Title

Spatio-temporal distribution patterns of the invasive macroalga Sargassum muticum within a Danish Sargassum-bed

Document Type

Journal Article

Publisher

Springer-Verlag

Faculty

Computing, Health and Science

School

Natural Sciences, Centre for Marine Ecosystems Research

RAS ID

4195

Comments

This article was originally published as: Thomsen, M. S., Wernberg, T., Stæhr, P. A., & Pedersen, M. F. (2005). Spatio-temporal distribution patterns of the invasive macroalga Sargassum muticum within a Danish Sargassum-bed. Helgoland Marine Research, 60(1), 50. Original available here

Abstract

Sargassum muticum was first observed in Scandinavia in Limfjorden (Denmark) in 1984, where it is now the most abundant and conspicuous macroalga. Despite the ecological importance of Sargassum, few studies have described seasonal patterns within Scandinavian Sargassum beds. We quantified the dynamics of macroalgae among years and seasons along a depth transect through a typical Sargassum bed in Limfjorden. The annual investigations (summer transects 1989–1999) showed a gradual increase in the dominance of Sargassum, especially at the 2–4-m depth interval. Significant seasonal dynamics in macroalgal abundance and assemblage structure were observed in this depth interval; the mean cover of Sargassum varied from ca. 5% (autumn and winter) to 25% (mid-summer). In comparison, encrusting algae had high and relatively stable covers throughout the year (ca. 20%). Other perennial macroalgae had low mean covers (Sargassum abundance was positively related to boulders >10 cm in diameter and species richness was negatively correlated to depth and stones diameter, and non-correlated to other algal form-groups or grazer densities. Thus, in Limfjorden, the distribution of Sargassum is determined by large- (>6 m) and small-scale (<1 >m) depth differences where low light limits Sargassum at depth, physical disturbance and sediment stress limits Sargasum in shallow waters, and the presence of stable boulder substratum facilitate Sargassum. Competition for space from other macroalgae and herbivory are probably of minor importance.

DOI

10.1007/s10152-005-0016-1

Access Rights

free_to_read

 

Link to publisher version (DOI)

10.1007/s10152-005-0016-1