CNR Institute for Coastal Marine Environment
Naples, Italy
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Domenici P.,CNR Institute for Coastal Marine Environment | Steffensen J.F.,Copenhagen University | Marras S.,CNR Institute for Coastal Marine Environment
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2017

Low-oxygen areas are expanding in the oceans as a result of climate change. Work carried out during the past two decades suggests that, in addition to impairing basic physiological functions, hypoxia can also affect fish behaviour. Given that many fish species are known to school, and that schooling is advantageous for their survival, the effect of hypoxia on schooling behaviour may have important ecological consequences. Here, we review the effects of hypoxia on school structure and dynamics, together with the mechanisms that cause an increase in school volume and that ultimately lead to school disruption. Furthermore, the effect of hypoxia generates a number of trade-offs in terms of schooling positions and school structure. Field observations have found that large schools of fish can exacerbate hypoxic conditions, with potential consequences for school structure and size. Therefore, previous models that predict the maximum size attainable by fish schools in relation to oxygen levels are also reviewed. Finally, we suggest that studies on the effect of hypoxia on schooling need to be integrated with those on temperature and ocean acidifications within a framework aimed at increasing our ability to predict the effect of multiple stressors of climate change on fish behaviour. © 2017 The Author(s) Published by the Royal Society. All rights reserved.

In aquatic microbial ecology, knowledge of the processes involved in the turnover of organic matter is of utmost importance to understand ecosystem functioning. Microorganisms are major players in the cycling of nutrients (nitrogen, phosphorus) and carbon, thanks to their enzymatic activities (leucine aminopeptidase, LAP, alkaline phosphatase, AP, and β-glucosidase, β-GLU) on organic polymers (proteins, organic phosphates and polysaccharides, respectively). Estimates of the decomposition rates of organic polymers are performed using fluorogenic compounds, whose hydrolysis rate allow us to obtain information on the "potential" metabolic activity of the prokaryotic community. This paper refers the enzyme patterns measured during recent oceanographic cruises performed in some coastal Mediterranean sites, not yet fully investigated in terms of microbial biogeochemical processes. Mean enzyme activity rates ranged from 5.24 to 5558.1 nM/h, from 12.68 to 244.73 nM/h and from 0.006 to 9.51 nM/h for LAP, AP and β-GLU, respectively. The highest LAP and AP activity rates were measured in the Gulf of Milazzo (Tyrrhenian Sea) and in the Straits of Messina, in association with the lowest bacterioplankton abundance; in contrast, the lowest ones were found in the northern Adriatic Sea. β-GLU was more active in the Straits of Messina. Activity rates were analysed in relation to the main environmental variables. Along the northern Adriatic coastal side affected by the Po river, significant inverse relationships linked LAP and AP with salinity, pointing out that fluvial inputs provided organic substrates for microbial metabolism. Both in the Gulf of Manfredonia and in the Straits of Messina, LAP and AP levels were inversely related with the concentration of nitrate and inorganic phosphorus, respectively. In the Gulf of Milazzo, high cell-specific AP measured in spite of phosphorus availability suggested the role of this enzyme not only in phosphorus, but also in carbon release. © 2010 by the authors; licensee Molecular Diversity Preservation International.

Killen S.S.,University of Glasgow | Marras S.,CNR Institute for Coastal Marine Environment | Nadler L.,University of California at San Diego | Domenici P.,CNR Institute for Coastal Marine Environment
Philosophical Transactions of the Royal Society B: Biological Sciences | Year: 2017

Individuals of gregarious species often group with conspecifics to which they are phenotypically similar. This among-group assortment has been studied for body size, sex and relatedness. However, the role of physiological traits has been largely overlooked. Here, we discuss mechanisms by which physiological traits—particularly those related to metabolism and locomotor performance—may result in phenotypic assortment not only among but also within animal groups. At the among-group level, varying combinations of passive assortment, active assortment, phenotypic plasticity and selective mortality may generate phenotypic differences among groups. Even within groups, however, individual variation in energy requirements, aerobic and anaerobic capacity, neurological lateralization and tolerance to environmental stressors are likely to produce differences in the spatial location of individuals or associations between group-mates with specific physiological phenotypes. Owing to the greater availability of empirical research, we focus on groups of fishes (i.e. shoals and schools). Increased knowledge of physiological mechanisms influencing among- and within-group assortment will enhance our understanding of fundamental concepts regarding optimal group size, predator avoidance, group cohesion, information transfer, life-history strategies and the evolutionary effects of group membership. In a broader perspective, predicting animal responses to environmental change will be impossible without a comprehensive understanding of the physiological basis of the formation and functioning of animal social groups. © 2017 The Authors.

