1) A mass mortality event occurred at Chek Jawa intertidal flat in January 2007, killing many soft-bodied invertebrates like sea anemones, sponges, sea stars, and sea cucumbers. 2) The student conducted an independent research project through the UROPs program to investigate the causes of this mass death, examining factors like changes in salinity from rainfall and river outputs. 3) Through field surveys over multiple months, the student monitored recovery of affected species and populations at Chek Jawa, finding signs that it was rebounding with recruitment of larvae from nearby areas.

1. LIFE AND DEATH AT CHEK JAWA A UROPS RESEARCH EXPERIENCE

4. Have you been to Chek Jawa before?

5. Where is Chek Jawa

6. Chek Jawa (103°59'E, 1°24'N), is an intertidal flat located at the eastern tip of Pulau Ubin, a small island to the northeast of Singapore’s main island Chek Jawa Johor Mainland Singapore

7. Chek Jawa is lauded for its high biodiversity Figure from Ria Tan Six distinct ecosystems exist at Chek Jawa and it is abundant with locally rare fauna and flora

8. Coastal Hill Forest

9. Mangroves

10. Rocky Shore Photos: N. Sivasothi

11. Sandy Ecosystems Photos: Ria Tan

12. Seagrass Lagoon

13. Coral Rubble Area Photos: Ria Tan

15. While Team Seagrass arrived for a field orientation on 20th January 2007…

16. Mass Death occurred on January 2007

17. Soft bodied invertebrates affected

19. Dying Carpet Anemones

20. Dying Sponges

21. Dying sea stars and sea cucumbers

24. What is UROPs

27. Finding my supervisors

28. Finding my supervisors

33. Grain size distribution analysis at Chek Jawa

39. Yes, we set off that early…

40. … and we also go back late

41. Six transect lines T1 T2 T3 T4 T5 T6 T1 T5 T4 T3 T2 T6

42. Transect surveying

43. Sometimes disasters do happen…

44. … after a day’s hard work

46. Monitoring Mussel Beds

47. A closer look

48. Asian date mussel ( Musculista senhousia ) An invasive species

50. Sea anemone morphology is variable NOT easy to study

52. Sand dollars ( Arachnoides placenta )

53. Sand stars ( Astropecten sp.)

54. Common sea stars ( Archaster typicus )

55. Button shells ( Umbonium vestiarum )

56. Peacock Anemones (Order Ceriantharia )

57. The sandbar before mass mortality is covered with several Stichodactyla haddoni . After the mass mortality, the sand bar is almost barren of Stichodactyla haddoni . These post mortality photographs were taken as part of using photographs for comparison and also to monitor recruitment over time. 12 January 2002 25 December 2007 16 August 2007 22 January 2008

58. Panoramic photo taken from tower 15 July 2007 16 August 2007 28 October 2007 25 December 2007 22 January 2008

59. Figure: Aerial photograph of Chek Jawa (squared in white) and its surrounding. Photo by Google Earth. Kuala Johore Salinity decreases

62. Side view Bird’s eye view

67. My honours project on sand star behaviour and ecology Astropecten indicus

69. Life at Chek Jawa

75. Some interesting experiences

76. Celebrating Christmas at Chek Jawa

78. My first filming experience

79. Featured at The Straits Time

80. Featured at NUS Advertorial, The Straits Time

82. Thank you & best wishes