Long-term modification of Arctic lake ecosystems: Reference condition, degradation under toxic impacts and recovery (case study Imandra Lakes, Russia)

Abstract

In this study, published data on Lake Imandra, north-west Russia, have been synthesised to investigate trends in lake contamination and recovery due to changing inputs of heavy metals and nutrients over time. Records of water chemistry, phytoplankton, zooplankton and fish communities have been used to determine the status of aquatic ecosystem health in three distinct phases of Lake Imandra's recent history. Firstly, background (reference) conditions within the lake have been established to determine lake conditions prior to anthropogenic influences. Secondly, a period of ecosystem degradation due to anthropogenic inputs of toxic metals and nutrients has been described. Finally, evidence of lake recovery due to recent decreases of toxic metals and nutrients has been explored. Pollution of Lake Imandra began in the 1930s, reaching a peak in the 1980s. Increases in heavy metal and nutrient inputs transformed the typical Arctic ecosystem. During the contamination phase, there was a decrease in Arctic species and in biodiversity. During the last 10 years, pollution has decreased and the lake has been recolonised by Arctic water species. Ecosystem recovery is indicated by a change of predominant species, an increase in the individual mass of organisms and an increase in the biodiversity index of plankton communities. In accordance with Odum's ecosystem succession theory, this paper demonstrates that the ecosystem has transformed to a more stable condition with new defining parameters. This illustrates that the recovery of Arctic ecosystems towards pre-industrial reference conditions after a reduction in anthropogenic stresses occur, although a complete return to background conditions may not be achievable. Having determined the status of current ecosystem health within Lake Imandra, the effect of global warming on the recovery process is discussed. Climate warming in Arctic regions is likely to move the ecosystem towards a predominance of eurybiontic species in the community structure. These organisms have the ability to tolerate a wider range of ARTICLE IN PRESS www.elsevier.de/limno 0075-9511/$ -see front matter (T.I. Moiseenko).environmental conditions than typical Arctic inhabitants and will gain advantages in development. This indicates that the full recovery of Arctic ecosystems in a warming climate may not be possible.

Differentiated Responses of Plankton and Zoobenthos to Water Quality Based on Annual and Seasonal Analysis in a Freshwater Lake

“…Biodiversity, which is one of the fundamental elements of ecosystem functioning [2], has been considered an important indicator that could be applied in biological restoration as well as assessing ecosystem health of a lake [3]. Previous studies of biodiversity in aquatic ecosystems, which refer to phytoplankton, zooplankton, and zoobenthos, focus mainly on the relationships between biological characteristics and environmental variables [4][5], spatiotemporal patterns [6][7][8], and biological restoration [9][10][11].…”

Overgrowing of two polymictic lakes in Central-Western Poland

“…In recent decades, the effect of natural processes on lake ecosystems has been enhanced by human impact (Havens et al 2001;Tarras-Wahlberg et al 2002). Increased nutrient supply to water bodies and morphological changes have been caused by land use changes associated with urbanisation (Moiseenko et al 2009) and agriculture, point and diffuse pollutions, increased demand for water supply to support population growth and greater uncertainties related to climate change. Those factors exert significant impact on water quality and quantity, as well as lifetime of lakes.…”

Is it possible to restore the Arctic lake ecosystems after long-term pollution?

“…Также была проведена модернизация технологий и оборудования [4]. В период снижения и стабилизации нагрузок были продолжены исследования озера [5][6][7][8][9][10]. Следует отметить, что по данным [11] за последние два десятилетия в Северо-Западном регионе отмечается потепление.…”