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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.

Marras S.,CNR Institute for Coastal Marine Environment | Domenici P.,CNR Institute for Coastal Marine Environment
PLoS ONE | Year: 2013

Animal groups such as fish schools, bird flocks and insect swarms appear to move so synchronously that they have long been considered egalitarian, leaderless units. In schooling fish, video observations of their spatial-temporal organization have, however, shown that anti-predator manoeuvres are not perfectly synchronous and that individuals have spatial preferences within the school. Nonetheless, when facing life-or-death situations, it is not known whether schooling fish react to a threat following a random or a hierarchically-based order. Using high-speed video analysis, here we show that schooling fish (Golden grey mullet, Liza aurata) evade a threat in a non-random order, therefore individuals that are first or last to react tend to do so repeatedly over sequential stimulations. Furthermore, startle order is strongly correlated with individual positional preferences. Because school members are known to follow individuals that initiate a manoeuvre, early responders are likely to exert the strongest influence on the escape strategy of the whole school. Our results present new evidence of the intrinsic heterogeneity among school members and provide new rules governing the collective motion of gregarious animals under predator attack. © 2013 Marras, Domenici.

Domenici P.,CNR Institute for Coastal Marine Environment | Allan B.,James Cook University | McCormick M.I.,James Cook University | Munday P.L.,James Cook University
Biology Letters | Year: 2012

Elevated carbon dioxide (CO2) has recently been shown to affect chemosensory and auditory behaviour, and activity levels of larval reef fishes, increasing their risk of predation. However, the mechanisms underlying these changes are unknown. Behavioural lateralization is an expression of brain functional asymmetries, and thus provides a unique test of the hypothesis that elevated CO2 affects brain function in larval fishes. We tested the effect of near-future CO2 concentrations (880 matm) on behavioural lateralization in the reef fish, Neopomacentrus azysron. Individuals exposed to current-day or elevated CO2 were observed in a detour test where they made repeated decisions about turning left or right. No preference for right or left turns was observed at the population level. However, individual control fish turned either left or right with greater frequency than expected by chance. Exposure to elevated-CO2 disrupted individual lateralization, with values that were not different from a random expectation. These results provide compelling evidence that elevated CO2 directly affects brain function in larval fishes. Given that lateralization enhances performance in a number of cognitive tasks and anti-predator behaviours, it is possible that a loss of lateralization could increase the vulnerability of larval fishes to predation in a future high-CO2 ocean. © 2011 The Royal Society.

Marras S.,New York University | Marras S.,CNR Institute for Coastal Marine Environment | Porfiri M.,New York University
Journal of the Royal Society Interface | Year: 2012

The integration of biomimetic robots in a fish school may enable a better understanding of collective behaviour, offering a new experimental method to test group feedback in response to behavioural modulations of its 'engineered' member. Here, we analyse a robotic fish and individual golden shiners (Notemigonus crysoleucas) swimming together in a water tunnel at different flow velocities. We determine the positional preference of fish with respect to the robot, and we study the flow structure using a digital particle image velocimetry system. We find that biomimetic locomotion is a determinant of fish preference as fish aremore attracted towards the robot when its tail is beating rather than when it is statically immersed in the water as a 'dummy'. At specific conditions, the fish hold station behind the robot, which may be due to the hydrodynamic advantage obtained by swimming in the robot's wake. This workmakes a compelling case for the need of biomimetic locomotion in promoting robot-animal interactions and it strengthens the hypothesis that biomimetic robots can be used to study and modulate collective animal behaviour. © 2012 The Royal Society.

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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