The Secret Life of Mangrove Fungi: Tiny Guardians of the Swamp

Mangroves: Nature’s Super-Shields and Animal Hotels

Hi there, young explorer! We are the fungi of the mangroves, and we have a super important job. Before we tell you about our secret lives, let us fungi introduce the amazing place we call home—the mangrove! Mangroves are like nature’s super-shields, growing where rivers meet the sea (Figure 1). Their twisty roots stick out of the mud and water, helping to protect the coastline from big waves and storms, and stopping soil from washing away.

Figure 1 - Representation of biodiversity associated with the mangrove ecosystem. These environments have a rich ecological organization and high diversity of organisms, ranging from birds and monkeys in the tree canopy, fungi on mangrove roots, and aquatic fauna, including fish, crabs, and shrimp, in the zone of contact between the sediment and the water. Mangroves are highly productive coastal environments, serving as nurseries for numerous species of ecological and economic importance.

Mangroves are much more than just forests—they are like giant animal hotels. All sorts of creatures live here with us: crabs scuttle through the mud, fish and shrimp hide among the roots, colorful birds perch in the branches, and sometimes even monkeys swing by for a visit. Many baby sea animals start their lives safely in the mangrove before heading out to the ocean.

Mangroves are also champions at fighting climate change, because they store lots of carbon in their soil and roots. Without mangroves, many animals would lose their homes, and the coast would be much less protected. That is why we fungi are so proud to be part of this incredible team, helping to keep the mangrove strong and full of life [1].

Who are the Fungi?

You might not see us, but we are everywhere, hiding on leaves, clinging to old wood, spreading through the mud, and even teaming up with the roots of mangrove trees. We come in all shapes, sizes, and colors, some of us look like tiny threads, others like little spots or fluffy patches, and a few even shine in the dark!

Some fungi are called Aspergillus (Figure 2 top left), famous for breaking down tough plant material and helping recycle nutrients. “Cousins” of Aspergillus include Penicillium (Figure 2 top right), which not only helps clean up plant debris but is also known for making life-saving antibiotics. There is Fusarium (Figure 2 bottom left), a bit of a mixed bag—some of its species help plants grow strong, while others can cause disease, so it is important to keep those species in balance. Trichoderma (Figure 2 bottom right) is another friendly fungus, always hanging out with plant roots, helping them grow and protecting them from harmful microbes. And do not forget about the tiny yeasts—they help keep the soil healthy and full of good microbes [2].

Figure 2 - Fungal genera commonly found in mangrove ecosystems: Aspergillus (top left), characterized by its globose conidial head; Fusarium (top right), showing elongated hyphae and macroconidia; Penicillium (bottom left), with its brush-like branching structure; and Trichoderma (bottom right), displaying branched conidiophores with clustered spores. These fungi play key roles in organic matter decomposition and nutrient cycling in mangrove sediments.

Did you know there are hundreds of different fungi species living in mangroves all over the world? Some of us can survive in salty, wet, and even very hot conditions. Scientists are still discovering new mangrove fungi and learning about our amazing powers every year. The four fungi in Figure 2 are not the only ones in the mangrove—there are actually hundreds of species. But you can think of these four as the “CEOs of the mangrove”: the most common and well-known members that help scientists understand how the whole fungal team works together.

Together, we fungi form a hidden team that works day and night to keep the mangrove healthy and full of life. We help plants grow, feed animals, clean up the environment, and even protect our home from disease. So, even though we are small and often invisible, we play a huge role in making the mangrove one of the most amazing places on the planet.

What do Fungi do All Day?

Imagine the mangrove as a giant, messy kitchen after a big party. There are leaves, twigs, and old roots everywhere. That is where we come in. We are the cleanup crew, breaking down all that plant “trash” into tiny pieces through a process called decomposition. We use proteins called enzymes (think of them as tiny molecular scissors) to chop up dead plants and turn them into food for the soil. This helps mangrove trees, crabs, fish, and even birds get the nutrients they need to grow strong.

We are also builders. As we break down organic matter, we create rich, dark soil that acts like a sponge, holding water and nutrients. This soil becomes the foundation for new life in the mangrove. We also help trap carbon from the atmosphere and store it safely in the ground, which is super important for fighting climate change.

Some of us, like Trichoderma and Fusarium, make friends with plant roots through special partnerships called mycorrhizae. We help the trees drink water and absorb minerals like phosphorus and nitrogen, like giving them a vitamin boost. In return, the plants share their sugary food with us—it is a win-win friendship!

