2014 Vol. 33, No. 4

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Petrologic perspectives on tectonic evolution of a nascent basin (Okinawa Trough) behind Ryukyu Arc:A review
YAN Quanshu, SHI Xuefa
2014, 33(4): 1-12. doi: 10.1007/s13131-014-0400-2
Okinawa Trough is a back-arc, initial marginal sea basin, located behind the Ryukyu Arc-Trench System. The formation and evolution of the Okinawa Trough is intimately related to the subduction process of the Philippine Sea Plate beneath the Eurasian Plate since the late Miocene. The tectonic evolution of the trough is similar to other active back-arcs, such as the Mariana Trough and southern Lau Basin, all of which are experiencing the initial rifting and subsequent spreading process. This study reviews all petrologic and geochemical data of mafic volcanic lavas from the Okinawa Trough, Ryukyu Arc, and Philippine Sea Plate, combined with geophysical data to indicate the relationship between the subduction sources (input) and arc or back-arc magmas (output) in the Philippine Sea Plate-Ryukyu Arc-Okinawa Trough system (PROS). The results obtained showed that several components were variably involved in the petrogenesis of the Okinawa Trough lavas: sub-continental lithospheric mantle underlying the Eurasian Plate, Indian mid-oceanic ridge basalt (MORB)-type mantle, and Pacific MORB-type mantle. The addition of shallow aqueous fluids and deep hydrous melts from subducted components with the characteristics of Indian MORB-type mantle into the mantle source of lavas variably modifies the primitive mantle wedge beneath the Ryukyu and subcontinental lithospheric mantle (SCLM) beneath the Okinawa Trough. In the northeastern end of the trough and arc, instead of Indian MORB-type mantle, Pacific MORB-type mantle dominates the magma source. Along the strike of the Ryukyu Arc and Okinawa Trough, the systematic variations in trace element ratios and isotopic compositions reflect the first-order effect of variable subduction input on the magma source. In general, petrologic data, combined with geophysical data, imply that the Okinawa Trough is experiencing the "seafloor spreading" process in the southwest segment, "rift propagation" process in the middle segment, and "crustal extension" process in the northeast segment, and a nascent ocean basin occurs in the southwest segment.
Speciation, distribution, and potential ecological risk assessment of heavy metals in Xiamen Bay surface sediment
LIN Cai, LIU Yang, LI Wenquan, SUN Xiuwu, JI Weidong
2014, 33(4): 13-21. doi: 10.1007/s13131-014-0453-2
Based on the survey of surface sediment in Xiamen Bay in October 2011, the speciation, distribution, and potential ecological risk assessment of heavy metals (Cu, Pb, Zn, Cd, and Cr) in this area were studied using the sequential extraction method and ecological risk assessment method. The results indicated: (1) the total concentrations of these heavy metals were influenced by runoff, industrial wastewater, and sewage, and were all higher in the coastal area than the offshore area while the highest area of Pb was a little farther away from the coastal water due to atmosphere deposition; (2) sequential extractions suggested that Cu was mainly composed with residual and Fe/Mn-oxide bound fractions, Pb was bound to Fe/Mn-oxide, Zn and Cr were dominated by residual, and Cd bound to exchangeable and carbonate fractions; (3) the order of migration and transformation sequence was Cd >Pb >Cu >Zn >Cr and the degree of pollution was Cd >Pb >Cu >Zn >Cr; and (4) the ratios of the secondary and primary phases showed that Zn and Cr were both clean, Cu may be polluted, Pb was moderately polluted, while Cd was heavily polluted.
