Isotopic evidence of particle size-dependent food partitioning in cocultured sea squirt Halocynthia roretzi and Pacific oyster Crassostrea gigas

• Published in: Aquatic Biology
• Main Authors: Kang, CK, Choy, EJ, Hur, YB, Myeong, JI
• Other Authors: 해양대학원, 10098613
• Format: Article in Journal/Newspaper
• Language: English
• Published: Inter-research 2009
• Subjects: Halocynthia roretzi; Crassostrea gigas; Coculture; Stable isotopes; Trophic relationship; Food partitioning; CIONA-INTESTINALIS L; STABLE CARBON; PARTICULATE MATTER; ORGANIC-MATTER; MYTILUS-EDULIS; PHYTOPLANKTON COMPOSITION; BIOCHEMICAL-COMPOSITION; CREPIDULA-FORNICATA; CULTIVATED OYSTERS; SUSPENSION-FEEDERS; Pacific; Pacific oyster
• Online Access: https://oasis.postech.ac.kr/handle/2014.oak/25529; https://doi.org/10.3354/AB00126

To examine the trophic relationship between the sea squirt Halocynthia roretzi and the Pacific oyster Crassostrea gigas cocultured in suspension, their delta C-13 and delta N-15 values were monitored monthly on the southern coast of Korea for a period of 2 yr. Suspended particulate organic matter was fractionated as coarse (>20 mu m, CPOM) and fine particles (<20 mu m, FPOM), and the seasonal variations in the delta C-13 and delta N-15 were determined. CPOM delta C-13 was slightly more variable than FPOM delta C-13 over the sampling period, whereas delta N-15 varied less for CPOM than for FPOM. Co- and monocultured sea squirts had a less variable VC, but a more variable delta N-15 than cocultured oysters over the sampling period, The delta C-13 and delta N-15 of cocultured sea squirts were consistently lower than those of cocultured oysters. The more pronounced difference in the delta C-13 between the cocultured suspension feeders was attributed to a striking isotopic change in oysters during their autumn to winter growing period. Differences in the VC were significant between co-, monocultured, and wild sea squirts, but not between co- and monocultured oysters. These suspension feeders can use different POM size fractions within the same habitat. The marked C-13-enrichment in oyster tissues, particularly during their fast growing period, may result from their strong selectivity of diatoms. In contrast, both the C-13- and N-15-depleted values in cocultured sea squirts indicate the importance of pico-/nano-size fractions as their dietary components. Size-related patterns in food resource exploitation between the cocultured suspension feeders may be due to different particle capture mechanisms. X 1 1 17 17 scie scopus