Macro- and microplastics affect cold-water corals growth, feeding and behaviour.

Plastic contamination is now recognized as one of the most serious environmental issues for oceans. Both macro- and microplastic debris are accumulating in surface and deep waters. However, little is known about their impact on deep marine ecosystems and especially on the deep-sea reefs built by emblematic cold-water corals. The aim of this study was to investigate whether plastics affected the growth, feeding and behaviour of the main engineer species, Lophelia pertusa. Our experiments showed that both micro- and macroplastics significantly reduced skeletal growth rates. Macroplastics induced an increased polyp activity but decreased prey capture rates. They acted as physical barriers for food supply, likely affecting energy acquisition and allocation. Inversely, microplastics did not impact polyp behaviour or prey capture rates, but calcification was still reduced compared to control and in situ conditions. The exact causes are still unclear but they might involve possible physical damages or energy storage alteration. Considering the high local accumulation of macroplastics reported and the widespread distribution of microplastics in the world ocean, our results suggest that plastics may constitute a major threat for reef aggradation by inhibiting coral growth, and thus jeopardise the resilience of cold-water coral reefs and their associated biodiversity.

Peripheral vasomotor activity assessment using a continuous wavelet analysis on webcam photoplethysmographic signals.

BACKGROUND: Vasoconstriction and vasodilation phenomena reflect the relative changes in the vascular bed. They induce particular modifications in the pulse wave magnitude. Webcams correspond to remote sensors that can be employed to measure the pulse wave in order to compute the pulse frequency. OBJECTIVE: Record and analyze pulse wave signal with a low-cost webcam to extract the amplitude information and assess the vasomotor activity of the participant. METHODS: Photoplethysmographic signals obtained from a webcam are analyzed through a continuous wavelet transform. The performance of the proposed filtering technique was evaluated using approved contact probes on a set of 12 healthy subjects after they perform a short but intense physical exercise. During the rest period, a cutaneous vasodilation is observable. RESULTS: High degrees of correlation between the webcam and a reference sensor were obtained. CONCLUSIONS: Webcams are low-cost and non-contact devices that can be used to reliably estimate both heart rate and peripheral vasomotor activity, notably during physical exertion.

Heat shock protein expression pattern (HSP70) in the hydrothermal vent mussel Bathymodiolus azoricus.

We previously reported evidence of increased levels of DNA damage in the hydrothermal mussel Bathymodiolus azoricus, which suggested that the species was not fully resistant to the natural toxicity of its deep-sea vent environment. In the present study, HSP70 was used as a biomarker of sub-cellular stress. Differences in HSP70 expression pattern were observed between vent sites, typified by different depths/toxicity profiles, and between different mussel tissue types. A comparison of specimens collected by remote operated vehicle (ROV) and acoustically-operated cages showed that less stress (as indicated by changes in HSP70 levels) was induced by the faster cage recovery method. Therefore alternatives to ROV collection should be considered when planning experiments involving live deep sea organisms. Significantly, a positive correlation was found between the levels of DNA strand breakage, as measured using the Comet assay, and HSP70 expression pattern; evidence was also obtained for the constitutive expression of at least one HSP isoform which was located within the cell nucleus.

High amounts of sulphur-amino acids in three symbiotic mytilid bivalves from deep benthic communities.

Three sulphur-amino acids, taurine, hypotaurine and thiotaurine, are shown to exist in deep-sea symbiotic mussels. Their relative and absolute importance differs in the three species of mussels studied and seems to be related to the metabolism of the symbionts. Thiotaurine only occurs in high concentration in thiotrophic species, whereas hypotaurine and taurine are found in all the species studied. Differences in sulphur-amino acid composition may also depend on the physiological condition of the organism or on environmental features. These compounds were previously found in Riftia pachyptila, Calyptogena phaseoliformis and in two hydrothermal vent mussels from the western Pacific. Given their abundance, they may play an essential role in these symbioses.