter: Regina Nobre, UFRN - Universidade Federal do Rio Grande do Norte (reginanobre.eco@gmail.com)

Authors:

Regina Nobre, UFRN - Universidade Federal do Rio Grande do Norte  (reginanobre.eco@gmail.com)

Stéphanie Boulêtreau, Université de Toulouse  (stephanie.bouletreau@univ-tlse3.fr)

Fanny Colas, Université Claude Bernard Lyon 1  (fanny.colas@univ-lyon1.fr)

Frédéric Azémar, Université de Toulouse  (frederic.azemar1@univ-tlse3.fr)

Loïc Tudesque, Université de Toulouse  (loic.tudesque@univ-tlse3.fr)

Nathalie Parthuisot, Université de Toulouse  (nathalie.parthuisot@univ-tlse3.fr)

Paul Millet, Université de Toulouse  (paulsalmotrutta@gmail.com)

Julien Cucherousset, Université de Toulouse  (julien.cucherousset@univ-tlse3.fr)