Multi-proxy evidence for millennial-scale changes in North Pacific Holocene hydroclimate from the Kenai Peninsula lowlands, south-central Alaska

Ornithogenic vegetation: How significant has the seabird influence been on the Aleutian Island vegetation during the Holocene?

“…The expansion of tall‐grass meadows would rather take place in the Early Holocene, when the highest temperatures were observed (Peteet et al., 2019 ) or in the Holocene maximum 7,000–5,000 years ago (Kaufman et al., 2016 ). However, according to various estimates, circa 4,500 years ago and later, the early Neoglacial events began, which resulted in an increase in storm activity and a decrease in temperature throughout the Bering Sea region (Barclay et al., 2009 ; Broadman et al., 2020 ; Kaufman et al., 2016 ; Peteet et al., 2019 ). Therefore, it remains unknown what climatic shifts during the subsequent cooling period could lead to the replacement of coastal tundra with more productive meadow vegetation.…”

“…The Aleutian Islands are a volcanic origin archipelago extending almost 2,000 km from Kamchatka to mainland Alaska. The fundamental climatic patterns of the Aleutian Islands are determined by the position of the Aleutian Low (Broadman et al, 2020;Rodionov et al, 2005Rodionov et al, , 2007. Mild winters, high humidity, cloudiness, fogs, frequent storms, and strong winds are the features that define the Aleutian landscape (Hultén, 1968).…”

Reconstructing postglacial hydrologic and environmental change in the eastern Kenai Peninsula lowlands using proxy data and mass balance modeling

“…In recent decades, the development of increasingly sophisticated methods for studying past environments has enhanced our ability to interpret paleoclimate datasets from southern Alaska. For example, developments in our understanding of oxygen isotope systematics and proxy systems have yielded numerous reconstructions of past hydroclimatic change inferred from lake sediment archives in the Kenai Peninsula and surrounding region (e.g., Schiff et al, 2009; Jones et al, 2014, 2019; Broadman et al, 2020).

Figure 1.( A ) Location of the Kenai Peninsula in Alaska; ( B ) location of the Hidden Lake and Kelly Lake region of the Kenai lowlands; ( C ) glacier margins during the Skilak (orange) and Elmendorf (red) stades of the Naptowne glaciation (Reger et al, 2007), with the location of Kelly (D) and Hidden (E) Lakes indicated; ( D ) bathymetric map of Kelly Lake; and ( E ) bathymetric map of Hidden Lake; ( D ) and ( E ) show locations of sediment cores discussed in the text.

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Holocene Hydroclimatic Reorganizations in Northwest Canada Inferred From Lacustrine Carbonate Oxygen Isotopes

“…Some recent studies around the Gulf of Alaska have proposed increases in AL activity during the middle Holocene ∼5–4 ka BP to explain shifts in isotope records, but this is not evident from δ 18 O values of Squanga Lake (Bailey et al., 2018; Broadman et al., 2020). Multi‐year monitoring of precipitation isotopes near Anchorage suggests that AL influences on moisture availability and precipitation δ 18 O values at coastal locations differ from the interior Yukon (Bailey et al., 2015, 2019), largely due to the influence of topographic effects.…”

“…In fact, oxygen isotope data spanning the Holocene around much of eastern Beringia are rare. Permafrost ice and fossil wood cellulose data on the North Slope of Alaska that date to the Pleistocene–Holocene transition and expression of the Younger Dryas (Gaglioti et al., 2017; Meyer et al., 2010), relict sediment pore ice data from the central Yukon Territory (referred to as Yukon herein), and a handful of diatom and cellulose records from southern Alaska have all provided insights into temperature and moisture changes over the Holocene (Bailey et al., 2018; Broadman et al., 2020; Jones et al., 2014; Porter et al., 2019). To provide new information about hydroclimatic evolution in the semi‐arid boreal interior regions, this study presents sediment calcite proxies from Squanga Lake (60.44°N, 133.56°W), located in the southwest Yukon.…”