2015 Vol. 34, No. 8

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Experiments and evidences: jellyfish (Nemopilema nomurai) decomposing and nutrients (nitrogen and phosphorus) released
LI Xuegang, SONG Jinming, MA Qingxia, LI Ning, YUAN Huamao, DUAN Liqin, QU Baoxiao
2015, 34(8): 1-12. doi: 10.1007/s13131-015-0703-y
The aim of this study was to investigate nitrogen and phosphorus released in the process of the decomposition of giant jellyfish in the laboratory and found the evidence to verify the influence of nutrients released by the decomposition of jellyfish on the ecosystem in the field. The release of nitrogen and phosphorus from the decomposition of Nemopilema nomurai was examined in a series of experiments under different incubation conditions such as different pH values, salinity values, temperatures and nitrogen and phosphorus concentrations. The results showed that the complete decomposition of Nemopilema nomurai generally took about 4-8 d. The release of nitrogen and phosphorus from the decomposition of Nemopilema nomurai could be divided into two stages: the early stage and the later stage, although the efflux rate of nitrogen was one order more than phosphorus. In the early stage of the decomposition of Nemopilema nomurai, the concentrations of dissolved nitrogen, dissolved phosphorus, total nitrogen and total phosphorus in seawater increased rapidly, and the concentration of nitrogen could reach the highest level in the whole degradation process. In the later stage of the decomposition, the concentrations of dissolved nitrogen and total nitrogen declined slowly, while the concentration of phosphorus in water could reach a maximum in the degradation process. High pH, low salinity, high temperature and N/P will promote the release of nitrogen; low pH is unfavorable to the release of nitrogen but favorable to the release of phosphorus. In addition, we found the concentrations of ammonium and phosphate in the bottom water were higher than those in the surface water during the period of jellyfish bloom in the Jiaozhou Bay, proving that nutrients released by the decomposition of jellyfish have significant influence on nitrogen and phosphorus in the field. For the whole Yellow Sea, nutrients released by jellyfish carcasses may reach up to (2.63±2.98)×107 mol/d of dissolved nitrogen (DN) and (0.74±0.84)×106 mol/d of dissolved phosphorus (DP) during the period of jellyfish bloom. The values are comparable to riverine inputs in a day, but much higher than sediment-water exchange flux in the Yellow Sea. The great amounts of nutrients must have significant influence on the nutrients balance of the Yellow Sea during the period of jellyfish dead and decomposition. Both the experimental data and field observations proved that the decomposition of jellyfish may release a great amount of nutrient to the surrounding environment during the period of jellyfish decomposition.
The distribution of iodine and effects of phosphatization on it in the ferromanganese crusts from the Mid-Pacific Ocean
JI Lihong, LIU Guangshan, HUANG Yipu, XING Na, CHEN Zhigang
2015, 34(8): 13-19. doi: 10.1007/s13131-015-0704-x
In the present paper, iodine (I), iron (Fe), manganese (Mn), cobalt (Co), phosphorus (P) and calcium (Ca) contents in three ferromanganese crusts from the Pacific Ocean are measured by spectrophotometric method and inductively coupled plasma atomic emission spectrometers (ICP-AES) to investigate the contents and distribution of iodine in ferromanganese crusts. The results show that iodine contents in three crusts vary between 27.1 and 836 mg/kg, with an average of 172 mg/kg, and the profile of iodine in the three crusts all exhibits a two-stage distribution zone: a young non-phosphatized zone and an old phosphatized zone that is rich in I, P and Ca. The iodine content ratios of old to young zone in MP5D44, CXD62-1 and CXD08-1 are 2.3, 3.4 and 13.7, respectively. The boundary depths of two-stage zone in MP5D44, CXD62-1 and CXD08-1 locate at 4.0 cm, 2.5 cm and 3.75 cm, respectively, and the time of iodine mutation in three crusts ranges from 17-37 Ma derived from 129I dating and Co empirical formula, which is consistent with the times of Cenozoic phosphatization events. The present study shows that the intensity of phosphatization is the main responsible for the distribution pattern of iodine in the crusts on the basis of the correlation analysis. Consequently, iodine is a sensitive indicator for phosphatization.
