Nicholas Dixon, Barry Leadbeater and Roger Wood
The University of Birmingham, Edgbaston, Birmingham, England, B15 2QU
Ectocarpus fasciculatus is a marine filamentous brown alga, and like many other members of the Ectocarpaceae, is known to be infected by a virus which is carried latently by vegetative cells and only expressed in the reproductive structures (sporangia). E. fasciculatus, in particular, has been selected for an ecological study into the distribution and transmission of virus infection, for the following reasons: (i) it is readily available on British shores, (ii) it forms almost exclusive epiphytic populations on the fronds of Laminaria digitata, (iii) details of its cell and molecular biology are well known, and (iv) the symptoms of infection are easily recognised in field populations. Peveril Point, Swanage, on the South Coast of England, has been chosen as the study site for: (i) it is a relatively small shore with well defined boundaries, (ii) it has a diversity of filamentous brown algae, and (iii) it has substantial epiphytic populations of E. fasciculatus. Sampling is currently being carried out at monthly intervals, and is randomised at three levels: within the L. digitata (basiphyte) population; on the selected basiphyte; and within the E. fasciculatus population. Preliminary results show that the levels of infection range between 1-5 % on differing parts of the shore. Work is now underway to monitor the spatial and temporal distribution of infection in this E. fasciculatus population, throughout the annual cycle.