摘要：The microbial degradation of North Sea macroalgae was studied in laboratory microcosms, containing autoclaved seawater and a mixture of equal parts of air-driedDelesseria sanguinea, Ulva lactuca, andLaminaria saccharina (red, green and brown algae, respectively). To determine the influence of different organisms on the decomposition rate (expressed in terms of algal dry weight loss relative to the material present at time zero) and their development during decomposition processes, yeast, flagellates, ciliates, nematodes and a harpacticoid copepod species were introduced to the microcosms. Results show that microbial degradation compared to the controls was enhanced in the presence of non-axenic nematodes (Monhystera sp.) and protozoans, including bacterivorous ciliates (Euplotes sp. and aUronema-like sp.) and flagellates. No enhancement occurred with yeast (Debaryomyces hansenii) or with the harpacticoid copepodTisbe holothuriae. The most rapid algal dry weight loss (78.7% after 14 d at 18°C) occurred with the addition of raw seawater sampled near benthic algal vegetation and containing only the natural microorganisms present. These consisted mainly of bacteria with different morphological properties, whereby their numbers alone (viable counts) could not be correlated with algal dry weight loss. Although no single dominant species could be determined, lemon yellow pigmented colonies were frequently found. During decomposition in all microcosms the formation of algal particles 40–400 μm was observed, which were rapidly colonized by the other organisms present.
