Trophic linkages among biological communities in Korean coastal waters examined by
stable isotope analyses
Nam-Il Won, Jun-Sop Kim, Hyeon Seok Kim and Youngsung Kim
K-water Institute, Korea Water Resources Corporation, Daejeon, R Korea
E-mail: namilwon@kwater.or.kr
The coastal ecosystem has been remarked as a critical part to sustain marine ecosystem resilience
for human. Fisheries production is likely to largely rely on ecosystem conditions and there are
increasing concerns of multiple stressors affecting the coastal resilience. Those stressors could
induce cascade effects on marine ecosystems through trophic linkages. In terms of ecosystembased management, understanding trophic linkages of a coastal ecosystem is essential to evaluate
environmental status of target coastal ecosystems. Korean coastal areas typically have both many
bay ecosystems closely related with land-based activities and offshore areas strongly affected by
oceanic currents. The present study reports trophic structures of biological communities of
Korean coastal areas including marine sand mining as a offshore environmental stressor. Fish
assemblages and benthic organisms were sampled along a depth gradient from shallow coastal
areas to deep offshore ones. Several size fractions of particulate organic matters were also
collected as potential primary food sources. Stable isotope analyses were applied to all the
samples to describe trophic structures of biological communities at each designated coastal area.
Bulk particulate organic matter (POM) were isotopically different each other along the depth
gradient, while surface POM fraction showed relatively strong size-dependent stable isotope
values with remarkably different values of the finest POM (<20 m). Fish compositions were
also slightly different among several coastal areas, indicating that fish assemblages could be
loosely connected among coastal areas. The present results imply that trophic linkages among
coastal biological communities could be an important factor to understand the ecological
resilience regarding possible cascade effects.