Watson S.A.,James Cook University | Watson S.A.,University of Oslo | Watson S.A.,CNR Institute for Coastal Marine Environment
Proceedings. Biological sciences / The Royal Society | Year: 2014

Ocean acidification poses a range of threats to marine invertebrates; however, the potential effects of rising carbon dioxide (CO2) on marine invertebrate behaviour are largely unknown. Marine gastropod conch snails have a modified foot and operculum allowing them to leap backwards rapidly when faced with a predator, such as a venomous cone shell. Here, we show that projected near-future seawater CO2 levels (961 μatm) impair this escape behaviour during a predator-prey interaction. Elevated-CO2 halved the number of snails that jumped from the predator, increased their latency to jump and altered their escape trajectory. Physical ability to jump was not affected by elevated-CO2 indicating instead that decision-making was impaired. Antipredator behaviour was fully restored by treatment with gabazine, a GABA antagonist of some invertebrate nervous systems, indicating potential interference of neurotransmitter receptor function by elevated-CO2, as previously observed in marine fishes. Altered behaviour of marine invertebrates at projected future CO2 levels could have potentially far-reaching implications for marine ecosystems.

Di Fiore V.,CNR Institute for Coastal Marine Environment
Engineering Geology | Year: 2010

This study concerns the evaluation of seismic site effects and their relation to the local topographical characteristics of a slope. The seismic amplification (SA) on the free surface is calculated by a numerical model using the finite elements (FE) method. Synthetic models by utilized in the FE analysis represent a slope with an inclination ranging from 10° to 41°. At the crest and valley of the slope the models were considered horizontal and indefinite. The site effects were calculated on the free surface in several nodal points. The input motion used in the analysis was a SV seismic wave with variable frequency between 0.5 and 32. Hz. The seismic site analysis confirmed that in absence of sediments, ground motion is more amplified at the upper slope break than in other points of the model.In regard to seismic amplification vs. the frequency we can affirm that seismic amplification reaches its maxima in the band 4-16. Hz and with slope angle value computed at the highest degree. It is also clear that a nonlinear seismic amplification response in the crest and valley zone while SA would seem to have a linear response in other zones. We propose an empirical method to estimate the SA in the regular slope far from the crest and valley zone. © 2010 Elsevier B.V.

Domenici P.,CNR Institute for Coastal Marine Environment
Journal of Experimental Zoology Part A: Ecological Genetics and Physiology | Year: 2010

Escape responses are used by most fish species in order to avoid predation. Escape responses include a number of behavioral and kinematic components, such as responsiveness, reaction distance, escape latency, directionality, and distance-derived performance. All of these components can contribute to escape success. Work on the context-dependent variability has focused on reaction distance, and suggests that this component is largely determined by the relative cost and benefits of escaping (economic hypothesis). For example, reaction distance was found to depend on many factors related to perceived risk and cost of escaping, such as the attack speed and size of the predators, the proximity to refuges, and engagement in other activities (e.g., feeding). Evidence from many behavioral, kinematic, and physiological studies suggest that performance in other components of the escape response is also not always maximized. For example, escape latencies may increase in the presence of schooling neighbors, and escape speed is higher in fish that have been subject to higher predation pressure. In addition, all escape components are further modulated by the effect of environmental factors. Variability in escape components can be interpreted by using both ultimate and proximate explanations, for example, the effect of stimulus strength on escape latency can be interpreted as the triggering neural threshold varying with stimulus strength (proximate explanation) and high intensity stimuli representing higher risk to the prey (ultimate explanation). An integrative approach is suggested for a full, ecologically relevant, assessment of escape performance in fish. © 2010 Wiley-Liss, Inc.

