From small irrigation ponds to large reservoirs, floating solar photovoltaics (FPV) — solar panels installed on water bodies — are expanding rapidly worldwide as a low-carbon energy solution that takes advantage of underutilized water surfaces of artificial water bodies to minimize land-use conflicts. However, this emerging renewable technology raises critical questions about its impacts on aquatic ecosystems, water quality, and environmental management.
By shading the water surface, FPV systems can alter light penetration, water temperature and wind shear – impacting mixing regimes, evaporation rates, and key ecological and biogeochemical processes. These changes may influence thermal regimes, primary production, oxygen dynamics, greenhouse gas emissions, nutrient cycling, and aquatic biodiversity. This session invites talks that explore ecological, biogeochemical, and water quality responses to FPV systems across lakes, reservoirs, estuaries, and other water bodies. We are particularly interested in empirical studies, remote sensing analyses, modeling approaches, and management-oriented syntheses addressing topics such as changes in thermal structure, mixing, and oxygen dynamics; effects on nutrient cycling, harmful algal blooms, and drinking water quality; impacts on aquatic biodiversity and ecosystem functioning; interactions with other water uses, including hydropower, aquaculture, recreation, and fisheries; and strategies to minimize trade-offs while enhancing co-benefits.
Contributions that integrate ecosystem science with environmental management (e.g., reservoir operations, evaporation control) are also encouraged. By bringing together an interdisciplinary group of scientists, this session will advance our understanding of how floating solar affects aquatic ecosystems and provide insights for guiding its deployment in ways that balance both ecological integrity and sustainability.
Lead Organizer: Rafael Almeida, Indiana University (rafalmei@iu.edu)
Co-organizers:
Regina Nobre, University of Toulouse (reginanobre.eco@gmail.com)
Simone Cardoso, Federal University of Juiz de Fora (simone.jcardoso@gmail.com)
Steven Grodsky, Cornell University (grodsky@cornell.edu)
Presentations
09:00 AM
TRACKING THE RISE OF FLOATING SOLAR ENERGY ON GLOBAL AQUATIC ECOSYSTEMS (11693)
Primary Presenter: Rafael Almeida, Indiana University (rafalmei@iu.edu)
Floating solar photovoltaics (FPV) are emerging as one of the fastest-growing water-based energy technologies worldwide. Yet despite this rapid proliferation, our understanding of how, where, and under what conditions FPV is deployed—and how these installations interact with aquatic ecosystems—remains fragmented. This opening talk will provide a global overview of FPV development, synthesizing trends in growth, geography, and system design. Using a novel remote sensing-derived global database of more than 3,000 FPV systems, we will characterize the primary types of water bodies being used, typical project sizes and construction patterns, and regional trajectories of expansion. We will also outline the major ecological and biogeochemical questions emerging from this growth, including how shading, altered thermal regimes, and hydrological changes may influence ecosystem processes. By situating FPV within both its technological promise and its environmental uncertainties, this presentation will establish a foundation for the session and highlight priority knowledge gaps for future research.
09:15 AM
AQUATIC GREENHOUSE GAS EMISSIONS OF FLOATING SOLAR PHOTOVOLTAIC SYSTEMS (FPV) (10331)
Primary Presenter: Daniela Seitz, Radboud University (daniela.seitz@ru.nl)
Floating solar photovoltaic (FPV) systems are a land-sparing and potentially more energy efficient application of PV energy and add to renewable energy capacity to mitigate climate change. However, FPV installations may impact greenhouse gas (GHG) dynamics and the local aquatic ecosystem, but this is not well understood. We conducted monthly monitoring for one year starting in February 2025 in a shallow artificial stormwater retention pond with FPV covering 70% of its surface. We measured methane (CH4) and carbon dioxide (CO2) diffusive emissions and CH4 ebullitive emissions, alongside physicochemical parameters, in sampling points below the FPV (FPV) and around the edges of the installation (open water). Preliminary results suggest that ebullitive and diffusive CH4 emissions were higher in open water than in FPV sites, which could be attributed to a reduced turbulence in the FPV area, combined with an increased input of bird faeces concentrated in the open water area. Initial assessment of the diffusive CO2 fluxes indicates that the pond is on average a source of CO2, with little variation between FPV and open water sites. Surface dissolved oxygen concentrations were slightly higher in the open water compared to the FPV sites, also potentially reflecting a reduced water-atmosphere mixing in the FPV area due to the physical barrier to natural wind and waves. Overall, the FPV installation has a range of impacts on water quality and surrounding ecosystems which should be carefully considered to ensure ecological sustainability of FPV projects.
