Abstract: This study used multiple analysis methods, such as scanning electron spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy, and particle size analysis to investigate the tests of agglutinated foraminifera, Polskiammina asiatica and Ammoglobigerina globigeriniformis, which were separated from the coastal sediments of the Dagang Bay, Taizhou, China. Results show that P. asiatica and A. globigeriniformis are similar in components, including mineral particles, organic membrane on the external surface of tests, organic lining on the internal surface of tests, organic membrane on the surface of minerals, and filaments which are used for connecting minerals. Quartz, microcline, and kaolinite are dominant minerals in the tests. Organic components in the tests are mainly acidic glycoproteins and lipids. Both foraminifera tend to select small sized particles which are within a narrow size range to construct their tests. Microcline particles in the tests are distributed mainly in the center of the tests and the outer wall. Few feldspar particles are observed in the clapboard of the chambers. The specific distribution of feldspars in the tests of foraminifer is probably by the curvatures of the tests and the chemical compositions of the feldspars. It is indicated that the specific distribution of feldspars would help the foraminifera with the stability of tests and access to energy as well as nutrient elements.

Key words: agglutinated foraminifer, test, feldspar, selectivity, physiological function