Mangrove forest found living in freshwater

Bob Yirka is a research scientist at Phys.org.

A mangrove forest has been found in a freshwater area of the Amazon. The group describes their study in a paper published in the journal Current Biology.

Mangroves are trees or shrubs that grow along tropical coastal areas and are known for their dense thickets and tangles of roots. Mangroves are some of the most efficient carbon sinks known to nature, which makes them an important player in the Earth's carbon cycle. A team sponsored by National Geographic was conducting research in a northeast part of Brazil, where the Amazon River meets the Atlantic Ocean, when they came across a stand of mangroves.

The original work done by the team was to take measurements of the mangrove forests in the delta and to determine plant composition and tree density. They were using drones and 3D lasers to estimate the amount of carbon in the plants.

In addition to the large amount of water in the river, the area also gets a lot of rain. The researchers were surprised to see mangroves growing close to the beach. They began measuring to make sure there wasn't a saltwater source. The surface water measured less than five on the scale and the soil samples ranged from zero to 11. The trees are the only known ones in the world to survive on freshwater mangrove. There are fresh/saltwater mangrove stands in the area.

The amount of mangrove forest known to exist is increased by 180 square kilometers, which has an impact on carbon capture and global warming.

More information: Angelo F. Bernardino et al, The novel mangrove environment and composition of the Amazon Delta, Current Biology (2022). DOI: 10.1016/j.cub.2022.06.071 Journal information: Current Biology

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