Search results for "Seagra"

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…

Effect of substrate and seagrass habitat complexity on detritus colonization and decomposition in a Mediterranean coastal lagoon (Thau Lagoon, France…

2019

Coherent flow and turbulence structures in fragmented meadows of the mediterranean seagrass posidonia oceanica

2004

Kelimpahan Makrozoobentos di Daerah Bervegetasi (Lamun) dan Tidak Bervegetasi di Teluk Doreri Manokwari

2017

Makrozoobentos di daerah bervegetasi (lamun) memiliki kepadatan yang lebih tinggi yaitu berkisar antara 0,070-0,085 ind/2738,06 cm3, dibandingkan dengan pada daerah yang tidak bervegetasi yaitu berkisar antara 0,035-0,067 ind/2738,06 cm3. Angka ini juga dibuktikan dengan uji t yang menunjukkan H1 diterima yang berarti ada perbedaan yang nyata antara kepadatan makrozoobentos yang ditemukan di daerah bervegetasi dan daerah tidak bervegetasi. Jumlah spesies yang ditemukan di daearah bervegetasi dengan alat corer di Teluk Doreri adalah 113 spesies dan di daerah tidak bervegetasi ditemukan 57 spesies.

Lulwoana sp., a dark septate endophyte (DSE) in roots of Posidonia oceanica (L.) Delile seagrass

2014

Posidonia oceanica is the most common, widespread and important monocotyledon seagrass in the Mediterranean Basin, and hosts a large biodiversity of species, including microorganisms with key roles in the marine environment. In this study, we ascertain the presence of a fungal endophyte in the roots of P. oceanica growing on different substrata (rock, sand and matte) in two Sicilian marine meadows. Staining techniques on root fragments and sections, in combination with microscope observations, were used to visualise the fungal presence and determine the percentage of fungal colonisation (FC) in this tissue. In root fragments, statistical analysis of the FC showed a higher mean in roots anch…

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…

Competition between algae and seagrasses: a Ruppia cirrhosa (Petagna) Grande bed in western Mediterranean Sea

2007

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…