09:30 AM
Floating photovoltaics restructure microbial communities through sustained light reduction and oxygen limitation (10726)
Primary Presenter: Sophia Aredas, Cornell University (sna49@cornell.edu)
Floating photovoltaic (FPV) systems are expanding rapidly on inland waters and offer major potential as renewable energy infrastructure. Yet their long-term ecological impacts on aquatic microbial communities remain poorly understood. We conducted a two-year whole-ecosystem manipulation in experimental ponds to test how sustained FPV coverage alters microbial abundance, community structure, and metabolic functional potential. We hypothesized that FPVs would reduce light and dissolved oxygen, suppressing oxygenic photoautotrophy and promoting anaerobic metabolism. Integrating 16S rRNA amplicon sequencing, water chemistry, and flow cytometry-derived cell abundances, we show that FPV coverage drives persistent hypoxia and light limitation, restructuring microbial communities in both the water column and sediments. FPVs strongly suppressed oxygenic photosynthesis by planktonic cyanobacteria and enriched benthic cyanobacteria and anoxygenic phototrophs, including green sulfur and non-sulfur bacteria. Methanotrophs increased modestly in 2023 but expanded by an order of magnitude in 2024 as hypoxia and methane accumulation intensified reductive metabolism. Sediments similarly exhibited a shift from oxygenic to anoxygenic phototrophy. Together, these persistent changes indicate a metabolic regime shift toward an alternative stable state. Our findings demonstrate that FPVs function as a long-term press disturbance that restructures aquatic microbial communities and biogeochemical cycling potential, underscoring the need to consider microbial responses in FPV design and management.
09:45 AM
GLOBAL PATTERNS OF PHYTOPLANKTON CHANGE ACROSS GRADIENTS OF FLOATING SOLAR ENERGY COVERAGE (11794)
Primary Presenter: Aline Valerio, Indiana University (alinedmv@gmail.com)
Floating photovoltaic (FPV) systems are expanding as countries decarbonize, solar costs fall, and land availability declines. FPV arrays modify light and temperature, potentially affecting stratification, biogeochemistry, and primary production in aquatic ecosystems. While shading is expected to curb algal blooms, the mechanisms and effects on different coverage levels remain uncertain. Using remote sensing, we assessed how FPV coverage relates to phytoplankton abundance, using Normalized Difference Chlorophyll Index (NDCI) as a proxy. For ~500 installations, we mapped FPV footprints and host waterbodies, developed a spectral index for FPV detection, and estimated installation dates. Chlorophyll-a was evaluated from Sentinel-2 MSI NDCI processed on Google Earth Engine. For each FPV site, we compared NDCI medians years before and after installation and contrasted trends with nearby reference waterbodies identified from HydroLAKES, a global database of >1 million natural and artificial lakes. We then computed ΔNDCI to isolate FPV-related effects and quantified FPV coverage relative to lake area. Across the global sample, ΔNDCI was generally small, near zero, at low to moderate coverage, but became slightly negative when FPV occupied >70% of the lake surface. Reductions were stronger in high-chlorophyll than in low-chlorophyll systems. Overall, results indicate that high-coverage FPV arrays modestly reduce phytoplankton relative to nearby non‑FPV lakes. These findings offer new insights into how large-scale, persistent shading influences algal dynamics in freshwater systems.
10:00 AM
The ecological effects of floating photovoltaic systems vary with panel coverage and lake trophic status: an experimental approach (10275)
Primary Presenter: Regina Nobre, UFRN - Universidade Federal do Rio Grande do Norte (reginanobre.eco@gmail.com)
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.
10:15 AM
THE IMPACT OF FLOATING SOLAR PHOTOVOLTAICS ON PRIMARY PRODUCTION IN A FRESHWATER LAKE (11961)
Primary Presenter: Emma van Veenendaal, Deltares & The University of Twente (emma.vanveenendaal@deltares.nl)
Despite the advantages of floating solar photovoltaics (FPVs), such as increased energy efficiency and reduced land use, their environmental impact remains unclear. Most studies addressing this knowledge gap have focused on FPVs’ impact on abiotic parameters, providing insight into their direct influence on the physical environment. However, little is known about how these changes may have knock-on effects on ecological processes and the rest of the food web. Moreover, most empirical studies rely on monitoring data of up to several months, highlighting the scarcity of multiyear observations. As part of the Horizon Europe project SuRE, we explored primary production, which is an important ecological process that supports ecosystem functioning in freshwater lakes. Using nearly three years of monitoring data from a quarry lake in the Netherlands, we found that oxygen levels under FPV systems were significantly lower, corresponding to a sharp decline in primary production in the upper water layer. Because primary production supports zooplankton and higher trophic levels and plays an important role in nutrient cycling, reductions can have consequences for the entire aquatic ecosystem. Our findings emphasize why multiyear monitoring and baseline data collection are essential for sustainable FPV deployment. Furthermore, we will share insights from ongoing modeling work that helps to explain these findings.
SS022 Floating Solar Energy in Inland and Coastal Waters: Ecosystem Responses and Sustainability Dimensions
Description
Time: 9:00 AM
Date: 13/5/2026
Room: 520A