An auditory study was conducted to derive data on temporary threshold shift (TTS) induced by single impulses. This information should serve as basis for the definition of noise exposure criteria for harbor porpoises. The measurements of TTS were conducted on a harbor porpoise by measuring the auditory evoked potentials in response to amplitude-modulated sounds. After obtaining baseline hearing data the animal was exposed to single airgun stimuli at increasing received levels. Immediately after each exposure the animal’s hearing threshold was tested for significant changes. The received levels of the airgun impulses were increased until TTS was reached. At 4 kHz the predefined TTS criterion was exceeded at a received sound pressure level of 199.7 dBpk-pk re 1 μPa and a sound exposure level (SEL) of 164.3 dB re 1 μPa2 s. The animal consistently showed aversive behavioral reactions at received sound pressure levels above 174 dBpk-pk re 1 μPa or a SEL of 145 dB re 1 μPa2 s. Elevated levels of baseline hearing sensitivity indicate potentially masked acoustic thresholds. Therefore, the resulting TTS levels should be considered masked temporary threshold shift (MTTS) levels. The MTTS levels are lower than for any other cetacean species tested so far.

Todd, V. L. G., Pearse, W. D., Tregenza, N. C., Lepper, P. A., and Todd, I. B. 2009. Diel echolocation activity of harbour porpoises (Phocoena phocoena) around North Sea offshore gas installations. – ICES Journal of Marine Science, 66: 734–745.

This paper was accepted for publication in the journal Continental Shelf Research and the definitive published version is available at http://dx.doi.org/10.1016/j.csr.2014.05.018.Three models were applied to obtaina first assessment of some of the potential impacts of large-scale operational wind turbine arrays on the marine ecosystem in a well-mixed area in a shelf sea: a biogeochemical model,a wave propagation model and an a coustic energy flux model.The results of the models are discussed separately and together to elucidate the combined effects. Overall,all three models suggested relatively weak environmental changes for the mechanisms included in this study, however these are only a subset of all the potential impacts,and a number of assumptions had to be made. Further work is required to address these assumptions and additional mechanisms. All three models suggested most of the changes with in the wind turbine array,and small changes up to several tens of km outside the array. Within the array, the acoustic model indicated the most concentrated, spatially repetitive changes to the environment,followed by the SWAN wave model,and the biogeochemical model being the most diffuse. Because of the different spatial scales of the response of the three models,the combined results suggested a spectrum of combinations of environmental changes with in the wind turbine array that marine organism smight respond to. The SWAN wave model and the acoustic model suggested a reduction in changes with increasing distance between turbines. The SWAN wave model suggested that the biogeochemical model, because of the in ability of its simple wave model to simulate wave propagation,over-estimated the biogeochemical changes by a factor of 2 or more. The biogeochemical model suggested that the benthic system was more sensitive to the environmental changes than the pelagic system

Flooding is one of the most frequent and costly natural disasters affecting mankind. However, implementing Internet of Things (IoT) technology to monitor river behavior may help mitigate or prevent future disasters. This article outlines the hardware development of an IoT system (RiverCore) and defines an application scenario in a specific hydrological region of the state of Colima (Mexico), highlighting the characteristics of data acquisition and data processing used. Both fixed position and moving drifter node systems are described along with web-based data acquisition platform developments integrated with IoT techniques to retrieve data through 3G cellular networks. The developed architecture uses the Message Queuing Telemetry Transport (MQTT) protocol, along with encryption and security mechanisms, to send real-time data packages from fixed nodes to a server that stores retrieved data in a non-relational database. From this, data can be accessed and displayed through different customizable queries and graphical representations, allowing future use in flood analysis and prediction systems. All of these features are presented along with graphical evidence of the deployment of the different devices and of several cellular communication and on-site data acquisition tests.

Tidal stream energy converters (turbines) are currently being installed in tidally energetic coastal sites. However, there is currently a high level of uncertainty surrounding the potential environmental impacts on marine mammals. This is a key consenting risk to commercial introduction of tidal energy technology. Concerns derive primarily from the potential for injury to marine mammals through collisions with moving components of turbines. To understand the nature of this risk, information on how animals respond to tidal turbines is urgently required. We measured the behaviour of harbour seals in response to acoustic playbacks of simulated tidal turbine sound within a narrow coastal channel subject to strong, tidally induced currents. This was carried out using data from animal‐borne GPS tags and shore‐based observations, which were analysed to quantify behavioural responses to the turbine sound. Results showed that the playback state (silent control or turbine signal) was not a significant predictor of the overall number of seals sighted within the channel. However, there was a localised impact of the turbine signal; tagged harbour seals exhibited significant spatial avoidance of the sound which resulted in a reduction in the usage by seals of between 11% and 41% at the playback location. The significant decline in usage extended to 500 m from the playback location at which usage decreased by between 1% and 9% during playback. Synthesis and applications. This study provides important information for policy makers looking to assess the potential impacts of tidal turbines and advise on development of the tidal energy industry. Results showing that seals avoid tidal turbine sound suggest that a proportion of seals encountering tidal turbines will exhibit behavioural responses resulting in avoidance of physical injury; in practice, the empirical changes in usage can be used directly as avoidance rates when using collision risk models to predict the effects of tidal turbines on seals. There is now a clear need to measure how marine mammals behave in response to actual operating tidal turbines in the long term to learn whether marine mammals and tidal turbines can coexist safely at the scales currently envisaged for the industry.