Many may squirm at being knee-deep in mud and handling worms, but teacher Heng Pei Yan, 29, could not have been happier doing so.

As one of the 270 volunteers involved in a three-week workshop on Pulau Ubin to study the marine plants and animals in the Johor Strait in 2012, the passionate marine enthusiast had to process marine worms. This involved removing the tubes which the worms lived in and preserving them in chemicals so scientists could study them later.

"The removal of worm tubes was the most challenging task as some worms are very small and have small tubes," she said. "It required patience, steady hands and staring through a microscope."

Ms Heng, who has been involved in marine conservation work since 2009, also helped scientists from the National Parks Board (NParks) and the National University of Singapore (NUS) sort through specimens collected from dredging surveys.

Dr Tan Koh Siang, senior research fellow from the NUS Tropical Marine Science Institute, said the volunteers played a crucial role.

"Not only did they help to collect material from various sites by going out with the scientists, but they also helped wash and sort the specimens - a time-consuming but necessary task - so scientists could immediately see what was collected."

Before the workshop, Ms Heng was already volunteering actively with nature group Naked Hermit Crabs, leading groups on walks to the Chek Jawa wetlands.

But when she read about various animals found during earlier parts of the Comprehensive Marine Biodiversity Survey, she wanted to do more.

"What wowed me was that despite most of our coastline being reclaimed, the marine animals somehow managed to find their way back to settle.

"The diversity may not be as large as what Singapore used to have, but it is the resilience of the animals, their reappearance and their choice of location that make me curious to know more about them," said Ms Heng.

"I felt that this was a great opportunity for someone like me, without a biology background, to experience fieldwork and learn more about our marine life."

Dr Lena Chan, director of NParks National Biodiversity Centre, said such citizen science efforts could help raise awareness about Singapore's marine life.

"If people don't know the ecosystems and the species within them, they wouldn't know why they need to be conserved," she said.

Audrey Tan