Indication of climatically induced natural eutrophication during the early Holocene period, based on annually laminated sediment from Lake Holzmaar, Germany

Palaeocladocerans as indicators of environmental, cultural and archaeological developments in Eifel maar lakes region (West Germany) during the Lateglacial and Holocene periods

“…The species richness of warm tolerant littoral cladocerans increased where A. guttata became abundant in at least one of the three samples being collected during the Preboreal and Boreal periods. Diatom-inferred eutrophication was reported in the nearby Lake Holzmaar during the Boreal period (Brüchmann & Negendank, 2004), however, this result is not coeval with the changes in Lake SMM as Lake SMM was oligotrophic during the Preboreal and Boreal periods (Zolitschka et al, 2000). Sustained Daphnia populations in Lake SMM during the Preboreal and Boreal periods were possibly the result of high primary production supported by continuous groundwater discharge across the catchment.…”

“…Most of Eifel maar crater lakes are deep and have closed basins with anoxic bottom waters creating suitable conditions for the formation of high-resolution laminated sediment records (Brauer et al, 1999a;Schaber & Sirocko, 2005). Abiotic and biotic assemblages preserved in varved lake sediment are excellent indicators of annual and subannual variation in climates (Litt et al, 2001a, b), catchment erosion (Zolitschka & Negendank, 1999;Zolitschka et al, 2003), water chemistry (Schettler & Romer, 1998;Lücke et al, 2003) and palaeoenvironmental changes such as variability in windstorms (Brüchmann & Negendank, 2004;Pfahl et al, 2009). Preservation of some significant anthropogenic signatures that are crucial to understand human civilisation in Central Europe has also been reported in sediment of Eifel maar crater lakes from the beginning of the Neolithic (Gronenborn & Sirocko, 2009;Sirocko, 2009).…”

Climate-induced changes in the trophic status of a Central European lake

“…5) are reflecting oligo-to mesotrophic conditions. Most research shows elevated nutrient conditions during the Holocene due to increased temperatures and external nutrient input (e.g., Brauer et al 1999;Lotter 2001;Baier et al 2004;Brüchmann & Negendank 2004). In the case of Sacrower See, however, both diatom and chironomid assemblages show stable oligo-to mesotrophic conditions and at least seasonally oxygenated hypolimnion throughout the warm Holocene.…”

Environmental changes in northern New Zealand since the Middle Holocene inferred from stable isotope records (δ15N, δ13C) of Lake Pupuke

“…Paleoclimatic implications Brüchmann and Negendank (2004) have shown that natural eutrophication can be the result of climatically induced catchment changes and lake-internal processes. At Lake Holzmaar (Germany) a shift from mesotrophic to eutrophic/polytrophic state was induced by increasing temperature, a decrease in the frequency of annual mixing events and changes in nutrient supply.…”

“…At Lake Holzmaar (Germany) a shift from mesotrophic to eutrophic/polytrophic state was induced by increasing temperature, a decrease in the frequency of annual mixing events and changes in nutrient supply. Mild winter temperatures and/or increased wind energy were made responsible for initiating natural eutrophication at the lake via enhanced nutrient supply and productivity (Brüchmann and Negendank 2004). Although a variety of factors play a role for a lake's phosphorus supply (Hupfer and Lewandowski 2008), the phosphorus release from sedimentary iron hydroxides often in combination with sulfate reduction plays a great role once a lake's hypolimnion became anoxic (Wetzel 2001).…”