The Effects of Environmental Factors on the Growth of Lithophyllum yessoense and Hildenbrandia rubra Sporelings in Laboratory Culture

Abstract

The effects of environmental factors, such as irradiance, daylength, salinity, and desiccation, on the growth of Lithophyllum yessoense and Hildenbrandia rubra sporelings were examined. Sporelings of each species were cultured with 10, 50, 80, 120, 150 mol photon m -2 s -1 for 14 days and their maximum growth occurred under 80 mol photon m -2 s -1. Germlings of both species survived for 21 days in darkness, and even the L.yessoense germlings grew. In the salinity experiment, sporelings of each species survived for 7 days and died after 14 days under 20 and 25 psu, but the sporelings grew well under 34 psu. Physiological features of each species with respect to the evaluated daylengths (8, 12, 14 and 16 h) were slightly different, and maximal growth occurred at 16 h for L. yessoense and at 14 h for H. rubra sporelings. Mortality of the sporelings increased with the exposure period, but H. rubra was less tolerant to desiccation than L. yessoense. In conclusion, sporelings of the two species showed similar growth responses to various environmental factors with slightly different physiological features with respect to salinity, daylength, and desiccation. However, more ecological and physiological studies on slow-growing crustose algae are required to elucidate the expansion of barren ground around the coastal areas of Korea.

Effects of Irradiance and Temperature on the Photosynthesis of the Crustose Coralline Algae Pneophyllum fragile (Corallinales, Rhodophyta) in the Coastal Waters of Korea

“…Recently, studies of whitening in the coastal waters of Korea have been initiated to restore the macroalgae meadows and assess their ecological functions [1][2][3][4]. However, most of the studies focused on the monitoring of the occurrence and evolution area of whitening because of the absence of appropriate methods to estimate CCA metabolism [24,25]. P. fragile, a crustose red alga (Corallines, Rhodophyta) that is widely distributed in Australia, Canada, the Caribbean, England, Japan, Mexico, Russia, the United States, and the Mediterranean Sea, was collected to examine its morphology and anatomical characteristics [26].…”