06/03/2026
🔎 Some of the most important structures in a mangrove are almost too small to see.
Look closely at the pencil-like roots (pneumatophores) poking up from the mud around a grey mangrove (Avicennia marina), and you'll find them dotted with tiny pores called lenticels.
👀 They're small but the tree can't breathe without them.
Mangroves grow in waterlogged, oxygen-starved sediment, so their roots can't get air the way most plants do. At low tide, these lenticels open up, letting gas pass between the atmosphere and the spongy internal tissue (aerenchyma) that channels oxygen down to the submerged roots. When the tide comes back in, they seal off.
🌳 And just like that, whole forests can thrive on the water's edge.