Dredging stirs things up. This is probably why the waters at Kusu are murky. Why does this matter?
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.
Healthy corals are better able to cope with other threats, such as the recent spell of coral bleaching.
More about the impact of dredging and sand mining, about hard corals on the wild fact sheets, and what is sedimentation and why does it matter?
This work is in addition to sand mining in Oct 09-Feb 10 renamed dredging and extended to Aug 10. More about notices about dredging around Kusu Island.
Dredging works at East Keppel Fairway
from Port Marine Notice No. 113 OF 2010 dated 8 Sep 2010
This is a revision of Port Marine Notice No. 83 of 2010. The working area and working period have been revised.
With effect from 12 Sep 2010 to 11 Mar 2011. 24 hours daily including Sundays and Public Holidays. East Keppel Fairway and its vicinity (see above chart).
Dredging works will be carried out by a Dredger “Kyoei No 18” held in position by spuds as anchors. The dredger, with hopper barges in attendance, will have a circular safety working zone of 50-metre radius centred at the dredger. Dredged materials will be transported to the designated dumping ground by the hopper barges assisted by pusher tugs. The tug boats will be used to shift the dredger, when required to clear the fairway for vessels.
Safety boat will be deployed in the vicinity to warn the other craft of the project work off the working area. Contact with the safety boats can be made via VHF Channel 18. Further general enquiries relating to the project can be directed to Mr. Kitagawa, the project manager at Tel: 8428 1216 (email: email@example.com).