The seagrass Posidonia oceanica (L. delile), endemic to the Mediterranean, Sea is the dominant species in the meadows that characterize the sandy and rocky coastal bottoms in Western Mediterranean. The meadows present an intense cover of the seabed between -4 and -40 m, although this pattern is altered by patches of irregular shapes, where the seabed is free of vegetation and which are known as seagrass meadow fairy circles. None study has addressed the irregularity of fairy circles sediments and what it implies in ecological and sedimentological terms. The present work characterizes the texture and composition of the sediment accumulated in the fairy circles and compares it with other nearby sub-environments from the samplings carried out in two locations in Mallorca, one from Menorca, and one from Girona. The results describe differences in the size of the sediment and in the composition between the interior and the margins of the fairy circles, as well as with respect to the interior of the meadow or the free accumulations of sand close to the fairy circle. As well as a differentiated spatial distribution of the sedimentary facies. The samples located inside the meadow show finer texture values associated with a predominant composition of foraminifera and undifferentiated bioclasts, while the samples more exposed to waves, such as those on the margins or inside the fairy circles, tend to retain coarser sediments associated with a larger abundance of gastropod fragments.

Primary Presenter: Lluis GOMEZ-PUJOL, University of the Balearic Islands (lgomez-pujol@uib.es)

Authors:

Eduard Cabalín, University of the Balearic Islands, Earth Sciences Research Group, Department of Biology  ()