Phenology of Caulerpa taxifolia and temporal dynamics of its epibiontic meiofauna in the port of Malinska (Croatia, northern Adriatic Sea)

The qualitative and quantitative composition of epibiontic meiofauna were studied in the C. taxifolia settlement recently recorded in the Malinska port (Krk Island, northern Adriatic Sea). The samples were taken monthly, from May 1998 till June 1999 covering the complete life cycle of C. taxifolia. In total, 14 meiofaunal taxa were recorded. The meiofauna assemblage was characterized by the dominance of Copepoda (58%), the subdominant position of Nematoda (25%), and the low single participation of other taxa. The results of monthly monitoring indicated a seasonal trend in meiofaunal distribution. The beginning of the summer was a period of a low meiofaunal abundance (139 ind. sample-1), and also a start of its exponential increase. The autumn was characterized by a fairly high abundance (~1000-1500 ind. sample-1) and moderate variation of the constituent taxa levels. During the winter exponential growth (to about 10000 ind. sample-1) and high faunal diversity was detected. In subsequent months meiofaunal abundance reached over 19.000 ind. sample-1 - remaining extremely high until May when C. taxifolia fronds disappeared. The increase of meiofaunal abundance was positively correlated with the increase of the algal frond´s length during the summer-autumn period, and with the increasing quantity of sediment particles and detritus accumulated on algal fronds during the C. taxifolia vegetative cycle. This study has shown that C. taxifolia can provide a suitable habitat for numerous benthic invertebrates, although it is known as a species that reduces the benthic biodiversity.