• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.22 no.3
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• pp.69-76
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• 2017

Eelgrass, Zostera marina is a marine flowering plant that grows in submerged habitats for most of its lifetime, and experiences desiccation stress when exposed to air. Although the desiccation stress observed in adult eelgrass has been frequently studied, there has been little research on desiccation stress in eelgrass seeds. To survey desiccation stress in eelgrass seeds, we studied the germination rate and moisture content upon desiccation caused by exposure to air. The germination rate of the eelgrass seeds exposed to air for 1 hour at $20^{\circ}C$ and 50% relative humidity decreased markedly, and it decreased consistently as the exposure time increased. Eelgrass seeds exposed to air for longer than 11 hours did not germinate. As the exposure time of eelgrass seeds to air increased, the germination rate and moisture content decreased, showing a negative correlation. In addition, eelgrass seeds exposed to air at $30^{\circ}C$ showed significantly lower germination rates than those exposed to air at $10^{\circ}C$ or $20^{\circ}C$. Our results revealed that desiccation causes a decrease in the germination of eelgrass seeds, which will provide useful information for eelgrass habitat restoration using seeds.

• ALGAE
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• v.25 no.2
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• pp.89-97
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• 2010

To test the feasibility of using chlorophyll ${\alpha}$ fluorescence to assess the establishment success of seagrass transplants, photosynthetic characteristics of eelgrass Zostera marina transplants were measured using a Diving-pulsed amplitude modulation fluorometer in Jindong Bay on the southern coast of Korea. Maximum quantum yield ($F_v/F_m$), photosynthetic efficiency ($\alpha$), saturating irradiance ($E_k$) and maximum electron transport rate ($ETR_{max}$) of transplants and reference plants in a nearby transplant site were measured using the fluorometer for 5 months. Additionally, shoot morphology, individual shoot weight and productivity of transplants and reference plants were also monitored. Shoot height, leaf weight and productivity of transplants were significantly reduced during the first two or three months after transplantation compared to those of reference plants, and then increased to the levels of reference plants Characteristics of chlorophyll a fluorescence, including $F_v/F_m$, $\alpha$, $E_k$ and $ETR_{max}$ of transplants were also significantly reduced in the initial period, but recovered slightly sooner than shoot morphology or leaf productivity. These results indicated that after transplantation, Z. marina transplant photosynthesis recovered faster than shoot morphology, biomass or productivity. Thus, chlorophyll a fluorescence can be used as an indicator for early assessment of the status of eelgrass transplants without destructive sampling.

• Archives of Pharmacal Research
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• v.27 no.2
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• pp.177-183
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• 2004

In order to develop new anti-photoaging agents, we examined the antioxidative activity and the inhibition effect of matrix metalloproteinase-1 (MMP-1) on the extracts of a marine product, Zostera marina L., which is known for its potent activity. Three compounds (compounds 1, 2, and 3) were isolated from an ethyl acetate (EtOAc) soluble fraction of the product; they were identified as apigenin-7 -O-$\beta$-D-glucoside (1), chrysoeriol (2), and luteolin (3). These compounds were found to scavenge radicals and reactive oxygen species (ROS) and were measured to have $SC_{50}$/ values of 0.18 mM, 0.68 mM, and 0.01 mM against the 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical and 0.04 mM, 0.03 mM, and 0.01 mM against the superoxide radical in the xanthine/xanthine oxidase system, respectively. Compound 3 suppressed the expression of MMP-1 by up to 44％ at 4.0 $\mu$M and inhibited the production of interleukin 6 (IL-6), which is known as a cytokine that induces MMP-1 expression. From these results, compound 3 and the other compounds were determined to have antioxidative activity and to inhibit MMP-1 expression. Thus, the three compounds are expected to be useful for preventing the photoaging of skin.

