Echinoderms, Malpelo Fauna and Flora Sanctuary, Colombian Pacific: new reports and distributional issues

A systematic list of echinoderms from Malpelo Fauna and Flora Sanctuary (MFFS) was prepared, based on local sampling, literature review and identification of specimens from Museo de Historia Natural Marina de Colombia (MHNMC) and from National Museum of Natural History, Smithsonian Institution, Washington D. C. (USNM). Standard methodology for monitoring the Eastern Tropical Pacific Seascape was used in December 2006 and March 2007 to sample shallow water echinoderms (1-20 m deep). Malpelo is the richest locality of the Colombian Pacific with 84 species reported (56 % of them deep water organisms), belonging to 22 orders, 42 families and 68 genera, distributed between the surface and a depth of 5000 m. Thirty-six new records for MFFS and Colombian Pacific are reported. In Colombia the shallow water species are widely distributed in the Pacific, while deep forms only occur at Malpelo. The majority of species are mostly related to the Panamanian and Galapagos region showing a possible connectivity. This list increases knowledge on the echinoderm biodiversity from the Malpelo Island in 68 %.

Echinoderms, Malpelo Fauna and Flora Sanctuary, Colombian Pacific: new reports and distributional issues

A systematic list of echinoderms from Malpelo Fauna and Flora Sanctuary (MFFS) was prepared, based on local sampling, literature review and identification of specimens from Museo de Historia Natural Marina de Colombia (MHNMC) and from National Museum of Natural History, Smithsonian Institution, Washington D. C. (USNM). Standard methodology for monitoring the Eastern Tropical Pacific Seascape was used in December 2006 and March 2007 to sample shallow water echinoderms (1-20 m deep). Malpelo is the richest locality of the Colombian Pacific with 84 species reported (56 % of them deep water organisms), belonging to 22 orders, 42 families and 68 genera, distributed between the surface and a depth of 5000 m. Thirty-six new records for MFFS and Colombian Pacific are reported. In Colombia the shallow water species are widely distributed in the Pacific, while deep forms only occur at Malpelo. The majority of species are mostly related to the Panamanian and Galapagos region showing a possible connectivity. This list increases knowledge on the echinoderm biodiversity from the Malpelo Island in 68 %.

Response to visual and mechano-acoustic predator cues is robust to ocean warming and acidification and is highly variable in European sea bass

Predator-prey interactions and, especially, the success of anti-predator responses are modulated by the sensory channels of vision, olfaction, audition and mechanosensation. If climate change alters fish sensory ability to avoid predation, community dynamics can be affected. We investigated whether mid-duration exposure to warming and/or acidification alters behavioural response to visual or mechano-acoustic predator cues in juvenile Dicentrarchus labrax. We measured kinematic variables before and after a visual or a mechano-acoustic challenge which mimicked an overflying bird shadow or a bird swoop attack, respectively. Due to large interindividual variability in responses before cue presentation, fish were categorized as slow and fast to account for baseline individual variability. Treatment did not impact kinematic variables as both slow and fast fish of every treatment elicited precautionary and escape responses. Interestingly, even slow fish swam as fast as fast fish after the cue, suggesting that regardless of initial category, fish managed to escape facing a danger. Anti-predator response varied according to the level of threat to survival with greater responses elicited after the swoop attack. Although wild juvenile sea bass aggregate in schools, school dynamics rely on single leaders which highlights the importance of the variability in individual behaviours. We demonstrated that anti-predator response in juvenile D. labrax is robust to mid-duration exposure to independent and combined effects of warming and acidification. If robustness is confirmed over long-duration, it could provide D. labrax with an evolutionary advantage in the future ocean, where cue transmission through changing environments can further modulate cue perception and predator-prey interactions

Seawater carbonate chemistry and survival rate of F2 Dicentrarchus labrax after viral challenge

