Search results for "SHALLOW"
showing 10 items of 144 documents
Cyclostratigraphy and high-frequency carbon isotope fluctuations in Upper Cretaceous shallow-water carbonates, southern Italy
2002
A detailed carbon isotope study has been carried out on a Santonian (Upper Cretaceous) carbonate platform succession that crops out at Monte Sant'Erasmo (southern Italy). Previous centimetre-scale studies on this succession have shown that high-frequency eustatic changes, resulting from the Earth's orbital fluctuations, controlled the hierarchical organization of the depositional and early diagenetic features in elementary cycles, bundles (groups of three to five elementary cycles) and superbundles (groups of three or four bundles). The elementary cycles, which correspond to single beds, suggest a control caused by Earth's precession; the bundles and superbundles record the short ( 100 kyr)…
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…
Temporal and spatial variation of the algal community in a southern Mediterranean shallow system
2010
The algal community of a shallow system located in Western Sicily (Mediterranean Sea) has been investigated over 1 year in eight ponds (fredde). The spatio-temporal variation in total algal coverage, species richness and coverage in relation to environmental variables has been analysed. The algal community was very species-poor. A total of 50 taxa, mainly detached algae, were identified. A dominance of filamentous and foliose taxa was observed. Significant spatio-temporal differences in total algal coverage, species richness and coverage between the ponds of group A and those of group B were found. The separation into groups A and B was made a priori on the basis of different levels of prox…
Filtration pressure by bivalves affects the trophic conditions in Mediterranean shallow ecosystems
2009
Bivalve filtration may control the amount of seston in coastal waters, reducing local euthrophication and keeping degrading phenomena like hypoxia and anthropogenic pollution under control. Two Sicilian brackish-marine ponds (Ganzirri and Faro) present us with the opportunity to gain data on the effect of bivalve filtration on the amount of particulate organic matter in the field. The cultivation of bivalves has been carried out in both of the ponds since the early 1990s but stopped in Ganzirri in 1995.We tested whether the cessation of bivalve cultivation influenced features of organic matter available to suspension feeders (total suspended matter, its inorganic and organic fractions, chlo…
The new Lessepsian entry Brachidontes pharaonis (Fischer P., 1870) (Bivalvia, Mytilidae) in the western Mediterranean: A physiological analysis under…
2000
The feeding behavior of Brachidontes pharaonis (Mollusca, Bivalvia), a new Lessepsian entry in the western Mediterranean, living in a cooling vat of a saltworks system in western Sicily, was assessed by estimating its physiological rates throughout a 6 month-long study (May 1998 to March 1999). Clearance, filtration, ingestion, and food absorption rates were estimated using the biodeposition method and the results correlated to variations in temperature, salinity, and quality and quantity of available food. Measured seston concentrations were on average 81.5 ± 95.5 mg L-1, its labile fraction (estimated as the sum of particulate lipids, carbohydrates and proteins) was on average 0.55 ± 0.07…
Study of the trophic and functional organization of fish assemblages in submarine shallow CO₂ vents
2014
Naturally acidified marine ecosystems are currently investigated to evaluate the effects of ocean acidification on species, communities and ecological processes. Among these, submarine shallow CO₂ vents represent a sort of natural mesocosms, where at small spatial scales marked gradient of pH are present. The aim of this project is to study the responses of fish assemblages to pH reduction in Mediterranean shallow CO₂ vents by using several descriptors such as community structure, trophic organization, chemical characteristics and composition of carbonic structures. Moreover as in CO₂ vents concentration and bio-availability of several trace elements, also toxic ones, may increase due to di…
Linking the effects of the Global Change to biodiversity and ecosystem services in shallow waters
2010
The genus Ruppia L. (Ruppiaceae) in the Mediterranean region: An overview
2015
Abstract This paper reviews the current knowledge on the diversity, distribution and ecology of the genus Ruppia L. in the Mediterranean region. The genus Ruppia, a cosmopolitan aquatic plant complex, is generally restricted to shallow waters such as coastal lagoons and brackish habitats characterized by fine sediments and high salinity fluctuations. In these habitats Ruppia meadows play an important structural and functional role. Molecular analyses revealed the presence of 16 haplotypes in the Mediterranean region, one corresponding to Ruppia maritima L., and the others to various morphological forms of Ruppia cirrhosa (Petagna) Grande, all together referred to as the “R. cirrhosa s.l. co…
The shallow seagrass system in Southern Mediterranean (Sicily, Italy): a large sink of organic matter available to upper consumers.
2006
The effects of human activities related to salt production on the global complexity of a shallow hyperhaline system (Sicily, Italy) were investigated. This through monitoring dynamics of some physical, chemical and trophic factors recognised as main constraints for the origin of organic matter and its availability to apex consumers. The system was dominated by seagrass Ruppia cirrhosa and large stands of macroalga Chaetomorpha linum; isopods and gasteropods were the most abundant taxa among benthic organisms, while Aphanius fasciatus and Atherina boyeri represented up to 90% of all catch among the small resident fishes. Ruppia could function as a multidimensional framework able to increase …