Epiphyte load on the seagrass Posidonia oceanica (L.) Delile does not indicate anthropogenic nutrient loading in Cabrera Archipelago National Park (Balearic Islands, Western Mediterranean)
Jorge Terrados and Francisco Javier Medina Pons
The epiphyte load on the leaves of the seagrass Posidonia oceanica (L.) Delile was estimated at the end of summer in three sites and two depths (7 m and 17 m) of the Cabrera Archipelago National Park (Balearic Islands, Western Mediterranean) from 2004 to 2006 to evaluate if epiphyte load could be used as an indicator of anthropogenic nutrient loading in the shallow marine ecosystems of the park. Asymmetrical ANOVA was used to divide data variability into two components: the contrast between the site receiving direct anthropogenic inputs of nutrients and organic matter (Es Port) and the two control sites (Cala Santa María, Es Burri); and the variability between the control sites. The nitrogen concentration in P. oceanica leaves was higher in Es Port than in Cala Santa María and Es Burri but only at 7 m depth. There was no difference between the epiphyte load on P. oceanica shoots in Es Port and the sites without inputs at both 7 m and 17 m. However, the epiphyte load in Es Burri was higher than that in Cala Santa María at both depths. The results show that the epiphyte load on P. oceanica shoots was not a sensitive indicator of anthropogenic nutrient and organic matter loading in Cabrera Archipelago National Park.
Keywords: seagrass, epiphytes, nutrient loading, Posidonia oceanica, Western Mediterranean
Sci. Mar. 72(3) : 503-510
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