Trine Bekkby1, Eli Rinde1, Camilla W. Fagerli1, Siri R Moy1, Lucas Hayes2, Ivana Lukić3, Janne K. Gitmark1, Marijana S Brkljacic1, Hedda P. Meier4, Ann-Elin Synnes1, Cátia Monteiro5, Stein Fredriksen4, Hartvig Christie1
1Norwegian Institute for Water Research (NIVA), Norway - 2University of Barcelona, Spain - 3GEOMAR, Helmholtz-Centre for Ocean Research, Germany - 4University of Oslo, Norway - 5CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, InBIO Laboratório Associado, Portugal
Intertidal areas are among the most diverse environments on Earth. The rockweed beds provide shelter and food for a high number of species. Despite their importance, these ecosystems are being degraded and lost globally, and the knowledge gaps for intertidal rockweed beds are many and large compared to other blue forests. Here we present results from field and mesocosm studies of Norwegian intertidal rockweed beds that provide insight into the impact of different pressures, such as climate change and habitat fragmentation, on rockweed communities. We have focused on two of the species forming habitats of high coverage and extent, Fucus vesiculosus and Ascophyllum nodosum. We present data on densities and biomass of these rockweeds, how structure is impacted by wave exposure, and differences between the ecoregions along the Norwegian coast. We also present data on the community structure of fauna associated with the two rockweed species. Further, to assess the importance of rockweeds as habitat builders and refugia against desiccation and heat stress, we studied the species composition within rockweed patches and unvegetated areas on the sunny and the shady side of intertidal boulders in the field. In mesocosm experiments (12 relatively large rocky seabed basins) we studied the impact of wave exposure and habitat fragmentation on the structure of the rockweeds and of their associated fauna. We also explored grazing, predation and the potential role of filamentous algae aggregations, “turf” (indicating eutrophication) in intensifying the challenges related to heat waves. These studies will increase our knowledge about intertidal rockweed structure and function, and cover some of the knowledge gaps.
Biography
Trine Bekkby works with marine benthic and coastal ecology. She focuses on variation and change - particularly on biodiversity, structure and function of blue forests (such as kelp forests, seagrass meadows and seaweed beds). To do so, she works both in the field and with mesocosm experiments. She works with mapping and monitoring, biostatistics and spatial analyses, GIS and distribution modelling, habitat classification, and assessment of ecological quality and status.