The shallow marine ostracod communities of the Azores (Mid- North Atlantic): taphonomy and palaeoecology
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| Natura: | Artículo científico |
| Lingua: | en |
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Universitat de Barcelona
2014
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| author | R. Piazza Meireles |
| author_facet | R. Piazza Meireles |
| contents | The shallow marine ostracod communities of the Azores (Mid- North Atlantic): taphonomy and palaeoecology R. Piazza Meireles D. Keyser P.A. Borges L. Silva A.M. de Frias Martins S.P. Ávila Ciencias de la Tierra Recent Ostracods Palaeoecology Bayesian model Oceanic islands 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. 2014 artículo científico 1695-6133 https://www.redalyc.org/articulo.oa?id=50530452004 en http://www.redalyc.org/revista.oa?id=505 Geologica Acta: an international earth science journal application/pdf Universitat de Barcelona Geologica Acta: an international earth science journal (España) Num.1 Vol.12 |
| format | Artículo científico |
| id | redalyc_50530452004 |
| institution | Redalyc |
| language | en |
| publishDate | 2014 |
| publisher | Universitat de Barcelona |
| spellingShingle | The shallow marine ostracod communities of the Azores (Mid- North Atlantic): taphonomy and palaeoecology R. Piazza Meireles Ciencias de la Tierra Recent Ostracods Palaeoecology Bayesian model Oceanic islands The shallow marine ostracod communities of the Azores (Mid- North Atlantic): taphonomy and palaeoecology R. Piazza Meireles D. Keyser P.A. Borges L. Silva A.M. de Frias Martins S.P. Ávila Ciencias de la Tierra Recent Ostracods Palaeoecology Bayesian model Oceanic islands 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. 2014 artículo científico 1695-6133 https://www.redalyc.org/articulo.oa?id=50530452004 en http://www.redalyc.org/revista.oa?id=505 Geologica Acta: an international earth science journal application/pdf Universitat de Barcelona Geologica Acta: an international earth science journal (España) Num.1 Vol.12 |
| title | The shallow marine ostracod communities of the Azores (Mid- North Atlantic): taphonomy and palaeoecology |
| topic | Ciencias de la Tierra Recent Ostracods Palaeoecology Bayesian model Oceanic islands |
| url | https://www.redalyc.org/articulo.oa?id=50530452004 |