Killen S.S.,University of Glasgow | Marras S.,CNR Institute for Coastal Marine Environment | Metcalfe N.B.,University of Glasgow | McKenzie D.J.,Montpellier University | Domenici P.,CNR Institute for Coastal Marine Environment
Trends in Ecology and Evolution | Year: 2013

Although correlations have frequently been observed between specific physiological and behavioural traits across a range of animal taxa, the nature of these associations has been shown to vary. Here we argue that a major source of this inconsistency is the influence of environmental stressors, which seem capable of revealing, masking, or modulating covariation in physiological and behavioural traits. These effects appear to be mediated by changes in the observed variation of traits and differential sensitivity to stressors among phenotypes. Considering that wild animals routinely face a range of biotic and abiotic stressors, increased knowledge of these effects is imperative for understanding the causal mechanisms of a range of ecological phenomena and evolutionary responses to stressors associated with environmental change. © 2013.

Allan B.J.,James Cook University | Allan B.J.,CNR Institute for Coastal Marine Environment
Proceedings. Biological sciences / The Royal Society | Year: 2014

Rising CO2 levels in the oceans are predicted to have serious consequences for many marine taxa. Recent studies suggest that non-genetic parental effects may reduce the impact of high CO2 on the growth, survival and routine metabolic rate of marine fishes, but whether the parental environment mitigates behavioural and sensory impairment associated with high CO2 remains unknown. Here, we tested the acute effects of elevated CO2 on the escape responses of juvenile fish and whether such effects were altered by exposure of parents to increased CO2 (transgenerational acclimation). Elevated CO2 negatively affected the reactivity and locomotor performance of juvenile fish, but parental exposure to high CO2 reduced the effects in some traits, indicating the potential for acclimation of behavioural impairment across generations. However, acclimation was not complete in some traits, and absent in others, suggesting that transgenerational acclimation does not completely compensate the effects of high CO2 on escape responses.

Milia A.,CNR Institute for Coastal Marine Environment
Special Paper of the Geological Society of America | Year: 2010

Seismic stratigraphic analysis of a submarine volcanic field allows the recognition of complex stratal architecture due to the interplay between the syneruptive and intereruptive stratigraphic units. This approach was applied to the offshore Campi Flegrei, eastern Tyrrhenian Sea margin. The area features Late Quaternary volcanism, shallow magmatic intrusions, and thick intereruptive volcaniclastic wedges. Seismic stratigraphic analysis is constrained by marker seismic reflectors defining volcanic boundaries and tied to wells drilled in Naples city, cropping out volcanic units, and a chronostratigraphic framework recognized within the Bay of Naples succession. On the basis of seismic configuration, it was possible: (1) to detect various typologies of magmatic features, such as scoria cones, tuff cones, domes, dikes, and pyroclastic flows; (2) to recognize three types of unconformities; and (3) to reconstruct the relation between monogenetic volcanoes and intereruptive sedimentary units. The eruptions of monogenetic volcanoes deeply modified the paleogeography of the Bay of Naples, transforming an intraslope basin into smaller basins separated by volcanic ridges. The former were successively filled during the intereruptive periods. The sediments eroded in the shoreface and subaerial environment were deposited along the volcano margins. Prograding wedges were deposited during the fall of sea level and filled the seaways between volcanoes, whereas during the rising of the sea level, deposition migrated toward the volcano crater until the latter were drowned below sea level. This paper defines the stratigraphic evolution of the south margin of the Campi Flegrei volcanic field and provides both an example of seismostratigraphic analysis in a complex volcanic area and additional data for the volcanologic interpretation of the Campi Flegrei. © 2010 The Geological Society of America. All rights reserved.

Prato E.,CNR Institute for Coastal Marine Environment | Biandolino F.,CNR Institute for Coastal Marine Environment
Food Chemistry | Year: 2012

The fatty acid (FA) profiles of 11 commercially important fish species from the sea of Southern Italy (Mar Grande Sea) were investigated. The results showed significant differences among the fatty acid profiles of the examined fish (p < 0.05). A relatively high proportion of n - 3 polyunsaturated fatty acids (PUFAs), of which more than 70% were accounted by docoesahexaenoic acid (DHA) and eicoesapentaenoic acid (EPA) in salema, bogue, common two-banded seabream and sand smelt, and lower proportions of oleic acid (C18:1n - 9) and palmitic acid (C16:0) also dominating. The percentages of EPA and DHA were between 5.03-8.61% and 9.85-17.39% of total lipid, respectively. The results showed that the fish examined are a good source of n - 3 PUFAs, resulting in a very favourable n3 - n6 ratio, especially in salema, sand smelt, common two-banded seabream and picarel. © 2011 Elsevier Ltd. All rights reserved.

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