Lake diatom response to recent Arctic warming in Finnish Lapland

Abstract

High‐resolution palaeolimnological data from a number of remote and nonpolluted lakes in Finnish Lapland reveal a distinct change in diatom assemblages. This parallels the post‐19th century Arctic warming detected by examination of long‐term instrumental series, historical records of ice cover and tree‐ring measurements. The change was predominantly from benthos to plankton and affected the overall diatom species richness. A particularly strong relationship was found between spring temperatures and compositional structure of diatoms. The change is irrespective of the lake type and catchment characteristics, and is reflected by several other biological indicators, such as chrysophytes and zooplankton, suggesting that entire lake ecosystems have been affected. No corresponding change in the diatom‐inferred lake‐water pH was observed; hence, atmospheric fallout of acid substances cannot have been the driving force for the observed biological change. The mechanism behind the diatom response is unclear, but it may be related to decreased ice‐cover duration, prolonged growing season and increased thermal stability. We postulate that 19th century Arctic warming, rather than acidic or other anthropogenic deposition, is responsible for the recent ecological changes in these high latitude lakes.

High concentrations of amorphous, biogenic Si (BSi) in the sediment of a small high-latitude lake: implications for biogeochemical Si cycling and for the use of BSi as a paleoproxy

“…This is in agreement with the trend in the organic matter concentration of the sediment, where an increase appeared at around the same time. Despite the relatively isolated and unperturbed location of the lake, such an increase in the productivity of the lake around this time follows general trends observed elsewhere in high-latitude areas (Sorvari et al 2002;Smol et al 2005;Thomas et al 2008 with references). The increasing trend in BSi was slight, however, and no clear conclusions about increases in productivity can be drawn from the BSi data alone.…”

Spatial, Environmental, and Biotic Determinants of Zooplankton Community Composition in Subarctic Lakes and Ponds in Wapusk National Park, Canada

“…Mallomonas) in the shallow inland lakes is consistent with findings from recent paleoecological studies from the same lakes (Rühland et al, 2014) and may be associated with climate-driven changes in lake water properties (Sorvari et al, 2002;Rühland et al, 2008). Recent evidence from our study lakes suggests that regional warming since the mid-1990s has resulted in increased diatom diversity, including increases in the relative abundances of planktonic diatoms and cladocerans (i.e.…”

Palaeolimnological evidence for recent climatic change in lakes from the northern Urals, arctic Russia

“…In ice-covered lakes diatoms are especially sensitive to the changes in growing season (i.e. period of icecover) and habitat availability (e.g., Smol 1988;Sorvari and Korhola 1998;Lotter and Bigler 2000;Korhola et al 2002;Sorvari et al 2002, Ru¨hland et al 2003. Planktonic taxa (e.g.…”

“…It is also well established that global warming is especially pronounced in the Arctic through amplified feedbacks (Overpeck et al 1997) and that arctic ecosystems are particularly vulnerable to environmental changes (ACIA 2004). There is substantial evidence that lake ecosystems in the Canadian Arctic and Fennoscandia are undergoing changes which have been linked to human-induced climate warming during the last 150-100 years (Douglas et al 1994;Overpeck et al 1997;Hughen et al 2000;Sorvari et al 2002;Perren et al 2003;Wolfe 2003;Smith et al 2004;Brooks et al 2005;). However, it is still unclear how other arctic regions respond to global environmental change and whether the cause of the recent changes in lakes can be solely explained by global warming.…”