Diatomaceous ooze in a sedimentary core from Mariana Trench: implications for paleoceanography
Authors
Jinpeng Zhang
Guangzhou Marine Geological Survey, China Geological Survey/Key Laboratory of Marine Mineral Resources, Ministry of Natural Resources, 188 Guanghai Rd., 510760 Guangzhou
Andrzej Witkowski
Paleoceanography Unit, Faculty of Geosciences, Institute of Marine and Environmental Sciences, University of Szczecin, Mickiewicza 18, PL-70-383 Szczecin
Michał Tomczak
Paleoceanography Unit, Faculty of Geosciences, Institute of Marine and Environmental Sciences, University of Szczecin, Mickiewicza 18, PL-70-383 Szczecin
Kevin McCartney
Department of Environmental Science and Sustainability, University of Maine at Presque Isle, Presque Isle, 04769 ME
Gaowen He
Guangzhou Marine Geological Survey, China Geological Survey/Key Laboratory of Marine Mineral Resources, Ministry of Natural Resources, 188 Guanghai Rd., 510760 Guangzhou
Izabela Zgłobicka
Faculty of Mechanical Engineering, Białystok Univeristy of Technology, Wiejska 45C, PL-15-352 Białystok
Keywords:
Diatomaceous ooze, Diatom, Ethmodiscus rex, Mariana Trench, Challenger Deep
Abstract
Diatomaceous ooze sampled from near the Mariana Trench sediment surface by gravity corer (Core JL7KGC05) revealed a high sedimentary abundance of Ethmodiscus rex (Rattray, 1890) Wiseman and Hendey, 1953 fragments and tropical open ocean planktonic diatom taxa including Azpeitia nodulifera (Schmidt, 1878) Fryxell and Watkins in Fryxell, Sims and Watkins, 1986 and Alveus marinus (Grunow, 1880) Kaczmarska and Fryxell, 1996. Subsurficial sediments from the ooze are assigned a Marine Isotope Stage 2 age, approximately at the Last Glacial Maximum. The occurrence of Ethmodiscus ooze suggests massive late Pleistocene blooms in the Northwestern Pacific Ocean and provides a plausible link to paleoceanographic and paleoclimatic changes related to Antarctic Intermediate Water mass, which carried a high dissolved silica content as silicon leakage that reduced dissolution rate of diatom frustules. Northward flow of Antarctic Intermediate Water was probably related to surface current migration and southward shift of the Northwest Pacific Gyre to form oligotrophic conditions that triggered Ethmodiscus rex blooms under unusual nutrient recycling conditions within the ocean system. This bloom hypothesis may help explain differential silica dissolution during the last glacial stage.
