IIMYC   23581
INSTITUTO DE INVESTIGACIONES MARINAS Y COSTERAS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Sclerobionts on Patagonian oysters: A multivariate analysis to establish ecological structure over time
Autor/es:
ROMERO, M.V.; BREZINA, S.S.; GIBERTO, D.A.; BREMEC, C.S.
Lugar:
Mar del Plata
Reunión:
Congreso; Reunión de Comunicaciones de la Asociación Paleontológica Argentina (RCAPA 2015); 2015
Institución organizadora:
Asociación Paleontológica Argentina
Resumen:
This study compared the composition and frequency of encrusting, boring and vagile organisms or?sclerobionts? on two patagonian oysters: Ostrea puelchana d´Orbigny (Recent) and Ostrea alvarezii d´Orbigny (Miocene). The structure of sclerobiontic assemblages and its preferential recruitment on left/right valves and their external/internal surfaces was evaluated by multivariate nonparametric analysis (MDS, SIMPER, ANOSIM) and non-parametric test for mean comparisons using abundance and coverage data. External surfaces and left valves were more colonized in both oysters. The same taxonomic and trophic groups were found on both oysters, albeit in different proportions. From a total of 12 phyla recorded on the recent shells, only four of them were not represented on the fossil shells. The sixteen recognized ichnotaxa reflect a similar sequence of tiers in both oysters, sharing different levels of colonization on valves by organisms with similar behaviors. Bivalves, polychaetes and bryozoans were the most representative encrusters. This implies similar environmental conditions and, therefore, a similar ecological structure. The diversity of Bryozoa and bioeroders recorded on O. alvarezii was higher than on the recent oyster. These differences may be explained by taphonomic feedback. Miocene bryozoans of warm, warm-cold and cold water recorded could evidence a climate transition consistent with a passage from warm to cold water in response to climate changes during the global warming of the middle Miocene. Based on these results, it is unarguable that the ecological role of O. alvarezii was not too different from that of O. puelchana, providing available substrates for similar macrofauna in similar environments.