Papers by Claudio Provenzani
Marine Pollution Bulletin
An interesting site for the wider population of the coral Dendrophyllia ramea has been identified... more An interesting site for the wider population of the coral Dendrophyllia ramea has been identified south-east of Syracuse (Sicilia Channel, Ionian Sea) at 75 water depth. Dendrophyllia ramea is a poorly known arborescent scleractinian coral, classified as ‘Vulnerable’ according to the Mediterranean IUCN Red List, listed in the Barcelona Convention (Annex B). To increase the knowledge about the ecology of the species, long-term in situ observations were carried out on two colonies using a specific homemade underwater recording system. D. ramea, in analogy with other Anthozoans of different environments, also showed a circadian rhythm of partial opening and closing of the polyps despite being strongly influenced by the intensity of the current. These aspects, of great interest to the ecology of this protected species, will be investigated with the aid of current meters to obtain a quantitative estimate of the intensity of the current. This project gave great results in terms of innovat...
Ecological Indicators, 2021
The coast of the Gulf of Orosei (Sardinia, Italy) consists of impressive cliffs set up on dolosto... more The coast of the Gulf of Orosei (Sardinia, Italy) consists of impressive cliffs set up on dolostones and limestones characterized by wide karst systems connected to the sea. Marine caves, which are part of these system flooded by seawater through marine entrances, may be considered as extreme environments because of wide spatial and temporal environmental variability due to changing marine and terrestrial contributions. This study presents the results of the third survey carried out in summer 2016 in the Bue Marino cave, as part of a research project started in 2014 aimed at the application of Benthic Foraminifera (BF) as ecological indicators in Mediterranean marine caves for the identification of different habitats and their environmental interpretation. Sediment and water samples were collected from a total of 25 stations from two distinct sectors of the cave (North Branch and Middle Branch); sediments were analysed for living and dead BF and grain size, while Temperature, Salinity, pH and Dissolved Oxygen were measured in water samples collected close to sediment water interface. Two main foraminiferal assemblages, with distinct characteristics with respect to the typical Mediterranean shallow-water ones, were recognized by means of Hierarchical Cluster Analysis and Non-metric Multidimensional Scaling, and a Canonical Correspondence Analysis deduced their environmental significance. A well oxygenated, less saline environment with coarse bottom sediment, correlated with a mixed calcareous-agglutinated assemblage (Gavelinopsis praegeri, Rosalina spp., Eggerelloides advenus and Reophax dentaliniformis) with high species diversity (H-index 2.32-3.57) and low foraminiferal density, was exclusive of the North Branch. A scarcely oxygenated, more saline environment with fine bottom sediment enriched in vegetal debris was related to a prevalently agglutinated assemblage characterized by low species diversity (H-index 1.60-2.68), with high dominance of E. advenus (up to 83.6%) associated to Ammonia tepida, and high foraminiferal density, recognized in the Middle Branch. These different environments were interpreted considering the different modes of feeding the karst systems of the two branches. They also corresponded to two distinct ecozones, Entrance and Confluence, already recognized in earlier studies. The environmental significance of the foraminiferal ecozones recognized in this study and their comparison with the ones identified in the previous years, helped to consider the ecological zonation as a tool for detecting seasonal and, possibly, long term annual environmental variability in the marine system. considered as natural laboratories where studying the response of such organisms to environmental variability, improving scientific knowledge on the effects of global changes. Several habitats may be recognized as extreme environments in the marine realm; they range from transitional zone to deep sea and include the intertidal belt, marshes and lagoons, hydrothermal vents, marine blue holes, but also extremely oligotrophic,
Aquatic Conservation: Marine and Freshwater Ecosystems, 2020
