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Response of Arctic marine microalgae to changes of salinity
Zhang Qing, Rolf Gradinger, Zhou Qingsong, Zeng Jiangning
2001(1): 141-151.
Keywords: Arctic, sea ice, algal community, salinity
An algal assemblage collected from the bottom of floe in the Greenland Sea was batchcultured at 1±1℃ and 10 salinity gradients varied from 4.0 to 90.8 for 19 d.The growth for both the algal community and individual populations was characterized by an initial lag phase of six days followed by positive growth.Maximum growth rates were obtained as 0.19/d for the algal community and 0.32 to 0.39 d-1 for individual populations for the whole experiment period, which mostly occurred at the lower salinities.The competition between the algal species and the evolution of the algal assemblages under the salinity changes was checked.After 14-d culture, the dominating algae in the lower salinities were centric diatoms, pennate diatoms and phytoflagellates, while ones in the higher salinities almost belonged to pennate diatoms.It is suggested that the sea ice algal community from the Greenland Sea prefer lower salinities to higher ones, and the decrease in salinity in small ranges could stimulate the growth of sea ice algae.
Effects of light and salinity on carotenoid biosynthesis in Ulva prolifera
Yuan He, Yuantu Ye, Songdong Shen
2020, 39(10): 50-57. doi: 10.1007/s13131-020-1577-1  Published:2020-10-25
Keywords: U. prolifera, carotenoid, MEP pathway, light, salinity
Ulva prolifera is a green alga that plays an important role in green tides. Carotenoid biosynthesis is a basic terpenoid metabolism that is very important for maintaining normal life activities in algae. In this study, we first reported the complete sequences of all genes in the 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway, which is the only carotenoid synthesis pathway in U. prolifera. Then, we compared these genes with those of other species. Additionally, by detecting the carotenoid contents and expression levels of key genes participating in carotenoid biosynthesis in U. prolifera under three different light (1 000 lx, 5 000 lx and 12 000 lx) and salinity (12, 24 and 40) regimes, we found that carotenoid synthesis could be influenced by light and salinity, such that low light and high salinity could promote the synthesis of carotenoids. The results showed that the expression levels of genes involved in the MEP and the downstream pathway could affect the biosynthesis of carotenoids at the molecular level. This study contributes to a better understanding of the roles of genes participating in carotenoid biosynthesis in U. prolifera and the environmental regulation of these genes.
Effect of temperature, salinity and irradiance on growth and photosynthesis of Ulva prolifera
XIAO Jie, ZHANG Xiaohong, GAO Chunlei, JIANG Meijie, LI Ruixiang, WANG Zongling, LI Yan, FAN Shiliang
2016, 35(10): 114-121. doi: 10.1007/s13131-016-0891-0
Keywords: Ulva prolifera, green tide, photosynthesis, growth rate, temperature, salinity
Intensive Pyropia aquaculture in the coast of southwestern Yellow Sea and its subsequent waste, including disposed Ulva prolifera, was speculated to be one of the major sources for the large-scale green tide proceeding in the Yellow Sea since 2007. It was, however, unclear how the detached U. prolifera responded and resumed growing after they detached from its original habitat. In this study, we investigated the growth and photosynthetic response of the detached U. prolifera to various temperature, salinity and irradiance in the laboratory. The photosynthetic rate of the detached U. prolifera was significantly higher at moderate temperature levels (14-27℃) and high salinity (26-32), with optimum at 23℃ and 32. Both low (<14℃) and highest temperature (40℃), as well as low salinity (8) had adverse effects on the photosynthesis. Compared with the other Ulva species, U. prolifera showed higher saturated irradiance and no significant photoinhibition at high irradiance, indicating the great tolerance of U. prolifera to the high irradiance. The dense branch and complex structure of floating mats could help protect the thalli and reduce photoinhibition in field. Furthermore, temperature exerted a stronger influence on the growth rate of the detached U. prolifera compared to salinity. Overall, the high growth rate of this detached U. prolifera (10.6%-16.7% d-1) at a wide range of temperature (5-32℃) and salinity (14-32) implied its blooming tendency with fluctuated salinity and temperature during floating. The environmental parameters in the southwestern Yellow Sea at the beginning of green tide were coincident with the optimal conditions for the detached U. prolifera.
Effect of salinity on the growth, biological activity and secondary metabolites of some marine fungi
HUANG Jingjing, LU Chunhua, QIAN Xiaoming, HUANG Yaojian, ZHENG Zhonghui, SHEN Yuemao
2011(3): 118-123. doi: 10.1007/s13131-011-0126-3
Keywords: marine fungi, salinity, secondary metabolites, antimicrobial activities
The study investigated the effects of salinity on growth, antimicrobial activities and secondary metabolites of 47 marine filamentous fungi isolated from the East China Sea near the western shore of the Taiwan Straits. The results indicate that NaCl promoted the growth up to 91.5% of test strains. However, only 14.9% of them showed a significant increase of antimicrobial activity against Candida albicans. When incubated in different concentrations of NaCl, the colony growth, antimicrobial activities and composition of secondary metabolites of the strain Ty01b-8 of Penicillium sp. varied. Treatment with KCl also showed a similar effect. An alkaloid isolated from the fermentation broth of Ty01b-8 was identified as chrysogine, inhibition activity of which against Hela cells was 15.05% at 20 μg/ml, and yield was 4.4 and 4.9 times higher in 3 percent and 6 percent NaCl treatments, respectively, compared with the non-salt culture condition. These findings prove that salinity is an important factor influencing growth and secondary metabolites of some marine fungi, which can be used to screen for new metabolites from marine fungi, and to enhance their metabolites production in industrial fermentation.
