Impact of eutrophication on shallow marine benthic foraminifers over the last 150??years in Osaka Bay, Japan

Tsujimoto, A.; Nomura, R.; Yasuhara, M.; Yamazaki, H.; Yoshikawa, S.

Abstract:

High-resolution foraminiferal analysis was conducted on a short sediment core from the inner part of Osaka Bay, Japan. Changes in foraminiferal assemblages were associated with eutrophication, bottom water hypoxia, and changes in red tide-causing algae. Before the 1920s, the calcareous species Ammonia beccarii, and the agglutinated species Eggerella advena and Trochammina hadai were rare, but calcareous foraminifers in general were abundant. Between the 1920s and 1940s, calcareous foraminifers decreased abruptly in abundance, while A. beccarii, E. advena and T. hadai increased in abundance. This faunal change corresponded in time to an increase in nutrients flowing in through the Yodo River, and bottom water hypoxia related to eutrophication. In the 1960s and 1970s, A. beccarii, E. advena and T. hadai further increased in abundance to become dominant, and many calcareous foraminifers nearly disappeared, corresponding to increasing bottom water hypoxia related to the rapid increase in discharged nutrients during the high economic growth period from 1953 to 1971. After the 1990s, A. beccarii decreased rapidly in abundance and E. advena and Uvigerinella glabra increased in abundance. The main components of red tide-causing algae changed from dinoflagellates to diatoms in the 1980s through 1990s, thus there was a change in the food supply to the benthos, which may have caused the increase in abundance of E. advena and U. glabra. ?? 2006 Elsevier B.V. All rights reserved.

Genre:

Article

ProdID:

70028172

Citation Author:

Tsujimoto, A.; Nomura, R.; Yasuhara, M.; Yamazaki, H.; Yoshikawa, S.

Citation Contributing Office:

Citation Datum:

Citation Day:

Citation Edition:

Citation Editor:

Citation End Page:

268

Citation Issue:

Citation Keywords:

Citation Language:

English

Citation Larger Work Title:

Marine Micropaleontology

Citation LatN:

Citation LatS:

Citation LonE:

Citation LonW:

Citation Month:

Citation No Pagination:

Citation Number Of Pages:

Citation Online Only Flag:

Citation Phsyical Description:

Citation Projection:

Citation Public Comments:

Citation Publisher:

Citation Series:

Citation Series Code:

Citation Series Number:

Citation Search Results Text:

Impact of eutrophication on shallow marine benthic foraminifers over the last 150??years in Osaka Bay, Japan; 2006; Article; Journal; Marine Micropaleontology; Tsujimoto, A.; Nomura, R.; Yasuhara, M.; Yamazaki, H.; Yoshikawa, S.