Field work – Dongsha Atoll Research Station (19 May to 7 June 2016)

Thanks to Professor Keryea Soong and Professor Li-Lian Liu (National Sun Yat-sen University, Taiwan), the Dongsha Atoll Research Award, and the National Marine Park for supporting our field research on Dongsha Atoll! Also, thanks to L’Oréal Singapore For Women in Science National Fellowship for supporting my research!

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Left: Dongsha Atoll National Park. Right: Monument citing “Island far, heart is close”.

Where is Dongsha Atoll?

Dongsha Atoll (東沙環礁), also known as the Pratas Island, is an atoll located in the north of the South China Sea. The atoll is part of the Dongsha islands that consist of three islets. The total area is 3,537 sq km, with 1.79 sq km of land. It is approximately 850km southwest of Taipei and 340km southeast of Hong Kong.

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An illustration of Dongsha Atoll National Park (東沙環礁國家公園).

Geopolitically, the People’s Republic of China made claims on these islands, but the Republic of China (R.O.C.) [Taiwan] declared them a national park. In 2007, the Dongsha Atoll National Park was established as R.O.C.’s seventh national park, managed by the Ministry of the Interior (responsible for home affairs and security). It is administered under Qijin District, Kaohsiung City.

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Rain in May (梅雨).

Dongsha Atoll Research Station (DARS)

DARS is now located on the main Dongsha Island (since 2012) to support various research studies. Previous works included geochemistry and coral coring, biology of lemon sharks, marine geology, etc… Currently, the National Sun Yat-sen University manages the marine station, led by PI Professor Keryea Soong and a group of co-PIs.

DARS was set up fairly recently, and the living quarters and laboratories are almost brand new! The first floor consists of the wet laboratory, dry laboratory, clean rooms, dive store, and meeting area, while the second floor is the dormitories and social room. Yes! Although the island was remote, we had television! 🙂

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Top photos: Wet laboratory (our work station); Bottom photos: Dry laboratory.

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Well-equipped living area: My dormitory room (tatami room), social room, pantry, and laundry area.

Our ocean office…

Dongsha Atoll and Island consist of almost all the typical coastal systems: mangroves, lagoons, seagrasses, sand bar, coral reefs, and deep-water reefs (>30m). Over a period of 20 days, we explored almost every nook and cranny surrounding Dongsha Island, the Inner Atoll, and Outer Atoll. We all agreed that the environmental conditions within and outside of atoll are entirely different – warmer on the inside and cooler on the outside! The internal waves and upwelling of seawater could change the seawater temperatures from warm 30 degrees to (freezing!) cold 21 degrees! On one dive, I had to sun myself to keep warm – brr! :\

The reef geology was absolutely fascinating, with plenty of grooves and spurs to influence the movement of seawater (thus probably causing seawater temperatures to fluctuate greatly). While, admittedly, reef diversity is not extremely high, the reef cover is amazing! The healthy areas of the outer reef atoll is covered densely with soft corals, hard corals, sea fans, zoantharia, sponges, ascidians, etc… Not much seaweed in the healthy reef corals, but the channels are mostly loose rubble, sand, and seaweed. Well, I’ll let the photographs do the talking here!

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Seagrass lagoons surrounding the Dongsha Island.

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Left: Shallow top reef; Right: Reefs located next to shipwreck.

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Coral reefs within the Inner Atoll. Shallow top reefs ~5m depth.

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Shallow coral reefs of outer atoll (5-10m). Check out the grooves and spurs!

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Searching the grooves for ‘gold’.

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Wrecks of the past that got stranded atop the atoll.

Anthropogenic impacts

While the coral reefs appear healthy, it seems to be missing fish, sea cucumbers, and large giant clams. Diving can be pretty quiet at times, as the little fish swim and hide away from you. The shoals of trevally and jacks are considerably small (~30s), and shy away from us. We did not encounter any sharks or large megafauna on the outer reefs too. 😦

The geopolitical and ecological threats in the South China Sea have been highlighted in the news recently. Sadly, both the coral reefs and fishermen suffer the most in such political entanglement. In the fishermen’s perspective, fuelled by demands for precious organic gems of the oceans, they are pressed to harvest valuable giant clams, sea fans, and corals, and in the process destroying large tracts of reefs. Reports have cited that marine resources in the South China Sea have been overfished down to 5 percent levels compared to 30 percent levels in the 1950s. Driven by political endeavours, the fishermen are encouraged to venture further offshore waters to extend their search to South China Seas, where islands are territorially disputed among neighbouring nations sharing the seas.

On the other hand, many of these fishermen are motivated to fish this far out from home because of poverty. These large fishing boats are controlled by owners and captains, and the fishermen are co-workers. In most instances, these fishermen have to work hard to reach a fishing quota before they can acquire some supplies (such as fresh water and food). There were instances where these fishing boats trade and barter for freshwater with neighbouring boats. Many of them stay at seas for almost a month long, facing unpredictable and dangerous weathers and seas. At the end of this supply chain, the marine environment suffers…

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Presence of Chinese fishing boats around the outer atoll of Dongsha.

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Outer atoll coral reefs – crest/slope (20-25m). From the background, it is quite obvious the lack of medium to large fish.

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Blue hole – an interesting reef feature, and this one here is connected to the deep end.

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Outer atoll coral reefs – slope/deep (30-40m).

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Diversity of marine invertebrates. Top left: Soft coral ovulid cowrie; Top right: Cultured juvenile giant clams; Bottom: Seastars.

Experience on Dongsha

Due to territorial and political disputes, the marine biodiversity of the South China Sea remains poorly or little understood. Thus, Dongsha is a great opportunity and platform to fill in some preliminary knowledge gaps. The staff of DARS and the marine park have been extremely helpful in facilitating our field work, and their local knowledge of the island’s surroundings. We were fortunate for the plentiful good weather days (except a few rainy days!), we were able to head out to the outer atoll reefs for diving. We had good dive and boat support, and thanks to them – we are all well and safe! I’m also very happy to get the opportunity to study the local giant clam populations, and found some interesting results! I can’t wait to study the genetic diversity in more detail, and will share our results once it’s ready. 🙂

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Coral cores from previous geochemistry work.

We worked hard and ‘played’ hard… During our day/night offs, we went for night walks and found ferocious crabs and rats (the size of cats!). One night, the tree was ‘raining’ caterpillars! We also had beautiful sunset days and star-gazing evenings.

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Land-bound crustaceans.

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Day-Night sceneries of Dongsha.

Research opportunities

For those who are interested to carry out research on Dongsha, please contact Professor Keryea Soong through this website. Not just the oceans, the terrestrial diversity is also waiting to be explored! 🙂

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