Do Mangrove Plants Grow In Water? [Salty/Fresh Water]

Do you know Mangrove Plants live in sea beach areas? But to survive in such hardy habitats, they have some neat tricks on their roots and leaves!

Generally, Mangrove Plants can thrive in salty water distributed around tropical coasts worldwide. But they also adopt fresh water. Some special adaptations for thriving in salt-ridden soil and water include waxy leaves, root modifications, salt filtration systems, and rotating foliage.

Learn more about Mangrove Plants and their different adaptations to survive in salty environments from the article!

Table of Contents Show

What Are Mangroves?

Mangroves are tropical or sub-tropical plants specially adapted to loose, wet, and highly porous coastal soil breached periodically by salty sea or ocean water.

All Mangroves grow around the nearshore areas of the equator and prefer highly saline to brackish tidal water and soil.

Although hardy, Mangroves cannot tolerate freezing temperatures below 41°F.

However, an average monthly surrounding temperature of around 68°F is ideal for Mangrove Plants.

Along with temperature, the growth of Mangrove Plants depends on the climate, salt water (salinity/ pH), tidal fluctuations, and soil type.

Image illustrates flooded Mangrove forests — Mangrove forests are partially flooded by sea or ocean water.

Due to the adaptations of Mangrove Plants in saline water and soil, they are also collectively called halophytes.

They are originally native to South-East Asia, but tidal currents have dispersed them worldwide. Altogether, there are around 80 species of Mangrove Plants.

Additionally, Indonesia is the country with the largest number of Mangrove forests, while Sundarban Mangrove is the largest Mangrove forest in the world.

Importance Of Mangrove Plants In The Water Ecosystems

Mangrove is a type of wetland ecosystem formed around coastal areas where water is flooded in and out periodically.

Due to these changes and special adaptations of Mangrove Plants, Mangrove forests are important for the ecosystem.

Mangrove Plants protect the coast and shoreline from erosion by trapping the sediments and absorbing the tidal energy.
Also, the complex branch and root networks of Mangrove Plants provide a safe haven for fish and aquatic crustaceans and act as nurseries for baby fish.
Roots of Mangroves trap the sediments and debris, protecting the coastline from pollution by acting as a pollution filter.
Moreover, Mangrove forests form complex habitats for native, rare, and endangered species creating a biodiversity hotspot.
Additionally, Mangrove roots help to store carbon in their tissues from the atmosphere, acting as a carbon sink and mitigating climate change.
Mangroves also promote ecotourism, with benefits ranging from fishing and timber extraction.
Further, Mangroves can reduce the storm surge by up to 50%, preventing forehand casualties and destruction of property.

Adaptations Of Mangrove Plants In Water

Mangroves thrive in a dynamic coastal ecosystem due to certain adaptations.

1. Types of Roots

Mangrove Plants have 4 types of roots as part of their special adaptation trick to loose, salty water and soil.

Pneumatophores, Buttress Roots, Stilt/ Prop Roots, and Aerial Roots are the types of roots in Mangrove Plants.

Image illustrates the stilt roots in Mangrove Plants — Mangrove Plants have special roots that help them to adhere to loose soil.

These roots have specific functions and may not be present in all Mangrove Plant species.

Pneumatophores: They grow outward in the soil above the water and have small openings that allow oxygen to enter inside the roots.
Buttress and Stilt/ Prop Roots: These drop down from the branches and trunks and fix themselves in the soft muddy soil granting the plant strong legroom stabilization.
Aerial Roots: These are special contorted roots that rise above the ground and have snake or knee-like knotted appearance, helping to take in oxygen for the plant.

Further, Mangrove Roots have a filtration system that helps screen sodium (Na) ions from the water.

Do You Know?

Indian Mangroves have evolved mechanisms to battle out the salt content.

Special salt glands on the leaves help to expel excess salt from their body.

2. Water Retention

Mangrove Plants have thick cuticles and a waxy coating in their leaves and stems.

These waxy coating and thick cuticles cover the stomatal opening in the leaves. Thus it prevents the loss of water.

Hence, they lose less water than other tropical plants during evapotranspiration in the tropical heat.

Additionally, like Cacti, the tissues of Mangrove Plants are filled with water that compensates for the water loss.

3. Leaf Adaptation

Mangroves have unique rotating leaves that change direction with the incident sunlight.

This reduces the light exposure on the leaves, keeping the temperature in check and reducing evapotranspiration.

Furthermore, the leaves are also thick and leathery, which can store some water during the transition period.

Since Mangroves are deciduous, they shed their leaves annually in the fall to reduce the water loss in winter.

Image illustrates special leaves of Mangrove Plants — Leaves of Mangroves have salt glands that exclude excess salt from the plant body.

4. Salt Tolerance

Different Mangrove Plant species have distinct salt-tolerating powers.

Normally Mangroves can tolerate soil and water salinities ranging from 60-90 parts per thousand (ppt).

Some Mangroves form salt glands on their leaves to expel the extreme salt. But some Mangroves have water-filled root cells that balance the salt content in their bodies.

Besides, researchers have discovered 4 different types of salt tolerance mechanisms in Mangroves.

Glandular Mechanism (formation of ‘salt glands’)
Salt Compartmentalization (inside or outside the cells)
Water Accumulation (inside the cells)
Salt Filtration (exclusion of salts from the roots)

Can I Grow Mangroves In Freshwater?

Although Mangroves show remarkable adaptability toward salty water, they barely tolerate freshwater habitats.

Mangroves are not compulsorily halophytes as they only ‘adapt’ to these saline environments.

Hence, you can switch Mangrove Plants to a freshwater area from a salty habitat, and they will still continue to grow.

However, they are not completely adapted to freshwater. So, they will be out-competed by other well-adapted vegetation.

Moreover, the adaptation of Mangroves to freshwater also counts on the species. Some Mangrove species have more tolerance to freshwater than others.

Do You Know?

You cannot grow Mangroves in freshwater aquariums as they require soil.

Also, they will rot dead long before they can even grow.

Mangroves cannot survive submerged inside the water like mosses and other aquarium plants that grow without soil.

Different Types Of Mangrove Plants In Water

There are many Mangrove Plant species distributed throughout the coastal regions of the world.

You can classify them into 4 main groups based on their families.

1. Rhizophoraceae

Rhizoporaceae is the largest Mangrove family with many famous freshwater and saltwater Mangrove Plants.

Some of the well-known plants include Red Mangrove (Rhizophora mangle).

2. Combretaceae

The Combretaceae family is also called the ‘Indian Almond family.’

This includes Mangrove Plants like White Mangrove (Laguncularia racemosa), Buttonwood (Conocarpus erectus), and Pithecellobium (Pithocellobium dulce).

3. Arecaceae

The Arecaceae family includes Nipa Palm fruits and other Mangrove Palm fruits.

4. Acanthaceae

The Acanthaceae family comprises Black Mangrove (Avicennia germinans) and Grey Mangrove (Avicennia marina).

From Editorial Team

Conclusion!

Mangrove Plants are hardy and flexible to changing salty soil and tides.

Hence, you should consider using brackish water (50% salty and 50% freshwater) while growing them.