Optical properties of estuarine dissolved organic matter isolated using cross-flow ultrafiltration
YI Yueyuan, ZHENG Airong, GUO Weidong, YANG Liyang, CHEN Ding
2014, 33(4): 22-29. doi: 10.1007/s13131-014-0451-4
Dissolved organic matter (DOM) from freshwater, mid-salinity, and seawater endmember samples in the Jiulong River Estuary, China were fractionated using cross-flow ultrafiltration with a 10-kDa membrane. The colloidal organic matter (COM; 10 kDa-0.22 μm) retentate, low molecular weight (LMW) DOM (<10 kDa) permeate, and bulk samples were analyzed using absorption spectroscopy and three-dimensional fluorescence excitation-emission-matrix spectroscopy. The UV-visible spectra of COM were very similar to those obtained for permeate and bulk samples, decreasing monotonically with increasing wavelength. Most of the chromophoric DOM (CDOM, expressed as the absorption coefficient a355) occurred in the LMW fraction, while the percentage of CDOM in the colloidal fraction was substantially higher in the freshwater endmember (13.4% of the total) than in the seawater endmember (6.8%). The bulk CDOM showed a conservative mixing behavior in the estuary, while there was removal of the COM fraction and a concurrent addition of the permeate fraction in the mid-salinity sample, implying that part of the colloidal CDOM was transformed into LMW CDOM. Two humic-like components (C1: <250, 325/402 nm; and C2: 265, 360/458 nm) and one protein-like component (C3: 275/334 nm) were identified using parallel factor analysis. The contributions of the C1, C2, and C3 components of the COM fraction to the bulk sample were 2.5%-8.7%, 4.8%-12.6%, and 7.4%-14.7%, respectively, revealing that fluorescent DOM occurred mainly in the LMW fraction in the Jiulong River Estuary. The C1 and C2 components in the retentate and permeate samples showed conservative mixing behavior, but the intensity ratio of C2/C1 was higher in the retentate than in the permeate fractions for all salinity samples, showing that the humic component was more enriched in the COM than the fulvic component. The intensity ratio of C3/(C1+C2) was much higher in the retentate than in the permeate fraction for mid-salinity and seawater samples, revealing that the protein-like component was relatively more enriched in COM than the humic-like component. The contribution of the protein-like component (C3) to the total fluorescence in the retentate increased from 14% in the freshwater endmember to 72% for the seawater endmember samples, clearly indicating the variation of dominance by the humic-like component compared to the protein-like component during the estuarine mixing process of COM.
Distributional characteristics of grain sizes of surface sediments in the Zhujiang River Estuary
JIANG Siyi, XU Fangjian, LI Yan, LIU Xiling, ZHAO Yongfang, XU Wei
2014, 33(4): 30-36. doi: 10.1007/s13131-014-0462-1
Distributions of the parameters of sedimentary grain sizes and their correlations were studied to trace the sources of silts and their movement trends in the Zhujiang River Estuary based on the analyses of grain sizes from more than 1 080 sedimentary samples. The distributions of the median diameter, public value, quartile deviation, and skewness of sediments were complex in the Zhujiang River Estuary mainly because of the impact of the matter source regions, distances from the source regions, and hydrodynamic conditions, such as waves, tidal currents, and coastal currents. Analyses of the parameters of the grain sizes for the various types of sediments showed that the distributions of the surface sediments in the Zhujiang River Estuary were controlled by many factors. Their matter sources were mainly the sediments discharged from the runoffs and ebb tidal currents, and from the open sea. The sediments mainly moved by suspension movement. The silts formed a large area of sediments with suspended fine silts in the Zhujiang River Estuary by internal adjustment transportation in the area, and moved toward the western coast of the Zhujiang River Estuary under the effect of Coriolis forces and coastal currents.
Spatial distribution pattern of seafloor hydrothermal vents to the southeastern Kueishan Tao offshore Taiwan Island
HAN Chenhua, YE Ying, PAN Yiwen, QIN Huawei, WU Guanghai, CHEN Chen-Tung Arthur
2014, 33(4): 37-44. doi: 10.1007/s13131-014-0405-x
Investigations of the diffusion activities both within and outside the seafloor hydrothermal vents, as well as related mineral genesis, have been one of the key focuses of ocean biogeochemistry studies. Many hydrothermal vents are distributed close to the southern Okinawa Trough on the less-than-30-m deep shallow seafloor off Kueishan Tao, northeast of Taiwan Island. Investigations of temperature, pH and Eh at four depths of hydrothermal plume were carried out near Kueishan Tao at the white (24.83°N, 121.96°E) and yellow (24.83°N, 121.96°E) vents. An 87 h of temperature time series observation-undertaken near the white vent showed that tide is the main factor affecting the background environment. Based on the observed data, 3-dimensional sliced diffusion fields were obtained and analyzed. It was concluded that the plume diffused mainly from north to south due to ebb tide. The yellow vent's plume could effect as far as the white vent surface. From the temperature diffusion field, the vortices of the plume were observed. The Eh negative abnormality was a better indicator to search for hydrothermal plumes and locate hydrothermal vents than high temperature and low pH abnormalities.
