Search results for "ecosystem"
showing 10 items of 1752 documents
Effects of fish-farm biodeposition on periphyton assemblages on artificial substrates in the southern Tyrrhenian Sea (Gulf of Castellammare, Sicily)
2007
An algal assemblage growing on artificial substrata of fish-farm cages was investigated. Specifically, algal response to the effects of fish-farm facilities was studied, in order to identify a possible future descriptor of biodeposition impact. Some sites were positioned upstream of the farms (at least 750 m; ‘controls’) and other sites were positioned downstream of the farms (‘impacts’). All sites were situated in the Tyrrhenian Sea. Control and impact sites differed significantly with regard to the dissolved nutrient profile. The fouling community (samples were scraped from buoys) displayed a reduction gradient in diversity which increased with the effect of fish farms. A total of 51 taxa…
Short-term exposure to concurrent biotic and abiotic stressors may impair farmed molluscs performance
2022
Global warming, through increasing temperatures, may facilitate the spread and proliferation of outbreak-forming species which may find favourable substrate conditions on artificial aquaculture structures. The presence of stinging organisms (cnidarian hydroids) in the facilities fouling community are a source of pollution that can cause critical problems when in-situ underwater cleaning processes are performed. Multiple stressor experiments were carried out to investigate the cumulative effect on farmed mussels' functional traits when exposed to realistic stressful conditions, including presence of harmful cnidarian cells and environmental conditions of increasing temperature and short-term…
The impact of climate change on Mediterranean intertidal communities: losses in coastal ecosystem integrity and services
2014
As has been shown for other ecosystems, the ecological and socio-economic impacts of climate change on Mediterranean intertidal habitats are highly variable in space and time. We conducted field and laboratory measurements of cellular, ecophysiological and behavioural responses of selected intertidal invertebrates (mussels, gastropods and sponges) and completed a literature review to determine what is known of socioeconomic consequences of these biological changes. Results suggest significant gaps in our knowledge that may impede a complete understanding of likely impacts (physical, biological, and socioeconomic) and that sufficient data for such an analysis is available only for mussels. A…
Bridging the knowledge gap on the distribution and typology of vermetid bioconstructions along the Maltese coastline : an updated assessment
2022
In the Maltese Islands, insufficient attention has been paid to vermetid reefs, endemic Mediterranean bioconstructions widely distributed along the southern part of the basin. As a result, this is a largely-overlooked coastal ecosystem despite the multitude of ecosystem services it provides. The perennial urban development in the Maltese Islands calls for the adoption of urgent action to protect coastal habitats, in particular bioconstructions that increase biodiversity and contribute to mitigating the effects of climate change. The objective of our study was to extensively document the presence and typology of the vermetid reef ecosystems along the coast of Malta and Gozo, assessing the oc…
Predicting the current and future global distribution of the invasive freshwater hydrozoan Craspedacusta sowerbii
2021
AbstractThe freshwater jellyfish Craspedacusta sowerbii is one of the most widespread invasive species, but its global distribution remains uncertain due to ephemeral appearances and general lack of information in various aquatic environments. The aim of this study was to map current and future distributions (2050 and 2100) using Species Distribution Models allowing to visualize the habitat suitability and make projections of its changes under potential climate change scenarios. Except in Oceania where the range decreased, an expansion of C. sowerbii was projected during the next century under modeled future scenarios being most intensive during the first half of the century. The present st…
Year-round variation in the isotopic niche of Scopoli's shearwater (Calonectris diomedea) breeding in contrasting sea regions of the Mediterranean Sea
2022
Top marine predators are key components of marine food webs. Among them, long-distance migratory seabirds, which travel across different marine ecosystems over the year, may experience important year-round changes in terms of oceanographic conditions and availability of trophic resources. We tested whether this was the case in the Scopoli’s shearwater (Calonectris diomedea), a trans-equatorial migrant and top predator, by sampling birds breeding in three environmentally different regions of the Mediterranean Sea. The analysis of positional data and stable isotopes (δ13 C and δ15N) of target feathers revealed that birds from the three regions were spatially segregated during the breeding per…
Inorganic carbon physiology underpins macroalgal responses to elevated CO2
2017
Beneficial effects of CO2 on photosynthetic organisms will be a key driver of ecosystem change under ocean acidification. Predicting the responses of macroalgal species to ocean acidification is complex, but we demonstrate that the response of assemblages to elevated CO2 are correlated with inorganic carbon physiology. We assessed abundance patterns and a proxy for CO2:HCO3− use (δ13C values) of macroalgae along a gradient of CO2 at a volcanic seep, and examined how shifts in species abundance at other Mediterranean seeps are related to macroalgal inorganic carbon physiology. Five macroalgal species capable of using both HCO3− and CO2 had greater CO2 use as concentrations increased. These s…
Fish-seastar facilitation leads to algal forest restoration on protected rocky reefs
2015
AbstractAlthough protected areas can lead to recovery of overharvested species, it is much less clear whether the return of certain predator species or a diversity of predator species can lead to re-establishment of important top-down forces that regulate whole ecosystems. Here we report that the algal recovery in a Mediterranean Marine Protected Area did not derive from the increase in the traditional strong predators, but rather from the establishment of a previously unknown interaction between the thermophilic fish Thalassoma pavo and the seastar Marthasterias glacialis. The interaction resulted in elevated predation rates on sea urchins responsible for algal overgrazing. Manipulative ex…
Highly contaminated areas as sources of pollution for adjoining ecosystems: The case of Augusta Bay (Central Mediterranean).
2014
An assessment of trace element and polycyclic aromatic hydrocarbon (PAH) contamination based on surface sediments collected in summer 2012 was carried out in Priolo Bay adjoining one of the most polluted areas of the Mediterranean Sea, the industrial Augusta harbour (Italy, Central Mediterranean). Inorganic and organic contaminants were generally not remarkable. Occasional elevated concentrations of Hg, Cd, Ni and PAHs exceeding sediment quality guidelines were detected in the northern sector of Priolo Bay, close to Augusta harbour, possibly as a result of water drainage of industrialised and urbanised areas and/or potential direct export of contaminated material from Augusta harbour, whose…
Analysis of stable carbon and nitrogen isotopes as a tool for assessing the environmental impact of aquaculture: a case study from the western Medite…
2005
Stable carbon and nitrogen isotope ratios ( 13C/ 12 C and 15N/14 N) of in situ dominant primary producers and consumers were investigated to assess the impact on a natural ecosystem of a land-based fish farm along the south-western coast of Sicily (Italy). The putatively impacted area close to the farm along outfall was compared with other locations at increasing distances from the outfall. Carbon and mainly nitrogen stable isotopes revealed evidence of widespread aquaculture waste in the study site: benthic organisms collected in the impacted area showed more enriched δ 15N signatures than those at greater distances from the outfall, suggesting a large contribution of aquaculture waste to …