Study of colloidal phosphorus variation in estuary with salinity
CHEN Ding, ZHENG Airong, CHEN Min
2010(1): 17-25. doi: 10.1007/s13131-010-0003-5
Keywords: truly dissolved phase, colloidal phosphorus, salinity
The variation of colloidal phosphorus with salinity in estuary was studied in this paper, which was compared with those of particle and truly dissolved phosphorus with the purpose of finding out the similarities and differences between their behaviors in the estuary. Distribution patterns of phosphorus in particle, colloidal and truly dissolved phase at different salinities and their relationships with suspended particulate matter were also studied to understand the transformation and transportation of colloidal phosphorus in estuarine area. The result showed that the concentrations of total colloidal phosphorus, organic colloidal phosphorus and inorganic colloidall phosphate all descended from river-end to sea-end, illustrating their terrigenous source. Ratios of organic to total colloidal phosphorus decreased with salinity's increment, indicating that organic phosphorus was influenced by scavenging process of colloid more significantly as compared with inorganic phosphate. Both of the phosphorus variation tendencies and the proportion between organic and inorganic phosphorus in colloidal phase was similar with that in truly dissolved phase while different from that in particle phase.
Analyses of the long-term salinity variability in the Bohai Sea and the northern Huanghai(Yellow) Sea
YU Huaming, BAO Xianwen, LÜ Cuilan, CHEN Xu'en, KUANG Liang
2009(5): 1-8.
Keywords: salinity, the Bohai Sea, the Northern Huanghai Sea, decadal variability, interannual variability
Based on the comprehensive collection of the field observed salinity of the Bohai Sea (BHS) and the northern Huanghai Sea (NHS) from the 1950s to the present,the patterns of 10-years-averaged salinity at the different layers in the recent five decades (the 1950s,the 1960s,the 1970s,the 1980s and the 1990s) are obtained by the spatial-temporal interpolation technique with the scrupulous data quality control in this study.Then,by combining the spatial-temporal interpolation technique with successive correction method,the annual distributions of salinity both in the BHS and in the NHS are obtained as well.The data analyses indicate that the overall salinity in the BHS and the NHS increases from the 1960s till the present,with the increase of annual mean salinity of 0.04 psu from the 1950s,and the maximum increase rate of salinity is about 0.14 psu/a in the Bohai Bay.The high salinity tongue extended significantly from the NHS into the BHS.The intensified eastern wind field is related to the western intrusion of the NHS warm current,which probably leads to the moving forward of the high salinity water mass into the BHS.However,it is rather different from the salinity distribution characteristics between the 1950s and the 1960s.The extensive precipitation in the 1960s could lead to an increase in the discharge of the Huanghe River,which might result in the decrease of salinity in the BHS.But the salinity isoline of 32 in the NHS still extended significantly into the BHS in the 1960s.Since the 1980s,the patterns of salinity distribution have changed thoroughly.The salinity in the central area of the BHS was low,while the salinity in the Bohai Bay and the Liaodong Bay was higher than the other regions with its horizontal salinity gradient decreasing in the 1980s.The Empirical Orthogonal Function Analysis (EOF) is also conducted to study the interannual salinity variability of the BHS and the NHS.The correlation coefficient between the time coefficient series of the main mode and the Huanghe River discharge can reach -64.57%.It can be concluded that salinity variation of the BHS and the NHS has strong negative correlation with the Huanghe River discharge.
Analysis of characteristics of time-frequency correlations between runoff, tidal range and salinity in the Changjiang Estuary
FEI Yuejun, XU Lili, DU Panjun, GUAN Qinle, KANG Xing, XIAO Wenjun
2011(5): 84-93. doi: 10.1007/s13131-011-0150-3
Keywords: salinity, runoff, tidal range, power spectrum, wavelet transform
Power spectrum and cross-wavelet transform analysis was adopted to study the time-frequency characteristics and multiscale correlations between runoff, tidal range and salinity in the Changjiang Estuary based on the runoff data collected at the Datong Station, the tidal range measured at the Baozhen Station, and the salinity at the Baogang Station from 2008 to 2009. The variations of the salinity showed significant periodicity at scales of 2-3, 7-8, 14-15 and 26-30 d. The correlation between the salinity and the runoff and the tidal range were found to be significantly related to shock at scales of 5-7, 14-15, 26-30 d and 0.5 a. The correlation between the runoff and the salinity was mainly in the same phase, while the correlation between the tidal range and the salinity was in the antiphase. Different frequency bands were related to different degrees, and their relevance increased as the resonance frequency decreased. In addition, changes of the seasonal runoff were obvious. Specifically, a point of discontinuity was reached in early June with a cycle of 7-8 d, which coincided with the periodicity of plum rains in the Changjiang-Huaihe region. High-frequency changes (8-16 d period) of the salinity corresponded to the time domain in January-April 2008, February-April 2009 and October-December 2009 and exhibited an approximately 0.5 a (184 d) long frequency oscillation. Short-period changes were found to be stronger than long-period changes. Cross-wavelet transforms for the salinity, the runoff and the tidal range revealed local features in the time domain, while the significant levels of different periodic oscillations were observed in the frequency domain. The correlation characteristics of the salinity and the runoff were significant in the 80-90 d frequency domain, indicating that the major impact of the runoff on the salinity was reflected in seasonal changes. The tidal range on the small scale of 14-15 and 30-32 d was more obvious than the runoff.
