报告时间：2019年7月19日（星期五）下午 15:00-16:00
报告地点：天津大学地科院（卫津路校区第16教学楼）221报告厅
报告题目：Coral Sclerochronology: High-temporal resolution windows for palaeoclimatology, paleoceanography, and paleoecology
主讲嘉宾：Dr. Tsuyoshi Watanabe (Hokkaido University/KIKAI institute for coral reefs sciences)
嘉宾简介：Tsuyoshi Watanabe（渡边刚）博士，北海道大学地球与行星科学系高级讲师。1999年毕业于毕业于北海道大学，获得环境地球科学博士学位。先后在日本地质调查所、澳大利亚国立大学、东京大学和法国国家科学研究中心开展博士后研究。自2004年至今，任职于北海道大学，期间赴东京大学、德国亚琛工业大学和美国夏威夷大学做访问研究员。2003年获得日本地球化学学会“青年科学家奖”，2008年获得日本珊瑚礁学会“川口奖”。Tsuyoshi Watanabe博士的研究兴趣包括：1）利用碳酸盐对古环境进行高分辨率气候/环境重建；2）生物矿化和生物碳酸盐保存；3）地球历史上生物地球化学循环和气候变化的生物响应。以第一/通讯作者在Nature、Geology、GCA、GRL、JGR等期刊发表多篇学术论文。
报告摘要：
The daily and annual growth bands formed in biogenic carbonates such as coral skeletons and molluscan shells could serve as the high-temporal resolution archives for the environmental and/or physiological changes during their life span. We use skeletological and geochemical approaches to investigate the histories recorded in living and fossil specimens. Understanding the past climate variability and oceanographic events in the tropical ocean is a high priority as long-term observation is very limited in these area. Tropical shallow water corals could live up to several hundreds years and the decadal to century-scale of climate and oceanic signals such as global warming, ocean acidification, El no-Southern Oscillation (ENSO), anthropogenic CO2 uptake, atmosphere, marine pollution, river discharge, and ocean circulation dynamics could be detected via reconstructing temperature, salinity, pH, nutrient, and chemical composition in seawater by using isotopic (e.g. oxygen, carbon, boron, lead, and nitrogen isotopes) and elemental (e.g. Sr/Ca, Mg/Ca, and Ba/Ca ratios) analysis along growth direction.
Ocean acidification and rising atmospheric CO2 with global warming are also predicted to severely damage the calcification processes of marine organisms and, thus, the sustainability of marine ecosystems in the near future. The skeletal density, extension rate, and calcification rate deduced from coral cores could be useful to estimate the response and acclimatization against such environmental changes during last few hundred years, and to predict the future of coral reefs and ecosystems exhibiting coral acclimation to warmer, more acidified, and polluted conditions.
On the other hand, such recent advance of microanalytical techniques also revealed large heterogeneity of these isotopic and elemental composition in nano to sub-micrometer scale of skeletal microstructures, which are difficult to explain simply by surrounding environmental changes, suggesting understanding biomineralization processes in cellular level with more complexity and plasticity are important to establish more reliable proxy for past environmental changes. I would like to introduce our recent and on-going researches applied on modern and fossil specimens in western pacific, Indian Ocean, and Caribbean Sea and also recent efforts to understand biomineralization process of coral reef dweller.
References:
Yamazaki, et al. (2016) A 150-year variation of the Kuroshio transport inferred from coral nitrogen isotope signature, Paleooceanography
Yamazaki, et al. (2014) The coral d15N record of terrestrial nitrate loading varies with river catchment land use, Coral Reefs
Ohmori, et al. (2013) Lead concentration and isotopic composition in the Pacific sclerosponge (Acanthochaetetes wellsi) reflects environmental lead pollution, Geology
Sano et al. (2012) Past daily light cycle recorded in the strontium/ calcium ratios of giant clam shells, Nature Communication.
Watanabe, et al. (2011) Permanent El Nino during the Pliocene warm period not supported by coral evidence, Nature, 471,
