The calcified seaweed (maerl) deposits of the Falkland Islands

Scattered across many foreshore areas around the Falkland Islands (Fig. 1) are fragments of white, limy material derived from carbonate-fixing, marine red algae. Locally, the limy detritus is sufficiently abundant to have built-up substantial beach deposits. In their report accompanying publication of the 1:250 000 scale geological maps of the islands, Aldiss and Edwards (1998) drew attention to the potential importance of these deposits as a source of agricultural lime, particularly in the absence of any other indigenous source of limestone. Very similar material has been exploited elsewhere in the world for both agricultural and horticultural use; for example, sub-tidal banks were extensively dredged in the English Channel off Cornwall and Brittanny. There, the limy, algal debris is referred to generically as Lithothamion, and commercially as maerl. The equivalent material in the Falkland Islands is known locally as calcified seaweed.