Background: Progressive CO2-induced ocean acidification (OA) impacts marine life in ways that are difficult to predict but are likely to become exacerbated over generations. Although marine fishes can balance acid–base homeostasis efficiently, indirect ionic regulation that alter neurosensory systems can result in behavioural abnormalities. In marine invertebrates, OA can also affect immune system function, but whether this is the case in marine fishes is not fully understood. Farmed fish are highly susceptible to disease outbreak, yet strategies for overcoming such threats in the wake of OA are wanting. Here, we exposed two generations of the European sea bass (Dicentrarchus labrax) to end-of-century predicted pH levels (IPCC RCP8.5), with parents (F1) being exposed for four years and their offspring (F2) for 18 months. Our design included a transcriptomic analysis of the olfactory rosette (collected from the F2) and a viral challenge (exposing F2 to betanodavirus) where we assessed survival rates. Results: We discovered transcriptomic trade-offs in both sensory and immune systems after long-term transgenerational exposure to OA. Specifically, RNA-Seq analysis of the olfactory rosette, the peripheral olfactory organ, from 18-months-old F2 revealed extensive regulation in genes involved in ion transport and neuronal signalling, including GABAergic signalling. We also detected OA-induced up-regulation of genes associated with odour transduction, synaptic plasticity, neuron excitability and wiring and down-regulation of genes involved in energy metabolism. Furthermore, OA-exposure induced up-regulation of genes involved in innate antiviral immunity (pathogen recognition receptors and interferon-stimulated genes) in combination with down-regulation of the protein biosynthetic machinery. Consistently, OA-exposed F2 challenged with betanodavirus, which causes damage to the nervous system of marine fish, had acquired improved resistance. Conclusion: F2 exposed to long-term transgenerational OA acclimation showed superior viral resistance, though as their metabolic and odour transduction programs were altered, odour-mediated behaviours might be consequently impacted. Although it is difficult to unveil how long-term OA impacts propagated between generations, our results reveal that, across generations, trade-offs in plastic responses is a core feature of the olfactory epithelium transcriptome in OA-exposed F2 offspring, and will have important consequences for how cultured and wild fish interacts with its environment

Attachment capacity of the sea urchin Paracentrotus lividus in a range of seawater velocities in relation with test morphology and tube foot mechanical properties

Intertidal rocky shores are stressful environments where benthic invertebrates experience large wave-induced hydrodynamic forces that can detach them from the substratum. The tube feet of echinoids counteract these forces and help them remain securely affixed. Sea urchins display a high degree of phenotypic plasticity which may help them cope with hydrodynamic stress. We evaluated whether habitats presenting different seawater velocities induce plastic responses in the attachment capacity of the sea urchin Paracentrotus lividus by quantifying their morphology and the adhesive and mechanical properties of their tube feet. Intertidal adult sea urchins from three subpopulations were collected around the Crozon peninsula (France). Localities differed according to measured water velocities. Size was significantly lower in the two most exposed sites where sea urchins also presented a higher density of tube feet. Tube foot adhesive properties were not significantly different between sites, but their extensibility and toughness were significantly higher in individuals from the most exposed site. Using this information, we calculated a safety factor to predict the flow velocity that would cause detachment from the substratum. It showed individuals from the most exposed habitat would resist higher flow velocities (up to 7.59 ± 0.90 m s−1). Both morphometry and tube foot mechanical properties vary among subpopulations and show an intraspecific plasticity in P. lividus. Although, differences in sea water velocity may be one cause of this intraspecific variation, it likely results from a combination of biotic and abiotic factors.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Ocean warming and acidification alter the behavioral response to flow of the sea urchin Paracentrotus lividus

Ocean warming (OW) and acidification (OA) are intensively investigated as they pose major threats to marine organism. However, little effort is dedicated to another collateral climate change stressor, the increased frequency, and intensity of storm events, here referred to as intensified hydrodynamics. A 2-month experiment was performed to identify how OW and OA (temperature: 21°C; pHT: 7.7, 7.4; control: 17°C-pHT7.9) affect the resistance to hydrodynamics in the sea urchin Paracentrotus lividus using an integrative approach that includes physiology, biomechanics, and behavior. Biomechanics was studied under both no-flow condition at the tube foot (TF) scale and flow condition at the individual scale. For the former, TF disk adhesive properties (attachment strength, tenacity) and TF stem mechanical properties (breaking force, extensibility, tensile strength, stiffness, toughness) were evaluated. For the latter, resistance to flow was addressed as the flow velocity at which individuals detached. Under near- and far-future OW and OA, individuals fully balanced their acid-base status, but skeletal growth was halved. TF adhesive properties were not affected by treatments. Compared to the control, mechanical properties were in general improved under pHT7.7 while in the extreme treatment (21°C-pHT7.4) breaking force was diminished. Three behavioral strategies were implemented by sea urchins and acted together to cope with flow: improving TF attachment, streamlining, and escaping. Behavioral responses varied according to treatment and flow velocity. For instance, individuals at 21°C-pHT7.4 increased the density of attached TF at slow flows or controlled TF detachment at fast flows to compensate for weakened TF mechanical properties. They also showed an absence of streamlining favoring an escaping behavior as they ventured in a riskier faster movement at slow flows. At faster flows, the effects of OW and OA were detrimental causing earlier dislodgment. These plastic behaviors reflect a potential scope for acclimation in the field, where this species already experiences diel temperature and pH fluctuations

