Effects of sedimentation on macroalgae: species-specific responses are related to reproductive traits

Abstract

Although increases in sedimentation have been proposed to interfere with benthic communities in many coastal areas worldwide, few experimental studies have investigated the effect of sedimentation on community composition and assessed species-specific responses. In a field experiment on a rocky shore on the Swedish east coast (northern Baltic Proper) we confirmed the hypotheses that ambient sedimentation influences macroalgal abundance and community composition, and that species-specific responses to sedimentation correlate with reproductive strategies. We followed the establishment and development of macroalgal vegetation on artificial substrates at 8-m and 15-m depth for 4.5 years while manipulating the depositional environment by regularly removing accumulated sediment. Sediment removal significantly favoured macroalgal development and vegetation cover. Responses of macroalgal species to the sediment treatments were clearly species-specific; for example, the ephemeral green algae (Cladophora glomerata and Enteromorpha spp.) were highly tolerant to sedimentation while belt-forming perennial brown algae (Fucus vesiculosus and Sphacelaria arctica) were not. Accordingly, multivariate analyses (redundancy analysis) showed that variance in species abundances were significantly correlated to sediment conditions. The effect of sediment removal was higher at 15-m than at 8-m depth and some species' distributions seemed limited in depth by the present sediment load (e.g. F. vesiculosus). Vegetative propagation was common in the study area and many species mainly depended on dispersal by fragmentation. Generally, species with an extended reproductive period, either by long continuous spore release (C. glomerata and Enteromorpha spp.) or vegetative dispersal by fragmentation (e.g. Furcellaria lumbricalis and Polysiphonia fucoides), were most tolerant to sedimentation. This paper demonstrates long-term effects of sediment deposition on the development of a macroalgal community over several growing seasons. The results indicate that variation in sediment loads is an important constraint for species' local distributions and abundances, and affects the composition of sublittoral rocky-shore macroalgal communities.

A novel obligate cultivation mutualism between damselfish andPolysiphoniaalgae

“…1 dispersed from other algal farms. In fact, some Polysiphonia species have a high capacity for dispersal by spores (Rindi & Cinelli 2000) or fragments (Eriksson & Johansson 2005), and inside algal farms, both sexual and asexual spores of Polysiphonia sp. 1 were observed.…”

Structure and temporal dynamic of tropical turf forming macroalgal assemblages of the western coast of Mexico

“…Sediment deposition and movement determines the depositional environment (Airoldi et al, 1995). Worldwide studies have shown that sedimentation plays a crucial role in the structure and dynamics of the algal assemblages (Piazzi & Cinelli, 2001;Miller et al, 2002;Eriksson & Johansson, 2005;Balata et al, 2007;Florez-Leiva et al, 2009;Shepherd et al, 2009). However in the Mexican tropical Pacific, the scarce studies carried out on sedimentation has been addressed to assess its effect on sponges communities (Carballo, 2006), on stony corals (Granja-Fernández & López-Pérez, 2008) and as an indicator of coral reef degradation (Nava & Ramírez-Herrera, 2011, nevertheless its relationship with macroalgal communities is unknown.…”

Climatic and environmental factors influencing occurrence and distribution of macroalgae — a fjord gradient revisited

“…Reports of conspicuous changes in macroalgal composition and abundances are due to anthropogenic impacts such as nutrient enrichment (e.g. Valiela et al 1997, Middelboe & SandJensen 2000, Worm & Lotze 2006, Liu et al 2013, inter actions between nutrient enrichment and grazers (Lotze & Worm 2000), and increased sedimentation (Eriksson et al 2002, Eriksson & Johansson 2005. More recently there has been a strong focus on effects of increasing sea temperatures in coastal areas, and a number of cases with concurrent changes in macroalgae range shifts (e.g.…”