Welcome back. Time flies and we are already in Week 10!
Recently I read the news about the Japanese voluntarily taking part in coastal clean-ups as part of the community initiative to keep their shores clear of marine litter. Such a movement resonates with me as I have taken part in Singapore’s East Coast Clean-Up Initiative before as well. This spurred me to blog about environmentally-induced coastal developments that were implemented in Japan.
Let us first talk about its ecological environment. Based on this scientific article, Japan’s coast is home to a vast range of ecosystems. One specific example is the seaweed that dwells on the coastal regions. Seaweed thrives in shallow water where the abundance of nutrients makes conditions feasible for growth. Seaweed beds are platforms for spawners to lay their eggs and this itself becomes another ecosystem habitat for coastal marine species. This contributes to high primary productivity.
However, there has been a decrease in seaweed beds due to land reclamation and eutrophication (given the high nutrient content of the waters), which prevents sunlight from reaching the seaweed beds. One prominent restoration effort includes the artificial growth of seaweed beds, which primarily involves the transplantation of seedlings and the establishment of coastal structures for seaweeds to grow on. In my opinion, the rehabilitation of seaweed beds could prevent them from becoming barren, which could reverse the repercussions on the coastal ecosystem.
Moving on, we shall explore coastal seawalls. Many of us should know that Japan is especially susceptible to natural calamities due to its geographical location near to ongoing tectonic plate activities (Pacific Ring of Fire). One of the natural disasters that Japan faces is Tsunami. According to this article, Japan spends an enormous sum of money on building seawalls to minimize the damage from these seismic waves.
While seawalls are important to reduce the catastrophic effects of Tsunamis, it can prove to be detrimental to the ecosystem as well. Based on a report, intertidal ecosystems are exposed to higher risks of deterioration caused by seawalls. Moreover, constructing seawalls increases the chances of coastal erosion and sedimentation of the ocean (although this can be negated with proper seawall designs).
Japan is a sea-locked nation that depends on the integrity of its coasts for its livelihood. Despite how effective measures like coastal seawalls are in preventing collateral damage to coastal residences, there are bound to be environmental implications. Therefore, it boils down to how we improvise our methods in tackling coastal degradation. In fact, alternative solutions like coastal forests can help to mitigate the disastrous effects of Tsunamis as well.
In Singapore, we have mangroves that not only provide the ecosystem for a myriad of amphibious and marine species, but they also play a part in stabilizing the shoreline and preventing soil erosion. Can you think of any other coastal developments that are beneficial to both humans and other animal species?
-Wen Han
(Cover photo by Oliver Sjöström from Pexels)
Hi Wen Han!
This was a very interesting post to me, as I have never considered how sea walls could harm ecosystems before. Regarding coastal forests, in that report you linked, it mentioned how the effectiveness of some trees is reduced with age, so do you think that they should be relocated after they reach the age at which they can’t protect against tsunamis anymore? I’m not very sure about which trees can grow where, but could this be a problem if the only trees suitable for a certain location are trees like these? The report did mention how mangroves do not pose this problem, but what about other trees?
Hope to hear your reply soon!
~Rayzel
Hi Rayzel
Thanks for dropping by! I do opine that old trees in coastal forests should not be relocated as new offsprings are constantly reproduced and added to the existing ones. When the old coastal trees die, they will decompose naturally and provide nutrients to the growing ones; the cycle of life. Furthermore when trees age, there might already be an ecosystem thriving in it; relocating the aged tree will indirectly tamper with the biodiversity of extant species that lives in synergism within them.
With respect to mitigating the effects of a tsunami wave, a few factors apart from the age of the trees play a part in its natural defence, such as spatial coverage of trees, how widely the trees are distributed (density) and the kind of forests. Different kinds of coastal forests emerge in various parts of the world, depending on the climate and landscape. Not just mangroves, casuarina shelterbelts and palm were observed to be equally resistant to tsunami waves, though yes their effectiveness do decrease with age as mentioned.
Hope that answers you!
Hi Wen Han!
Fantastic post, really enjoyed learning more about Japan’s actions to protect their coastlines. In Singapore, the amount of mangroves has decreased significantly despite their overwhelming perks. This is probably to increase land space. Currently mangrove’s forest cover is only at 0.5% of our total land area. Do you think it is more important to create land space or conserve our remaining mangroves?
Hi Chloe!
Thanks for visiting. I support the stance to conserve our remaining mangroves, simply because mangroves have a multitude of function, but I’m just going to point out the one that applies more to Singapore- biodiversity conservation. Mangroves, as learnt in class, are home to many native species. Moreover, its ecosystem services can provide us with provisional, regulating, cultural and supporting benefits. This is furthermore corroborated in an article on how Singapore needs to find a balance between its socio-economic value and environmental value.
As seen from this report, NPV of mangroves is many folds higher than NPV of aquaculture (converted from mangrove patch). While expanding Singapore economically as a cosmopolitan city is vital for our global reputation, we must not forgo the benefits that mangroves are able to bring to us. Hope this answers your question!
Hi Wen Han! It’s interesting to learn about seawalls and how they affect the ecosystems. Like Rayzel, that has never occurred to me before.
I’m curious about whether similar coastal engineering measures in Singapore do have the same impacts, and if there is anything we can do about it. The coasts of East Coast Park is being eroded and is receding. We have breakwaters further out in the sea to minimise the destructive impacts of the wave on the coast. However, similar to seawalls as you mentioned, I would expect them to have some sort of environmental damage. Planting mangroves or other coastal vegetation may be a way to achieve both objectives, but it is not practical as it defeats the purpose of the beaches at ECP.
I’m curious to know (hopefully you’ll know too!) if there is any feasible and practical method to achieve both coast protection and coastal ecosystem preservation. Thanks!
Hi Ernest!
Thanks for dropping by! I agree with you that breakwaters can have detrimental impacts on the coastal and marine ecosystems. I found a website that encompasses efforts such as coral rehabilitation and seagrass planting (IMO might be more feasible in ECP’s context in terms of mitigating storm waves), which are funded towards achieving the objectives of a vibrant ecosystem and biodiversity of species. As can be inferred from this report, vegetation growth along the coast is essential in maintaining the integrity of the coasts as the roots of the plants hold the sand together. Pertaining to ECP, this article implies that the government has plans to plant mangroves and other vegetation in priority zones like ECP and Jurong Island to act as carbon sinks and to increase biodiversity. Personally, I opine that while existing breakwater systems are disastrous to biodiversity and contribute to coastal erosion, we can probably find ways to improvise on them rather than completely taking them out which might incur huge costs in doing so. Hope that sort of answers you:)
P.s. Honestly, I am no expert in this but I just feel we should take one step at a time, starting with the priorities such as coral reef, for instance.
Hi Wen Han,
Great effort to answer your peers’ questions ! And the post is quite good too. You may be interested to learn more about the work done in Peter Todd’s lab, that mainly involves R&D related to making seawalls more hospitable to marine life.
If I could respectfully suggest… “I opine” sounds stuffy. Actually, I’ve never seen that used other than in very formal, British writing. How about “I think” instead ? That way, you’ll sound more like a guy in his 20s, no ?
Hi Dr. Coleman
Oh is it? I shall look into it then. Thanks for the feedback too!
Maybe there’s an opportunity to even do a UROPES ?