title: Changes in subtidal assemblages in a scenario of warming: proliferations of ephemeral benthic algae in the Canary Islands (eastern Atlantic Ocean).
abstract: The present work analysed the main changes in subtidal algal assemblages in the last decade in an oceanic archipelago (Canary Islands--eastern Atlantic Ocean). Changes result from increases in cover of ephemeral benthic algae, such as the non-native chlorophyte Pseudotetraspora marina and the native cyanophytes Blennothrix lyngbyacea, Schizothrix calcicola and Schizothrix mexicana. Ephemeral algae overgrow subtidal assemblages which are extensively dominated by Lobophora variegata, but competitively do not exclude other species. Increases in the abundance of species coincided with a warming of about 2 °C in surface seawater temperature (SST) linked to the weakening of the Cold Canary Current and the Northwestern African upwelling. Shifts in the distribution and cover of ephemeral species follow the SST gradient from warmer waters in the western islands to colder waters in the eastern ones. While in the warmest western islands, species have spread quickly colonizing all type of substrates in just a few years (2005-2008), the occurrence of ephemerals towards the coldest eastern islands is yet inconspicuous.
authors.affiliation: Área de Biodiversidad, Reserva Mundial de la Biosfera La Palma, Av. Marítima, 3, 38700 Santa Cruz de La Palma, Canary Islands, Spain. casangil@ull.es
authors.forename: Carlos
authors.initials: C
authors.lastname: Sangil
authors.forename: Marta
authors.initials: M
authors.lastname: Sansón
authors.forename: Julio
authors.initials: J
authors.lastname: Afonso-Carrillo
authors.forename: Rogelio
authors.initials: R
authors.lastname: Herrera
authors.forename: Adriana
authors.initials: A
authors.lastname: Rodríguez
authors.forename: Laura
authors.initials: L
authors.lastname: Martín-García
authors.forename: Tania
authors.initials: T
authors.lastname: Díaz-Villa
mesh_terms: D000704:Analysis of Variance; D001267:Atlantic Ocean; D058448:Biota; D000460:Chlorophyta / Q000254:growth & development*; D000458:Cyanobacteria / Q000254:growth & development*; D057232:Global Warming; D011157:Population Dynamics; D013030:Spain; D013045:Species Specificity; D013696:Temperature; D014872:Water Movements