A Preliminary Study on Growth and Habitat Characteristics of Zostera marina (Zosteraceae) in Gamak Bay, Yeosu

This study was performed to obtain basic information on the ecology of Zostera marina and to promote efficient conservation of this species which has been decline in Gamak Bay, Yeosu, Korea. Water column characteristics and eelgrass morphology at Anpori, Jangsuri and Wonpori were investigated every month from December 1999 to November 2000. The water temperature, salinity and pH at the three sites were 10.0-27.0 degree C, 29.4-34.7ppt and 8.1-8.5, respectively. The water temperature at Anpori tended to be slightly lower than that at the other locations; the salinity at Wonpori from July to November was a little lower than that of the other locations. The concentrations of NO sub(2)-N, NO sub(3)-N, NH sub(4)-N, PO sub(4)-P and Si(OH) sub(4)-Si at the three sites were 0.9-1.3, 2.0-6.2, 7.8-9.0, 3.0-3.6 and 22.2-30.2 mu M, respectively. The concentration of NO sub(3)-N at Wonpori from June to November was somewhat lower than that at the other locations; that of NH4-N at Jansuri was somewhat lower than the others. The mean shoot height and leaf width of the Anpori, Jangsuri and Wonpori populations were 80.6 cm and 0.9 mm, 90.0 cm and 1.0 mm, and 95.3 cm and 1.0 mm, respectively. The mean total shoot weight of the Anpori, Jangsuri and Wonpori ones was 24.5, 31.0 and 29.7 g, respectively. The mean leaf and branch numbers of the Anpori, Jangsuri and Wonpori populations were 16.5 and 2.6, 16.1 and 2.4 and 15.4 and 2.6 individuals, respectively. The correlation coefficients between shoot height and water temperature, leaf width and total shoot weight, leaf number and branch number, and Si(OH) sub(4)-Si and NO sub(3)-N were 0.726, 0.692, 0.862, and 0.693, respectively. The coefficients between shoot height and NO sub(3)-N, total shoot weight and NO sub(3)-N, water temperature and Si(OH) sub(4)-Si, water temperature and salinity, and water temperature and NO sub(3)-N were -0.716, -0.536, -0.775, -0.685 and -0.685, respectively. The first four principal components explain 71.1% of the total sample variance. For axis 1, shoot height and water temperature tended to correlate with the population of Jansuri, followed by the Wonpori population, and Si(OH) sub(4)-Si and NO sub(3)-N tended to correlate strongly with the Anpori population. For axis 2, total weight, leaf width, leaf number and branch number showed a tendency to correlate with the Anpori and Jangsuri populations. For axis 3, the Anpori population tended to be influenced by NO sub(2)-N and PO sub(4)-P. For axis