Late Holocene dinoflagellate cysts as indicators for short‐term climate variability in the eastern Laptev Sea (Arctic Ocean)

Abstract

Kunz-Pirrung, M., Matthiessen, J. and de Vernal, A. 2001. Late Holocene dinoflagellate cysts as indicators for short-term climate variability in the eastern Laptev Sea (Arctic Ocean).ABSTRACT: A sediment sequence from the eastern Laptev Sea shelf (Siberian Arctic, Russia) has been studied for dinoflagellate cysts in order to reconstruct sea-surface conditions during the late Holocene. Variability of assemblage composition and derived sea-surface temperature estimates indicate that the neoglacial cooling was not a gradual climate change from 2510 to 900 cal. yr BP. Relatively stable conditions, with temperatures that were warmer than today, were punctuated by a few cooling events in summer on centennial time-scales. During these events temperatures reached modern values. This suggests that modern conditions may have been established abruptly within a short period in the past 1000 yr, which is not documented in our record.

Arctic sea-ice proxies: Comparisons between biogeochemical and micropalaeontological reconstructions in a sediment archive from Arctic Canada

“…The primary micropalaeontological data – dinocyst assemblages (relative abundances; Figure 5) – agree well with the P B IP 25 sea-ice regimes (Figure 4). The interval prior to AD 1740 is characterized by a high proportion of autotrophs (particularly O. centrocarpum sensu Wall and Dale (1966)), whose producers require seasonally open water for photosynthesis (and are generally distributed along the inflow of relatively warmer waters within an Arctic context; Kunz-Pirrung et al, 2001; Matthiessen et al, 2005) and a reduced component of heterotrophs found in regions characterized by extended SIC (producing dinocysts such as I. ? cezare ; De Vernal et al, 2013b; Zonneveld et al, 2013).…”

“…Dinocysts are only indirectly influenced by sea ice. Autotrophs such as O. centrocarpum need seasonally open water for photosynthesis (Kunz-Pirrung et al, 2001; Matthiessen et al, 2005). Conversely, heterotrophs (e.g.…”

“…Briefly, preparation followed standard protocols (known volumes and weights of samples sieved at 10 µm followed by digestion in 10% HCl and 49% HF followed by sieving at 10 µm; Marret and Zonneveld, 2003) with a minimum of 300 dinocysts counted from each sample. Taxonomy followed Head et al (2001), Kunz-Pirrung et al (2001) and Marret and Zonneveld (2003). Dinocyst data were used for quantitative reconstructions of SSTs, sea-surface salinities (SSSs) and sea ice, based on MAT (Guiot and De Vernal, 2007, 2011), which compares fossil dinocyst data with a modern distribution reference database ( n = 1492 sites; De Vernal et al, 2013c).…”

Middle–Late Holocene palynology and marine mollusks from Archipiélago Cormoranes area, Beagle Channel, southern Tierra del Fuego, Argentina

“…were grouped together into Echinidinium-Islandinium complex. Islandinium minutum is the more specific taxa of shelf assemblages of the Arctic Ocean, including polynyas (Kunz-Pirrung et al, 2001). It is an euryhaline taxon dominating assemblages from the continental margins where summer temperatures rarely exceeding 7 °C ranging from −2 to 5 °C and salinity varies between 17 to 34 PSU.…”

Diatom‐inferred salinity records from the Arctic Siberian Margin: Implications for fluvial runoff patterns during the Holocene

“…So far, there was little data available on past hydrology from the Laptev Sea due to a scarcity of sediment cores and the lack of reliable age control of these cores [ Holmes and Creager , 1974; Aksenov et al , 1987]. Recent micropaleontological studies now indicate that groups such as diatoms and aquatic palynomorphs offer the opportunity to also investigate past hydrological processes [ Bauch et al , 2000; Bauch and Polyakova , 2000; Kunz‐Pirrung et al , 2001].…”