Biomechanics and behaviour in the sea urchin Paracentrotus lividus (Lamarck, 1816) when facing gradually increasing water flows.

info:eu-repo/semantics/publishe

Seawater carbonate chemistry and the behavioral response to flow of the sea urchin Paracentrotus lividus

Ocean warming (OW) and acidification (OA) are intensively investigated as they pose major threats to marine organism. However, little effort is dedicated to another collateral climate change stressor, the increased frequency, and intensity of storm events, here referred to as intensified hydrodynamics. A 2‐month experiment was performed to identify how OW and OA (temperature: 21°C; pHT: 7.7, 7.4; control: 17°C‐pHT7.9) affect the resistance to hydrodynamics in the sea urchin Paracentrotus lividus using an integrative approach that includes physiology, biomechanics, and behavior. Biomechanics was studied under both no‐flow condition at the tube foot (TF) scale and flow condition at the individual scale. For the former, TF disk adhesive properties (attachment strength, tenacity) and TF stem mechanical properties (breaking force, extensibility, tensile strength, stiffness, toughness) were evaluated. For the latter, resistance to flow was addressed as the flow velocity at which individuals detached. Under near‐ and far‐future OW and OA, individuals fully balanced their acid‐base status, but skeletal growth was halved. TF adhesive properties were not affected by treatments. Compared to the control, mechanical properties were in general improved under pHT7.7 while in the extreme treatment (21°C‐pHT7.4) breaking force was diminished. Three behavioral strategies were implemented by sea urchins and acted together to cope with flow: improving TF attachment, streamlining, and escaping. Behavioral responses varied according to treatment and flow velocity. For instance, individuals at 21°C‐pHT7.4 increased the density of attached TF at slow flows or controlled TF detachment at fast flows to compensate for weakened TF mechanical properties. They also showed an absence of streamlining favoring an escaping behavior as they ventured in a riskier faster movement at slow flows. At faster flows, the effects of OW and OA were detrimental causing earlier dislodgment. These plastic behaviors reflect a potential scope for acclimation in the field, where this species already experiences diel temperature and pH fluctuations

Attachment capacity of the sea urchin Paracentrotus lividus in a changing ocean

info:eu-repo/semantics/nonPublishe

Ocean warming and acidification alter the behavioral response to flow of the sea urchin Paracentrotus lividus

Ocean warming (OW) and acidification (OA) are intensively investigated as they pose major threats to marine organism. However, little effort is dedicated to another collateral climate change stressor, the increased frequency, and intensity of storm events, here referred to as intensified hydrodynamics. A 2-month experiment was performed to identify how OW and OA (temperature: 21°C; pHT: 7.7, 7.4; control: 17°C-pHT7.9) affect the resistance to hydrodynamics in the sea urchin Paracentrotus lividus using an integrative approach that includes physiology, biomechanics, and behavior. Biomechanics was studied under both no-flow condition at the tube foot (TF) scale and flow condition at the individual scale. For the former, TF disk adhesive properties (attachment strength, tenacity) and TF stem mechanical properties (breaking force, extensibility, tensile strength, stiffness, toughness) were evaluated. For the latter, resistance to flow was addressed as the flow velocity at which individuals detached. Under near- and far-future OW and OA, individuals fully balanced their acid-base status, but skeletal growth was halved. TF adhesive properties were not affected by treatments. Compared to the control, mechanical properties were in general improved under pHT7.7 while in the extreme treatment (21°C-pHT7.4) breaking force was diminished. Three behavioral strategies were implemented by sea urchins and acted together to cope with flow: improving TF attachment, streamlining, and escaping. Behavioral responses varied according to treatment and flow velocity. For instance, individuals at 21°C-pHT7.4 increased the density of attached TF at slow flows or controlled TF detachment at fast flows to compensate for weakened TF mechanical properties. They also showed an absence of streamlining favoring an escaping behavior as they ventured in a riskier faster movement at slow flows. At faster flows, the effects of OW and OA were detrimental causing earlier dislodgment. These plastic behaviors reflect a potential scope for acclimation in the field, where this species already experiences diel temperature and pH fluctuations.SCOPUS: ar.jinfo:eu-repo/semantics/publishe