A journey into the mangroves

As tropical scenery goes, mangroves, with their tangled, impenetrable mass of roots, don’t have quite the same appeal that palm fringed beaches and vivid coral reefs have. They can even look a little forbidding, as if they might be harbouring all manner of crawling, slithering life forms in their darker recesses.  

For years I steered clear of them, putting them down to one of the less attractive aspects of the landscape in these latitudes.  

A new approach 

Taking a trip out to a mangrove lagoon and snorkelling right up into their weird, arching roots is a lesson in not judging a book by its cover. A little knowledge and understanding goes a long way. 

Danny, our guide and co-owner of Sea Elements, made it clear before we entered the water that swimming in the mangroves is not everyone’s cup of tea. Knowing what to expect and what you are looking at makes a world of difference, however, and following a very interesting and informative talk on mangrove ecosystems, it was hard not to want to get right in and see the bright orange and blue sponges, the tiny mermaids’ wine glasses and the hard-to-spot sea horses first hand.  

Because one of the unique – and very valuable – abilities of mangroves is to trap sediment, one has to swim with caution, to avoid stirring up the silty bottom and clouding the water completely. And so one moves slowly, carefully, minutely examining the roots and spaces between them for different life forms. 

Quiet and tranquil 

Even though sumptuous new homes are visible just across the other side of the canal, no sounds from the modern, developed world can be heard in the small lagoon. It’s an incredibly tranquil way to while away an afternoon.  

Thousands upon thousands of Cassiopeia jellyfish carpet the seabed. Also known as upside down jellyfish, these creatures rest tentacle side up, absorbing passing nutrients and drawing energy from the sun. On cloudy days, they will float up toward the surface to get more sunlight, but when the skies are blue, the Cassiopeias barely move. 

No two jellyfish seem to be exactly alike, with their varying shades of white, brown, green and blue and their cauliflower-like tentacles, but they are almost hypnotic to watch as they gently pulsate in the warm, shallow water. 

It’s possible to swim up to the tree line and then peer into the shadowy, watery world within. This is where young fish spend their early life. Often described as nursery grounds for fish, the small spaces between the mangrove roots afford juvenile fish places to hide from larger predators. Once they are big enough to fend for themselves, the fish will make their way out of the mangroves and on to the reefs.  

Absence of lionfish 

As far as Danny is aware, the predatory, invasive lionfish have yet to find their way into the mangroves. As lionfish have a particular taste for juveniles of pretty much any fish species, this is good news for the continued health of reef fish populations.  

Should the lionfish invade this habitat, however, the consequences could be devastating.  

It’s not only the fish that mangroves protect. They protect shorelines from coastal erosion, anchoring down the soil. The roots are so strong that during hurricanes boats often tie themselves to mangroves for safety. Over the course of centuries they can even create land.  

Many species of birds live in the canopies of these trees and, in some parts of the world, a wide variety of other animals shelter in these dense forests. Sadly, mangroves around the world are being cut down to make way for housing, tourism and fish farms.  

Good for the environment 

New research, however, shows that in addition to harbouring so much wildlife and filtering pollution and sediment, mangroves have six times the ability of rainforests to trap and store carbon. It is the rising levels of carbon dioxide in the atmosphere that scientists believe is causing global temperatures to rise. Being able to counteract this makes mangroves an invaluable tool in the fight against climate change and it may be this particular ability that will ultimately ensure their protection. 

For a fairly unassuming, untidy-looking bunch of trees, mangroves have some extraordinary qualities and abilities. An afternoon spent learning about and exploring a tiny bit of these forests has given this reporter, for one, a new appreciation of this strange, slightly eerie habitat that is neither land nor sea.