New research on north east Atlantic kelp forests examines whether 'novel ecosystems', brought about by warming seas, can provide the same vital services as pre-warming ecosystems.

Large canopy-forming kelp forests are foundation species In temperate marine environments. The warm-water kelp, Laminaria ochroleuca is expanding its range northwards, and is increasingly common in the kelp communities of south west England. Lead author of the research Albert Pessarrodona explains: “As the ocean warms, species are moving up slopes and towards the poles in order to remain within their preferred environmental conditions. Species with warm affinities are migrating to many habitats previously dominated by cold-water ones, transforming ecosystems as we know them. These so-called novel ecosystems feature a mix of warm- and cold-affinity species, but we don’t know whether they can retain desirable ecological processes and functions on which human wellbeing relies”.

Co-author of the study Dr. Dan Smale said, “The warm-water kelp Laminaria ochroleuca was actually first detected in the UK in the late 1940s, but is now a common sight along the southwest coast and is predicted to continue expanding northwards in response to climate change, occupying most of the UK and large sections of the wider North-East Atlantic coastline by the end of the century”.

Mr Pessarrodona added: “We found that the warm-water kelps essentially acted as a conveyor belt of food production, growing and shedding its leaf-like lamina throughout the year, providing a continuous supply of food. In contrast, the cold-water species only grew during short, discrete periods of the year”.

Overall, the warm water species was functionally “faster”, with its organic material being rapidly processed by herbivores such as sea snails and limpets and with faster rates of decomposition.

The warm-water kelp, Laminaria ochroleuca, exposed at low tide in south west England.

“Our findings suggest that the proliferation of the warm-water kelp will alter the dynamics of North-East Atlantic marine forests by modifying the quantity, quality and availability of food. In other research we have also seen that the warm-water kelp harbors less biodiversity than the cold species. Such changes in the provision of habitat and food could eventually affect commercially important species such as crabs, lobsters and coastal fish”, Dr. Smale said.

Read the full paper at the Journal of Ecology website.

Find out more at the Benthic Ecosystems and Environmental Change web pages.

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Aug 28, 2018 By guba