TY - JOUR
T1 - Cycladophora davisiana (Radiolaria) in the Okhotsk Sea
T2 - A key for reconstructing glacial ocean conditions
AU - Okazaki, Yusuke
AU - Seki, Osamu
AU - Nakatsuka, Takeshi
AU - Sakamoto, Tatsuhiko
AU - Ikehara, Minoru
AU - Takahashi, Kozo
N1 - Funding Information:
We express our appreciation to the captain, crew, and scientists on board the R/V Khromov cruise and members of the Okhotsk sediment core project. We thank three anonymous reviewers for their critical and constructive comments. This study was funded by the CREST program (M. Wakatsuchi, PI), Japan Science and Technology Corporation and MEXT Grants-in-Aid for Scientific Research B2 Project No. 10480128, and B1 Project No. 13440152.
PY - 2006/10
Y1 - 2006/10
N2 - Cycladophora davisiana, a radiolarian species dwelling at mesopelagic depths, is known as a representative glacial fauna due to its unique distribution during glacial periods. In the present ocean, abundant production of C. davisiana is only observed in the Okhotsk Sea, indicating an adaptation of C. davisiana for seasonal sea-ice covered conditions. We found pronounced abundant production of C. davisiana during the early to middle Holocene in the Okhotsk Sea, suggesting more favorable conditions for C. davisiana than the present Okhotsk Sea. In order to clarify the reason, oceanographic conditions during the Holocene were reconstructed based on biomarkers, lithogenic grains including ice-rafted debris (IRD), biogenic opal, and total organic carbon (TOC) in two sediment cores from the Okhotsk Sea. These indicators suggest that the pronounced C. davisiana production may be attributed to: 1) a supply to mesopelagic depths under intensified stratification of fine organic particles derived from coccolithophorids, bacteria, and detrital materials; and 2) cold, well-ventilated intermediate water formation.
AB - Cycladophora davisiana, a radiolarian species dwelling at mesopelagic depths, is known as a representative glacial fauna due to its unique distribution during glacial periods. In the present ocean, abundant production of C. davisiana is only observed in the Okhotsk Sea, indicating an adaptation of C. davisiana for seasonal sea-ice covered conditions. We found pronounced abundant production of C. davisiana during the early to middle Holocene in the Okhotsk Sea, suggesting more favorable conditions for C. davisiana than the present Okhotsk Sea. In order to clarify the reason, oceanographic conditions during the Holocene were reconstructed based on biomarkers, lithogenic grains including ice-rafted debris (IRD), biogenic opal, and total organic carbon (TOC) in two sediment cores from the Okhotsk Sea. These indicators suggest that the pronounced C. davisiana production may be attributed to: 1) a supply to mesopelagic depths under intensified stratification of fine organic particles derived from coccolithophorids, bacteria, and detrital materials; and 2) cold, well-ventilated intermediate water formation.
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U2 - 10.1007/s10872-006-0082-2
DO - 10.1007/s10872-006-0082-2
M3 - Article
AN - SCOPUS:33748418882
SN - 0916-8370
VL - 62
SP - 639
EP - 648
JO - Journal of Oceanography
JF - Journal of Oceanography
IS - 5
ER -