연안생태계에서 아미노산의 질소 안정동위원소 비를 이용한 배경질소 안정동위원소 비 파악

Determination of Nitrogen Isotopic Baseline Using Nitrogen Isotope Ration of Individual Amino Acids in Coastal Environment

In order to estimate trophic position and to determine nitrogen isotopic baseline in the coastal ecosystems, present study analyzed nitrogen isotope ratio of individual amino acid of oyster which sampled in two different estuaries. Trophic position (TP) of oysters estimated by nitrogen isotope ratio of bulk tissue showed spatial and temporal variation (1.4 to 2.2), while trophic position of oyster estimated by nitrogen isotope ratio of amino acids was nearly varied between sampling sites and seasons (1.8 to 2.2). In addition, present study showed depleted nitrogen isotope ratio of phenylalanine compare to that of bulk tissue in the sampled oysters (approximately 3.0‰). The light nitrogen isotope ratio of phenylalanine is expected to be an indicator of nitrogen isotopic baseline with elimination of trophic enrichment in the consumers. Moreover, we estimated nitrogen isotopic baseline using both bulk and compound specific nitrogen isotope ratio of oyster and found similar values among sampling sites and seasons. The suggested estimation will be alternatively applied to the trophic ecology.