Testing coral paleothermometers (B/Ca, Mg/Ca, Sr/Ca, U/Ca and δ18O) under impacts of large riverine runoff
CHEN Tianran, YU Kefu, ZHAO Jianxin, YAN Hongqiang, SONG Yinxian, FENG Yuexing, CHEN Tegu
2015, 34(8): 20-26. doi: 10.1007/s13131-015-0705-9
Sea surface temperature (SST) proxies including B/Ca, Mg/Ca, Sr/Ca, U/Ca and δ18O were analyzed in the skeleton of a Porites coral collected from the Zhujiang River (Pearl River) Estuary (ZRE). These geochemical proxies are influenced by river runoff and this area of the northern South China Sea is strongly affected by seasonal freshwater floods. We assessed the robustness of each SST proxy through comparison with the local instrumental SST. Coral Sr/Ca shows the highest correlation with SST variations (r2=0.59), suggesting Sr/Ca is the most robust SST proxy. In contrast, coral δ18O (r2=0.46), B/Ca (r2=0.43) and U/Ca (r2=0.41) ratios were only moderately correlated with SST variations, suggesting that they are disturbed by some other factors in addition to SST. The poor correlation (r2=0.27) between SST and Mg/Ca indicates that Mg/Ca in coral skeletons is not a simple function of SST variations. This may ultimately limit the use of Mg/Ca as a coral paleothermometer.
Characteristics of Sr, Nd and Pb isotopic compositions of hydrothermal Si-Fe-Mn-oxyhydroxides at the PACMANUS hydrothermal field, Eastern Manus Basin
YANG Baoju, ZENG Zhigang, WANG Xiaoyuan
2015, 34(8): 27-34. doi: 10.1007/s13131-015-0706-8
Si-Fe-Mn-oxyhydroxides dredged at the PACMANUS (Papua New Guinea-Australia-Canada-Manus) hydrothermal field, Eastern Manus Basin, have 87Sr/86Sr=0.708 079-0.708 581; εNd=5.149 833-6.534 826; 208Pb/204Pb=38.245-38.440; 207Pb/204Pb=15.503-15.560; 206Pb/204Pb=18.682-18.783. 87Sr/86Sr isotope ratios are relatively homogeneous and close to the value of the surrounding seawater (0.709 16). The content of Sr in the samples contributed by seawater was estimated to be 76.7%-83.1% of total amount. The mixing temperature of hydrothermal fluids and seawater were ranging from 53.2℃ to 72.2℃ and the hydrothermal activities were unstable when the samples precipitated. The εNd values of all the samples are positive, which differ from the values of ferromanganese nodules (crusts) with hydrogenic origin. Nd was mainly derived from substrate rocks leached by hydrothermal circulation and preserved the hydrothermal signature. Pb isotopic compositions of most samples show minor variability except Sample #9-2 that has relatively high values of Pb isotopes. The Pb may be derived from the Eastern Manus Basin rocks leached by the hydrothermal fluid. The slightly lower 208Pb/204Pb and 207Pb/204Pb values of the samples indicated that the hydrothermal circulation in PACMANUS was not entire and sufficient, or that hydrothermal circulation had transient changes in the past. Si-Fe-Mn-oxyhydroxides in the samples preserved the heterogeneities of local rocks.
Mass movements in small canyons in the northeast of Baiyun deepwater area, north of the South China Sea
LI Xishuang, LIU Lejun, LI Jiagang, GAO Shan, ZHOU Qingjie, SU Tianyun
2015, 34(8): 35-42. doi: 10.1007/s13131-015-0702-z
The process of mass movements and their consequent turbidity currents in large submarine canyons has been widely reported, however, little attention was paid to that in small canyons. In this paper, we document mass movements in small submarine canyons in the northeast of Baiyun deepwater area, north of the South China Sea (SCS), and their strong effects on the evolution of the canyons based on geophysical data. Submarine canyons in the study area arrange closely below the shelf break zone which was at the depth of -500 m. Within submarine canyons, seabed surface was covered with amounts of failure scars resulted from past small-sized landslides. A complex process of mass transportation in the canyons is indicated by three directions of mass movements. Recent mass movement deposits in the canyons exhibit translucent reflections or parallel reflections which represent the brittle deformation and the plastic deformation, respectively. The area of most landslides in the canyons is less than 3 km2. The trigger mechanisms for mass movements in the study area are gravitational overloading, slope angle and weak properties of soil. Geophysical data indicate that the genesis of submarine canyons is the erosion of mass movements and consequent turbidity currents. The significant effects of mass movements on canyon are incision and sediment transportation at the erosion phases and fillings supply at the fill phases. This research will be helpful for the geological risk assessments and understanding the sediment transportation in the northern margin of the SCS.
