English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Models of benthic community dynamics for the extensively studied, shallow rocky ecosystems in eastern Canada emphasize kelp-urchin interactions. These models may bias the perception of factors and processes that structure communities, for they largely overlook the possible contribution of other seaweeds to ecosystem resilience. We examined the persistence of the annual, acidic (H 2 SO 4 ), brown seaweed  Desmarestia viridis  in urchin barrens at two sites in Newfoundland (Canada) throughout an entire growth season (February to October). We also compared changes in epifaunal assemblages in  D. viridis  and other conspicuous canopy-forming seaweeds, the non-acidic conspecific  Desmarestia aculeata  and kelp  Agarum clathratum . We show that  D .  viridis  can form large canopies within the 2-to-8 m depth range that represent a transient community state termed “ Desmarestia  bed”. The annual resurgence of  Desmarestia  beds and continuous occurrence of  D. aculeata  and  A. clathratum , create biological structure for major recruitment pulses in invertebrate and fish assemblages (e.g. from quasi-absent gastropods to >150 000 recruits kg −1   D. viridis ). Many of these pulses phase with temperature-driven mass release of acid to the environment and die-off in  D. viridis . We demonstrate experimentally that the chemical makeup of  D. viridis  and  A. clathratum  helps retard urchin grazing compared to  D. aculeata  and the highly consumed kelp  Alaria esculenta . In light of our findings and related studies, we propose fundamental changes to the study of community shifts in shallow, rocky ecosystems in eastern Canada. In particular, we advocate the need to regard certain canopy-forming seaweeds as structuring forces interfering with top-down processes, rather than simple prey for keystone grazers. We also propose a novel, empirical model of ecological interactions for  D. viridis . Overall, our study underscores the importance of studying organisms together with cross-scale environmental variability to better understand the factors and processes that shape marine communities.

Canopy-Forming Seaweeds in Urchin-Dominated Systems in Eastern Canada: Structuring Forces or Simple Prey for Keystone Grazers?