Algae and sediment affect coral settlement

Marine biologists have demonstrated how coral settlement is inhibited by the presence of sediment and algal turfs.

Birrel, Cook and Willis from the Department of Marine Biology at Queensland\'s James Cook University studied the settlement of planktonic Acropora corals in environments affected by sediment, algae and a combination of the two.

Successful coral settlement on reefs affected by bleaching has long been known to be adversely affected by the presence of algae that form there. Similarly, reefs heavily infested with algal turfs following bleaching episodes may suffer from silting.

The researchers studied the effects of the larvae of Acropora millepora and showed that sediment did indeed inhibit settlement.

They also found that the presence of algal turfs inhibited settlement to different degrees.

In one case, one type of algal turf inhibited settlement, while another type only inhibited coral settlement when combined with silting causing by particles becoming trapped among the algal fronds.

For more details see the paper: Birrell, CL, McCook, LJ and BL Willis (2005) - Effects of algal turfs and sediment on coral settlement. Marine Pollution Bulletin, 2005; 51 (1-4); 408-14.