TIMES EVOKE ‘Submerged mangrove forests are scientific wonders — and home to rich biodiversity’ n ocean. And a forest. It might seem that when two such forces of nature meet, one Graeme P Berlyn is EH Harriman Professor of Forest Management and Physiology of Trees at Yale University’s School of water roots. These vertical roots are Aoverwhelms the other. However, the op- called pneumatophores because they posite is true. When oceans and forests meet, Forestry and Environmental Studies. Writing for Times Evoke, the distinguished environmental expert discusses the complex contain pores (lenticels) on their sur- their worlds mingle and merge together in science of submerged mangroves, spread across coastlines from Africa to Asia — and home to thousands of species: face that can take up oxygen. They extraordinary harmony. The balance achieved Photos: Getty Images also produce less developed seedlings between these elements then creates a stunning angrove forests comprise on their branches. These are shed and panorama of life. Submerged forests feature the the interface between wet- can float for a time but these will not world’s greatest biodiversity, each layer blossom- lands and sea grass mead- complete seedling development un- ing with living beings, from bacteria and phyto- Mows along a vast expanse less they find muddy or solid ground. plankton, fish and worms, all sheltered within of tropical shorelines all over the Black mangrove roots can only filter wet woods, to shorebirds and migratory flocks world. They also occur along bays, es- out about 90% of the salt in its envi- nestled in branches and over-ground roots, to tuaries or mouths of rivers by these ronment, but it can expel the extra animals, from tiny tree-climbing crabs to mighty shores. Mangroves have a tremendous salt on its leaf surfaces. tigers, hiding and prowling in the sediments and environmental impact — mangrove The third group of classic man- sands, the thick foliage of a submerged forest. forests are one of the greatest sources groves is the white mangrove (Lagun- The amazing biodiversity of such sunken of biodiversity on this planet. They cularia racemosa). This family gener- jungles then becomes a marvel of science itself. have a rich underwater component, a ally grows inland from black man- At its tiniest level, the bacteria it shelters reju- surface component and an aerial com- groves and above the high tide line. venates an entire submerged forest, breaking ponent. Mangrove com- White mangrove leaves have down leaves and branches in water and releasing munities include fish, two glands on the base of their nutrients into this ecosystem. Underwater insects, shellfish, birds their leaf stalks (petioles) plants like kelp sequester about 20 times as much of many species (like that secrete sugars — this carbon dioxide as terrestrial forests while the pelicans, egrets and attracts bees and makes the complex root systems of these wildernesses col- spoonbills), saltwater white mangrove a premier lect the sediments carried in by tides, guarding crocodiles, monkeys, honey tree. Thus, the man- the ground firmly against erosion. As Times algae and fungi. Many groves form an environmen- Evoke’s global experts explain, even an ancient organisms, especially fish, spend their tal sequence, with the red submerged forest, over 50,000 years old, holds early years in the protection of the mangroves closest to the within it answers to medicines humanity needs. mangroves and their intricate below- shore, then the black man- Significantly, such scientific miracles come and above-ground root systems. groves in sites that can be with an astonishing aesthetic world. The Mangroves, along with sea grasses periodically inundated, and depths and shallows of underwater forests and wetlands, comprise the ‘blue car- NEVER ALONE: From underwater to the surface and air, life teems at every level in mangrove ecosystems then, the white mangroves throb with beautiful, vibrant forms of life, its bon’ ecosystem of stored carbon in above the high tide line. strata and dimensions nature’s palaces of shad- sediments along many tropical and ated by human activities. When man- There are over 100 species of trees and red mangrove is The mangroves do so ows and light. Times Evoke presents glimpses subtropical coastal zones. Their com- grove trees die of natural causes, they shrubs designated as mangroves. How- that its seeds germi- much for the planet — but from three kinds of submerged forests — man- plex aerial and submerged root sys- generally fall into the sea and the car- ever, there are three classic groups of nate while still on we are losing them very groves, kelp and ancient cypress. It is from tems moderate current flows and the bon may be stored in the sediment on mangroves — the red mangroves (Rhiz- the tree — if the disturbingly and rapidly to these wonders that we can learn about nature’s canopies moderate wind flow — they the sea floor for long periods of time. ophoraceae), the