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

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. Source

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

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. Source

Di Fiore V.,CNR Institute for Coastal Marine Environment
Engineering Geology

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. Source

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

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. Source

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

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. Source

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