Epiphytic macroalgae mediate the impact of a non-native alga on associated fauna

Aquacult. Environ. Interact.

Kutti

et al. 2021

Large-scale finfish farms are increasingly located in dispersive hard-bottom environments where Laminaria hyperborea forests dominate; however, the interactions between farm effluents and kelp forests are poorly understood. Effects of 2 levels of salmonid fish-farming effluents (high and low) on L. hyperborea epiphytic communities were studied by sampling canopy plants from 12 sites in 2 high-energy dispersive environments. Specifically, we assessed if farm effluents stimulated fast-growing epiphytic algae and faunal species on L. hyperborea stipes—as this can impact the kelp forest community composition—and/or an increased lamina epiphytic growth, which could negatively impact the kelp itself. We found that bryozoan biomass on the stipes was significantly higher at high-effluent farm sites compared to low-effluent farm and reference sites, resulting in a significantly different epiphytic community. Macroalgal biomass also increased with increasing effluent levels, including opportunistic Ectocarpus spp., resulting in a less heterogeneous macroalgae community at high-effluent farm sites. This habitat heterogeneity was further reduced by the high bryozoan biomass at the high-effluent sites. Such changes in the epiphyte community could have implications for the faunal community that relies on the epiphytes for food and refuge. On the kelp lamina, no clear response to farm effluents was found.

Section: Introductionmentioning

confidence: 99%

Large-scale salmon farming in Norway impacts the epiphytic community of Laminaria hyperborea

Haugland

Aquacult. Environ. Interact.

Kutti

et al. 2021

“…Codium fragile subsp. fragile is not associated with large negative impacts on abundances or diversity of macroalgae-associated invertebrates or epiphytic macroalgae, but can affect the community composition of these groups (Schmidt and Scheibling 2006;Jones and Thornber 2010;Armitage and Sjøtun 2016b), and influence detritus cycling (Krumhansl and Scheibling 2012). Once established, it may occupy space and prevent reestablishment of kelp (Levin et al 2002, Scheibling andGagnon 2006).…”

Section: Introductionmentioning

confidence: 99%

Can an old alien benefit from rising ocean temperatures? An experimental and field study on the growth and local distribution of Codium fragile subsp. fragile (Chlorophyta)

Sjøtun

2017

Mar Biol

Self Cite

“…This subspecies has good dispersal and establishment abilities (Nyberg and Wallentinus 2005) and has spread worldwide over the last 200 years (Provan et al 2008). In new habitats, it can have ecological and economic impacts; for example, it may compete with native kelps or fucoids Gagnon 2006, Armitage et al 2014), influence seaweed-associated fauna composition (Schmidt and Scheibling 2006, Drouin et al 2011, Armitage and Sjøtun 2016, negatively affect commercial bivalve beds (summarised in Trowbridge 1998) and impact ecosystem services (Vilà et al 2010). In Norway, C. fragile subsp.…”

Section: Introductionmentioning

confidence: 99%

Codium fragile in Norway: subspecies identity and morphology

Sjøtun

2016

Botanica Marina

Self Cite

Abstract:The green alga Codium fragile consists of 10 subspecies, of which subspecies fragile is a well-known invasive seaweed. Morphological work carried out in the 1950s suggested that there were three subspecies along the Norwegian coast: subsp. fragile, subsp. atlanticum and subsp. scandinavicum. However, more recent molecular data have shown the existence of only two subspecies and that these are frequently misidentified. The aims of the present study were therefore to verify which subspecies occur in Norway using the rpl16-rps3 chloroplast marker, to ascertain their likely time of arrival and to compare their morphology to their genetic identity. DNA sequences were obtained for 60 thalli from 18 sites along the coast (57-69° N) and 10 herbarium specimens . The sequences indicated that both subsp. fragile and subsp. atlanticum occur at present and have been in Norway since at least 1932 and 1948, respectively. The subspecies co-occurred at one site, but in general, subsp. atlanticum appears to have a narrower distribution than subsp. fragile, both geographically and in terms of habitat. Importantly, mucron length, other utricle features, or habitat were not always sufficiently reliable to give an accurate subspecies identification, demonstrating the necessity of DNA sequencing for the identification of these subspecies.