The eelgrass ( Zostera marina L.) was treated with artificial seawater (ASW) of different salinities ( 100%, 150% and 200% seawater) for 5 d. The activities of two enzymes extracted from the plant leaves were determin...The eelgrass ( Zostera marina L.) was treated with artificial seawater (ASW) of different salinities ( 100%, 150% and 200% seawater) for 5 d. The activities of two enzymes extracted from the plant leaves were determined under a salinity grade in vitro So were the photosynthesis rates of the plants from the three treatments in the media with different salinities 100%, 150%, 200%, 300% ASW) and Some physiological data. The data showed that under increased salinities (concentrated seawater), Na+, Cl-, MDA (malon dialdehyde) and glucose contents and the osmotic potentials ( absolute value) in the leaves increased with the salinity elevation in the medium (ASW), but both K+ and free amino acid (mainly proline) contents decreased. Malate dehydrogenase (MDH) from the plant leaves under a salinity grade showed its activities (A) as follows: A(100%) (ASW) > A(150%) (ASW) > A(200%) (ASW). Phosphoenolpyruvate carboxylase (PEPC) extracted from the 100% ASW- and 200% ASW-treated plants showed similar activities (both insensitive to salinities) under the salinity grade in vitro, but the activities of PEPC from plants treated with 150% ASW were dependent oil salinity. Whether the plant is stressed at 150% ASW and can stand higher salinity than seawater needs to be studied further. Meantime, die data do not agree with the opinion that the adaptation of the eelgrass to seawater salinity is partly fulfilled by its insensitiveness to salinities in Some metabolic enzymes. It can be inferred that the lack of transpiration may be an important aspect of tire plant's tolerance to seawater salinity.展开更多
Seagrass restoration as part of ocean ecosystem protection has been launched for many years all over the world, but intensive research on this subject in China has just begun in recent years. Seed broadcasting has bee...Seagrass restoration as part of ocean ecosystem protection has been launched for many years all over the world, but intensive research on this subject in China has just begun in recent years. Seed broadcasting has been widely accepted as the most potentially useful method for seagrass restoration over large areas. We examined the influence of key environmental factors on seed germination to help promote eelgrass bed restoration. Under anoxic conditions, the influence of temperature and salinity on the germination rate of eelgrass (Zostera marina L.) seeds was examined at different combinations of four temperatures (4, 9, 14, and 24℃) and nine salinities (5 to 45, increment of 5). The effect of significant interaction of temperature and salinity on germination rate was observed (ANOVA) (P<0.001). The highest germination rate (83.3 ± 3.5)% was reached in 8 weeks at 14℃ and salinity 5. Higher temperature significantly increased the germination rate at salinity 5 (P<0.001) during the whole observation period except for 24℃, while lower salinity significantly increased the germination rate at 14℃ (P<0.001). Although significant interaction was found between temperature and salinity (P<0.001), the influence of salinity was stronger than that of temperature for the germination of eelgrass seeds. These results provide useful information for the propagation of artificial seedlings for seagrass restoration in China.展开更多
Short-term tidal and diel variations of autumn fish assemblage in a Zostera marina bed were investigated using 3 h interval samplings for 24 h in both spring and neap tide using a small beam trawl.A total of 1 346 fis...Short-term tidal and diel variations of autumn fish assemblage in a Zostera marina bed were investigated using 3 h interval samplings for 24 h in both spring and neap tide using a small beam trawl.A total of 1 346 fishes belonging to 19 species were collected at spring tide,whereas 1 115 fishes belonging to 17 species were at neap tide.The common fish species were Nuchequula nuchalis,Acanthogobius flavimanus,Takifugu niphobles,Acentrogobius pflaumii,and Pholis nebulosa with the former three species dominating at spring tide,while the latter two species being abundant at neap tide.Diel variation in abundance was significant with higher abundance at night than day,but there were no significant differences between spring and neap tides,and between ebb and flood tides（three-way ANOVAs）.Diel variation in the abundance of fishes may be influenced by tidal range and cycle,and day-night differences of food availability and behaviors of fishes indirectly.Non-metric multidimensional scaling（n MDS） ordination and analysis of similarity（ANOSIM） results revealed significant differences in species compositions both between day and night,and between spring and neap tide.Eelgrass beds are highly productive marine ecosystem,and thus,our results will contribute to conservation of seagrass ecosystem in the study area.展开更多
