한반도 동해 연안에 자생하는 말잘피, 새우말의 생장 특성

Growth Dynamics of the Surfgrass, Phyllospadix iwatensis on the Eastern Coast of Korea

Abstract

말잘피 새우말은 북태평양에 위치한 북동아시아 연안의 암반에 자생한다. 우리나라에서 새우말은 주로 동해 중부해역의 암반조하대에 나타나며, 본 조사에서는 이 곳에 서식하는 새우말의 생태적 특성을 알아보기 위해, 2017년 8월부터 2018년 7월까지 새우말 군락지의 수중광량, 수온의 변화와 함께 매월 새우말의 형태적 특성, 밀도, 생체량과 잎 생산성의 변화를 조사하였다. 수중광량과 수온은 봄과 여름에 증가하고 가을과 겨울에 감소하는 뚜렷한 계절 경향을 보였다. 새우말의 형태, 밀도, 생체량과 잎 생산성은 겨울과 봄에 증가하고, 여름과 가을에 감소하였다. 새우말의 개체당 잎 생산성과 단위면적당 잎 생산성은 수중광량과 유의한 양의 상관관계를 보였다. 새우말의 연간 평균 단위면적당 잎 생산량은 $6.3{\pm}1.3g\;m^{-2}d^{-1}$로, 2018년 5월 최대값($16.4{\pm}4.4g\;m^{-2}d^{-1}$)과 2월에 최소값($2.4{\pm}0.3g\;m^{-2}d^{-1}$)을 나타내었다. 새우말 생장의 최적 수온은 $12-13^{\circ}C$로 조사되었다.

The surfgrass Phyllospadix iwatensis is native in the exposed rocky shores of the Northwestern Pacific Ocean. In Korea, P. iwatensis is mainly found on the rocky subtidal zone in the central eastern coast. In this study, to examine the ecological characteristics of P. iwatensis, we investigated changes in morphological characteristics, density, biomass, and leaf productivity as well as changes in the underwater irradiance and water temperature of its habitat monthly from August 2017 to July 2018. Underwater irradiance and water temperature showed clear seasonal changes; increases in spring and summer and decreases in fall and winter. Morphological characteristics, shoot density, biomass, and leaf productivities of P. iwatensis exhibited significant seasonal variations, increasing in winter and spring and decreasing in summer and fall months. P. iwatensis leaf productivities both per shoot and per unit area showed significant positive correlations with underwater irradiance. The average leaf productivity of P. iwatensis per area was $6.3{\pm}1.3g\;m^{-2}d^{-1}$, while minimum and maximum values were $2.4{\pm}0.3g\;m^{-2}d^{-1}$ in February 2018 and $16.4{\pm}4.4g\;m^{-2}d^{-1}$ in May 2018, respectively. The optimum water temperature for the growth of P. iwatensis in this study was between $12-13^{\circ}C$.

Fig. 1. Study site of Phyllospadix iwatensis growth dynamics. The site was located in Goseong-gun, Gangwon-do, on the open shores of the eastern coast of the Korean peninsula.

Fig. 2. Monthly changes in underwater irradiance (A), and water temperature (B) at the study site from August 2017 to July 2018.

Fig. 3. Monthly changes in number of leaves per shoot (A), leaf width (B), leaf thickness (C), sheath length (D), sheath width (E), and shoot height (F) of Phyllospadix iwatensis from August 2017 to July 2018.

Fig. 4. Monthly changes in shoot density of Phyllospadix iwatensis from August 2017 to July 2018. Vegetative shoot (A), spadix (B), and total shoot (C).

Fig. 5. Monthly changes in biomass of Phyllospadix iwatensis from August 2017 to July 2018. Above ground (A), rhizome+root (B), and total biomass (C).

Fig. 6. Monthly changes in leaf productivity per shoot (A), and areal leaf productivity (B) of Phyllospadix iwatensis from August 2017 to July 2018.

Fig. 7. Best-fit regressions of Phyllospadix iwatensis areal leaf production on underwater irradiance (A), and water temperature (B).

Table 1. Pearson‘s correlation analysis results (two-tailed) for number of leaves (NL), leaf width (LW), sheath width (SW), sheath length (SL), leaf thickness (LT), shoot height (SH), leaf productivity per shoot (SP), areal leaf productivity (AP), vegetative shoot density (VD), spadix density (SD), total shoot density (TD), above ground biomass (AB), rhizome+root biomass (RB), total biomass (TB), underwater irradiance (UI), and water temperature (WT)