Effects of environmental variations on the abundance of western winter-spring cohort of neon flying squid (Ommastrephes bartramii) in the Northwest Pacific Ocean
YU Wei, CHEN Xinjun, CHEN Yong, YI Qian, ZHANG Yang
2015, 34(8): 43-51. doi: 10.1007/s13131-015-0707-7
During 1995-2011, annual production of winter-spring cohort of Ommastrephes bartramii for Chinese squid-jigging fishery has greatly fluctuated, which is closely related to the environmental conditions on the spawning and fishing grounds. To better understand how squid recruitment and abundance were influenced by ocean environmental conditions, biological and physical environmental variables including sea surface temperature (SST), SST anomaly (SSTA), chlorophyll a (Chl a) concentration and the Kuroshio Current were examined during years with the highest (1999), intermediate (2005), and lowest (2009) catches. Catch per unit effort (CPUE) of the squid-jigging vessels was used as an indicator of squid abundance. The results indicated that high SST and Chl a concentration on the spawning ground in 1999 resulted in favorable incubation and feeding conditions for squid recruitment. Whereas the suitable spawning zone (SSZ) in 2009 shifted southward and coincided with low SST and Chl a concentration, resulting in a reduction in the squid recruitment. The small difference of SSZ area in the three years suggested the SSZ provided limited influences on the variability in squid recruitment. Furthermore, high squid abundance in 1999 and 2005 was associated with warm SSTA on the fishing ground. While the cool SSTA on the fishing ground in 2009 contributed to adverse habitat for the squid, leading to extremely low abundance. It was inferred that strengthened intensity of the Kuroshio force generally yielded favorable environmental conditions for O. bartramii. Future research are suggested to focus on the fundamental research on the early life stage of O. bartramii and mechanism of how the ocean-climate variability affects the squid abundance and spatial distribution by coupling physical model with squid biological process to explore transport path and abundance distribution.
Cloning of catalase and expression patterns of catalase and selenium-dependent glutathione peroxidase from Exopalaemon carinicauda in response to low salinity stress
REN Hai, LI Jian, LI Jitao, YING Yu, GE Hongxing, LI Dongli, YU Tianji
2015, 34(8): 52-61. doi: 10.1007/s13131-015-0640-9
Catalase (CAT) and selenium-dependent glutathione peroxidase (Se-GPx) play a vital role in protecting organisms against various oxidative stresses by eliminating H2O2. The objective of this paper is to evaluate the roles of these antioxidant molecules in the ridgetail white prawn Exopalaemon carinicauda in response to low salinity stress. A complementary DNA (cDNA) containing the complete coding sequence of CAT was cloned from the hepatopancreas using reverse-transcription polymerase chain reaction (RT-PCR) and rapid amplification of cDNA ends. The full-length cDNA of CAT (2 649 bp) contains a 5'-untranslated region (UTR) of 78 bp, a 3'- UTR of 1 017 bp, with a poly (A) tail, and an open reading frame of 1 554 bp encoding a 517-amino-acid polypeptide with predicted molecular mass of 58.46 kDa and estimated isoelectric point of 6.64. This CAT sequence contained the proximal active site signature (60FDRERIPERVVHAKGAG76), proximal heme-ligand signature sequence (350RLFSYPDTH358) and three catalytic amino acid residues (His71, Asn144 and Tyr354). Sequence comparison showed that the CAT deduced amino acid sequence of E. carinicauda shared 68%-92% of identities with those of other species. Quantitative real-time PCR analysis revealed that CAT mRNA was widely expressed in the hepatopancreas (highest), hemocyte, eyestalk, heart, gill, muscle, ovary and stomach. Under low salinity stress, CAT and GPx mRNA expression levels both in the gill and hepatopancreas increased significantly at the first 48 h and 6 h respectively, indicating a tissue- and time-dependent antioxidant response in E. carinicauda. All these results indicate that E. carinicauda CAT is a member of the CAT family and might be involved in the acute response against low salinity stress.
