Calcareous microfossil-based orbital cyclostratigraphy in the Arctic Ocean

Central Arctic Ocean paleoceanography from ~ 50 ka to present, on the basis of ostracode faunal assemblages from SWERUS 2014 expedition

“…In general, the data confirm the sensitivity of Arctic benthic fauna to relatively large climate transitions, such as those seen in benthic foraminifera during the last deglacial and Holocene intervals from the Laptev Sea (Taldenkova et al, 2008(Taldenkova et al, , 2013 and the Beaufort Sea and Amundsen Gulf (Scott et al, 2009). These records provide a useful context for understanding orbital-scale Arctic faunal variability during the last 500 ka, as seen in benthic foraminifera and ostracodes (Cronin et al, 2014;Marzen et al, 2016). These millennial faunal changes seem to be distinct from microfaunal events in which a species is found in certain stratigraphic intervals in sediment cores located far outside that species normal depth and/or geographic range.…”

“…The new sites are located beneath the Transpolar Drift, a surface circulation pattern that transports sea ice across the central Arctic Ocean from the Siberian and Latpev seas towards the Fram Strait, and hence influences ice export into the Nordic Seas and the North Atlantic. The central Arctic Ocean has exhibited significant oceanographic changes over orbital timescales as reflected in various lithological, geochemical and micropaleontological proxies (Nørgaard-Pederson et al, 1998;O'Regan et al, 2008;Marzen et al, 2016). In addition to records of orbitally forced climate changes, some Arctic Ocean records contain evidence for suborbital changes, including the prevalence of frequent, rapid geographic range shifts of ecologically sensitive species.…”

Interglacial Paleoclimate in the Arctic

“…Our approach was to use radiocarbon dating of the uppermost 10 to 30 cm of sediment from box and multicores (see Poirier et al, ), two key foraminiferal markers, Bolivina aculeata (a dominant species in MIS 5a, ~80 ka, summarized in Cronin et al, ) and the planktic species Turborotalita egelida (discussed above, ~400 ka; O'Regan et al, ), and cyclostratigraphy of calcareous microfossil density (benthic foraminifera, ostracodes; Marzen et al, ). Due to highly varying sedimentation rates during glacial and interglacial cycles, we developed age‐depth models for each core using foraminiferal tiepoints and MIS boundaries identified from microfaunal density.…”

“…Figure 8 shows Mg/Ca ratios converted to°C from Figure 6. (a) Arctic Productivity Index constructed from benthic foraminiferal and ostracode density curves modified slightly into higher resolution binning from Marzen et al (2016) using the stacking procedure in Lisiecki and Lisiecki (2002). Arctic productivity is an indicator of biological productivity in benthic ecosystems linked directly to near-surface sea ice cover, algal primary productivity, and surface-to-seafloor food flux.…”

“…Sources, 1 Cronin et al, , , 2 Marzen et al, , 3 This paper, 4 Cronin et al, , 5 DeNinno et al, , 6 Polyak et al, , Dipre et al, , 7 Hanslik et al, …”