Dredging stirs up sediments which make the water murky and affects the amount of sunlight that reaches the corals.
Reef-building hard corals need sunlight because they harbour microscopic, single-celled algae (called zooxanthellae) inside their bodies. The algae undergo photosynthesis to produce food from sunlight. The food produced is shared with the coral polyp, which in return provides the algae with shelter and minerals. It is believed this additional source of nutrients from the zooxanthellae help hard corals produce their hard skeletons and thus expand the size of the colony faster. Thus clear waters that let sunlight through for photosynthesis is important for healthy reef growth.
More about hard corals on the wild fact sheets, and more about sedimentation in Singapore waters and other threats to our reefs on the Coral Reefs of Singapore website.
Dredging works at East Keppel Fairway
from Port Marine Notice No. 41 of 2009 dated 31 Mar 09 (PDF)
With effect from 03 Apr 09 to 02 Aug 09. 24 hours daily including Sundays and Public Holidays. At East Keppel Fairway within a working area (see attached plan):
Dredging works will be carried out by the grab dredger “Kyoei No.18”, held in position by 2 spud poles. The dredger, with hopper barges in attendance, will have a circular safety working zone of 50-metre radius centred at the dredger. Dredged material will be transported to the designated dumping ground by the hopper barges and assisted by pusher tugs. During the operation, the tug boat “Kyoei No.16” will be used to shift the dredger. Safety boats will be in attendance at all times to warn and re-direct craft in the vicinity. Further general enquiries can be directed to Mr Christoper Goh, the project coordinator, at Tel: 6476 8823 (email: email@example.com).