Molecular characterization and expression of HSP70, HSF and HSBP genes in Octopus vulgaris during thermal stress
HONG Jingni, MAO Yong, NIU Sufang, SUN Tiantian, SU Yongquan
2015, 34(8): 62-72. doi: 10.1007/s13131-015-0708-6
Temperature is an important environmental factor that affects the growth and survival of Octopus vulgaris, the common octopus. To understand the protective mechanism that O. vulgaris exhibits under heat stress, we used rapid amplification of cDNA ends (RACE) to obtain full-length sequences of three heat stress response related genes: (1) the heat shock protein 70 (OvHSP70), (2) the heat shock transcription factor (OvHSF) , and (3) the heat shock factor-binding protein (OvHSBP) of O. vulgaris. The OvHSP70, OvHSF, and OvHSBP proteins contained 2 222 bp, 2 264 bp, 841 bp that encoded for 635, 458 and 90 amino acids, respectively. The results of multiple sequence alignment showed that the amino acid sequences of OvHSP70 were highly conserved with respect to other species. Similarly, the DNA binding domain, the trimerization domain of OvHSF, and the coiled coil region of OvHSBP also had highly conserved regions. The real-time polymerase chain reaction (PCR) results indicated that OvHSP70 was temperature-dependent and time-dependent, showing a positive response to heat stress. On exposure to 28℃ and to 30℃, the mRNA expression levels of OvHSF and OvHSBP were higher than those in the control group at 24℃. The mRNA expression of OvHSBP significantly increased with heat treatment at 26℃, while the mRNA expression of OvHSF decreased. The experimental results indicated that the expression of OvHSP70, OvHSF and OvHSBP were all sensitive to heat stress, which suggests that these three genes may play an important role for O. vulgaris in responding to environmental stress. Thus, this study sets a theoretical foundation for further in-depth studies on the molecular protective mechanisms of the heat response in O. vulgaris.
Phylogenetic analysis and biological characteristic tests of marine bacteria isolated from Southern Ocean (Indian sector) water
2015, 34(8): 73-82. doi: 10.1007/s13131-015-0709-5
Fifty-seven bacteria were isolated from Southern Ocean (Indian sector) water samples which were collected from different latitude and longitude of the ocean. All the isolates were able to grow at 4℃, 20℃, 37℃ and tolerable NaCl concentration up to 13.5% (w/v). 29 out of 57 isolates were identified using 16S rDNA amplification and the sequences were submitted to National Center for Biotechnology Information (NCBI). All the isolates were classified by using Ribosomal Database Project (RDP) and found that isolates belongs to Proteobacteria and Bacteriodes. The average G+C content was 56.4%. The isolates were screened for the presence of extracellular enzymes, viz. amylase, catalase, urease, esterase, lipase and protease. The disc diffusion method is used to screen antibiotic production by the isolates against four pathogenic bacteria, viz. Salmonella typhimurium (NCIM 2501), Staphylococcus aureus (NCIM 2122), Bacillus subtilis (NCIM 2193), and Pseudomonas aeruginosa (NCIM 2036). Nine out of 29 were found to be antibiotic producer.
Seasonal and spatial distribution of ammonia-oxidizing microorganism communities in surface sediments from the East China Sea
HE Hui, ZHEN Yu, MI Tiezhu, LU Xinglan, YU Zhigang
2015, 34(8): 83-92. doi: 10.1007/s13131-015-0710-z
Ammonia oxidation plays a significant role in the nitrogen cycle in marine sediments. Seasonal and spatial distribution of ammonia-oxidizing archaea (AOA) and betaproteobacteria (β-AOB) in surface sediments from the East China Sea (ECS) were investigated using ammonia monooxygenase α subunit (amoA) gene. In order to characterize the community of AOA and β-AOB, real-time quantitative polymerase chain reaction (qPCR) was carried out in this study, along with environmental parameters. The abundance of β-AOB amoA gene (2.17×106-4.54×107 copy numbers per gram wet weight sediment) was always greater than that of AOA amoA gene (2.18×105-9.89×106 copy numbers per gram wet weight sediment) in all sampling stations. The qPCR results were correlated with environmental parameters. AOA amoA gene copy numbers in April were positively related to temperature and nitrite concentration (p <0.05). β-AOB amoA gene copy numbers in August correlated negatively with salinity (p <0.01), and correlated positively with ammonium concentration (p <0.05). With the increase of salinity, the amoA gene copy ratio of AOB to AOA had a tendency to decrease, which suggested β-AOB dominated in the area of high level ammonium and AOA preferred high salinity area.
