17 / BIG OCEAN QUESTION

How can trees grow in saltwater?

Mangroves filter, store or push out salt—and some of their roots stick into the air so the tree can breathe.

THE SHORT ANSWER

Different mangrove species filter salt at the roots, excrete it through leaves or store it in tissues that are later shed. Specialized roots obtain oxygen above waterlogged mud and stabilize trees in shifting intertidal sediment.

Three things to know

Global diversity
~80 species
‘Mangrove’ describes unrelated trees and shrubs with similar tidal adaptations.
Soil challenge
Low oxygen
Pneumatophores and prop roots expose gas-exchange surfaces.
Coastal role
Buffer + nursery
Roots trap sediment, reduce wave energy and shelter young animals.
01

More than one solution to salt

Some mangroves exclude much of the salt before water enters the roots. Others excrete crystals through leaf glands or concentrate salt in older leaves. Thick leaves and controlled stomata reduce water loss in an environment where water is abundant but physiologically difficult to use.

02

Roots that breathe

Waterlogged mud contains little oxygen. Pencil-like pneumatophores, arching prop roots and enlarged pores let oxygen enter tissues during exposure. These roots also slow tides and trap sediment, gradually shaping the shoreline around the forest.

03

A bridge between land and sea

Mangrove litter feeds detrital food webs, while the root maze shelters fish and crustaceans. Birds, reptiles and mammals use the canopy and channels. Mangroves also store large amounts of carbon in wet soils, where decomposition can be slow.

What people usually ask

Do mangroves drink seawater?

They take up water from salty soils but use physiological filters and salt-management mechanisms to protect their tissues.

Can mangroves stop every storm surge?

No. They can reduce wave energy and erosion, but protection depends on forest width, condition, storm intensity and coastal shape.

WANT TO CHECK US?

Here’s where the answer came from

Open the original government science or research-institution source behind this page.

01
NOAA Ocean Service — Mangrove adaptations

Salt, root and sediment adaptations in tidal forests.