0000000000744055
AUTHOR
S Calvo
Descriptors of Posidonia oceanica meadows: Use and application
This work benefited partly from the financial support of the European program ΓNTERREG IIIA Corsica, Sardinia. Tuscany
Signs of local adaptation by genetic selection and isolation promoted by extreme temperature and salinity in the Mediterranean seagrass Posidonia oceanica
Adaptation to local conditions is known to occur in seagrasses; however, knowledge of the genetic basis underlying this phenomenon remains scarce. Here, we analysed Posidonia oceanica from six sites within and around the Stagnone di Marsala, a semi-enclosed coastal lagoon where salinity and temperature exceed the generally described tolerance thresholds of the species. Sea surface temperatures (SSTs) were measured and plant samples were collected for the assessment of morphology, flowering rate and for screening genome-wide polymorphisms using double digest restriction-site-associated DNA sequencing. Results demonstrated more extreme SSTs and salinity levels inside the lagoon than the outer…
The suitability of a topographical instrument for an integrated approach to the cartography of posidonia-oceanica meadows
A large-scale map of the phytobenthic communities and, in particular, of the Posidonia oceanica meadow in the Bay of Mondello (Palermo, Italy) was made. The map was set up from aerial photography, which was verified by divers along ground-lines. The upper limit of the underwater vegetation, with special reference to the Posidonia oceanica meadow, was accurately located using a geodimeter. This topographical instrument proved to be very useful in realizing such cartography.
Study on Posidonia oceanica (L.) Delile roots growing on different substrata by isto-anatomical and micro-morphological analysis
Posidonia oceanica (L.) Delile grows on different substratum types, ranging from sand, which is easily penetrable by the roots, to rock, in which they are able to enter through crevices (1). In this study a survey was carried out on roots of plagiotropic rhizomes growing on sand (matte), and rock (dolonstone and calcarenite), to assess difference in morphological and anatomical features. In particular, for each substratum, nine rhizomes were randomly sampled by scuba diver at 10 meters of depth. In each rhizome histological and morphometric data (2, 3) were recorded on roots up to the second lateral order. Roots on rock were isolated from their substratum by chemical dissolution. Data analy…