The impact of atmospheric nutrient fractions on phytoplankton composition and primary production in the marmara region

Considering the recently observed mucilage events in the Sea of Marmara, it is observed that studies examining the relationship between regional atmospheric data and surface water are limited. In this study, sea water and atmospheric samples are taken in the Marmara Region, micro nutrient analyzes and microcosm studies are carried out. It is observed that Na+ and Mg2+ ions have their origin from sea salt, some of K ions originates from soil, a significant part of WSON (Water Soluble Organic Nitrogen), comes from secondary aerosols, and Mn and Fe concentrations are affected by anthropogenic sources. When the solubility of atmospheric micronutrients in seawater is compared, it is observed that the highest solubility is observed in Zn. The atmosphere of the region is measured to have approximately 2 times higher N content for both dry and total precipitation in comparison to the Redfield (N/P:16/1) ratio. When it is assumed that atmospheric total annual flux of nitrogen and phosphorus is fully available to the primary producers, the phosphorus and nitrogen in the Sea of Marmara can sustain new production at levels of 13.9 ve 24.6 mgC/m2.d. Considering the micronutrient inputs and their molar ratios to nitrogen, it is found that Fe and Zn are richer in the atmospheric flux compared to nitrogen, and Mn, Co, Cu and Cd micronutrient salts are deficient compared to nitrogen. In the microcosm experiments conducted, it is observed that Diatoms are the dominant species in the spring period and Cryptophyceae are the dominant species in the summer period. It is observed that Arabinose and Soluble Organic Carbon concentrations showed significant increases in the spring period samples. In summer period samples, it is concluded that diatom species could multiply very quickly under conditions where nutrients and light is abundant and does not allow other phytoplankton species to dominate until they complete their full life cycle, and during this process, Glucose and Galactose concentrations increases in the environment. Considering the use of micronutrient by phytoplankton and bacteriophytoplankton, their production, and the increase in monosaccharides, this study findings suggest that the phytoplankton species that make the major contribution to the large scale biomass increase in a very short time, would be Skeletonema costatum at the beginning and Cyanobacteria at later times. The results of the present study will contribute to determination of the relationship between the Marmara's regional atmosphere and sea water, and to the examination of the temporal changes of chemical and biological parameters.