Vertical distribution of polycystine radiolarians in the northern East China Sea

New northwest Pacific radiolarian data as a tool to estimate past sea surface and intermediate water temperatures

“…profunda / truncatum group, and D . elegans [e.g., Ishitani and Takahashi , ; Kamikuri et al ., ; Lombari and Boden , ; Matsuzaki et al ., ; Yamashita et al ., ; Okazaki et al ., ] belong into our factor S‐1 (Table ). As described above the factor S‐1 corresponds to the area influenced by the NPEC and the KC (Figure ).…”

“…According to Lombari and Boden [], the area between 0 and 10°N, which is influenced by the NPEC, is characterized by higher relative abundances of Dictyocoryne profunda / truncatum and Dictyocoryne elegans . Plankton tow and sediment trap studies have also shown that these species have higher standing stocks in the equatorial region of the North Pacific rather than in the region influenced by the KC [ Yamashita et al ., ; Ishitani and Takahashi , ; Matsuzaki et al ., ; Okazaki et al ., ]. In this study, D .…”

“…First, the tool proposed by the University of Bremen is only applicable to near‐surface depths. The second is that based on previously published works, intermediate water radiolarians are not restricted to a single water depth, but rather occur over a range of depths [ Ishitani and Takahashi , ; Matsuzaki et al ., ; Okazaki et al ., ; Tanaka and Takahashi , ; Yamashita et al , ]. The last problem is that intermediate water temperature varies drastically from 200 to 500 m, while a relatively low temperature change is recorded between 500 and 1000 m [ Locarnini et al ., ].…”

Taxonomy and species diversity of Holocene pylonioid radiolarians from surface sediments of the northeastern Indian Ocean

“…(Itaki, 2009;Matsuzaki et al, 2015a;Motoyama et al, 2016) grouped together Tetrapyle and "Octopyle" species as the "Tetrapyle octacantha Müller group" because of the practical difficulties in identification when a large number of samples must be examined in a short time. This grouping may be convenient in temperate and colder regions such as the Sea of Japan (Itaki, 2003(Itaki, , 2009Motoyama et al, 2016) and the Northwest Pacific (Matsuzaki et al, 2016) because the number of these taxa is abundant or rare in middle-high latitude regions. However, members of the "Tetrapyle octacantha group" are dominant in subtropical to tropical regions like the South China Sea (Tan and Chen, 1990;Zhang et al, 2009;Hu et al, 2015) and Indian Sea (this study), and should therefore be identified to the species level.…”

Quaternary radiolarian biostratigraphy in the subarctic northeastern Pacific (IODP Expedition 341 Site U1417) and synchroneity of bioevents across the North Pacific

“…The deep-sea sediments collected at Site U1417 span the time interval from the Pleistocene to the Miocene (Jaeger et al, 2014). Of particular interest in the retrieved cores are polycystine radiolarians, which are siliceous microorganisms that inhabit shallow, intermediate and deep waters (e.g., Renz, 1976;Anderson, 1983;Kling, 1979;Kling and Boltovskoy, 1995;Nimmergut and Abelmann, 2002;Okazaki et al, 2004;Suzuki and Not, 2015;Matsuzaki et al, 2016). Their skeletons composed of amorphous silica are generally well-preserved and abundant in the seafloor of the North Pacific, and the high levels of radiolarian preservation and abundance in deep-sea sediments of this region have facilitated numerous paleoceanographic and biostratigraphic studies (e.g., Hays, 1970;Kling, 1973;Foreman, 1975;Morley et al, 1982;Motoyama, 1996;Pisias et al, 1997;Matul et al, 2002;Kamikuri et al, 2004Kamikuri et al, , 2007Matul and Abelmann, 2005;Itaki et al, 2012;Matsuzaki et al, 2014aMatsuzaki et al, -c, 2015aKamikuri, 2017).…”