Fatty acid markers as an indicator for temporal changes in food sources of the bivalve Quidnipagus palatum

Abstract

Changes in the fatty acid composition in the tissues of the bivalve Quidnipagus palatum from the Tomigusuku intertidal flat, Okinawa, Japan, collected in four different seasons (November 2000, the beginning of cold season; January 2001, the cold season; May 2001, the rainy season; and July 2001, the warm season) were examined and compared to the composition of surface sediments and suspended particulate materials. Assessment of fatty acid markers suggested that the food sources of Q. palatum differed between seasons and depended on the sources of organic material present in the sediment and water column. Vascular plants and bacteria were the main dietary components from July to November because of their abundance in the sediment. From November to January, macroalgae and phytoplankton were the major food sources of Q. palatum, corresponding to their predominance in sediments and algal blooms, respectively. During the May rainy season, organic matter in the sediment was dominated by diatoms, whereas the water column contained diatoms and resuspended macroalgal detritus. The transition to the warm season by July significantly increased the contribution of diatoms to the organic matter present in both the sediment and the water column. Consequently, from May to July, diatoms became the main food source for Q. palatum.

Keywords:

• Fatty acid biomarkers
• sediment
• intertidal flat
• Okinawa

Acknowledgements

Z.B. is grateful to the Ministry of Education, Science, Sport and Culture, Japan (Monbukagakusho) for scholarship grant during his study. The authors would like to thank the Okinawa Prefecture for the use of the facilities at Tomigusuku Marine Laboratory. Thanks are given to the members of Laboratory of Ecology and Systematics for technical assistance, and to anonymous referees for critical reading of an earlier version of the manuscript.

Notes

^a Dunstan et al. (1994)

^b Gillan and Johns (1986)

^c Perry et al. (1979)

^d Meziane and Tsuchiya (2000)

^e Volkman et al. (1989)

^f Pond et al. (1998)

^g Napolitano et al. (1997)

^h Johns et al. (1979)

ⁱ Vascovsky et al. (1996)

^j Scribe et al. (1991)