Other fungi, like certain yeasts, help keep the soil healthy and full of good microbes. We also produce special chemicals that can protect plants from diseases and harmful bacteria. Some of us even help filter pollutants from the water, making the mangrove a cleaner, safer place for all the animals that live here.

And here is something really cool: we work in shifts! Some fungi are more active during the day, while others prefer the night. Some love the wet season, while others thrive when it is drier. This means there is always a fungus on duty, keeping the mangrove ecosystem running smoothly 24/7!

Why are Fungi Important?

Without us fungi, mangroves would quickly become buried under piles of dead leaves and wood, making it difficult for new plants to grow and leaving animals with less food. But we are more than just nature’s cleanup crew—we are the engine that keeps the nutrient cycle spinning [3].

Here is how it works: when leaves fall and plants die, we break them down and release essential nutrients like nitrogen, phosphorus, and potassium back into the soil. These nutrients then feed the mangrove trees, which grow bigger and stronger. The trees provide shelter and food for animals, which eventually produce waste that we break down again. It is like a giant recycling system that never stops.

We also help mangroves capture carbon from the air, which is important in the fight against climate change. As we decompose organic matter, we help store carbon deep in the muddy soil, where it stays locked away for hundreds of years. Some scientists estimate that mangroves can store up to four times more carbon than tropical rainforests—and we fungi are a big part of making that happen.

Here is something even cooler: some of us produce special chemicals called secondary metabolites that protect plants from getting sick. These natural antibiotics and antifungals help keep harmful bacteria and disease-causing organisms away from the mangrove trees. We are like tiny doctors, keeping the whole ecosystem healthy.

We also help filter pollutants from the water. As water flows through the mangrove, we break down harmful chemicals and heavy metals, making the water cleaner for fish, crabs, and other marine life. This natural water treatment system protects coral reefs and seagrass beds downstream.

Now you know why it is so important to protect mangrove fungi. Mangroves are facing serious threats from pollution, climate change, and human activities like coastal development and shrimp farming. If the mangroves disappear, we fungi disappear too—and that would break the nutrient cycle, release stored carbon back into the atmosphere, and leave coastal communities vulnerable to storms and flooding.

By protecting mangroves, you are also giving us fungi the chance to keep working, making sure these amazing habitats stay healthy and full of life for future generations.

Glossary

Fungi: ↑ Living things like mushrooms, molds, and yeasts. Fungi break down dead plants and animals, recycle nutrients, and help other organisms grow.

Mangroves: ↑ Coastal ecosystems found in tropical and subtropical regions, where trees, animals, and microorganisms live together in saltwater environments. They protect coastlines from erosion.

Decomposition: ↑ The natural process where fungi and other organisms break down dead plants and animals, turning them into nutrients for the soil.

Enzyme: ↑ A tiny protein made by fungi (and other living things) that speeds up chemical reactions, like breaking down dead leaves into nutrients.

Organic Matter: ↑ Material made of carbon compounds that comes from living or once-living organisms, such as dead leaves, animals, and microorganisms, that can be broken down and recycled in nature.

Mycorrhizae: ↑ A helpful partnership between fungi and plant roots where both share food and nutrients to grow better.

Nutrient Cycle: ↑ The process by which nutrients are reused and recycled nutrients in nature. Fungi help turn dead plants into food for new plants and animals.

Conflict of Interest

The author(s) declared that this work was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

AI Tool Statement

The author(s) declared that generative AI was used in the creation of this manuscript. The digital images were generated with the aid of Artificial Intelligence, based on original watercolor paintings on paper by author Susana Frases.

Any alternative text (alt text) provided alongside figures in this article has been generated by Frontiers with the support of artificial intelligence and reasonable efforts have been made to ensure accuracy, including review by the authors wherever possible. If you identify any issues, please contact us.

[1] ↑ Thatoi, H., Behera, B. C., and Mishra, R. R. 2013. Ecological role and biotechnological potential of mangrove fungi: a review. Mycology 4:54–71. doi: 10.1080/21501203.2013.785448

[2] ↑ Sarma, V. V., and Hyde Kevin, D. 2001. A review on frequently occurring fungi in mangroves. Fungal Divers. 8:1–34.

[3] ↑ Hyde, K. D., and Lee, S. Y. 1995. Ecology of mangrove fungi and their role in nutrient cycling: what gaps occur in our knowledge? Hydrobiologia 295:107–18. doi: 10.1007/BF00029117