Regionalized primary paleoproduction variability in the sea of Okhotsk during late Pleistocene and Holocene

A Comparison of Late Quaternary Organic Proxy‐Based Paleotemperature Records of the Central Sea of Okhotsk

“…MIS 5e is characterized by a higher percentage of 1,14-diols (30% of all LCDs; Figure 7b), derived from Proboscia diatoms (Rampen et al, 2011;Sinninghe Damsté et al, 2003) and a high opal content (up to 0.63% at 129 ka; Figure 7c; from Liu et al, 2006), indicating increased diatom productivity (Leinen et al, 1986), and an increased TOC content (up to 0.81% at 129 ka; Figure 7a), suggesting higher primary productivity and, hence, more nutrient-rich water. This is supported by opal records from other cores from the Sea of Okhotsk (core PC3B, Iwasaki et al, 2012;and core GC09A, Khim et al, 2012;Bosin et al, 2015), with high opal content indicating high productivity during this time period. MIS 5e was characterized by open water…”

“…Similar to MIS 5, there is evidence of an increase in diatomaceous production during the mid-Holocene with increase in biogenic opal content in the sediment (Figure 7c; Liu et al, 2006), paleontological indications of the remains of diatoms (Bosin et al, 2015), and increases in relative proportion of 1,14-diols (Figure 7b; up to 33%), as well as elevated TOC level (up to 1.5%), all suggesting increased (diatom) productivity. This agrees with the findings of Bosin et al (2015), who showed that diatoms are the main primary producers presently in the Sea of Okhotsk (Sorokin & Sorokin, 1999) and that a phytoplankton transition occurred at the onset of the Holocene going from mainly haptophyte productivity toward a diatom productivity (Katsuki et al, 2010;Khim et al, 2012;Shiga & Koizumi, 2010).…”