Search results for " SEAGRASS"

Biodegradable anchor modular system for transplanting Posidonia oceanica cuttings

2014

Mapping Posidonia oceanica lower limit combining high resolution instruments (SSS and MBS)

2014

The use of very high-resolution images for mapping of Posidonia oceanica reef

2020

Posidonia oceanica is an endemic Mediterranean seagrass that forms wide and dense meadows from the surface up to about 40 m depth. P. oceanica can develop on matte, a typical terraced structure built up by itself, consisting of intertwined rhizomes, roots and sediment, which may allow shoots to reach the sea surface, where may form typical reefs (récif barrière) considered “natural monuments”. These structures have received increasing attention for the potential ecosystem services they provide in protecting the coasts from erosion, forming new habitats (coastal lagoons) and contributing to carbon sink. P. oceanica reefs are particularly exposed to the expected increase in temperature and to…

Large-scale Posidonia oceanica restoration in a Site of National Interest using an innovative bio-plastic transplant system

2015

Along the Italian coasts there are many areas affected by industrial activities defined as "Sites of National Interest" (SNI), which require urgent and effective remediation and restoration actions. In the framework of TETIDE project (PON01_03112 www.progettotetide.it)a restoration program was developed in SNI Priolo(Sicily) in response to a dramatic decline and regression of Posidonia oceanicameadow, caused byseveral years of petrochemical industries dumping. In particular, a large scale P. oceanicarestoration plan was carried out in four steps: (1) habitat selection, by calculation of the Preliminary Transplant Suitability Index (PTSI); (2) field assessments and test-transplanting, to eva…

Study on Posidonia oceanica (L.) Delile roots growing on different substrata by isto-anatomical and micro-morphological analysis

2016

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…

A contribution to the characterization of Ruppia drepanensis (Ruppiaceae), a key species of threatened Mediterranean wetlands

2021

To elucidate the taxonomic status of Ruppia drepanensis Tineo ex Guss. (Alismatales, Ruppiaceae), we performed morphological analysis and DNA barcoding of historical materials (including the lectotype) and fresh samples (including those from a recently discovered population near the locus classicus in Sicily, Italy). We conclude that R. drepanensis is a separate species, closely related to R. spiralis L. ex Dumort., that occurs in temporary inland waters from the western to central sectors of the Mediterranean region. We also highlight the importance of vouchers and the need to link molecular investigations to field, ecological, and morphological investigations.

Signs of local adaptation by genetic selection and isolation promoted by extreme temperature and salinity in the Mediterranean seagrass Posidonia oce…

2023

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…

CAN HALOPHILA STIPULACEA OUTCOMPETE CYMODOCEA NODOSA? A CASE STUDY OF A MEDITERRANEAN SHALLOW WATER HABITAT

2022

The tropical seagrass Halophila stipulacea (Forsskål) Ascherson entered the Mediterranean Sea through the Suez Canal more than 100 years ago. In the coastal-marine ecosystems the spatial niche of H. stipulacea is often overlapped with that of native Mediterranean Sea seagrasses and therefore it might out-compete them. On the basis of previous observations, we monitored for one year a Southern Mediterranean shallow water habitat (North-Western Sicily Island, Italy, Southern Mediterranean Sea), where H. stipulacea co-occurred with the native seagrass Cymodocea nodosa (Ucria) Ascherson. In this paper we compare sites with (impacted sites) and without H. stipulacea (non-impacted sites) to analy…

Spreading of the alien seagrass Halophila stipulacea (Hydrocharitaceae) along the sicilian coast (western Mediterranean Sea)

2009

Halophila stipulacea (Forsskål) Ascherson is a tropical seagrass distributed along the western coasts of the Indian Ocean and in the Red Sea (den Hartog, 1977). This species was previously considered a paleomediterranean element, survived as a relict in the eastern Mediterranean Sea, but later on Por (1971) hypothesized that it was a Lessepsian immigrant entered the Mediterranean Sea after the opening of the Suez Canal (1869). H. stipulacea remained in the eastern Mediterranean for several decades (Lipkin, 1975), and only recently it spreads towards the western basin through Malta and the Ionian coast of Sicily (Lanfranco, 1970; Van der Velte and Den Hartog, 1989; Alongi et al., 1993). The …

Life on the edge: Adaptations of Posidonia oceanica to hypersaline conditions in a Mediterranean lagoon system

2023

Hypersaline stress is a major stressor in semi-enclosed coastal lagoons, affecting the distribution and survival of key foundation species. In this study, we investigated how Posidonia oceanica meadows responded physiologically and morphologically to different salinity concentrations both in-situ, across a natural saline gradient occurring inside the lagoon system, and in a mesocosm experiment. Leaf water relations, organic osmolytes, photosynthesis, respiration, Chlorophyll-a fluorescence, pigments content, and leaf growth were studied in P. oceanica from three different sites within the Stagnone of Marsala lagoon, as well as after exposing P. oceanica to a salinity level of 46 psu in a 30…