• Korean Journal of Environmental Biology
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• v.19 no.1
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• pp.7-17
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• 2001

Growth optima and tolerance ranges of marine algae species nay vary greatly during the developmental stage. The establishment stage is clearly of great importance for each generation, affecting the performance of the adult population. The present study was aimed to determine the effect of various concentrations of inorganic nutrients and heavy metals on germination and germlings of Ulva pertusa Kjellman (Chlorophyta). Percent germination increased rapidly as irradiance level increased, reaching the maximum at 100 ${\mu}$mol m$\^$-2/s$\^$-1/ in both east and west seawater. Percent germination in the east seawater was higher than that in the west seawater at irradiances lower than 30 ${\mu}$mol m$\^$-2/s$\^$-1/, and there was no difference in percent germination between the two different seawaters at irradiances higher than 60 ${\mu}$mol m$\^$-2/s$\^$-1/. Germling growth increased in the both cases with increasing irradiances but no growth was found in the dark. Overall germling area was larger in the east seawater than in the west seawater. Number of cell increased with increasing irradiance and became light-saturated at 100 ${\mu}$mol m$\^$-2/s$\^$-1/ in the both cases. Germlings grown in the east seawater had more cells than those cultivated in the west seawater at irradiances lower than 60 ${\mu}$mol m$\^$-2/s$\^$-1/. In various combinations of nitrate and phosphate, percent germination increased with increasing nitrate concentrations irrespective of phosphate concentrations. At 3 days after inoculation, nitrate concentration of 2.5 ppm with all phosphate concentrations promoted germination. Area and number of cell of germlings increased with increasing nitrate concentrations in all phosphate concentrations. In various combinations of copper and lead, germination was delayed as copper concentrations increased in all lead concentrations. Percent germination was severely reduced at 1 ppm Cu$\^$2+/. Area and number of cell of germlings decreased with increasing copper concentrations in all lead concentrations. The highest copper concentration (1 ppm) clearly suppressed the germling growth in U. pertusa.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.26 no.4
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• pp.343-355
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• 2021

Eelgrass, Zostera marina L., was widely distributed around Sinyangseopji Beach in Bangdu Bay, on the eastern coast of Jeju Island, until breakwater construction in the late 1990s resulted in its complete loss. Six experimental sites were identified for restoration of the Z. marina bed in Bangdu Bay. Using the staple method, 500 Z. marina shoots were transplanted at each site in January 2019 and 2020. The transplants, along with environmental parameters, were monitored for 10 months following transplantation. There were significant differences in underwater irradiance, water temperature, and salinity among the sites, but all were suitable for Z. marina growth. The Ulva species, an opportunistic alga, appeared in spring and accumulated during summer at all sites; however, there was no significant effect of Ulva species on the survival and growth of the eelgrass transplants. Most of the transplanted Z. marina survived, and after 3 months, the density increased by 112.5-300% due to vegetative propagation, with a rapid rate of increase observed during spring and early summer at all sites. For 1-2 months after transplanting, the Z. marina shoots showed signs of transplant shock, after which the shoot density increased at all sites, confirming that all transplants adapted well to the new environment. However, in both 2019 and 2020, during late summer to early fall, the sites experienced heavy damage from typoons (twice in 2019 and three times in 2020) that hit Bangdu Bay. The transplants at two sites located in the center of Bangdu Bay were completely destroyed, but those at three sites located to the west of the bay showed a 192-312% increase in density. Thus, we confirmed that the Bangdu Bay Z. marina bed can be restored, with the highest probability of success for Z. marina restoration on the western side of Bangdu Bay, which is protected from typhoons.