title: Climate change and glacier retreat drive shifts in an Antarctic benthic ecosystem.
abstract: The Antarctic Peninsula (AP) is one of the three places on Earth that registered the most intense warming in the last 50 years, almost five times the global mean. This warming has strongly affected the cryosphere, causing the largest ice-shelf collapses ever observed and the retreat of 87% of glaciers. Ecosystem responses, although increasingly predicted, have been mainly reported for pelagic systems. However, and despite most Antarctic species being benthic, responses in the Antarctic benthos have been detected in only a few species, and major effects at assemblage level are unknown. This is probably due to the scarcity of baselines against which to assess change. We performed repeat surveys of coastal benthos in 1994, 1998, and 2010, analyzing community structure and environmental variables at King George Island, Antarctica. We report a marked shift in an Antarctic benthic community that can be linked to ongoing climate change. However, rather than temperature as the primary factor, we highlight the resulting increased sediment runoff, triggered by glacier retreat, as the potential causal factor. The sudden shift from a "filter feeders-ascidian domination" to a "mixed assemblage" suggests that thresholds (for example, of tolerable sedimentation) and alternative equilibrium states, depending on the reversibility of the changes, could be possible traits of this ecosystem. Sedimentation processes will be increasing under the current scenario of glacier retreat, and attention needs to be paid to its effects along the AP.
authors.affiliation: Instituto de Diversidad y Ecología Animal [Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional de Córdoba (CONICET-UNC)], Facultad de Ciencias Exactas, Físicas y Naturales, UNC, Avenida Vélez Sarsfield 299, 5000 Córdoba, Argentina.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Sahade
authors.affiliation: Instituto de Diversidad y Ecología Animal [Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional de Córdoba (CONICET-UNC)], Facultad de Ciencias Exactas, Físicas y Naturales, UNC, Avenida Vélez Sarsfield 299, 5000 Córdoba, Argentina.
authors.forename: Cristian
authors.initials: C
authors.lastname: Lagger
authors.affiliation: Instituto de Diversidad y Ecología Animal [Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional de Córdoba (CONICET-UNC)], Facultad de Ciencias Exactas, Físicas y Naturales, UNC, Avenida Vélez Sarsfield 299, 5000 Córdoba, Argentina.
authors.forename: Luciana
authors.initials: L
authors.lastname: Torre
authors.affiliation: Instituto de Ciencias, Universidad Nacional de General Sarmiento, Juan M. Gutiérrez 1150, B1613GSX Los Polvorines, Argentina. ; Instituto de Ecología y Desarrollo Sustentable, Universidad Nacional de Luján, Luján 6700, Argentina.
authors.forename: Fernando
authors.initials: F
authors.lastname: Momo
authors.affiliation: Institute for Chemistry and Biology of the Marine Environment, Carl-von-Ossietzky Straße 9-11, 26129 Oldenburg, Germany. ; Department of Geosciences, University of Bremen, Klagenfurter Straße (GEO), 28359 Bremen, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Monien
authors.affiliation: Instituto Antártico Argentino, Balcarce 290, Ciudad Autónoma de Buenos Aires C1064AAF, Argentina.
authors.forename: Irene
authors.initials: I
authors.lastname: Schloss
authors.affiliation: British Antarctic Survey, Natural Environment Research Council, Madingley, Road, Cambridge CB3 0ET, UK.
authors.forename: David K A
authors.initials: DK
authors.lastname: Barnes
authors.affiliation: Instituto de Diversidad y Ecología Animal [Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional de Córdoba (CONICET-UNC)], Facultad de Ciencias Exactas, Físicas y Naturales, UNC, Avenida Vélez Sarsfield 299, 5000 Córdoba, Argentina.
authors.forename: Natalia
authors.initials: N
authors.lastname: Servetto
authors.affiliation: Instituto de Diversidad y Ecología Animal [Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional de Córdoba (CONICET-UNC)], Facultad de Ciencias Exactas, Físicas y Naturales, UNC, Avenida Vélez Sarsfield 299, 5000 Córdoba, Argentina.
authors.forename: Soledad
authors.initials: S
authors.lastname: Tarantelli
authors.affiliation: Instituto de Diversidad y Ecología Animal [Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional de Córdoba (CONICET-UNC)], Facultad de Ciencias Exactas, Físicas y Naturales, UNC, Avenida Vélez Sarsfield 299, 5000 Córdoba, Argentina.
authors.forename: Marcos
authors.initials: M
authors.lastname: Tatián
authors.affiliation: Instituto de Diversidad y Ecología Animal [Consejo Nacional de Investigaciones Científicas y Técnicas-Universidad Nacional de Córdoba (CONICET-UNC)], Facultad de Ciencias Exactas, Físicas y Naturales, UNC, Avenida Vélez Sarsfield 299, 5000 Córdoba, Argentina.
authors.forename: Nadia
authors.initials: N
authors.lastname: Zamboni
authors.affiliation: Alfred Wegener Institut for Polar and Marine Research, Columbusstraße, 27568 Bremerhaven, Germany.
authors.forename: Doris
authors.initials: D
authors.lastname: Abele
keywords: Antactic fjords; Antarctica; Ascidians; Benthic ecosystems; Filter feeders; Glacier retreat; Sedimentation; Sudden changes; Thresholds; climate change