A STUDY ON CARBON ABSORPTION BY SEAWEEDS IN THE ARTIFICIAL SALT MARSH AT OSAKA-NANKO BIRD SANCTUARY

Abstract

 To clarify the carbon absorption characteristics of seaweeds growing in the artificial salt marsh at the Osaka-Nanko Bird Sanctuary, we measured the gross photosynthetic rate of Ulva ohnoi, Gracilaria parvispora, Ulva prolifera sampled in the bird sanctuary by laboratory experiments. Furthermore, we examined the annual variation in the photosynthetic activity of each algae in the bird sanctuary after creating equations for estimating the gross production rate under arbitrary environmental conditions. We found that the carbon absorption of Ulva ohnoi and Ulva prolifera strongly depended on salinity while that of Gracilaria parvispora depended on light quantum from the relationship between the gross photosynthetic rate and the light intensity of each alga with respect to water temperature and salinity. A comparison of the monthly changes in the photosynthetic activity of the algae in the aviary during seasonal variations in water quality revealed that the carbon absorption capacity of Ulva ohnoi was greater than that of Gracilaria parvispora, Ulva prolifera throughout the year, indicating that Ulva ohnoi contribute significantly to the carbon absorption function of the Osaka-Nanko bird sanctuary.