Japan Geoscience Union Meeting 2021

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[E] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS01] Environmental, socio-economic, and climatic changes in Northern Eurasia

Sun. Jun 6, 2021 10:45 AM - 12:15 PM Ch.13 (Zoom Room 13)

convener:Pavel Groisman(NC State University Research Scholar at NOAA National Centers for Environmental Information, Asheville, North Carolina, USA), Shamil Maksyutov(National Institute for Environmental Studies), A Dmitry Streletskiy(George Washington University), Yoshihiro Iijima(Graduate School of Bioresources, Mie University), Chairperson:Yoshihiro Iijima(Graduate School of Bioresources, Mie University), Shamil Maksyutov(National Institute for Environmental Studies), Pavel Groisman(NC State University Research Scholar at NOAA National Centers for Environmental Information, Asheville, North Carolina, USA)

11:45 AM - 12:00 PM

[MIS01-11] Long-term temporal trends in water chemistry of lakes in response to decreases in acidic deposition and climate warming of the Kola arctic region

★Invited Papers

Tatyana I Moiseenko1, *Marina I Dinu1, Maria M Bazova1 (1.Russian Institute of Geochemistry and Analytical Chemistry RAS)

Keywords:Acidification , Metals, Climate change

Acidification of waters had been identified in acid-sensitive areas of many countries by the 1960s because of regional and global emissions of acid-forming gases. Although the emission of SO2 and NOx had notably diminished by the 1990s, the problem of water acidification remains pressing: the anticipated recovery of water chemistry does not occur in some lakes because of the effects of associated factors and climate warming. We studied the long-term response of water chemistry to reduced acid deposition and climate warming in the northern Kola part of Russia, based on the monitoring data on 75 lakes. The monitoring was carried out once every 4–5 years in 1990–2018, with analysis for major anions an cations, dissolved organic carbon (DOC), and heavy metals (Ni and Cu). Analysis of archive data on the weather allowed us to reliably identify trends toward a systematic temperature increase over the past 28 years (when our studies were carried out). The population of the lakes under study was proved to generally show a decrease in concentrations of anthropogenic sulfates and strengthening of the acid-neutralizing capacity (ANC) of the waters during this period of time. The lakes were analyzed in six subareas depending on the bedrock geology of the catchment areas and distances from the emission sources. The water chemistry of the lakes responded notably differently to a decrease in the influx of acids: in the most acid-sensitive areas, whose catchment bedrocks are granite and quartz sand, ANC did not increase, and acidification continued to develop. The concentrations of both DOC and nutrients in the lake waters were determined to increase. Simultaneously the Ptot/PO43- and Ntot/NO3- ratios systematically increased, which indicates that bioavailable forms of nutrients are successively utilized in the ecosystems, which means that the lakes are eutotrophied. This phenomenon can be explained by the following two mechanisms: a decrease in the deposition of strong acids and climate warming. We suggest that the effects of multiple factors on the surface waters results in an irreversible evolution of the lakes, and hence, the term recovery does not adequately reflect the processes occurring in this industrially well-developed part of the Arctic.

The research was carried out with the financial support of the Russian Foundation for Basic Research 18-05-60012