The shallow marine ostracod communities of the Azores (Mid-North Atlantic) : taphonomy and palaeoecology
Piazza Meireles, R. (University of the Azores. Marine PalaeoBiogeography Working Group)
Keyse, D. (University of Hamburg. Zoological Institute and Museum)
Borges, P. A. (University of the Azores. Department of Geoscience)
Silva, L. (Universidade dos Açores. Departamento de Biologia)
Frias Martins, A. M. de (Universidade dos Açores. Departamento de Biologia)
Ávila, Sérgio P. (Universidade do Porto. Faculdade de Ciências)
Universidade dos Açores. InBIO Laboratório Associado

Data:	2014
Resum:	This is the first palaeoecological and taphonomical study of the Recent marine ostracods from the Azores. The aims of this work were to address the following questions: i) to establish the typical ostracod assemblages from the shallow waters of the Azores; ii) to determine the bathymetric ranges for each ostracod species; iii) to investigate the time span and depth in which significant transport occurs; iv) to quantify the amount of out of habitat transport between sandy beaches, tide pools and the sublittoral; v) to determine distinctive taphonomic features that can be used to recognize the amount of temporal resolution in ostracod assemblages. Fifteen species were recovered, representing 8 families and 12 genera (Loxoconcha, Neonesidea, Xestoleberis, Aurila, Urocythereis, Heterocythereis, Carinocythereis, Callistocythere, Leptocythere, Semicytherura, Lanceostoma and Cylindroleberis). The living assemblages are dominated by specimens of the Loxoconchidae, Xestoleberidae and Hemicytheridae, whereas the dead assemblages are dominated by specimens of the Loxoconchidae, Hemicytheridae, Bairdiidae, Xestoleberidae and Trachyleberidae. The shift from life-dominated assemblages in the shallower depths to death-dominated assemblages at greater depths is a consequence of significant transport downwards. The abundance of ostracods is higher in the first 10-20 m depth, especially in fine to medium sandy substrates. Considerable differences among islands were supported by the Bayesian model, as a consequence of the physical and hydrodynamic factors that differently affect each of the Azorean islands. Large-scale (sea-surface currents, Holocene relative sea-level, storms) and small-scale processes are responsible for shaping the Azorean Recent marine ostracod communities. No living specimens were found in the samples collected at the beach faces, thus reinforcing former interpretations of one of the authors (S. Ávila) that advocate that at a global scale, sandy beaches in oceanic islands located at temperate latitudes are almost or even completely devoid of life due to historical reasons related with the sea level changes.
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Ostracods ; Recent ; Oceanic islands ; Taphonomic processes ; Palaeoecology ; Bayesian model
Publicat a:	Geologica acta, Vol. 12, Núm. 1 (March 2014) , p. 53-70, ISSN 1696-5728

Adreça alternativa: https://raco.cat/index.php/GeologicaActa/article/view/275588
Adreça alternativa: https://revistes.ub.edu/index.php/GEOACTA/article/view/105.000002073
DOI: 10.1344/105.000002073

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