Sponges Contribute to Coral Reef Productivity

Marine sponges, long known for filtering plankton and detritus from the water column, may also harness sunlight to produce their own food, a discovery reported in the journal *Functional Ecology*. Researchers at the University of Amsterdam’s Institute for Biodiversity and Ecosystem Dynamics (IBED) found that certain tropical reef sponges host photosynthetic symbionts capable of converting light energy into organic compounds, a process previously attributed mainly to plants and algae.

The study, which examined sponge samples from coral reef ecosystems, showed that photosynthetic activity contributes significantly to the sponges’ carbon budget, especially during periods of low food availability. By supplementing their diet with photosynthates, these sponges can maintain growth and reproduction, thereby enhancing overall reef productivity and resilience. The findings suggest that sponge-mediated photosynthesis may play a broader role in nutrient cycling across marine habitats where sponges are abundant.

If the photosynthetic capacity of sponges is widespread, it could reshape our understanding of energy flow in marine ecosystems and inform conservation strategies aimed at preserving reef biodiversity and function. Further research will determine how widespread this trait is among sponge species and its implications for ecosystem health in the face of climate change.