Using palaeolimnological and limnological data to reconstruct the recent history of European lake ecosystems: introduction

Abstract

Summary 1. As future climate change is expected to have a major impact on freshwater lake ecosystems, it is important to assess the extent to which changes taking place in freshwater lakes can be attributed to the degree of climate change that has already taken place. 2. To address this issue, it is necessary to examine evidence spanning many decades by combining long‐term observational data sets and palaeolimnological records. 3. Here, we introduce a series of case studies of seven European lakes for which both long‐term data sets and sediment records are available. Most of the sites have been affected by eutrophication and are now in recovery. 4. The studies attempt to disentangle the effects of climate change from those of nutrient pollution and conclude that nutrient pollution is still the dominant factor controlling the trophic state of lakes. 5. At most sites, however, there is also evidence of climate influence related in some cases to natural variability in the climate system, and in others to the trend to higher temperatures over recent decades attributed to anthropogenic warming. 6. More generally and despite some problems, the studies indicate the value of combining limnological and palaeolimnological records in reconstructing lake history and in disentangling the changing role of different pressures on lake ecosystems.

The interaction between climate warming and eutrophication to promote cyanobacteria is dependent on trophic state and varies among taxa

“…This was also observed for 143 eutrophic and hypereutrophic lakes in South America, indicating that in systems characterized by high biovolume, the interaction of light availability with temperature and nutrients was the main driver of phytoplankton (Kosten et al 2012). This was confirmed by other studies conducted in eutrophic systems either using modeling (Elliott et al 2006;Elliott and May 2008) or monitoring data (Jö hnk et al 2008;Blank et al 2009). …”

“…Nutrients (i.e., either TN or TP, or both) in isolation were found to be solely responsible for changes in cyanobacteria in 8 of the 35 studies (23%) (Battarbee and Bennion 2012;Feuchtmayr et al 2012). Of those eight studies, four were conducted in microcosms or mesocosms with eutrophic conditions ( Moss et al 2003;Christoffersen et al 2006;Feuchtmayr et al 2010), three were conducted in eutrophic and mesotrophic lakes (Elliott 2010;Battarbee and Bennion 2012;Feuchtmayr et al 2012), and one in a hyper-eutrophic system (Eilers et al 2004). Only three studies found that other factors (e.g., zooplankton, macrophytes) were most responsible for driving variation in cyanobacterial biomass (Ruggiu et al 1998;Genkai-Kato and Carpenter 2005;Loverde-Oliveira et al 2009).…”

“…Of these four studies, one was conducted in an oligotrophic lake (Bloch and Weyhenmeyer 2012), one in a eutrophic lake undergoing restoration (Thies et al 2012), and two included multiple ecosystems with different trophic states ranging from oligotrophic to eutrophic (Blenckner et al 2007;Shimoda et al 2011). Nutrients (i.e., either TN or TP, or both) in isolation were found to be solely responsible for changes in cyanobacteria in 8 of the 35 studies (23%) (Battarbee and Bennion 2012;Feuchtmayr et al 2012). Of those eight studies, four were conducted in microcosms or mesocosms with eutrophic conditions ( Moss et al 2003;Christoffersen et al 2006;Feuchtmayr et al 2010), three were conducted in eutrophic and mesotrophic lakes (Elliott 2010;Battarbee and Bennion 2012;Feuchtmayr et al 2012), and one in a hyper-eutrophic system (Eilers et al 2004).…”

Progress towards the implementation of the European Water Framework Directive (2000–2012)

“…This is not surprising given that for some MS river basin management was a new departure, but it is also a reflection of the difficulties in restoring aquatic systems and similar problems have been reported from North America (George and Boyd, 2007). For lakes, recovery times can extend over at least 15 years (Battarbee and Bennion, 2012;Carvalho et al, 2012;Hobaek et al, 2012;Jeppesen et al, 2005), often caused by internal nutrient load and/or long retention times Søndergaard et al, 2007). The WFD recognises that in such situations achieving good status may take more time and it allows MS to extend deadlines for the achievement of good status on the basis of the natural conditions of the water body.…”

A 850-year record climate and vegetation changes in East Siberia (Russia), inferred from geochemical and biological proxies of lake sediments

“…Hence, sedimentary research plays a key role in deciphering the effects of increasing environmental pressure on aquatic ecosystems as sediments collect and unify environmental signals of both local and regional change (e.g. Cohen 2003;Battarbee and Bennion 2012). Understanding the variation in lake ecosystems, be it as a result of natural or anthropogenic causes, is of utmost importance if we are to fully comprehend how these ecosystems function and how they can be restored and protected (Smol 2002;Sayer et al 2010).…”