Community structure and controlled factor of attached green algae on the Porphyra yezoensis aquaculture rafts in the Subei Shoal, China
LI Yan, XIAO Jie, DING Lanping, WANG Zongling, SONG Wei, FANG Song, FAN Shiliang, LI Ruixiang, ZHANG Xuelei
2015, 34(8): 93-99. doi: 10.1007/s13131-015-0677-9
This study analyzes the community structure, the quantity changes of the algae and the effect of important environmental factors and estimates the total biomass of the attached green algae in the survey areas. The study uses data from surveys of the attached green algae on the Porphyra yezoensis aquaculture rafts and data regarding the environmental factors from October 2010 to April 2011 in the Subei Shoal. The attached green algae on the rafts included Ulva prolifera, Capsosiphon groenlandicus, U. linza, U. intestinalis, U. clathrata, and U. compressa. The biomass changes of the attached green algae exhibited an inverted parabola: the biomass was the highest (14 898 t) in April, and was the second highest (2 034 t) in November; it was lowest in February (only 729 t) and increased sharply from March to April. The species diversity differed significantly among the seasons. In September and October, when the P. yezoensis aquaculture rafts were initially set up, the attached green algae had a high biodiversity, while from December to the next February, a variety of green algae species coexisted on the rafts, although the biomass was low, and from March to April, as the biomass increased sharply, the species diversity dropped to the minimum. During this time, C. groenlandicus was apparently dominant with the maximum biomass proportion up to 80%, while the U. prolifera proportion increased exponentially to 20% to 40%. The water temperature had a direct regulating effect on the biomass and the species succession of the attached green algae. The estimation of the community dynamics and the biomass of the green algae provided the evidence needed to track the origin of the large-scale green tide in the southern Yellow Sea.
Study on ecosytem service function change of island based on remote sensing
WANG Li'an, PAN Delu, FU Dongyang
2015, 34(8): 100-107. doi: 10.1007/s13131-015-0587-x
Based on the interpretation of the remote sensing data presented by the resource satellite, this paper states the fact that the land-use area in Donghai Island, which is located in the south of Zhanjiang, Guangdong Province, had expanded by 576.71 hm2 in the 25 years from 1986 to 2010 because of human activities such as land reclamation; in the meantime, great changes in types of land cover on the island have occurred. The definite change in land use leads to the remarkable transition in its ecosystem service value. Therefore, by applying the Costanza method in this paper to quantificationally analyze the changes in its ecosystem services on this island; the Costanza method is a calculation technique that shows the service value per unit area of island. It is found that from 1986 to 2010, especially in the recent years, due to the rapid development in the petrifaction, steel and port industries, the areas of cultivated land, woodland, grassland and desert have decreased in different degrees, while the lands for residence, industry and traffic construction and the areas of water and wetlands have increased. Consequently, compared with the number of RMB 547.57×106 yuan per year in 1986, the ecosystem service value of Donghai Island was greatly reduced to RMB 493.94×106 yuan per year in 2010. As for the spatial distribution, it presents a feature that it is higher in the west and low in the east. The results manifest that it is of great significance to analyze the changes in the ecosystem service function on the basis of the service value of the island presented by the remote sensing data in a quantificational way, which will contribute to the promotion of ecological compensation.
Research Notes
Altered seawater salinity levels affected growth and photosynthesis of Ulva fasciata (Ulvales, Chlorophyta) germlings
CHEN Binbin, ZOU Dinghui
2015, 34(8): 108-113. doi: 10.1007/s13131-015-0654-3
Seawater salinity is greatly influenced by tide, evaporation and rain falls. In this study, we investigated the growth and photosynthetic responses of zygote-derived Ulva fasciata Delile germlings to short-term (minutes) and prolonged (days) exposure to different salinity gradients, to evaluate the effect of salinity variation on the early stage of life history in this seaweed. The results showed that, the maximum net photosynthetic rates (NPRm) of U. fasciata germlings was observably decreased in desalted (25 and 15) and high (45) salinity seawater in short-term exposure tests (in minutes). However, after 30 min, the photosynthesis activity in medium salinity (25) was maintained at a relative high level (above 70%). After 8 d prolonged culture, the photosynthesis and mean relative growth rate (RGR) of germlings were all markedly lowered, whereas the malondialdehyde (MDA) contents increased as the salinity desalted from 34 to 15. The salinity decrease from 34 to 25 had no significant effect on the RGR, but obviously influenced the morphology of the germlings. High salinity level (45) significantly depressed the RGR and photosynthesis of U. fasciata germlings, while it notably increased the MDA contents. The results showed that the salinity elevation had more detrimental effects on Ulva fasciata germlings than salinity decrease did. The germlings grown at the salinity seawater levels from 25 to 34, performed preferable photosynthetic acclimation both in temporary and prolonged culture. Broad salinity tolerance from 25 to 34 in U. fasciata germlings may have partly evolved as a response to regular diurnal tides.