by Brett Garling
A month ago, an oil tanker spilled hundreds of thousands of liters of oil into the largest mangrove forest in the world, called The Sundarbans. This immense brackish estuary on the border of India and Bangladesh is also a bengal tiger sanctuary and home to countless other flora and fauna. While the story hasn’t gotten much media attention, what coverage it did receive focused more on the area’s status as an endangered dolphin sanctuary. (Yes unfortunately it’s one of those, too. It’s also a UNESCO World Heritage Site.) However, a disaster like this should also alarm us with regards to climate change: healthy mangroves play a crucial role in the delicate dance of carbon into and out of our atmosphere.
Mangroves grow in salty, muddy coastal waters in the tropics and subtropics. And it’s a good thing they do, because most any other plant would wither under conditions so saline. Instead, mangroves thrive in these waters and provide the ecological bedrock for a host of life and processes. One such process is the sequestration of carbon into the local sediments. The dead branches, leaves and roots of mangroves – which are filled with carbon previously removed from the atmosphere – are stored in the oxygen-poor, slow-moving local sediments and kept from re-entering the atmosphere.
In addition to this critical climate function, NASA has also recognized the importance of coastal mangroves for supplying “many essential environmental amenities, such as preventing soil erosion, filtering water pollution, and protecting shorelines from harmful waves, floods, storms and winds.” The mangroves’ costal buffering effect is especially important when you consider this region’s history of destructive typhoons and cyclones. Indeed, mangroves matter to many stakeholders in the ecological sphere – humans included! – in a multidimensional web of delicate relationships. They are much, much more than sticks in the mud. Mangroves matter.
Which brings us back to oil. By spilling its cargo, the tanker managed to still negatively impact global warming – not by transporting hydrocarbons for combustion, but by damaging an ecosystem that is so proficient at removing existing carbon from the atmosphere. One would hope that the shipping company will be held accountable. (Yet their name isn’t cropping up in reports, so who knows.) Furthermore, though the United Nations recommended a permanent ban on the movement of transport boats and tankers through the Sundarbans, the local authorities have just this week reopened the shipping lanes. That’s a shame.
In a study conducted in 2012, the Zoological Society of London (ZSL) found out that the Sunderban coast was retreating up to 200 meters a year. The official estimates are that agricultural activities had destroyed tens of thousands of hectares of mangrove in the last decades. An additional many thousands have been destroyed by shrimp cultivation.
But it’s not all doom and gloom: NASA has gotten wise to the importance of coastal mangroves and is now conducing extensive baseline measurement using Landsat. And there are also wonderful organizations doing important work on the ground to protect these regions. One such organization, in fact, just came on as a Mission Blue partner. We’ll have their story in a forthcoming Partner Feature. Stay tuned.
We hope with increased understanding of mangroves – and real action to preserve them – we can begin to treat these salt-loving, carbon-sequestering plants with the respect they have earned over millennia, creating a planet that works in our favor.