Text and Photo by Henrylito D. Tacio
So much has been written about planting trees as one possible solution to the problem of climate change, which is caused by the build-up of greenhouse gases (carbon dioxide, methane, and nitrous oxide, among others) in the atmosphere.
Respected atmospheric scientists claim that one way to curb the release of the greenhouse gases into the atmosphere is by sequestering them. Trees have been identified as the most capable of doing so.
But what most people don’t know is that the lowly seagrasses can accomplish more.
Worldwide Fund for Nature (WWF) said seagrasses can capture 30 times faster than tropical rainforests. Even though seagrasses cover only 0.2% of the seafloor, they can absorb 10% of the ocean’s carbon each year, “making it an incredible tool in the fight against climate change.”
In an interview with Euronews Green, Alec Taylor said seagrasses capture carbon dioxide in the same way that the grass on land would. (Carbon-capture is the process by which carbon dioxide is removed from the atmosphere. This can be done by innovative technology or anything that photosynthesises, like a tree.)
Some studies show seagrasses can store twice as much carbon per square kilometer as tropical forests do on land.
Taylor, WWF’s head of the land-use climate program, said seagrasses are particularly good at rapidly harvesting carbon, working over 30 times faster than a rainforest on land would. “As seagrasses can stay undisturbed underwater, they can also remove the carbon for thousands of years,” he pointed out.
Whereas trees might capture carbon, when they get cut down, the carbon is released back into the atmosphere. In comparison, seagrasses can hold on to it, and they bury the captured carbon dioxide into the roots, he said.
Seagrasses are neither algae nor seaweeds. Neither are they true grasses. They are monocotyledonous plants. Left alone and not disturbed in the quiet salty water of coastal zones, they form dense meadows resembling more familiar undulating grasslands in the uplands.
The seagrasses are one of the most important components of the coastal ecosystem. They reproduce through rhizomes and seeds. They produce seeds annually, which are dispersed by tidal currents.
The Philippines has 16 species of seagrasses thriving along its coasts. This makes the country as having the second highest species of seagrasses around the world – after Western Australia, which has more than 17 species of seagrasses. The Philippines has more seagrass species than Indonesia, Malaysia, and Brunei.
Dr. Theresa Mundita S. Lim, when she was still the director of the Biodiversity Management Bureau, said the Philippines has a total seagrass area of 27,282 square kilometers, which are widely distributed throughout the country: from Bolinao Bay (Pangasinan) in the north, Palawan and the Cebu-Bohol-Siquijor area to the center, and Zamboanga and Davao in the South.
“Despite their high biodiversity and abundance, seagrass habitats are still poorly understood in our country,” said Dr. Miguel D. Fortes, the country’s foremost expert on seagrasses. “Hence, it appears only marginally useful when, in fact, the ecosystem plays significant economic and ecological roles.”
Dr. Fortes, retired professor of the Marine Science Institute of the University of the Philippines in Diliman, Quezon City considered seagrasses as among the most productive of coastal ecosystems, matching coral reefs and mangroves in terms of environmental and economic importance.
“As meadows, seagrasses are an important link between land and ocean and support a high primary production,” he pointed out.
Seagrasses have been utilized by humans for over 10,000 years, according to the Smithsonian Ocean. They have been used to fertilize fields, insulate houses, weave furniture, thatch roofs, make bandages, and fill mattresses and even car seats.
But it’s what they do in their native habitat that has the biggest benefits for humans and the ocean. The high primary production rates of seagrasses are closely linked to the high production rates of associated fisheries.
Among the diversified species found in the seagrass beds are fishes, sea cucumbers, sea urchins, crabs, scallops, mussels, and snails. Shrimps spend the early stages of their lives in seagrass areas.
Large animals like sea cows (dugong) and green sea turtles graze extensively in seagrass meadows. Seahorses, a tourist attraction and of medicinal value, reside in seagrass beds. A study done in five seagrass sites in the country identified a total of 1,384 individuals and 55 species from 25 fish families.
Despite their economic uses, seagrasses are on the brink of disappearing from the Philippine waters.
“Seagrasses are at great risk of being lost and if the trend continues at current rates, a further 30-40% of seagrasses and nearly all unprotected mangroves could be lost in the next 100 years,” deplored Dr. Fortes.
Marine experts traced the rapid disappearance of seagrasses to various destructive disturbances caused by both natural and man-induced influences. Among the natural threats are typhoons, tidal waves, and volcanic activity.
Man-made causes include industrialization, development of recreational areas along the coast, dredging, and mining which led to heavy siltation in estuarine areas, resulted in lower productivity and even burial of seagrasses, according to a report from the Department of Environment and Natural Resources (DENR).
Something must be done soon. “If seagrass beds continue to disappear, there will be serious economic and ecological consequences,” warns the regional office of the Bureau of Fisheries and Aquatic Resources (BFAR) in Davao City.
In a paper presented during the first National Conference on Seagrass Management, Research and Development, Dr. Fortes suggested at least three environmental concepts for better management of the resource: preservation, conservation and production intensification.
Preservation or non-use guarantees the continued survival of seagrass beds or meadows, which may be available for scientific and educational purposes only.
Conservation or wise use means maximum yield in minimum time. In time, the seagrass area expands and becomes a renewable resource.
Production intensification can be done through large-scale plantings and so-called “afforestation.” This transforms biologically desolate and barren impacted subtidal areas into seagrass beds with appropriate techniques.
“Conservation and restoration of seagrass meadows (in the Philippines) are effective strategies for climate change mitigation,” Dr. Fortes stressed.