The intertidal zone of the North-East Atlantic region: pattern and process.

The north-east Atlantic region is an area where clades originating in the north Pacific (fucoids, balanoids, littorinids, thaids, laminarians) collide with clades from further south in the Atlantic (e.g., patellids, trochids, chthamalids). At high latitudes in the north, seaweeds dominate the midsho...

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Bibliographic Details
Main Authors: Hawkins, SJ, Pack, KE, Firth, LB, Mieskowska, N, Evans, AJ, Martins, GM, Aberg, P, Adams, LC, Arenas, F, Boaventura, DM, Bohn, K, Borges, CDG, Castro, JJ, Coleman, R, Crowe, T, Cruz, T, Davies, MS, Epstein, G, Faria, J, Ferreira, JG, Frost, NJ, Griffin, JN, Hanley, ME, Herbert, RJH, Hyder, K, Johnson, MP, Lima, FP, Masterson-Algar, P, Moore, PJ, Moschella, PS, Notman, GM, Pannacciulli, FG, Ribeiro, PA, Santos, AM, Silva, ACF, Skov, MW, Sugden, H, Vale, M, Wangkulangkul, K, Wort, EJG, Thompson, RC, Hartnoll, RG, Burrows, MT, Jenkins, SR
Other Authors: SJ Hawkins, K Bohn, LB Firth, GA Williams
Format: Book Part
Language:English
Published: Cambridge University Press 2019
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Online Access:http://hdl.handle.net/10174/26129
Description
Summary:The north-east Atlantic region is an area where clades originating in the north Pacific (fucoids, balanoids, littorinids, thaids, laminarians) collide with clades from further south in the Atlantic (e.g., patellids, trochids, chthamalids). At high latitudes in the north, seaweeds dominate the midshore zone of all but the most exposed shores. Further south, midshore space-occupying invertebrates (mussels and barnacles) win, facilitated by grazing by patellid limpets that controls algal recruitment; propagule pressure is much less as fucoids become rarer, and juvenile growth is slower due to environmental stress, thereby reducing the probability of escapes from grazing (Figure 2.4) (Ferreira et al., 2014, 2015a, 2015b). Low on the shore seaweeds dominate space by forming algal turfs or kelp or fucoid canopies. These algae outpace the ability of grazing limpets to control them in the low-intertidal zone. L. digitata canopies can lead to rock covered by encrusting algae and sponges, facilitating limpets. If canopy is removed, then colonising ephemeral algae and turf-forming algae swamp the limpets. There is usually too much water movement immediately either side of low water for effective foraging by sea urchins. Psammechinus miliaris and Echinus esculentus only appear in the subtidal, and Paracentrotus lividus is confined to refuges in burrows relying mainly on the drift of food (Benedetti-Cecchi and Cinelli, 1995;Boudouresque and Verlaque, 2007; Jacinto and Cruz, 2012). High on the shore, physical factors dominate. At high latitudes in the north of the Atlantic, ephemeral algae are present all year round. Further south they are only present in the winter, dying-off in the summer. Grazing has limited effects, only occurring around refuges that littorinids maintain (Stafford and Davies, 2005; Skov et al., 2010, 2011). Patterns are also strongly modified by mesoscale processes driven by upwelling that influences nutrient and larval supply (North Africa, Iberia) and coastal configuration, where embayed versus ...