Image of the Day: Bubbling Plants
Image of the Day: Bubbling Plants

Image of the Day: Bubbling Plants

Plants use two different strategies to photosynthesize underwater.

Nov 18, 2019
Emily Makowski

ABOVE: Hemianthus callitrichoides forming oxygen bubbles as it photosynthesizes using carbon dioxide
OLE PEDERSEN

Plants need carbon dioxide for photosynthesis, but freshwater aquatic plants can have a tough time getting enough of it from water. To overcome this, some also make use of bicarbonate, inorganic carbon derived from the weathering of rocks and soil. An increase in bicarbonate due to human activities could alter these aquatic ecosystems, according to a study published Friday (November 15) in Science.

Researchers produced a global map of the proportion of bicarbonate– and carbon dioxide–using aquatic plants and compared it to a map of bicarbonate concentrations in streams and lakes. They found that bodies of water with higher bicarbonate concentrations also had more species of bicarbonate-using plants.

According to the paper, human activities such as deforestation, increased cultivation, and the use of nitrate fertilizers are all contributing to a large-scale increase in bicarbonate concentrations. This means that bicarbonate-using plants could thrive and overcrowd plants that depend solely on carbon dioxide to make energy.

The white material on this curly waterweed (Lagarosiphon major) is precipitated calcium carbonate, formed as a byproduct of photosynthesis using bicarbonate.
OLE PEDERSEN

L.L. Iversen et al., “Catchment properties and the photosynthetic trait composition of freshwater plant communities,” Science, doi:10.1126/science.aay5945, 2019.

Emily Makowski is an intern at The Scientist. Email her at emakowski@the-scientist.com.