Magnon relaxation processes in the nematic phase of a magnet with spin S=1 are investigated for a general form of the isotropic exchange interaction, including bilinear and biquadratic interactions in respect to the site spin operators. The temperature dependence and momentum dependence of the magnetic decrement are found in the long-wavelength approximation. It is shown that the elementary excitations in a spin nematic (magnons) have all the properties of Goldstone excitations; in the limit of small wave vectors they have a linear dispersion law, while the damping is quadratic in the wave vector. The similarity of magnon behavior in a spin nematic to that in an antiferromagnet is noted.

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The purpose of the paper is to discuss practical results of pilot running of a domestic ship ferry box system. Methods and Results. The results were obtained in course of in situ studies of structure and spatialtemporal variability of optical, hydrological and hydrochemical fields of surface water during the complex cruises in which the scientists from Marine Hydrophysical Institute, Russian Academy of Sciences, participated in 2015-2017. The considered polygons were of different scales and located nearby the Southern Coast of Crimea. The ferry box measurements were carried out continuously in real time with high spatial resolution and showed good reliability. Based on the contact ferry box surveys carried out at the test sub-satellite polygons near the Herakleian Peninsular, the background structure of the surface water hydrophysical fields was mapped. In the polygon surface layer, small-scale water lenses were authentically identified. They accompany the intensive hydrological torch-type formations that arise in an outbreak of industrial and sewage waters discharge near the bottom and then reach the surface. Conclusions. The information of the ferry box system surveys carried out at the large-scale polygons during the cruises of R/V Professor Vodyanitsky (the 89 th-October, 2016 and the 98 th-November, 2017) nearby the Southern Coast of Crimea provided new in situ data that were impossible to obtain by contact methods. The represented results demonstrate high information content of the ferry box measurements, its efficiency and possibility of its further application for studying hydrophysical processes and phenomena in a wide range of their variability and in various weather conditions. The principle possibilities and further prospects of the ferry box system in obtaining new notions on submeso-and small-scale hydrodynamic processes are confirmed. Besides, the system implies development both of the approaches for rational use of marine resources near the Crimean and Sevastopol coasts and the elements of the advanced technology for the instrumental shelf monitoring in critical situations.

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