Eelgrass species worldwide are valued for the ecosystem service they provide to estuarine and marine habitats. One species, Zostera japonica, however, has some negative impacts outside its native range and is consider...Eelgrass species worldwide are valued for the ecosystem service they provide to estuarine and marine habitats. One species, Zostera japonica, however, has some negative impacts outside its native range and is considered invasive. In Willapa Bay WA, USA, the nonnative eelgrass has expanded to the level where the shellfish industry is concerned about its potential impacts on its livelihood. Studies were conducted using paired plots, Z. japonica controlled with the herbicide imazamox vs. untreated controls, to assess the effects of Z. japonica on Manila clams (Ruditapes philippinarum) and Pacific oysters (Crassostrea gigas). Recruitment of new Manila clams was not affected by Z. japonica. The growth of young clams, total commercial clam harvests, clam quality and clam harvest efficiency, however, were greater on plots where Z. japonica was chemically controlled than where it was not treated. The response of oysters to Z. japonica control varied by site;there was no effect at one site, while the other sites had a 15% increase in shucked meat with Z. japonica control. The potential economic impact of a Z. japonica infestation of a shellfish bed was ~$47,000 ha-1 for Manila clams and $4000 ha-1 for oysters for each crop harvest cycle.展开更多
In recent years, extreme heat events have occurred worldwide and the ocean temperature has been rising, causing stress on the photosynthesis and growth of seagrass. Metabolomics enables detection of metabolic changes ...In recent years, extreme heat events have occurred worldwide and the ocean temperature has been rising, causing stress on the photosynthesis and growth of seagrass. Metabolomics enables detection of metabolic changes under environmental stress. In this study, the photosynthetic physiology and metabolic changes of the eelgrass Zostera marina L. in response to 48 h exposure to 32°C were investigated. The results showed that high temperature induced signi?cant inhibition of photosynthetic effciency(Δ F/F′ m)(23.9%lower than the control), enhanced respiration(58.3% higher), and decreased carbohydrate decomposition products and tricarboxylic acid(TCA) cycle intermediate products, indicating that the energy supply of the eelgrass may be insuffcient at high temperature. In addition, high temperature decreased stearic acid and linoleic acid in eelgrass, suggesting the composition of the membrane system of eelgrass may change at high temperature and implying that high temperature may cause the membrane system to be unstable.展开更多
文摘The eelgrass ( Zostera marina L.) was treated with artificial seawater (ASW) of different salinities ( 100%, 150% and 200% seawater) for 5 d. The activities of two enzymes extracted from the plant leaves were determined under a salinity grade in vitro So were the photosynthesis rates of the plants from the three treatments in the media with different salinities 100%, 150%, 200%, 300% ASW) and Some physiological data. The data showed that under increased salinities (concentrated seawater), Na+, Cl-, MDA (malon dialdehyde) and glucose contents and the osmotic potentials ( absolute value) in the leaves increased with the salinity elevation in the medium (ASW), but both K+ and free amino acid (mainly proline) contents decreased. Malate dehydrogenase (MDH) from the plant leaves under a salinity grade showed its activities (A) as follows: A(100%) (ASW) > A(150%) (ASW) > A(200%) (ASW). Phosphoenolpyruvate carboxylase (PEPC) extracted from the 100% ASW- and 200% ASW-treated plants showed similar activities (both insensitive to salinities) under the salinity grade in vitro, but the activities of PEPC from plants treated with 150% ASW were dependent oil salinity. Whether the plant is stressed at 150% ASW and can stand higher salinity than seawater needs to be studied further. Meantime, die data do not agree with the opinion that the adaptation of the eelgrass to seawater salinity is partly fulfilled by its insensitiveness to salinities in Some metabolic enzymes. It can be inferred that the lack of transpiration may be an important aspect of tire plant's tolerance to seawater salinity.
