Relevant scales of variability of the benthic allochthonous microalga Chrysophaeum taylorii

Chrysophaeum taylorii (Pelagophyceae) is an allochthonous benthic microalga recently recorded in the Mediterranean Sea. During summer, the occurrence of C. taylorii is usually visible to the naked eye due to the large amount of mucilage this species produces. Information on the spatio-temporal variability of this species and on the predictability of massive mucilage events is still scarce and requires to define ad hoc managing strategies of major bloom events. The aim of this work was to identify the relevant scales of variation in the abundance of C. taylorii abundance and to estimate the relative recurrence of its blooms, testing the hypothesis that mucilage was depend- ent on the cell density. The first approach was the identi- fication of the most appropriate sampling procedure to estimate benthic cell abundance of C. taylorii. The second one was the estimation of the magnitude of variation in C. taylorii cell abundance attributable to each of several spa- tial (areas, sites, zones and replicates) and temporal scales (fortnights and years) in the Marine Protected area of Tavolara Punta Coda Cavallo (Western Mediterranean Sea). The results indicate fortnight and year as the most relevant scales of variability in the cell abundance of C. taylorii and