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11/08/2021 - 09:04

Seagrass seeker

With a passion for plants, especially marine plants since the days of sitting in the lecture hall over the past 15 years, Assoc. Prof. Dr. Hoang Cong Tin, Vice Dean of the Department of Environment, University of Science, Hue University has travelled throughout the territorial waters in the Central Coast to do research on seagrass, which he calls the "tropical forest in the ocean".

The research team member takes the samples of seagrass

“Predestination” with seagrass

“Since my school days, I have had a passion for plants. For that reason, I chose to study plant biology at the Department of Biology, University of Science, Hue University,” Assoc. Prof. Dr. Hoang Cong Tin started the story.

Graduating from the Department of Biology, he had the opportunity to take the course on marine ecology on Bermuda Island (North Atlantic Ocean). “It is a place with a developed marine ecosystem, especially seaweed and seagrass. As “a predestination", he had the opportunity to meet and research marine plants," laughed he. Since then, he has specialized in research on seagrass beds in Central Vietnam.

Generalizing about seagrass, he said that, in the coastal wetland ecosystems, the seagrass, angiosperms living in seawater or brackish water seem faint in front of the “bright stars" like coral. But behind that ordinary look, its role is so important that few people can imagine.

“Seagrass beds are one of the crucial marine ecosystems. They are shelters and habitats of aquatic and marine species, which are effective in erosion prevention, coastal protection, climate regulation; provision of genetic material, food, cosmetics... for humans," he shared.

Even seagrass plays an important role in combating climate change because each hectare of seagrass has the capacity to store twice as much CO2 as each hectare of tropical rainforest.

“The Central coastal region is one of the places with the richest and most diverse seagrass bed distribution in Vietnam”, said Assoc. Prof. Dr. Hoang Cong Tin. With diverse terrain, many bays not affected by large rivers such as the Red River or the Mekong River, this is a very ideal place for seagrass to grow. The abundance of shrimp, fish, and seaweed... in the Central sea area is partly thanks to these seagrass beds.

Assoc. Prof. Dr. Hoang Cong Tin (right) locates the survey and collects the samples

However, the seagrass beds in Central Vietnam are dying out. They are in a very fragile state. “Every year in the rainy and stormy season, Central Vietnam bears the brunt of storms; the number and frequency of storms are on the rise. When a tropical storm hits the shore, it will cause a disturbance to the soil layers beneath the seagrass beds, affecting the habitat and health of the seagrass beds. Therefore, the seagrass bed ecosystem in Central Vietnam is very sensitive and vulnerable," commented he.

Central Vietnam’s son does research on marine ecology in Central Vietnam

As a son of Central Vietnam, desiring to contribute to the research and conservation of marine environmental resources, he set up a research team of highly qualified lecturers and students to specialize in research on the resources and biodiversity in the marine environment.

Since 2016, he and his research team have decided to carry out the research projects on seagrass and have achieved a huge success. Notably, the research results of numerous articles were published on the international scientific journals.

In the context of climate change and the increasing impact of humans on the ecosystem, Assoc. Prof. Dr. Hoang Cong Tin and his colleagues repeatedly asks themselves whether the seagrass beds in Central Vietnam can continue to retain the distribution area and biodiversity.

In response to that question, the research team found the answer by conducting the surveys during the dry season in four areas: Lang Co Lagoon (Thua Thien Hue), Cua Dai Coastal Area (Quang Nam), Ly Son Marine Protected Area (Quang Ngai) and Van Phong Bay (Khanh Hoa).

“Apart from the representativeness of the typical coastal ecosystems in Central Vietnam, there previously appeared many studies of seagrass in these areas, so it will be convenient for comparison and evaluation,” he explained the selection of survey site.

After being collected at different depths, seagrass samples will be transferred to the laboratory to determine the species composition. “If the survey site is nearby, it will take 1-2 days to carry out sampling. But if it is far away, it takes from 5 days to 1 week. Such long trips require careful preparation of instruments in order to best preserve samples, before they are brought to the laboratory for analysis,” said Assoc. Prof. Dr. Hoang Cong Tin.

Some days, after returning from the surveys and sampling, he and his research team continued to bury themselves in their research in the laboratory until late at night, in order to promptly process and preserve the samples for subsequent days of analysis. In addition, his research team also had to search for remote sensing data, satellite images of seagrass beds from previous years to compare and contrast to get the most accurate results.

In the research process, he was "amazed" at the results: the number and distribution area of seagrass species in all zones was decreasing over time. Even in some areas, the number of species decreased by 80%.

“The seagrass bed in Lang Co can be mentioned. Increasingly, the area of ​​seagrass beds in beautiful zones with rich ecosystems such as Lang Co Bay is shrinking. If reviewing this entire period, we will see that in 1998-2004, the seagrass beds have not yet suffered much human impact. However, in the stage of economic development, the decrease rate of seagrass area in this zone has increased substantially. To date, the area of​​seagrass in Lang Co Bay has fluctuated between 0.39-0.53km2," informed Mr. Tin.

The depletion of seagrass beds is a disadvantage of the marine ecosystem and has other consequences such as its adverse effect on the abundance of fish and shrimp species in Central Vietnam. The depletion of area and biodiversity on seagrass beds is a concern for researchers like Assoc. Prof. Dr. Hoang Cong Tin.

“Like most other degraded ecosystems, the depletion of seagrass beds in Central Vietnam originates from humans. Currently, the depleted seagrass beds are caused by human activities such as aquaculture, construction of seaports, development of infrastructure, tourist areas, etc.,” said Mr. Tin. Even urbanization and land vegetation variation also have an impact on the seagrass beds under the water bodies.

For the question "Can seagrass beds be restored naturally?” he thoughtfully replied that after the 1999 historic flood in Central Vietnam, the ​​seagrass area in Lang Co decreased drastically to only 0.27 km2. At that time, it took nature only over two years to restore the seagrass area, and the seagrass area peaked at 0.97 km2 in 2002. However, by then, human activities were not yet affected the marine ecosystem. Currently, resilience may no longer be in the hands of nature.

Story: DANG TRINH - Photos: CONG TIN

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