Variations of oceanic fronts and their influence on the fishing grounds of Ommastrephes bartramii in the Northwest Pacific
CHEN Xinjun, TIAN Siquan, GUAN Wenjian
2014, 33(4): 45-54. doi: 10.1007/s13131-014-0452-3
Two predominant currents, the warm Kuroshio Current and the cold Oyashio Current, meet in the Northwest Pacific Ocean. The dynamics of physical oceanographic structures in this region, including frontal zones and meandering eddies, result in a highly productive habitat that serves as a favorable feeding ground for various commercially important species. Neon flying squid, Ommastrephes bartramii, is an important oceanic squid, which is widely distributed in the North Pacific Ocean. Based on the catch data collected by Chinese squid jigging fleets and relevant environmental data, including sea surface temperature (SST) and fronts (represented by gradients of SST and thermocline) during 1998-2009, the variations of oceanic fronts and their influence on the fishing grounds of O. bartramii were evaluated, and the differences in distribution of fishing grounds of O. bartramii in 2000 and 2002 were compared by describing the differences in vertical temperature between 0-300 m. It was found that the preferred horizontal temperature gradient of SST for O. bartramii tended to be centered at 0.01-0.02℃/nm, which attracted nearly 80% of the total fishing effort, and the preferred horizontal temperature gradients at the 50 m and 105 m layers were mainly located at 0.01-0.03℃/nm, which accounted for more than 70% of the total fishing effort during August-October. The preferred vertical temperature gradient within the 0-50 m layer for O. bartramii tended to be centered at 0.15-0.25℃/m during August and September and at 0.10-0.15℃/m in October, implying that the mixed surface layer was distributed at depths of 0-50 m. It was concluded that the vertical temperature gradient was more important than the horizontal temperature gradient in playing a role in forming the fishing ground. The results improved our understanding of the spatial dynamics of the O. bartramii fishery.
16S rRNA is a better choice than COI for DNA barcoding hydrozoans in the coastal waters of China
ZHENG Lianming, HE Jinru, LIN Yuanshao, CAO Wenqing, ZHANG Wenjing
2014, 33(4): 55-76. doi: 10.1007/s13131-014-0415-8
Identification of hydrozoan species is challenging, even for taxonomic experts, due to the scarcity of distinct morphological characters and phenotypic plasticity. DNA barcoding provides an efficient method for species identification, however, the choice between mitochondrial cytochrome c oxidase subunit Ⅰ (COI) and large subunit ribosomal RNA gene (16S) as a standard barcode for hydrozoans is subject to debate. Herein, we directly compared the barcode potential of COI and 16S in hydrozoans using 339 sequences from 47 pelagic hydrozoan species. Analysis of Kimura 2-parameter genetic distances (K2P) documented the mean intraspecific/interspecific variation for COI and 16S to be 0.004/0.204 and 0.003/0.223, respectively. An obvious "barcoding gap" was detected for all species in both markers and all individuals of a species clustered together in both the COI and 16S trees. These results suggested that the species within the studied taxa can be efficiently and accurately identified by COI and 16S. Furthermore, our results confirmed that 16S was a better phylogenetic marker for hydrozoans at the genus level, and in some cases at the family level. Considering the resolution and effectiveness for barcoding and phylogenetic analyses of Hydrozoa, we strongly recommend 16S as the standard barcode for hydrozoans.
Re-identifying Grateloupia yangjiangensis (Rhodophyta, Halymeniaceae) based on morphological observations, life history and rbcL sequence analyses
WANG Hongwei, GUO Shaoru, ZHANG Xiaoming, ZHAO Dan, ZHANG Wen, LUAN Rixiao
2014, 33(4): 77-84. doi: 10.1007/s13131-014-0450-5
On the basis of morphological observations, life history and molecular phylogeny, Grateloupia yangjiangensis, which is similar to G. filicina, G. orientalis, G. catenata, and G. ramosissima in appearance, was re-examined. The results are as follows: (1) the auxiliary-cell ampullae of G. yangjiangensis were of Grateloupia type, thalli was fleshy and gelatinous in texture, and the erect axes were compressed; the cortex was 0.25-0.30 mm thick, consisting of five to seven outer layers, and there were five inner layers of triangular or stellate cells; (2) there was no filamentous stage in the development of the carpospores; (3) the ribulose-1,5-bisphosphate carboxylase/oxygenase gene (rbcL) sequence of four G. yangjiangensis examined showed that there was no intergeneric divergence among them, and for the phylogenetic tree, four sequences of G. yangjiangensis formed a single monophyletic subclade within the large Grateloupia clade of Halymeniaceae. In conclusion, G. yangjiangensis was a single species within the genus Grateloupia. This research provided criterion for identification and cultivation of G. yangjiangensis.
