Mid‐Wisconsin to Holocene Permafrost and Landscape Dynamics based on a Drained Lake Basin Core from the Northern Seward Peninsula, Northwest Alaska

Abstract

Permafrost-related processes drive regional landscape dynamics in the Arctic terrestrial system. A better understanding of past periods indicative of permafrost degradation and aggradation is important for predicting the future response of Arctic landscapes to climate change. Here, we used a multi-proxy approach to analyse a~4 m long sediment core from a drained thermokarst lake basin on the northern Seward Peninsula in western Arctic Alaska (USA). Sedimentological, biogeochemical, geochronological, micropalaeontological (ostracoda, testate amoebae) and tephra analyses were used to determine the long-term environmental Early-Wisconsin to Holocene history preserved in our core for central Beringia. Yedoma accumulation dominated throughout the Early to Late-Wisconsin but was interrupted by wetland formation from 44.5 to 41.5 ka BP. The latter was terminated by the deposition of 1 m of volcanic tephra, most likely originating from the South Killeak Maar eruption at about 42 ka BP. Yedoma deposition continued until 22.5 ka BP and was followed by a depositional hiatus in the sediment core between 22.5 and 0.23 ka BP. We interpret this hiatus as due to intense thermokarst activity in the areas surrounding the site, which served as a sediment source during the Late-Wisconsin to Holocene climate transition. The lake forming the modern basin on the upland initiated around 0.23 ka BP and drained catastrophically in spring 2005. The present study emphasises that Arctic lake systems and periglacial landscapes are highly dynamic and that permafrost formation as well as degradation in central Beringia was controlled by regional to global climate patterns as well as by local disturbances.

Limnological evolution of Zelma Lake, a recently drained thermokarst lake in Old Crow Flats (Yukon, Canada)

“…In June 2007, members of our research team witnessed the rapid, partial drainage of Zelma Lake -one of the largest lakes in OCF -caused by outlet erosion stemming from above-average winter and spring precipitation prior to the event (Wolfe and Turner 2008). Considerable attention has been given to the mechanisms and in situ observations of lake drainage (Yoshikawa and Hinzman 2003;Hinkel et al 2007;Marsh et al 2009;Pohl et al 2009;Jones and Arp 2015) and early to late Holocene thermokarst dynamics and landscape evolution (Jones et al 2012;Lenz et al 2016aLenz et al , 2016b, but much less is known about the limnological conditions of residual waterbodies following drainage and how they differ from pre-drainage conditions. Hobbie et al (1999) and Frey and McClelland (2009) generally predict that accelerated thermokarst activity will impact the biota of aquatic ecosystems throughout the Arctic.…”

Impacts of shore expansion and catchment characteristics on lacustrine thermokarst records in permafrost lowlands, Alaska Arctic Coastal Plain

“…Secondary thermokarst lakes are typically (1) small and shallow ponds at the low-lying margins or (2) slightly deeper and larger lakes in the basin center created by thawing into ice-and organic-rich lacustrine material of a drained primary thermokarst lake [45]. Both have been observed in recent basins of Alaskan permafrost lowlands [40,43,45,56] or interpreted in paleo-records [57]. In the early stage of Peatball Lake development, the winter lake ice cover apparently has not disturbed the sediment layering.…”

New microsporidia, Glugea sardinellensis n sp (Microsporea, Glugeida) found in Sardinella aurita Valenciennes, 1847, collected off Tunisian coasts

“…4), although some outlying group members occur. Beyens et al 1986aBeyens et al , 1986b 2 Jan Mayen Beyens et al 1986aBeyens et al , 1986b 3 Central and North West Spitsbergen Beyens et al 1986aBeyens et al , 1986b 4 Edgeøya, Svalbard Chardez 1986c, 1995;Chardez and Beyens 1987 Meyer et al 2010, Wetterich et al 2012, Bobrov et al 2013, Lenz et al 2015 40 Chokurdakh (Yakitia) Bobrov et al 2013, Teltewskoi et al 2016 …”