Vademecum: Mariene beleidsinstrumenten en wetgeving voor het Belgische deel van de Noordzee

B

Metatranscriptome of a marine pelagic crustacean community using nanopore sequencing

Due to their rapid responses to environmental variation, planktonic organisms are used as bio-indicators of ecosystem changes. Most zooplankton monitoring studies focus mainly on variability in biodiversity, densities and biomass. Advances in practical, cost-effective molecular approaches can help overcome the issues with morphology-based biomonitoring. While molecular studies are growing in popularity, a fundamental challenge remains the transport of biological material to a laboratory for DNA/RNA extractions and sequencing. The MinION™, a portable nanopore-based DNA/RNA sequencing platform (Oxford Nanopore Technologies), offers big potential advantages in the context of biodiversity research, i.e. portability and low costs of instrument and reagents. It weighs less than 100 g, is therefore easily transportable and is powered to sequence RNA using the USB port on a standard laptop, hence making it suitable for mobile research setups and real time monitoring campaigns onsite. In a first step, we wanted to understand how the gene expression in zooplankton fluctuates over the course of a short time period. Therefore, we monitored the gene expression of the dominant zooplankter, the calanoid copepod Temora longicornis, over a short time span (one day), making use of the infrastructure of the research vessel Simon Stevin. We compared gene expression results with in situ determined biotic and abiotic patterns. Moreover, due to the recent development of the VolTRAX, a small device designed to perform library preparation automatically, for the first time we were able to prepare a biological sample for analysis in situ and hands-free, making in-field, molecular monitoring of marine life possible

To Pee, or Not to Pee:A Review on Envenomation and Treatment in European Jellyfish Species

There is a growing cause for concern on envenoming European species because of jellyfish blooms, climate change and globalization displacing species. Treatment of envenomation involves the prevention of further nematocyst release and relieving local and systemic symptoms. Many anecdotal treatments are available but species-specific first aid response is essential for effective treatment. However, species identification is difficult in most cases. There is evidence that oral analgesics, seawater, baking soda slurry and 42–45 °C hot water are effective against nematocyst inhibition and giving pain relief. The application of topical vinegar for 30 s is effective on stings of specific species. Treatments, which produce osmotic or pressure changes can exacerbate the initial sting and aggravate symptoms, common among many anecdotal treatments. Most available therapies are based on weak evidence and thus it is strongly recommended that randomized clinical trials are undertaken. We recommend a vital increase in directed research on the effect of environmental factors on envenoming mechanisms and to establish a species-specific treatment. Adequate signage on jellyfish stings and standardized first aid protocols with emphasis on protective equipment and avoidance of jellyfish to minimize cases should be implemented in areas at risk

Molecular mechanisms of self-mated hydrogel friction

Self-mated hydrogel contacts show extremely small friction coefficients at low loads but a distinct velocity dependence. Here we combine mesoscopic simulations and experiments to test the polymer-relaxation hypothesis for this velocity dependence, where a velocity-dependent regime emerges when the perturbation of interfacial polymer chains occurs faster than their relaxation at high velocity. Our simulations reproduce the experimental findings, with speed-independent friction at low velocity, followed by a friction coefficient that rises with velocity to some power of order unity. We show that the velocity-dependent regime is characterized by reorientation and stretching of polymer chains in the direction of shear, leading to an entropic stress that can be quantitatively related to the shear response. The detailed exponent of the power law in the velocity dependent regime depends on how chains interact: We observe a power close to $1/2$ for chains that can stretch, while pure reorientation leads to a power of unity. Our simulations quantitatively match experiments and show that the velocity dependence of hydrogel friction at low loads can be firmly traced back to the morphology of near-surface chains.Comment: 18 pages, 6 figures, includes supplementary materia