It has been said that since the time of dinosaurs, this marine plants has made marine life thrive inside an unproductive-looking sandy (or often muddy) coastal waters. Shortly said, seagrass helps to stabilize the sediment, filtering the small water debris, and giving marine animals places to hide, feed, and raise their juveniles. They can be found growing on the shallow coastal waters, forming a dense meadow that mimicking the terrestrial grassland, but what makes it a little bit different that the seagrass meadow is completely submerged in seawater, and in the fact that seagrasses are more closely related to water lilies than the terrestrial grasses.
Seagrass plays a noteworthy role inside the marine ecosystem cycle, at some point even it was referred as marine powerhouse. Seagrass are flowering plants, it means that they can utilize solar power to produce an important food source. Moreover, what’s photosynthesis without the existence of the inorganic carbon ?. Seagrass needs these inorganic carbon for their growth, and in fact, they can directly draw the inorganic carbon from their surrounding. Seagrass can both utilize the inorganic carbon in bicarbonate (HCO3–) form or the carbon dioxide (CO2) form, making seagrass meadow as one of the most important carbon sink in the entire planet. Howard et. al., (2017) was estimating that the global seagrass meadow can capture more than 41.4 – 82.8 Million Mg Carbon annually. When it was simplified to a per hectare-basis carbon sequestering capability, seagrass meadow is ranked third as the most valuable ecosystem in the planet, only behind the mangroves forest and tidal marshes ecosystem. Seagrass also has the ability to recycle some certain nutrients, like nitrogen and phosphorus that keep them healthy, while the excess of unused nutrients will leave the waters toxic and lethal to the marine life. A recent study conducted by Lamb et. al., (2017) in Sulawesi, Indonesia emerged a new finding to the surface as the seagrass meadow could reduce about 50% of potential bacterial pathogens that capable of causing disease both on human being and the marine organisms. It is also noted that the coral reef area without adjacent to the seagrass meadow are more prone to disease than the coral reef with adjacent seagrass meadow.
Precious, but in peril
But now, let’s be honest, apart for all of its importance for the environment, this ecosystem is currently receiving little to no attention at all. As the conservationist are pleading about the degradation of mangrove forest and coral reef ecosystem, the seagrass meadow are receiving a hapless treatment. Whereas, the destruction that it has faced are equal or might be greater to those another marine ecosystem. Waycott et. al., (2009) has been estimated that since 1990, the world is losing about 7% of its seagrass meadow each year. Why does the seagrass ecosystems are disappearing so fast ?. It is clear that the human activities are converting this underwater meadow into an underwater desert. Coastal development are the main reason why the seagrass meadow become completely absent in some parts of the world’s shore. Moreover, the excess flow of sewage discharge, and the coastal terraforming activity leaves the surviving seagrass meadow suffering with the degenerated water quality. Take Singapore for example, the rapid development of this island has made the country’s nearshore waters lost about 45% of its seagrass meadow over the past 50 years. In some settlement area that are less developed, the damage that caused from the fishing activity might be slowly reduce the ecosystem quality, the destructive fishing practice and boating activity are all rounded up to the seagrass ecosystem degradation. Add the climate change factor, and that frightening devastation could be even worse. Scientists calculated that if the sea level rise just by 1.1 meters, 17% of the world’s seagrass meadow would be perished.
Seagrass disappearance also bringing a dreadful chain effect to the marine life and coastal community. As the seagrass meadow harbors a hefty sum of marine species on its ecosystem, from the tiny marine epiphyte that live in the seagrass’ leaf blade, invertebrates like clam, sea urchin, sea cucumber, cuttlefish, and octopus, and even the endangered species like sea horses, dugong, and sea turtles that are very dependent on the seagrass, the loss of the seagrass meadow could made these biodiversity banished. Coastal community that also dependent on marine resources would be greatly affected, as the seagrass meadow being a ‘feeding pasture’ for a myriad of economically important fishes. Surveys that has been conducted in some places in Indonesia like Ambon (Latuconsina, Nessa, & Rappe, 2012), Jayapura (Tebaiy, Yulianda, Fahrudin, & Muchsin, 2014), and Riau Islands (Rostika, Raza’i, & Zulfikar, 2016), shows that the herbivorous and omnivorous economically important fishes like Rabbitfish (Siganidae; id:Beronang), Emperorfish (Lethrinidae; id: Lencam , Goatfish and Mullets (Mullidae; id: Biji Nangka & Belanak), and Threadfin Bream (Nemipteridae; id:Kuniran) are the common inhabitant of the seagrass meadow in the Indonesian waters. Based on the economic valuation did by Dirhamsyah (2007), the seagrass of the East Bintan, Riau Islands, contributed about $ 1,131,600 (Rp. 15.183.243.000,-) per year to commercial fishing in that area. It is a clear evidence that the destruction of the seagrass meadow wouldn’t just affect these fish assemblage, but furthermore, affect the local economy.
