Search results for "Mediterranean."
showing 10 items of 3129 documents
Temporal speciation pattern in the western Mediterranean genus Tudorella P. Fischer, 1885 (Gastropoda, Pomatiidae) supports the Tyrrhenian vicariance…
2009
The land snail genus Tudorella shows a peculiar disjunct distribution around the western Mediterranean coasts. Despite high phenotypic plasticity, only two species with a disputed number of subspecific taxa are currently recognised. We delimited the species with mitochondrial (COI & 16S) and nuclear (ITS-1) markers based on the unified species concept and suggested that there are eight species in the genus, two of them currently undescribed. Applying Bayesian phylogenetic model selection, we tested four different biogeographic hypotheses that could be causal for the current distribution pattern of extant Tudorella species. A scenario involving vicariance events resulting from the repeated s…
Reviewing the identity of the Maltese Polypodium (Polypodiaceae) – new evidence from morphology and flow cytometry
2020
The first record of Polypodium from Gozo (Maltese Islands) was described as a new endemic taxon, Polypodium vulgare subsp. melitense, based on its unique set of morphological characters. It was treated as a novelty and designated as a subspecies of P. vulgare mainly due to the lack of paraphyses, the presence of 10–16 annular cells, and a mean spore length of 64 μm. The fern was reassessed by us employing a more rigid morphological analysis and the application of flow cytometry. The absence of paraphyses was confirmed, but the number of annular cells (5–11) and the spore length (70–79 μm) differed from the previous study. These and other morphological traits, the phenology (leaf-shedding in…
New records of Characeae for Sicily (Italy)
2018
During the last year, the first two authors continued their survey of the scarcely known Characeae flora of the island of Sicily: plants were collected in different periods, habitats and areas of the island, and identifications – made on fresh material – were based mainly on Mouronval et al. (2015). We had the opportunity to include here some results deriving from the visit in Sicily made by Klaus van de Weyer in March 2018. Roman Romanov identified some specimens and revised some identifications. Data for Sicily are basically limited to more than one hundred years old reports; data for the national Flora have been completed with recent reports for Sardinia (cf. the work made by Ralf Becker…
Effects of overabundant nitrate and warmer temperatures on charophytes: The roles of plasticity and local adaptation
2018
Global change effects, such as warming and increases in nitrogen loading, alter vulnerable Mediterranean aquatic systems, and charophytes can be one of the most affected groups. We addressed the possible interaction between these factors on two populations of the cosmopolitan charophytes Chara hispida and Chara vulgaris. Populations were taken from two different environments, a nitrate-poor mountain lake and a nitrate-rich Mediterranean coastal spring. The laboratory experiment had a 2 × 2 factorial design based on two nitrate levels (similar to and double the local conditions) and two temperatures. Increased temperatures favoured the growth of the four populations, but an increase in nitra…
<p class="HeadingRunIn"><strong><em>Charybdis glaucophylla</em> (Asparagaceae), a new species from Sardinia</strong><…
2012
Charybdis glaucophylla (Asparagaceae), a new species from Sardinia, is described and illustrated. It is a diploid species with 2n = 20 chromosomes growing along the rocky coast, sandy dunes and mountain top in the south-western part of the island. Within the genus, this species results taxonomically well isolated and differentiated due to relevant morphological and phenological features, such as the leaves wide and short, very rigid and glaucous-pruinose, as well as the very late foliation (winter). It shows only some relationships with C. pancration for the whitish bulb tunics and the diploid chromosome complement, and with C. maura and C. aphylla due to the glaucous leaves.
Nuevo registro y caracterización molecular de la tortuga verde Chelonia mydas (Testudines, Cheloniidae) en las aguas costeras sicilianas
2017
A juvenile specimen of the Green Turtle, Chelonia mydas, was recovered in Sicilian coastal waters close to Avola (Syracuse province, south-eastern Sicily, Italy). Before being released, the specimen was measured and inspected for the presence of ingested hooks or other possible harms to its health. A fragment of the mtDNA marker COI was amplified and sequenced in order to provide the first molecular data for the species from the central Mediterranean area. The possible influence of climate change on the occurrence of this thermophilic species in the central Mediterranean area is briefly discussed.
A new record and molecular characterization of the Green Turtle Chelonia mydas (Testudines, Cheloniidae) in Sicilian coastal waters
2017
A juvenile specimen of the Green Turtle, Chelonia mydas, was recovered in Sicilian coastal waters close to Avola (Syracuse province, south-eastern Sicily, Italy). Before being released, the specimen was measured and inspected for the presence of ingested hooks or other possible harms to its health. A fragment of the mtDNA marker COI was amplified and sequenced in order to provide the first molecular data for the species from the central Mediterranean area. The possible influence of climate change on the occurrence of this thermophilic species in the central Mediterranean area is briefly discussed.
Observations on mucus aggregates along Sicilian coasts during 1991–1992
1995
Abstract The results of some observations on gelatinous material accumulating on the sea ground and free floating in the water column along Sicilian coasts are reported. The phenomenon showed different development patterns moving from the Tyrrherian to the Jonian coast and to the Sicilian Channel. Moreover, in 1991, mucus aggregates in the Tyrrhenian sea showed a similar structure, behaviour and origin to those observed in the Adriatic sea, whereas, in 1992, only a massive growth of metaphytic threadlike algae, more or less producing gelatinous sheaths, occurred.
Identification and climatology of cut-off lows near the tropopause.
2008
Cut-off low pressure systems (COLs) are defined as closed lows in the upper troposphere that have become completely detached from the main westerly current. These slow-moving systems often affect the weather conditions at the earth's surface and also work as a mechanism of mass transfer between the stratosphere and the troposphere, playing a significant role in the net flow of tropospheric ozone. In the first part of this work we provide a comprehensive summary of results obtained in previous studies of COLs. Following this, we present three long-term climatologies of COLs. The first two climatologies are based on the conceptual model of a COL, using European Centre for Medium-range Weather…
How diffusivity, thermocline and incident light intensity modulate the dynamics of Deep Chlorophyll Maximum in Tyrrhenian Sea
2015
During the last few years theoretical works have shed new light and proposed new hypotheses on the mechanisms which regulate the spatio-temporal behaviour of phytoplankton communities in marine pelagic ecosystems. Despite this, relevant physical and biological issues, such as effects of the time- dependent mixing in the upper layer, competition between groups, and dynamics of non-stationary deep chlorophyll maxima, are still open questions. In this work, we analyze the spatio-temporal behaviour of five phytoplankton populations in a real marine ecosystem by using a one-dimensional reaction-diffusion-taxis model. The study is performed, taking into account the seasonal variations of environm…