12th Pacific Science Inter-Congress, 8-12 July 2013
University of the South Pacific, Laucala Bay Campus, Suva, Fiji
Aspects of carbonate production and beach nourishment in
Fiji, SW Pacific
Susanne M.L. Pohler1 , Zulfikar Begg2, Sharon Raj1, and
Ashishika Sharma1
1
School of Marine Studies, University of the South Pacific,
Private Mail Bag, Suva, Fiji Islands
2
Secretariat of the Pacific Community (SPC), Applied
Geoscience and Technology Division (SOPAC), Private Mail
Bag, GPO, Suva, Fiji Islands
On low-lying tropical islands reef systems are commonly the
sole providers of sediments to nourish and maintain beaches
whereas on high volcanic islands the terrestrial source is also
important. Marine sediments produced in reef, backreef and
lagoonal environments depend firstly on abundance and
growth rates of carbonate producing organisms. In the
Caribbean production rates of contributing reef organisms,
are quite well known and information about reef carbonate
budgets is readily accessible. This is not the case in the Pacific
where reef diversity is higher and different species reside.
The same is true for bioeroders which are important for the
sand cycle because they break down carbonate biogenes to
sand and gravel sized bioclasts. Many reefs in Fiji and
elsewhere are impacted by eutrophication and overfishing,
factors which lead the affected reef systems to the negative
side of the carbonate budget with dire consequences for
beach nourishment. The additional stressors of temperature
rise and ocean acidification on carbonate producers will
exacerbate sediment starvation in a system that would be
naturally capable of keeping up with sea level rise. This
contribution attempts to disseminate knowledge gained on
12th Pacific Science Inter-Congress, 8-12 July 2013
University of the South Pacific, Laucala Bay Campus, Suva, Fiji
carbonate production and bioerosion, particularly by coralline
red algae, soft corals, foraminifera and boring sponges.
Key Words: beach nourishment, carbonate budgets,
carbonate production, Fiji Islands.