• Korean Journal of Ecology and Environment
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• v.33 no.4 s.92
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• pp.336-341
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• 2000

This study was conducted to clarify the habitat characteristics and distribution of seagrass. Zostera marina L. (Zosteraceae) in the brackish Hwajinpo Lake, Korea in June 1998 and July 2000. Z. marina beds were distributed along the sea-side cost of the lower lake mouth at 0.8 to 1.5m in death, and the seagrass bed area was about 3,200 m$^{2}$. Salinity, water temperature and pH were in the range of 8.0${\sim}$23.0$%_{o}$, 22.0${\sim}$23.7$^{\circ}C$ and 8.34${\sim}$8.62, respectively. Nutrient concentrations were generally now (TN: 24.34 ${\mu}$M, NH$_{4}$-N: 2.57 ${\mu}$M, NO$_{3}$-N: 0.56 ${\mu}$M, NO$_{2}$-N: 0.27 ${\mu}$M, TP: 2.08 ${\mu}$M, PO$_{4}$-P: 0.34 ${\mu}$M). Suspended particulate matters (SPM) concentration averaged 62.8 mg/l and particulate organic matter (POM) averaged 21.3 mg/l. Organic content of SPM averaged 33.9%. The beds substratum was composed of well-sorted, fine sand and its mean brain size was 3.13${\Phi}$. The Z. marina vegetation was almost submerged, and the morphological characteristics can be classified as steno-leaf phenotype by the shoot length, leaf width, and number of leaf vein. Shoot length and leaf width were 70.0${\sim}$126.5 cm and 5${\sim}$7 mm, respectively. Shoot densities ranged from 264 to 296/m$^{2}$, and the plants biomass was estimated at 332.6 to 373.0 g dw/m$^{2}$. Therefore, the habitats of Z. marina in Korea were recognized in a brackish lake, and morphological characteristics appeared to be variable.

• Ocean and Polar Research
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• v.27 no.2
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• pp.125-133
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• 2005

This study described the phonology and reproductive potential of four species of Korean seagrasses, Zostera caespitosa, Z. caulescem, Z. Japonica and Z. marina. Z. caespitosa and Z. caulescens sampled from a mixed stand at the subtidal area of Yulpo Bay, Geojedo of the South Sea of Korea in November 2002 and August 2003. Z japonica and Z. marina occurred at the depth between the middle intertidal and shallow subtidal (<1m below mean sea level) of Seungbongdo (in Yellow Sea) samples collected in February and October 2003. The sexual reproductive phase of the four Zostera species was apparently different in timing of flowering, reproductive period, fruiting and seed maturing. Z. caespitosa flowered from February to early May $(10-16^{\circ}C)$, and its seed production completed in early May. The reproductive shoots of Z. caulescens began to appear in January $(9^{\circ}C)$, and its flowering followed from February to June $(10-19^{\circ}C)$. The flowers of Z. japonica were observed from July to September $(18-22^{\circ}C)$, and its seeds matured from August to September. The most commonly I marina flowered from April to August $(7-21^{\circ}C)$ and developed into seeds in July. Z. caulescens, the largest plant, had the highest number of seeds per shoot and longest spadix length. Z. marina, which was intermediate In size, recorded the highest reproductive potential. The study indicates that the reproductive phase and potential of the four species of seagrass from Korea are highly related to water temperature, and the populations of these species show a perennial lifespan with a low sexual reproductive input.

• Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.219-226
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• 2009

Seasonal variation in the biomass of eelgrass (Zostera marina) and epiphytic algae in two eelgrass beds (Dongdae and Aenggang Bay) around Namhae Island was investigated throughout 2005. Shoot density and eelgrass biomass differed across months and locations. Peak shoot density occurred from April to August 2005, whereas eelgrass biomass was higher in July and August 2005. Shoot density as well as eelgrass biomass were higher in Dongdae Bay compared to Aenggang Bay. A total of 21 epiphytic algal species (4 Chlorophyta, 2 Phaeophyta, and 15 Rhodophyta) were collected, and dominant species included Polysiphonia japonica, Lomentaria hakodantensis, Symphyocladia latiuscula, Champia sp., and Heterosiphonia japonica. Seasonal variation in both the species composition and biomass of epiphytic algae was substantial: peak epiphytic algal biomass occurred in January and December 2005. We also observed high epiphytic algal biomass in the eelgrass bed of Dongdae Bay. Seasonal changes in the biomass of eelgrass and epiphytic algae were primarily influenced by water temperature, whereas those of the epiphytic algal community were also correlated with eelgrass (substrate) morphology and growth, the life cycle of epiphytic algae, and physical characteristics within eelgrass beds. The spatial variation of eelgrass density and biomass were also limited by sediment characteristics.