black mangroves seedlings are shed A 19th century engraving oil spills, pollution and tapestry of life, and how we can fit more har- are the interface between the wetlands Mangroves are present worldwide (Acanthaceae) and the white man- into the water, they of a mangrove details shoreline development. moniously in this. Our attempts at overwhelm- and sea grass communities for the con- on various shorelines between approx- groves (Combretaceae). can float for many herons in its habitat Still, it remains a wonderful ing nature are causing the destruction of mul- tinental flow of water and solutes into imately 25°N and 25°S latitude. The The most classic mangrove is the months until they experience to visit the man- tiple ecosystems, including submerged forests. the ecosystem. Mangroves also supply term ‘mangrove’ is used to refer to a red mangrove (Rhizophora mangle). find a muddy or soil site to take root, grove ecosystems, but remember, if It is imperative that we now adopt harmony fuelwood and other forest products, like whole community of trees and shrubs. Red mangroves have stilt roots that grow and mature on. you go down to these tropical shores — and awe — towards nature, crucial for the food and medicine, for people. And, in But the trees designated as mangroves arch above the water and provide sur- The black mangrove (Avicennia with birds and beasts galore, you bet- well-being of our home, the Earth. This is also addition to the nutrition they give us, are not closely related; they belong to faces with pores that allow the entry of germinans) generally occupies sites ter not go alone. Ferocious creatures crucial for our own well-being, for by emulating mangroves protect us — along with a number of different plant families. oxygen which compensates for the low interior to the red mangrove. It has a are gathered there simply because the the harmony of an ocean meeting a forest can other trees and forests, mangroves se- However, they have all adapted to harsh oxygen environment of the submerged unique adaptation for inundated sites mangroves are their natural home. we perhaps discover a new consciousness, quester a sizeable amount of carbon to coastal environments of saline, brack- portion of the complex root system. with low oxygen — it produces verti- Watch out for tigers, pythons, croco- submerged deep within us. offset greenhouse gas emissions cre- ish waters and low oxygen conditions. Another remarkable adaptation of the cal roots from its network of under- diles and much more. Photos: Getty Images A vital coastal ROOKERIES AND NURSERIES TIDAL MOVERS PREDATORS barrier against The thickets of the mangrove High tides bring From estuarine storms and fl oods, roots and its sprawling nesting marine fi sh and sea crocodiles to stingrays a protector against areas house multiple organisms, snakes to mangroves and lemon sharks, the soil erosion and a from fi sh and molluscs like while low tides waters of the mangroves crucial carbon sink, oysters to shrimp and other see hermit crabs, are rich with predators. mangroves are also crustaceans, small birds like turtles, raccoons In addition, the home to diverse kingfi shers, long-legged wading and land-adapting Sundarbans mangroves kinds of beings birds like spoonbills, migratory amphibious fi sh like resound with the roar of fl ocks and seabirds like pelicans mudskippers emerge the famed Bengal tiger Hermit Crab Spoonbill Mangrove Kingfisher Lemon Sharks ‘The African sea forest is a magical world ‘An ancient sunken forest — its animals taught me about life and love’ can give us vital medicines Craig Foster is a well-known natural history filmmaker and founder of the Sea Change Trust, working to protect the Great African Sea Forest. Speaking to Srijana Mitra Das at — and climate lessons’ Times Evoke, Foster discussed why this astonishing forest is so crucial, how we can help conserve it — and his unique underwater friendship with an octopus: Daniel L Distel is Director of the Ocean Genome Legacy Center Photos courtesy: The Sea Change Project at Northeastern University. Having recently led a famous scientific What is the African sea forest like? expedition into an ancient sunken forest off the coast of Alabama, This is a 1,200 kilometre-long stretch Distel tells Times Evoke why this quest was so important — of underwater kelp forest, all along the west coast of the tip of Africa and and the secrets this submerged forest holds within it: some of the east coast. It’s an enor- Photo courtesy: Daniel Distel mous ecosystem, based on an extraor- ear the modern coast dinary process called upwelling — the of Alabama, a bald wind drives colder, rougher waters cypress forest once up the continent and deep, nature- Nsprang up. It likely rich volumes come up in the shallows. flourished for tens of thousands At the heart of such waters are great of years, with new trees grow- forests, which provide food and shel- ing over the fallen trunks of ter for thousands of species.