# Contribution of Atmospheric Depositions to Inventory of Nutrients in the Coastal Waters of Crimea
###### Abstract
The amount of nutrients discharged with wastewater into coastal waters of Sevastopol region can be up to 1600 t year\({}^{-1}\) for ammonium, 550 t year\({}^{-1}\) for nitrate, and up to 406 t year\({}^{-1}\) for phosphate [17]. The source of nutrients to marine ecosystems with atmospheric wet and dry depositions is far less accounted for. Yet, exhaust gases, fuel combustion products, and a continuous increase in the number of transport vehicles are the main sources of nitrogen oxide emissions to the local atmosphere [18]. About 90% of ammonium emissions are from agricultural activities [19]. The main natural sources of phosphorus to the atmosphere are due to the wind erosion of soil in arid areas, generation of biogenic aerosols by terrestrial vegetation (spores, pollen, plant residues, etc. ), destruction of air bubbles on the surface of water bodies, and volcanic activity. Anthropogenic inputs of phosphorus are associated  
Figure 1: The Chernaya river near Sevastopol city (Images are from the Yandex map). with the production and application of fertilizers, as well as with the metallurgical industry [20]. The presence of silica in atmospheric precipitations is primarily an indication of terrigenous particles. All these nutrients are removed from the atmosphere and deposited at the underlying surface with atmospheric precipitations [21]. [PERSON] (1995) [22] reviewed publications showing a dramatic increase in atmospheric nitrogen fluxes in the 20 th century. The author of [22] argues that atmospheric depositions may support from 5 to 25% of nitrogen needed for new primary production under conditions of intense stratification in the water column in summer time. [PERSON] et al. [23] used the WRF/CMAQ modeling system to estimate dry and wet atmospheric nitrogen fluxes to be up to 0.36 Tg (N) year\({}^{-1}\) (about 825 kg km\({}^{-2}\) year\({}^{-1}\)) for 2008. Though nitrogen is often recognized as the limiting nutrient, phosphorus can also limit the rate of primary production. Mineral aerosols are the main source of phosphorus on the global scale (82%), with particles of biogenic origin (12%) and combustion products (5%) playing an important role with depositions far away from the site of dust generation [20]. The contribution of anthropogenic sources to the atmospheric input of total phosphorus and phosphate can reach 50% for oligotrophic marine ecosystems, in which productivity can be limited by phosphorus [20]. Unlike riverine inputs, atmospheric depositions affect surface waters directly and largely bypass marginal filters in river mouths [5]. The importance of atmospheric deposition for the nutrient budgets in coastal regions can vary greatly [5]. Thus, atmospheric N depositions contribute about 10% of total N inputs in Jiaozhou Bay, China [24]. It might account about 20% of nitrogen requirement in reefs of the Bahamas [25] and provide most of nitrogen inputs to the area off the central coast of Cuba, exceeding the estimated nitrogen fixation rates [26]. Finally, inorganic phosphorus and silica atmospheric fluxes and their importance for the ecosystems of coastal regions remain practically unknown. This study is aimed to quantify the input of nutrients with atmospheric precipitations and to study its relative contribution to the coastal waters of Crimea on different time scales.