Specialists of Marine Hydrophysical Institute of the Russian Academy of Sciences studied the wave regime of Laspi Bay on the Southern Coast of Crimea. For the first time, the degree of influence of storm waves on the bottom vegetation in this water area was studied. The study results were published in the scientific journal Ecological Safety of the Coastal and Shelf Zones of the Sea.
40 years ago, Laspi Bay was considered a benchmark of the natural Black Sea ecosystem. It was characterized by an abundance of unique habitats of bottom vegetation such as cystoseira, phyllophora and eelgrass. The appearance of a coastal protection pier in the bay in the late 1980s and the destruction of its coastal slope as a result of active coastal development could have caused a violation of the hydrodynamic regime, which, in turn, entailed the erosion of the pebble beach and an additional influx of terrigenous material that formed due to construction. Over a period of more than 30 years, the bay has undergone significant changes: the reserves of valuable algae species have decreased, the species composition of vegetation and the configuration of coastal boundaries have changed. Scientists set out to find out what caused these negative processes – anthropogenic impact or natural factors.
Using modern methods of mathematical simulation, the parameters of waves and currents during storms of varying strength and frequency were calculated. Simulation of wave fields in the Laspi Bay was carried out using the Simulating WAves till SHore (SWASH) numerical model. The model allows for calculations of wave fields in the coastal zone in a wide range of spatial and temporal scales, taking into account nonlinearity, refraction, diffraction and reflection of waves. Calculations were carried out on the Institute's powerful computing cluster.
"We analyzed how wave energy is distributed across the bay during storms that occur once a year, every 5, 10 and 25 years. It turned out that coastal slopes in the depth range from 2 to 12 meters are subject to the greatest impact. At the same time, in the central part of the bay, where degradation of bottom vegetation is also observed, wave loads are small,” said one of the authors of the study, Alexandra Belokon, the Researcher at the Department of Computational Technologies and Mathematical Modeling of FSBSI FRC MHI, PhD in Physics and Mathematics.
Scientists have concluded that the disappearance of algae in the middle part of the bay is most likely caused not by storm impact, but by an increase in water turbidity due to anthropogenic factors. In the near future, it is planned to simulate the spread of suspended particles in the bay waters formed as a result of coastal development.
Research on wave characteristics in Laspi Bay can be used to develop recommendations for economic activities in the bay waters and to estimate the impact of storm waves on the phytocenosis of bottom vegetation.
Such studies are of great practical importance for ensuring the safety of navigation, designing coastal infrastructure and preserving the unique ecosystem of Laspi Bay.
The work was carried out within the framework of the state assignment of FSBSI FRC MHI No. FNNN-2021-0005 "Coastal Research" with the support of the Ministry of Science and Higher Education of the Russian Federation.