Polymorphism of Picea obovata Ledeb. pollen under industrial pollution of the Arctic

The Murmansk region is one of the most urbanized and industrially developed areas within the Russian Arctic sector, characterized by established mining, metallurgical, energy, and food industries. This study was conducted in Murmansk, Russia’s largest ice-free seaport located beyond the Arctic Circle. Among the ports of Northwestern Russia, Murmansk holds a leading position in terms of dry cargo throughput. The primary environmental pollutants in the city include polycyclic aromatic hydrocarbons, volatile substances such as SO2 and NO2, heavy metals, and oil. Bioindication of the city’s environmental quality was performed using novel ecological palynology methods. The purpose of the work is to study the polymorphism of pollen of Picea obovata Ledeb. under conditions of industrial pollution in the city of Murmansk. Palynological studies of Siberian spruce (Picea obovata Ledeb.) were conducted within the impact zones of industrial enterprises, including combined heat and power (CHP) plants, waste incineration facilities, and ship repair plants. In each sampling plot, 5–6 trees were selected, and male cones were collected during the P. obovata pollination period at the end of June 2024. Pollen was examined using the acetocarmine staining method. A high degree of pollen polymorphism was observed, with the proportion of pollen grains exhibiting developmental anomalies ranging from 62.2% to 87.6% at impacted sites, compared to 25.8% in the control samples. The highest incidence of teratomorphic pollen was recorded in samples collected near energy enterprises: Roslyakovo Yuzhnoye (87.6%), South CHP Plant (81.6%), and Murmansk CHP Plant (76.4%). Three size categories of teratomorphic P. obovata pollen were identified – normal, dwarf, and hypertrophied – each displaying various pathologies of the sacci and exine. Emissions from Murmansk thermal power plants, which operate on fuel oil and coal, contain elevated concentrations of heavy metals and exhibit high toxicity, resulting in disruptions of microsporogenesis and the formation of teratomorphic pollen in P. obovata. Consequently, to improve environmental safety for the local population and reduce pollution levels in Murmansk, it is necessary to adopt new environmentally sustainable technologies and transition the city’s boiler houses to natural gas.