Search results for "MORPHOLOGY"
showing 10 items of 1425 documents
Towards a quality assessment of freshwater ecosystems through the morphological analysis of phytoplankton.
2012
Among the organisms living at low Reynolds numbers, those belonging to the ecological group of phytoplankton offer an amazing morphological diversity and all the scientists involved in phytoplankton research have commonly observed that they may express a quite high variability, both intra- and inter-specific, in their size and morphology. These features have been traditionally used just for taxonomic classification. However, the ecological value of morphological descriptors in phytoplankton is increasingly used to investigate their abilities in resource (light and nutrients) uptake as a result of natural selection and competition. At the same time, the analysis of suitable morphology and si…
Steady-state assemblages in a Mediterranean hypertrophic reservoir. The role of Microcystis ecomorphological variability in maintaining an apparent e…
2003
Lake Arancio is a hypertrophicMediterranean man-made lake, located on the southern coast of Sicily. Its artificial origin and the climate make it a very dynamic environment, strongly characterised by very wide water-level fluctuations. These vertical water movements interfere with the thermal stability of the water body often causing the breaking of the thermocline in mid-summer. In addition, the summer level-decrease influences the nutrient dynamics and modifies the zmix/zeu ratio. All these modifications were observed to support a high environmental variability, which was reflected by the richness of its phytoplankton composition and by its dynamics. Nevertheless, an investigation carried…
A taxonomic revision of western Eupholidoptera bush crickets (Orthoptera: Tettigoniidae): testing the discrimination power of DNA barcode.
2014
The genus Eupholidoptera includes 46 Mediterranean species distributed from Turkey to Greece, Italy and southern France. In the eastern part of its range, Eupholidoptera has been considered to consist of several distinct species, while in the Balkans and Italian peninsula only E. chabrieri has been recognized. However, the status of some Italian populations, confined to particular geographic areas, remains uncertain. To investigate the delimitation of the Italian taxa of Eupholidoptera, we performed both morphological and molecular analyses. Morphological analysis was carried out by considering diagnostic characters usually used to distinguish different taxa, such as the shape of titillator…
In spermatozoa collected after pellet swim up, when total dna fragmentation is higher than 15%, the normal morphologically spermatozoa population sho…
2020
Study question: We investigated the DNA Fragmentation Index (DFI) in motile normal morphologically spermatozoa comparing samples with total DFI < 15% Vs ≥ 15% collected after pellet swim up Summary answer: In the case of DFI ≥15% the percentage of normal morphologically spermatozoa with fragmented DNA is significantly higher than the population with DFI < 15% What is known already: Intracytoplasmic sperm injection (ICSI) is widely used in the treatment of male infertility. Only morphologically normal spermatozoa are mainly used by embryologists to fertilize an oocyte. Different papers have reported that spermatozoa with apparently normal morphology may have DNA fragmentation. These ev…
Cool barnacles: Do common biogenic structures enhance or retard rates of deterioration of intertidal rocks and concrete?
2017
Sedentary and mobile organisms grow profusely on hard substrates within the coastal zone and contribute to the deterioration of coastal engineering structures and the geomorphic evolution of rocky shores by both enhancing and retarding weathering and erosion. There is a lack of quantitative evidence for the direction and magnitude of these effects. This study assesses the influence of globally-abundant intertidal organisms, barnacles, by measuring the response of limestone, granite and marine-grade concrete colonised with varying percentage covers of Chthamalus spp. under simulated, temperate intertidal conditions. Temperature regimes at 5 and 10 mm below the surface of each material demons…
The influence of light attenuation on the biogeomorphology of a marine karst cave: A case study of Puerto Princesa Underground River, Palawan, the Ph…
2015
Karst caves are unique biogeomorphological systems. Cave walls offer habitat for microorganisms which in-turn have a geomorphological role via their involvement in rock weathering, erosion and mineralisation. The attenuation of light with distance into caves is known to affect ecology, but the implications of this for biogeomorphological processes and forms have seldom been examined. Here we describe a semi-quantitative microscopy study comparing the extent, structure, and thickness of biocover and depth of endolithic penetration for samples of rock from the Puerto Princesa Underground River system in Palawan, the Philippines, which is a natural UNESCO World Heritage Site.\ud \ud Organic gr…
Comparing marine geology and coastal geomorphology vertical tectonic data, a case study between Acquedolci and Patti (Messina)
2011
The study of new data on vertical movements show a complex geologic response in a restricted sector of coastal area between Acquedolci and Patti (north-eastern Sicily). Different surveys allowed to the recognition of morphological, biological and archaeological markers of paleo-sea level. The analysis of these markers and the absolute datings performed, allowed to reconstruct the history of vertical deformation of this sector but only the comparison among coastal geomorphological data and marine geological data of platform-scarp continental system associates, allowed to find the necessary keys words to explain the geologic complexity of this sector.
Spatial extent of recent vertical tectonic motions misured in NE Sicily coastal area. Insights from marine geology and coastal geomorphology studies.
2011
Vertical position of sea-level, pointed out by related deposits and morphologies, provide useful markers to estimate tectonic uplift rates. For the Holocene very high uplift rates are misured in the northeast Sicily coast (Antonioli et al., 2009). This study compare vertical tectonic movements and marine geology data in the coastal sector between Capo d’Orlando and Brolo (NE Sicily); tectonic lineaments show different trends both onland (Nigro & Sulli, 1995) and offshore (Nicolich et al.,1982) and also the morphological response follow closely this difference. The geomorphologic survey provided data on Holocene uplift rates. We studied an archaeological ancient quarry of grinding wheels for…
Geomorphological and Morphometric Analyses of the Catanzaro Trough (Central Calabrian Arc, Southern Italy): Seismotectonic Implications
2022
In this work, we investigated the landscape response to the recent activity of the faults affecting the Catanzaro Trough, a seismically active structural basin that developed transversally to the Calabrian Arc (Southern Italy) during the Neogene–Quaternary. We carried out a geomorphological and morphometric study of the drainage networks and basins intercepted by the Quaternary faults that were previously mapped through remote and field analyses. The study confirms the occurrence north of the Catanzaro Trough of a WNW–ESE-oriented left-lateral strike-slip fault system (here named the South Sila Piccola Fault System), which accommodates the differential SE-ward migration of the u…
Identification and assessment of geosites for territorial enhancement – the study and geoheritage exploitation of the Torre Salsa natural reserve (Si…
2014
The “Ecological Cross-‐border Networks Malta-‐Sicily” (RE.MA.SI.) is an international research project founded by the Italia-‐Malta 2007-‐2013 Programme. A part of the project aims to carry out a multidisciplinary study for the identification and enhancement of geosites in the Maltese Islands and Sicily. Some areas have been picked out; these areas are spectacular and interesting for the tourists and can make a significant contribution to the understanding the geological and geomorphological history. Field surveys took place for the identification and classification of the most significant geomorphosites and the verification of the collected bibliographical data; in particular, the iden…