Tatian M.,National University of Cordoba |
Schwindt E.,CONICET |
Lagger C.,National University of Cordoba |
Varela M.M.,Institute Ecologia Litoral
Spixiana | Year: 2010
Despite the poorly studied biodiversity of the Southwestern Atlantic, several exotic species have already been detected. Here we detail the distribution and abundance of the invasive ascidian Ascidiella aspersa (Müller, 1776) in the SW Atlantic and review its historical records. For this purpose, we determined ascidians collected since 1914 from museum collections and inspected randomly sampled natural biota collections as well as colonization on plates deployed in situ for two years throughout six major harbours along the Patagonian Argentine coast. Museum collections revealed a sudden presence of A. aspersa early in the 1960's. The species is actually distributed over 10 latitudinal degrees in harbours and subtidal areas along the SW Atlantic. Altogether, results suggest that this species, an exotic for the SW Atlantic, is able to colonize new areas. Further studies are needed to assess A. aspersa invasion impacts on biodiversity in the study area.
Garcia-March J.R.,University of Alicante |
Jimenez S.,Institute Ecologia Litoral |
Sanchis M.A.,University of Alicante |
Monleon S.,University of Alicante |
And 3 more authors.
Marine Biology | Year: 2016
The rhythms and responses of animals to environmental factors are important issues for their adaptation to natural cycles. These rhythms assure an optimum synchrony between organisms and their environment. Bio-logging enables monitoring these activity cycles remotely. To characterize rhythms and responses of fan mussels (Pinna nobilis) to environmental factors, six individuals were monitored from April 2009 to October 2011. The study was conducted at a station in the western Mediterranean at 11 m depth in Tabarca Island Marine Reserve (Alicante, Spain). Sensors at the station monitored dissolved oxygen (mg l−1), turbidity (ntu), temperature (°C), chlorophyll a concentration (chl a) (mg m−3), current speed (cm s−1), and direction (°). One pattern of gaping activity (P1) occurred from mid-July–early August–early November, whereas another pattern (P2) occurred the rest of the time (i.e., from early November–mid-July–early August). The activity was synchronized among the fan mussels and showed autocorrelation peaks at a period of 21.9–24 h. In P1, the fan mussels opened their valves according to the position and illumination of the sun and moon. In P2, however, individuals did not track sun and moonlight, although their gaping activity was regular and synchronized. Likewise, individuals were unaffected by high-frequency (daily) variation in dissolved oxygen and (chl a). Gaping activity was directly influenced by current intensity and direction. The shift between the two patterns and the presence of similar periods of autocorrelation in the activity time series indicate that P. nobilis has an internal clock. © 2016, Springer-Verlag Berlin Heidelberg.
Guillen J.E.,Institute Ecologia Litoral |
Sanchez Lizaso J.L.,University of Alicante |
Jimenez S.,Institute Ecologia Litoral |
Martinez J.,Institute Ecologia Litoral |
And 5 more authors.
Journal of Sea Research | Year: 2013
Results of the monitoring network of the Posidonia oceanica meadows in the Valencia region in Spain are analysed. For spatial comparison the whole data set has been analysed, however, for temporal trends we only selected stations that have been monitored at least 6. years in the period of 2002-2011 (26 stations in 13 localities).At the south of the studied area, meadows are larger, and they have higher density and covering than that in the Valencia Gulf, excluding Oropesa meadow. Monitoring of P. oceanica meadows in the Valencia region in Spain indicates that most of them are stationary or they are increasing their density and covering while no decline was observed in the studied meadows. These results indicate that there is not a general decline of P. oceanica meadows and that the decline of P. oceanica, when it has been observed in other studies, is produced by local causes that may be managed at the local level. This study also reflects the importance of long series of direct data to analyse trends in the population dynamics for slow-growing species. © 2013 The Authors.