Less fizz, more plants – acids and eutrophication in Arctic lakes

Russian researchers identified acidification of lakes during 1990s in Murmansk, Karelia, Archangelsk and Vologda regions and found up to 5% of lakes have acidification due to human causes in humid areas of European Russia and West Siberia. Nornickel was identified as the main contributor of sulphur dioxide SO2 in Kola and Norilsk areas. However since then, there has been a trend of reducing acid deposits across European Russian and a similar trend across Europe.

Scientists decided to build on existing research and analyse the climate trends and current water chemistry, acidification and eutrophication of Arctic lakes, using the Kola Peninsula as a study site featuring 75 lakes over a 28 year period. The peninsula neighbours the Barents, White seas and is a mix of tundra then further south forest tundra and taiga forest, with a winter between November and May. There are natural acidic and alkaline rock formations, human activity includes copper-nickel smelter industry.

Water chemistry research in the region started in 1995 including collaborations with Norway, Sweden and Finland, then repeated every 4 or 5 years up to 2018. Researchers sampled the water in September for tundra lakes and October for taiga lakes. Bottles for the water sampling were rinsed with the lake water, stored and transported at approx 4 °C, to labs at the Institute of Problems of Industrial Ecology of the North (INEP). The samples were filtered through membrane and conductivity, ph were determined as part of the overall chemical analysis. Statistical analysis was used to identify changes and trends during 1990s and 2018.

To understand the climate influence, they used data to identify low average annual air temperatures (−1 °C) and how the air temperature has increased, particularly during non-ice (open water) months. Atmospheric precipitation has also increased.

They found that leaching, heavier rainfall, thinner soil and reduced soil quality reduced the ability of the soil to absorb anthropogenic sulphates (SO4+), changes in nutrients affected by warmer weather leading to increases in eutrophication.

Figure 7. Scheme of the development of lakes from acidification to eutrophication in the Arctic region Figure 7. Scheme of the development of lakes from acidification to eutrophication in the Arctic re-
under the influence of reduced acid deposition and climate warming, (Moiseenko et al.,2022)

Overall the decline in industrial (metals and SO2) emissions has improved the water health in local areas but overall there has not been a significant decrease resulting in improvement of nutrients diversity and quality. Based on current anthropogenic practices and climate changes, this suggests further eutrophication and evolution of the biogeochemical balances in the water in the Kola Peninsula.

Moiseenko T I, Bazova M M and Gashkina N A 2022 Development of Lake from Acidification to Eutrophication in the Arctic Region under Reduced Acid Deposition and Climate Warming Water 14 3467 Online: http://dx.doi.org/10.3390/w14213467

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