Distribution of Recent Shallow Water Foraminifera of Matsushima Bay, Miyagi Prefecture, Northeast Japan

• Main Author: Matoba Yasumochi
• Format: Report
• Language: English
• Published: Tohoku University 1970
• Subjects: Inner Bay; Middle Bay; Pacific; Planktonic foraminifera
• Online Access: http://hdl.handle.net/10097/28811; https://tohoku.repo.nii.ac.jp/?action=repository_uri&item_id=12008; https://tohoku.repo.nii.ac.jp/?action=repository_action_common_download&item_id=12008&item_no=1&attribute_id=18&file_no=1

The distribution of the Recent shallow water Foraminifera in Matsushima Bay on the Pacific coast of northern Japan was studied to analyse the fauna from the view point of taxonomic classification and environment. The foraminifers taken from the top part of the 47 sediment samples obtained by Phleger's bottom sampler, with one exception of a small pipe sampler, were used for the analyses. The living specimens were distinguished by the rose Bengal staining method. Matsushima Bay measures one to three meters in depth except for a few narrow channels at the bay mouth. The larger part of the bay bottom consists of mud overgrown at places with Zostera. The sea water flows in and out of the bay through several narrow channels at the bay mouth area, and a river and two canals drain into the bay. Oceanographic observations, analyses of the bottom sediments, details of chlorinity, temperature and other features of the different areas in the bay and of the different seasons are described. Of the oceanographic data chlorinity seems to be most important with regard to the distribution of the Foraminifera. The approximate variation ranges of the chlorinity and temperature of the bottom water at each station as related with the distribution of the Foraminifera are described. The distribution of the planktonic Foraminifera, number of species, and agglutinated Foraminifera show general correlation with chlorinity distribution, but the living benthonic population and calcareous procellaneous Foraminifera differ somewhat. By the abundancy occurrences of benthonic Foraminifera, three facies and six subfacies are discriminated in the bay. Facies A (outer bay facies) is characterized by the abundant occurrences of Pararotalia nipponica, P.? minuta, Elphidium subarcticum, "E". somaense, Ammonia japonica and many other open shallow-sea species. Facies B (middle bay facies) comprises two subfacies and is a facies transitional between the outer bay and inner bay facies and characterized by a mixed assemblage. Facies C (inner bay facies) ...