This horror story did not ended here as when we look at the global scale, the loss of seagrass meadow could make the climate change even worse. Scientist said that a hectare of seagrass could hold up as many carbon as one hectare of a pristine Amazonian Forest, and also seagrass meadow could bind the carbon for a longer period of time than the rainforest. It is also said that if the seagrass from around Australia is completely disappeared, it would be equivalent to releasing up to three times Australia’s current annual greenhouse gas emission. This could be happened as the ancient carbon that has been stored on the seagrass meadow and the sediment beneath them are released and oxidized when exposed to air, releasing the greenhouse gases to the atmosphere. This silent and unseen calamity is still unthinkable while currently we are only focused on reducing greenhouse gas emissions that comes from the human-based activity, and paying no attention to the greenhouse gasses that leaking from our ocean.
Don’t think that something that goes unseen, does not exist, and don’t think that something that cannot be seen by the common eye is not dangerous
–Emha Ainun Najib, Indonesian Poet and Humanist-
Looking for a better way to save them
A new dawn of hope for this ecosystem emerges as in the early 2000s, several attempts to restore this ecosystem are documented on some places, like USA, Australia, and the Mediterranean Sea. The brand new seagrass transplantation method becomes a promising solution to recover this ailing ecosystem back to its original form. But, all af those innovative yet expensive technique are coming up with the same result. It all need to be improved as the worldwide restoration projects have shown a large variations of success. Seagrass restoration techniques have still only successful to replace small areas of seagrasses, making the seagrass ecosystem’s devastation seems more inrecuperable. It is noted that the failure of those attempts are caused by the local environmental factor and poor restoration planning. It is obvious that turning the underwater desert into a wondrous underwater greens needs a lot of efforts and time, and our scientists are still racing with the ticking time to innovate a better restoration technique, or at a greater extent, a better ecosystem management before it’s likely becoming too late to save this precious but fragile ecosystem.
Remarks
All of those pic are taken on my dive trip around the Sempu Strait, Malang, East Java.
Their contribution of ideas should not be forgotten
Creagh, S. (2013, 5 15). Seagrass carbon sinks fast disappearing: study . Retrieved 1 1, 2018, from The Conservation: https://theconversation.com/seagrass-carbon-sinks-fast-disappearing-study-14284
Creagh, S. (2015, 2 11). Failure to protect seagrass may cost Australia $45b . Retrieved January 3, 2018, from The Conversation: https://theconversation.com/failure-to-protect-seagrass-may-cost-australia-45b-12110
Dirhamsyah. (2007). An economic valuation of seagrass ecosystem in East Bintan, Riau Archipelago, Indonesia. Oseanologi Limnologi Indonesia Vol. 33, 257-270.
Ganassin, C., & Gibbs, P. (2008). A review of seagrass plantingas a means of habitat compensation following loss of seagrass meadow . Cronulla, Australia: NSW Department of Primary Industries .
Howard, J., Sutton-Grier, A., Herr, D., Kleypas, J., Landis, E., McLeod, E., et al. (2017). Clarifying the role of coastal and marine systems in climate mitigation. Frontiers in Ecology and the Environment Volume 15, Issue 1, 42 – 50.
Lamb, J. B., Water, J. A., Bourne, D. G., Altier, C., Hein, M. Y., Fiorenza, E. A., et al. (2017). Seagrass ecosystems reduce exposure to bacterial pathogens of humans, fishes, and invertebrates. Science Vol. 355, Issue 6326, 731-733.
Latuconsina, H., Nessa, M., & Rappe, R. A. (2012). Komposisi Spesies dan Struktur Komunitas Ikan Padang Lamun di Perairan Tanjung Tiram – Teluk Ambon Dalam. Jurnal Ilmu dan Teknologi Kelautan Tropis, Vol. 4, No. 1, 35-46.
Lavery, P. (2013, September 6). Seagrass is a huge carbon store, but will government value it? Retrieved January 3, 2018, from The Conversation: https://theconversation.com/seagrass-is-a-huge-carbon-store-but-will-government-value-it-17878
Rostika, Raza’i, T. S., & Zulfikar, A. (2016). Struktur Komunitas Ikan Padang Lamun di Perairan Teluk Baku Pulau Bintan Kepulauan Riau. Jurnal UMRAH, 1-15.
Seagrass Watch. (2015). What Is Seagrass ? Retrieved January 1, 2018, from Seagrass Watch: http://www.seagrasswatch.org/seagrass.html
Tebaiy, S., Yulianda, F., Fahrudin, A., & Muchsin, I. (2014). Struktur komunitas ikan di Teluk Youtefa, Jayapura, Papua. Jurnal Iktiologi Indonesia volume 14, no. 1, 49-65.
Unsworth, R. K., Jarvis, J., McKenzie, L., & van Keulen, M. (2016, October 10). Seagrass is a marine powerhouse, so why isn’t it on the world’s conservation agenda? Retrieved January 2, 2018, from The Conversation: https://theconversation.com/seagrass-is-a-marine-powerhouse-so-why-isnt-it-on-the-worlds-conservation-agenda-66503
Waycott, M., Duarte, C. M., Carruthers, T. J., Orth, R. J., & Dennison, W. C. (2009). Accelerating loss of seagrasses across the globe. PNAS volume 106, no. 30, 12377–12381.