Artificial seed germination and seedling production of Zostera marina L. by salinity manipulation
LIU Yunlong, ZHANG Xuelei, SONG Wei, WANG Zongling
2016, 35(8): 99-105. doi: 10.1007/s13131-016-0866-1
Keywords: Zostera marina L., rehabilitation, seed, germination, seedling, salinity
Vast declines in Zostera marina seagrass beds demand effective methods of rehabilitation. In this study, we developed a practical method by reducing salinity to induce seed germination followed with recovering salinity to facilitate seedling production of Z. marina. The results showed that Z. marina seeds collected from natural seawater (salinity 30) were induced to germinate at reduced salinities. Percent germination (GR) was higher and mean-time-to-germinate (MTG) was shorter at lower salinities. The highest GR and shortest MTG occurred at salinity 0 (deionized freshwater). After germination in freshwater, seeds could develop into seedlings at salinities 5-30 and continue the growth. Viability or development of germinated seeds was not significantly different during the 40 d of post-germination incubation at salinities 5-15 after 1-20 d of germination in freshwater. However, during the process of translating germinated seeds from salinity 0 and 5 to salinity 30, reducing the gradients of post-germination acclimation facilitated more seeds forming seedlings in less time. On average, after 60 d of static incubation, including 20 d in freshwater for germination followed with immediate shift to salinity 5 and increasing to salinity 30 at increment of 5 every two days until cultivation at constant salinity 30, 33% of Z. marina seeds produced healthy seedlings. The results indicate that the salinity-manipulation based method of artificial germination and seedling production is practical and effective in supporting rehabilitation of Z. marina bed.
Flocculation process of fine-grained sediments by the combined effect of salinity and humus in the Changjiang Estuary
LIU Qizhen, LI Jiufa, DAI Zhijun, LI Daoji
2007(1): 140-149.
Keywords: Changjiang Estuary, fine-grained sediment, flocculation, salinity
For the great amount of organic compounds and the variation of salinity in the Changjiang Estuary, the study on the flocculation process of fine-grained sediments by the combined effect of salinity and humus in the high-turbid system is of critical significance for the understanding of the mechanism of the formation of the turbidity maximum (TM).For the great amount of organic compounds and the variation of salinity in the Changjiang Estuary, the study on the flocculation process of fine-grained sediments by the combined effect of salinity and humus in the high-turbid system is of critical significance for the understanding of the mechanism of the formation of the turbidity maximum (TM).The effects of salinity and humus on the fine-grained sediments have been analyzed through the synthetic study of the aspects of flocculation/coagulation power (F), diameter (D) and zeta potential (Z).And the microcosmic configuration of the flocs has been analyzed by using a scan electron microscope and Fourier Transform Infrared Spectrometry.The results show that:(1) with the increase of salinity, F and D become greater and Z becomes smaller, and with the increase of the concentration of humus, F becomes smaller, but D and Z become greater; (2) the microcosmic configuration of the flocculation shows that humus packs on the fine sediments in the form of salt, and the flocculation model of C-P-OM (C stands for clay; P cations; OM organic materials) can successfully demonstrate the mechanism of the formation of the fine-grained sediments in the high-turbid area of the Changjiang Estuary.
Distributional features of temperature and salinity in the southern Taiwan Strait and its adjacent sea areas in late summer, 1994
Hu Jianyu, Liang Hongxing, Zhang Xuebin
1999(2): 237-246.
Keywords: Temperature, salinity, distributional feature, late summer, southern Taiwan Strait and its adjacent areas
Based on the CTD data obtained in the southern Taiwan Strait and its adjacent areas in August and September of 1994, the distributional features of the temperature and salinity in the studied area have been analyzed in detail.The results are as follows:(1) There are two low temperature and high salinity regions in the nearshore area between Dongshan and Shantou and in the southeastern Taiwan respectively, which may be caused by upwellings.(2) There exists a cold eddy in the northwestern sea area and a warm eddy with two high temperature cores in the eastern sea area of the Islands, which are related to the anti-cyclonic turning of the seawater near the Dongsha Islands.(3) A westward high temperature and high salinity water tongue extends through the northern Luzon Strait and reaches the sea areas near the Dongsha Islands and southern Taiwan Strait.
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