Are Drifting Algal Mats Conquering the Bottom of the Archipelago Sea, SW Finland?

Effects of Pilayella littoralis on Fucus vesiculosus recruitment: implications for community composition

“…Over the past few decades, mass developments of annual filamentous algae, such as Enteromorpha spp., Pilayella littoralis and Cladophora spp., have increased in coastal areas around the world (Rosenberg et al 1996, Schramm & Nienhuis 1996, Eriksson et al 2002, including the Baltic Sea (Hällfors et al 1984, Cederwall & Elmgren 1990, Rönnberg & Mathiesen 1998, Vahteri et al 2000. At the same time, the distribution of the perennial macroalga Fucus vesiculosus has become more restricted (Kangas et al 1982, Kautsky et al 1986, Schramm 1999, Middelboe & Sand-Jensen 2000, except for some local recovery in recent years (Kautsky 2000, Nilsson et al 2004.…”

“…In a laboratory study, Aneer (1987) found that some filamentous algae, including Pilayella, had negative effects on fish egg survival, and suggested that the high natural mortality of Baltic herring Clupea harengus may be locally correlated to the toxic exudates of brown filamentous algae. Decomposition of filamentous algae locally generates high levels of nutrients (Vahteri et al 2000) such as nitrate, phosphate and ammonium, which can all have damaging effects on the early life stages of macroalgae (Kevekordes 2001, Bergström et al 2003. Thus, high abundance of detaching Pilayella during Fucus reproduction may have negative consequences for the recruitment of Fucus.…”

Cyanobacteria and macroalgae in ecosystem of the Neva estuary

“…According to the data on the Archipelago Sea, the areas with loose-lying algal mats reached more than 30 ha. The coverage of the mats varied between 10-70% of coastal area, and their thickness was found to vary between 2 and 30 cm (Vahteri et al, 2000). In our study the feature of the algal mats in the Neva estuary is an absolute dominance of C. glomerata, which reflects the "fresh-face" communities of macroalgae on studied area.…”

“…The drifting macroalgae can form loose algal mats or accumulate on beaches, posing a serious threat to both biodiversity and recreation in coastal areas (Norkko et al, 2000;Vahteri et al, 2000;Berglund et al, 2003). Conditions of hypoxia and anoxia, forming under algal mats, result to mortality of benthic fauna (Berezina et al, 2007).…”

An Adenovirus Associated With Intestinal Impaction and Mortality of Male Common Eiders (Somateria Mollissima) in the Baltic Sea

“…In some areas of the Baltic Sea, algae of Cladophora sp. have markedly increased in density during the recent decades as a result of eutrophication (Vahteri et al, 2000). In the affected areas, such as those surrounding the Utö archipelago, the vegetation covers musselbeds in the bottom of the waterbed and eiders feeding on mussels inevitably also ingest large quantities of algae.…”