We used a neutral solution of Alcian Blue to stain transparent particles in eutrophic Lake

Frederiksborg Slotss0, Denmark. Alcian Blue-stained particles (ABSP) appeared to be similar to the

so-called transparent exopolymer particles (TEP) identified with an acidic solution of Alcian Blue.

Our results on the abundance, size distribution and bacterial colonization of ABSP therefore reflect

general patterns of TEP. The abundance of ABSP in the size range 3-162 urn and retained by 3 um

pore size filters averaged 3.6 ± 2.49 x 10s ml"1 (± SD), which is among the highest concentrations

reported for comparable size spectra of TEP. On average, 35 % of ABSP (by number) were colonized

by bacteria and 8.6 x 105 bacteria ml"1 lake water were attached to ABSP, which corresponds to 7%

of the total bacterial abundance.