Grateloupia asiatica and G. divaricata are edibile marine red algae that commonly occur on the east coast of Korea: G. asiatica occurs in sheltered locations such as estuaries or tide pools, and G. divaricata usually grows at the depth of 2~5 meters under the sea where freshwater flows. We compared growth pattern of both species in Aninjin, Gyoam, Hosan, and Sacheon in order to find suitable location for mass culture of the Grateloupia species. In case of G. asiatica, vegetative and tetrasporangial thalli were found in Gyoam and Sacheon, while gametophytic thalli were found in Aninjin. Population from Aninjin was the largest on the average length of thalli (20.6 cm) among populations studied. Population of G. divaricata in Sacheon seems to be maintained mostly with sporophytes. However, Aninjin and Hosan populations consisted of gametophytes and sporophytes in summer. Population from Hosan was the largest on the average length of thalli (19.8 cm). Based on our results, G. asiatica and G. divaricata repeat a typical triphasic life history of red algae on the east coast of Korea.

To assess the trophic function of an artificial macroalgal habitat, we compared the stable carbon and nitrogen isotope ratios of two amphipods (Caprella sp. and Ampithoe sp.) and their potential food sources in a transplanted macroalgal habitat (Grateloupia asiatica) with those in a natural habitat . There were no significant differences in the isotopic values of both consumers and their potential food sources between the transplanted and natural habitats. Such isotopic similarities between the two sites indicate a comparable resource consumer relationship. Additionally, our results showed similar isotopic niche areas and high dietary overlap (>65%) of the two amphipods between the transplanted and natural sites, suggesting that the transplanted habitat plays ecological roles similar to the natural habitat. Overall, isotopic assessment can provide information on the trophic function of diverse transplanted macroalgal habitats and improve post-monitoring efforts in the management of artificial ecosystems.