• ALGAE
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• v.25 no.2
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• pp.57-64
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• 2010

A variety of Cyclotella atomus were discovered among the epiphytic diatoms on eelgrass (Zostera marina L.) in Korean waters. Cyclotella atomus var. marina has a flat and disc-shaped valve, and is clearly differentiated into a striate marginal zone and a smooth central zone. The valves have a very small diameter ranging from 3.1-3.4 ${\mu}m$. This small diatom does not have any central ornamentation. The marginal striate zone has numerous granules toward the mantle. The valves have five or six marginal fultoportulae with two satellite pores and a single marginal rimoportula.

• Fisheries and Aquatic Sciences
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• v.13 no.4
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• pp.272-277
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• 2010

Seagrasses are marine angiosperms of ecological importance in providing shelter and food to aquatic species as well as maintaining the carbon cycle on earth. Phyllospadix iwatensis is a seagrass of the family Zosteraceae and is distributed along the eastern coast of Korea. The nucleotide sequences of P. iwatensis nuclear genes encoding 18S ribosomal RNA (rRNA) and internal transcribed spacer-1 (ITS-1) were determined for molecular phylogenetic analysis. Genomic DNA was isolated from P. iwatensis and used for PCR amplification of 18S rRNA and ITS-1. Examination of the 18S rRNA sequence of P. iwatensis showed a close (99% similarity) relationship to Zostera noltii, another genus of Zosteraceae, but a distant (84% similarity) evolutionary relationship to other macroalgal Laminariales species. Further discrepancies found in ITS-1 nucleotide sequences between closely related species indicate that the sequence information could be used for species identification.

• Advances in Traditional Medicine
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• v.4 no.4
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• pp.253-260
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• 2004

Zosterin is a pectin from a seagrasses of the family Zosteraceae. Zosterin was given to rats intragastrically once 1h before the emotional stress or injection of indomethacin, or administration of 2, 4-D solution daily for seven days at dose of 100 mg/kg. The data obtained demonstrate that zosterin enhances resistance of the stomach tissue to various ulcerogenic factors (emotional stress, indomethacin, pesticide 2, 4-D). It was shown to possess a gastroprotective effect, which is accompanied by diminution of the number and sizes of destructive regions in the gastric mucosa during the ulcer affection, as well as reduction of ATP and glycogen deficit, decrease of lactate excess, and normalization of the energy balance in the gastric mucosa. According to its antiulcer effect, zosterin may be recommended for application in prevention and treatment of stomach diseases together with the basic therapy.

• Ocean and Polar Research
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• v.28 no.3
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• pp.225-236
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• 2006

Seagrass meadows are considered as critical habitats for a wide variety of marine organisms in coastal and estuarine ecosystems. In many cases, studies on the spatial/temporal distribution of seagrass have depended on direct observations using SCUBA diving. As an alternative method fur studying seagrass distribution, an application of hydroacoustic technique has been assessed for mapping seagrass distribution in Dongdae Bay, on the south coast of Korea, in September 2005. Data were collected using high frequency transducer (420 kHz split-beam), which was installed with towed body system. The system was linked to DGPS to make goo-referenced data. Additionally, in situ seagrass distribution has been observed using underwater cameras and SCUBA diving at four stations in order to compare with acoustic data. Acoustic survey was conducted along 23 transects with 3-4 blot ship speed. Seagrass beds were vertically limited to depths less than 3.5m and seagrass height ranged between 55 and 90cm at the study sites. Dense seagmss beds were mainly found at the entrance of the bay and at a flat area around the center of the bay. Although the study area was a relatively small, the vertical and spatial distributions of the seagrass were highly variable with bathymetry and region. Considering dominant species, Zostera marina L., preliminary estimation of seagrass biomass with acoustic and direct sampling data was approximately $56.55g/m^2$, and total biomass of 104 tones (coefficient variation: 25.77%) was estimated at the study area. Hydroacoustic method provided valuable information to understand distribution pattern and to estimate seagrass biomass.