Introduction to the JoPL special issue, “Holocene paleoenvironmental records from Arctic lake sediment”

Abstract

The 18 papers in this Special Issue of the Journal of Paleolimnology report new records of Holocene environmental and climate change from Arctic lake sediment. At least 15 distinct physical, chemical, and biological properties were analyzed at lakes located across the North American Arctic and subarctic, and northwestern Europe. The studies are notable for their multi-proxy approach (eight present data for at least five different proxies), and for the high quality of their geochronological control. Three of the studies analyzed sediment from more than one lake to test the influence of contrasting physiographic settings on the response of proxies to the same climate forcing. The sedimentary sequences analyzed in seven studies extend beyond 11.5 cal ka, providing evidence for pronounced climate shifts that took place during the late-glacial period. Two-thirds extend beyond 8 cal ka; many of these records were interpreted in terms of the shift in temperature and moisture that occurred during the transition from the warm early to middle Holocene to the cooler late Holocene. These records contribute to the growing network of sites that is needed to reconstruct the spatial pattern of this pronounced paleoclimate transition, and to address how ocean-atmospheric circulation changed with the mean state of climate.

The relative influences of climate and catchment processes on Holocene lake development in glaciated regions

“…The role of catchment processes in producing regional heterogeneity in paleolimnological studies indicates the need for more widespread use of multiple sites (i.e. regionally replicated studies) when using lake sediment records for reconstructing past climate (Fritz 2008;Kaufman 2012). The prominent role of localscale processes in mediating the impact of climate on lacustrine biotic communities and lakewater chemistry serves to emphasize the critical role of ecosystem processes in affecting lake structure and function (cf Lantz et al 2010).…”

Responses of microbial phototrophs to late‐Holocene environmental forcing of lakes in south‐west Greenland

“…This is true even in a relatively small area (<150 km) such as the Kangerlussuaq lake district, which is reasonably homogenous in terms of geology and vegetation. As highlighted by Kaufman (2012), recognising the spatial complexity of lake responses to regional climate forcing and the associated non‐climatic filters is critical if lake sediment records are to be used to reconstruct past‐climate variability in the Arctic. There is clearly a need for greater replication at the regional scale to help identify signals of environmental change.…”