Work

Geochemical and Microstructural Signals in Giant ClamTridacna maximaRecorded Typhoon Events at Okinotori Island, Japan

Year: 2018

Type: article

Abstract: To validate the usability of the giant clam shell as a recorder of short‐term environmental changes such as typhoons, we collected a liveTridacna maximafrom Okinotori Island, Japan, on 15 June 2006. Growth increment thickness, stable isotope ratio (δ18Oshell, δ13Cshell), and the barium/calcium ratio (Ba/Ca) in theT. maximashell sample were measured and compared to Okinotori Island instrumental environmental data. In the outer layer of the shell sample, there were 365 ± 6 growth increments per year, as estimated by the δ18Oshellprofile compared with sea surface temperature. The growth increments in the specimen were formed daily, and thus, we can determine the date of the sampling points of δ18Oshell, δ13Cshelland the Ba/Ca ratio by counting growth increments. After typhoon approach, there is a decrease in increment thickness and some disturbed growth increments. The positive peaks in the shell Ba/Ca ratio and δ18Oshellcorresponded to lower sea surface temperature caused by typhoons. These results indicated that the microstructural and geochemical record inTridacna maximashells could be useful for detecting past typhoon events.

Source: Journal of Geophysical Research Biogeosciences

DOI: 10.1029/2017jg004082

Authors: Taro Komagoe, Tsuyoshi Watanabe, Kotaro Shirai, Atsuko Yamazaki, Mitsuo Uematu

Institutions: Hokkaido University, KIKAI institute for Coral Reef Sciences, Atmosphere and Ocean Research Institute, The University of Tokyo, The University of Tokyo, Kyushu University

Language: English

Topic: Geology and Paleoclimatology Research

Subfield: Atmospheric Science

Field: Earth and Planetary Sciences

Domain: Physical Sciences

SDGs: Life below water, Climate action

Open Access status: bronze

Funder: Japan Society for the Promotion of Science