基金supported by a Municipal Research and Developmental Program of Science and Technology of Yantai, Shandong Province, China (Grant No. 2009211)an Open Foundation of the State Oce-anic Administration of China (Grant No. 200905020-12)
文摘Seagrass restoration as part of ocean ecosystem protection has been launched for many years all over the world, but intensive research on this subject in China has just begun in recent years. Seed broadcasting has been widely accepted as the most potentially useful method for seagrass restoration over large areas. We examined the influence of key environmental factors on seed germination to help promote eelgrass bed restoration. Under anoxic conditions, the influence of temperature and salinity on the germination rate of eelgrass (Zostera marina L.) seeds was examined at different combinations of four temperatures (4, 9, 14, and 24℃) and nine salinities (5 to 45, increment of 5). The effect of significant interaction of temperature and salinity on germination rate was observed (ANOVA) (P<0.001). The highest germination rate (83.3 ± 3.5)% was reached in 8 weeks at 14℃ and salinity 5. Higher temperature significantly increased the germination rate at salinity 5 (P<0.001) during the whole observation period except for 24℃, while lower salinity significantly increased the germination rate at 14℃ (P<0.001). Although significant interaction was found between temperature and salinity (P<0.001), the influence of salinity was stronger than that of temperature for the germination of eelgrass seeds. These results provide useful information for the propagation of artificial seedlings for seagrass restoration in China.
文摘Short-term tidal and diel variations of autumn fish assemblage in a Zostera marina bed were investigated using 3 h interval samplings for 24 h in both spring and neap tide using a small beam trawl.A total of 1 346 fishes belonging to 19 species were collected at spring tide,whereas 1 115 fishes belonging to 17 species were at neap tide.The common fish species were Nuchequula nuchalis,Acanthogobius flavimanus,Takifugu niphobles,Acentrogobius pflaumii,and Pholis nebulosa with the former three species dominating at spring tide,while the latter two species being abundant at neap tide.Diel variation in abundance was significant with higher abundance at night than day,but there were no significant differences between spring and neap tides,and between ebb and flood tides（three-way ANOVAs）.Diel variation in the abundance of fishes may be influenced by tidal range and cycle,and day-night differences of food availability and behaviors of fishes indirectly.Non-metric multidimensional scaling（n MDS） ordination and analysis of similarity（ANOSIM） results revealed significant differences in species compositions both between day and night,and between spring and neap tide.Eelgrass beds are highly productive marine ecosystem,and thus,our results will contribute to conservation of seagrass ecosystem in the study area.
文摘Eelgrass species worldwide are valued for the ecosystem service they provide to estuarine and marine habitats. One species, Zostera japonica, however, has some negative impacts outside its native range and is considered invasive. In Willapa Bay WA, USA, the nonnative eelgrass has expanded to the level where the shellfish industry is concerned about its potential impacts on its livelihood. Studies were conducted using paired plots, Z. japonica controlled with the herbicide imazamox vs. untreated controls, to assess the effects of Z. japonica on Manila clams (Ruditapes philippinarum) and Pacific oysters (Crassostrea gigas). Recruitment of new Manila clams was not affected by Z. japonica. The growth of young clams, total commercial clam harvests, clam quality and clam harvest efficiency, however, were greater on plots where Z. japonica was chemically controlled than where it was not treated. The response of oysters to Z. japonica control varied by site;there was no effect at one site, while the other sites had a 15% increase in shucked meat with Z. japonica control. The potential economic impact of a Z. japonica infestation of a shellfish bed was ~$47,000 ha-1 for Manila clams and $4000 ha-1 for oysters for each crop harvest cycle.
基金Supported by the National Natural Science Foundation of China(Nos.41306117,41676147,U1405234)the International Science&Technology Cooperation Program of China(No.2016YFE0112600)
文摘In recent years, extreme heat events have occurred worldwide and the ocean temperature has been rising, causing stress on the photosynthesis and growth of seagrass. Metabolomics enables detection of metabolic changes under environmental stress. In this study, the photosynthetic physiology and metabolic changes of the eelgrass Zostera marina L. in response to 48 h exposure to 32°C were investigated. The results showed that high temperature induced signi?cant inhibition of photosynthetic effciency(Δ F/F′ m)(23.9%lower than the control), enhanced respiration(58.3% higher), and decreased carbohydrate decomposition products and tricarboxylic acid(TCA) cycle intermediate products, indicating that the energy supply of the eelgrass may be insuffcient at high temperature. In addition, high temperature decreased stearic acid and linoleic acid in eelgrass, suggesting the composition of the membrane system of eelgrass may change at high temperature and implying that high temperature may cause the membrane system to be unstable.
