Why We Need Seagrasses

Giuseppe Di Carlo in Madagascar.

Giuseppe Di Carlo in Madagascar.

As the world’s nations hash out a plan for curbing the extinction crisis at the Convention on Biological Diversity (CBD) this week, we asked some of CI’s top scientists to reflect on their careers and what biodiversity means to them. Here’s what Dr. Giuseppe Di Carlo—a seagrass expert and manager of CI’s marine climate change program—had to say. Read the other blogs in this series.

If I had to give someone a one-minute “elevator speech” about why seagrasses are important, what would I say? I couldn’t tell them the whole story about seagrasses providing habitat for key species like dugongs (Dugong dugon) and green sea turtles (Chelonia mydas), reducing sediments in the water column, supporting coral reefs…all of that takes too long.

The truth is, seagrasses are neglected because their beauty is hidden. When you go to the grocery store, what do you buy—the beautiful, shiny apple that looks delicious, or the ugly, not-so-shiny one? The answer seems obvious. However, sometimes we buy the ugly apple by mistake and discover it has an amazing taste, unveiling hidden exotic flavours that make us feel it is the best thing we have ever eaten. Maybe this isn’t the best example, but I hope I’m getting my point across: seagrasses are the ugly apple.

So how I did get into seagrass science? Did I buy the ugly apple my mistake? Actually, I bought the beautiful one like everyone else.

I started my career working with sea turtles. Nobody can deny the incredible experience of seeing those little hatchlings emerging from the sand and making their way into the ocean for the first time. But then I looked deeper and realized that without seagrasses we would have no sea turtles. Seagrass ecosystems also support many other amazing marine creatures, including manatees, groupers and lobsters. Some of them feed directly on the seagrasses, while others use them as nursery habitat while in their juvenile stage before moving out to the coral reefs or the open ocean. I learned how seagrasses are for patient people—for those who can look beyond appearance and seek out hidden stories and adventures.

Seagrasses off the coast of Madagascar.

Seagrasses off the coast of Madagascar.

Earlier this year, I was in Madagascar studying the seagrasses of the northeastern coast. During our expedition, we had to survey mangroves and seagrasses, which meant crawling across long mucky mudflats under the burning sun, carefully avoiding stepping on sea urchins, bending to see the plants in the most uncomfortable positions. But once you get through those challenges, you are rewarded. Millions of fish—from small barracudas to jacks and sweetlips—hide among mangrove roots and seagrass leaves, avoiding predators. Sunbeams penetrate these otherworldly habitats, creating shifting patterns of light and shadow.

Seagrasses are complex ecosystems which are currently threatened by pollution, coastal development and other human impacts, as well as climate change. As seagrasses provide the connection between mangroves and coral reefs, they play a critical role in maintaining ecosystem functions like flood protection—services that coastal populations across the planet depend on.

The protection of mangrove, coral and seagrass ecosystems must be a critical global priority. It is simply impossible to imagine a world without them.

Dr. Giuseppe Di Carlo is the manager of CI’s marine climate change program. Check out his previous posts from the Rapid Assessment Program (RAP) species survey off the northeastern coast of Madagascar earlier this year.


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  2. Charity M. says

    Hi. I am an NSF GK-12 fellow and one of my high school seniors is working on a seagrass pollution project for her senior project/science fair project. Could she use you as a resource to bounce ideas off of?
    Charity Lander
    KU Geology Department

  3. N. Enolva says

    While doing PCRA in Masbate, Philippines, I have noticed that commercially important species of algae like Kappaphycus and Eucheuma are introduced/cultured within the seagrass beds and patches. To more dismay, breakwaters/dikes are constructed to limit tidal current from damaging the cultured seaweeds. If we really are to manage and protect this critical habitat a stricter legislation should be made by the local government units. PCRA is a good tool in this endeavor along with the formulation of a good municipal CRM Plan. Conflict of resources should be limited. An ordinance on good culture method and zoning for seaweeds must be considered, for it not to conflict with the seagrass habitat.

  4. N. Enolva says

    To the author Dr. Guiseppe,
    Overwhelmed by the reply.
    I look forward to be working with you here in the Philippines, even as a volunteer, as regards to the management and protection of the most neglected and critical habitat, the seagrass.
    I am a biologist and is working in the Bureau of Fisheries and Aquatic Resources in Region 5.
    There are interesting seagrass habitats here in Bicol where you can probably conduct a study in the future.
    May I solicit an info, is there a successful seagrass reforestation already conducted anywhere in the world? If so, can that be considered as a material to cite if I am to recommend seagrass reforestation to preserve this critical habitat. Can I recommend for an establishment of a seagrass protected area thru passing an ordinance or any legislation? and perhaps the ordinance goes along with the legislation for the protection of mangrove and coral reef within the area, too.

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