1. As a result of their location at the boundary between marine and continental domains, marine c... more 1. As a result of their location at the boundary between marine and continental domains, marine caves are affected by wide spatial and seasonal environmental changes. Only recently have benthic foraminifera been recognized as reliable indicators for the ecological zonation of these environments. 2. The present study is focused on two marine caves of the Orosei Gulf, Sardinia, Italy: Bue Marino and Bel Torrente. It investigates the spatial and seasonal variability of benthic foraminiferal assemblages relative to sediment grain size and water parameters (temperature, salinity, pH, and dissolved oxygen) collected during two campaigns in August 2014 and April 2015. The results from 2014 have been partially published. 3. Based on a comparison of the results of the two campaigns, the considerable reduction of foraminiferal abundance in Bel Torrente was deduced to occur because of the strong freshwater flows occurring during the rainy season; in Bue Marino, the less severe water flow allowed the identification of both living and dead foraminifera, although strongly reduced in number. These identifications allowed benthic foraminifera to be used to define the ecological zonation. 4. Entrance, confluence, and transitional ecozones were identified in Bue Marino cave on the basis of species abundance. The second ecozone, not recognized in 2014, was correlated with plant debris at the confluence of the two cave branches. The other two ecozones, which are characterized by the faunal shift from hyaline-to agglutinated-prevalent assemblages, were attributed to the gradient of abiotic parameters detected from the outer to the inner portions of the cave. In both campaigns the same ecozones were recognized in terms of species composition, with exceptions being found to different extents as a result of seasonal variability. 5. As the distribution of foraminiferal ecozones is conditioned by a decreasing gradient of marine influence, long-term monitoring may be regarded as a promising tool for future studies on sea-level change.
Marine environmental research, 2018
The use of benthic foraminifera as ecological indicators in submarine caves of temperate seas hav... more The use of benthic foraminifera as ecological indicators in submarine caves of temperate seas have never been studied before and it represents a new approach, verified by this research. The Bel Torrente submarine cave (Gulf of Orosei, Sardinia, Italy) was surveyed by GUE (Global Underwater Explorers) scuba divers in order to georeferencing the cave before positioning the sampling stations, from the entrance to 430 m inside the cave. A total of 15 water samples were collected to investigate abiotic parameters (temperature, salinity, pH) while 15 sediment samples were collected to analyze grain size and benthic foraminifera. Benthic foraminifera, investigated for the first time in a submarine cave of temperate areas, were exclusively found from the entrance to 300 m inside the cave. Species distribution and assemblage diversity have been found to be correlated to the environmental gradient towards the inner cave, mainly due to the decreasing of temperature and salinity and the increas...
Rendiconti Lincei. Scienze Fisiche e Naturali, 2018
Because submarine caves are affected by wide spatial and temporal environmental variability, they... more Because submarine caves are affected by wide spatial and temporal environmental variability, they are ideal environments for studying the effects of environmental changes on ecological indicators. Benthic foraminifera are protozoa living in marine and transitional habitats, developing typical assemblages as a response to different environmental conditions. For this, they have been increasingly used as ecological indicators for environmental characterization and monitoring. This study was the first one aimed to compare benthic foraminiferal fauna of two different submarine caves of temperate areas, Bel Torrente and Bue Marino, in the Orosei Gulf (Sardinia, Italy). It resumes the main results obtained in Bel Torrente cave by a previous research, implemented by new data acquired by the study of Bue Marino cave. The caves were surveyed and sampled by GUE (Global Underwater Explorers) divers for the first 450 m to recognize distinct ecozones, their ecological significance, and to compare them as regards species composition and extent. The succession of Marine, Entrance and Transitional Ecozones was recognized in both the caves. While the Marine Ecozone pointed out environmental conditions very similar to those of shallow water marine environment, the Entrance and Transitional Ecozones indicated increasing environmental stress. In the Entrance Ecozone, the dominance of tolerant species was probably due to the high environmental variability for the episodic high energy floods and, locally, reduced oxygenation events. In the Transitional Ecozone, the decrease of seawater salinity and temperature, especially after rainy periods, probably encouraged the prevalence of agglutinated taxa, which are normally rare in Mediterranean shallow water marine environment, while they are common in high latitude basins.
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Papers by Claudio Provenzani