Phosphorus deficiency affects multiple macromolecular biosynthesis pathways of Thalassiosira weissflogii
WANG Xiuxiu, HUANG Bangqin, ZHANG Huan
2014, 33(4): 85-91. doi: 10.1007/s13131-014-0413-x
Phosphorus (P) is one of the key nutrients for the growth of phytoplankton. In this study, we used a method coupling label-free quantitation with liquid chromatography-mass spectrometry (LFQ-LC-MS/MS) to track the change of relative protein abundance between P-replete and P-deficient treatments in a non-model diatom, Thalassiosira weissflogii. Out of the 631 proteins identified, 132 were found to have significant changes in abundance (>1.5 folds) between the two treatments, especially those proteins involved in macromolecular biosynthesis pathways. For example, the up-regulation of sulfolipid biosynthesis protein in the P-deficient culture suggested a switch from using phospholipids to sulfolipids. In addition, the ribosome subunits and tRNA synthetases were down-regulated, which might explain the decrease in protein content in the P-deficient culture. A vacuolar sorting receptor homologous protein was found to be 9.2-folds up-regulated under P-deficiency, indicating an enhancement in the vacuolar sorting pathway for protein degradation. Our results show that T. weissflogii has sophisticated responses in multiple macromolecular metabolism pathways under P-deficiency, a mechanism which can be critical for this species to survive under various levels of P availability in the environment.
Cloning and expression analysis of the chloroplast fructose- 1,6-bisphosphatase gene from Pyropia haitanensis
XIAO Haidong, CHEN Changsheng, XU Yan, JI Dehua, XIE Chaotian
2014, 33(4): 92-100. doi: 10.1007/s13131-014-0455-0
Fructose-1,6-bisphosphatase (FBPase) is one of the key enzymes in Calvin circle and starch biosynthesis. In this study, the full-length of cpFBPase gene from Pyropia haitanensis was cloned by using rapid amplification of cDNA ends (RACE) technology. The nucleotide sequence of PhcpFBPase consists of 1 400 bp, including a 5' untranslated region (UTR) of 92 bp, a 3' UTR of 69 bp, and an open reading frame (ORF) of 1 236 bp, which can be translated into a 412-amino-acid putative peptides with a molecular weight of 44.3 kDa and a theoretical pI of 5.23. Multiple sequence alignment indicated that the protein belonged to the chloroplast FBPase enzyme. Phylogenetic analysis showed that the protein assembled with the cpFBPase of a thermal tolerant unicellular red micro-algae Galdieria sulphuraria. Expression patterns analyzed by qRT-PCR revealed that the expression of PhcpFBPase gene in the thallus phage was 7-fold higher than in the conchocelis phage, which suggested the different mechanisms of inorganic carbon utilization among the different life phages of P. haitanensis. And the different response modes of PhcpFBPase mRNA levels to high temperature and desiccation stress indicated that PhcpFBPase played an important role in responsing to abiotic stress.
Research Notes
Distribution and sources of heavy metals in the sediment of Xiangshan Bay
SUN Weiping, YU Jianjun, XU Xiaoqun, ZHANG Weiyan, LIU Ruijuan, PAN Jianming
2014, 33(4): 101-107. doi: 10.1007/s13131-014-0456-z
Heavy metals in the surface sediments and sediment core from the Xiangshan Bay, a mariculture base on the coast of the East China Sea, were determined by inductively coupled plasma mass spectrometry (ICP-MS) in order to evaluate their levels and sources. The results showed that the levels of Cu, Pb, Zn, and Cr in the sediments of the bay have been generally influenced by anthropogenic inputs since the founding of the People's Republic of China. In particular, Cu and Zn were polluted to some extent, as evidenced by high enrichment factors. Organic matter, grain size, wastewater discharge, and low energy hydrodynamic environment played dominant roles in the heavy metal enrichment in the sediments. The ratio of terrigenous source to marine biogenic deposit of trace metals in the sediments was calculated, revealing that terrigenous inputs were the main source of Cu, Pb, and Zn, while biological pellets contributed much more to the enrichment of Cr and Cd. Considering the influence of biological sources on the enrichment of Cd and Cr, and the fact that the sediment has been polluted by Cu and Zn, the development of mariculture and discharge of wastewater into the Bay should be restricted.
Are assemblages of the fireworm Hermodice carunculata enhanced in sediments beneath offshore fish cages?
Rodrigo Riera, Oscar Pérez, Myriam Rodríguez, Eva Ramos, Óscar Monterroso
2014, 33(4): 108-111. doi: 10.1007/s13131-014-0449-y
Abundances of the fireworm Hermodice carunculata were counted through a monitoring assessment study of fish cages in Barranco Hondo (NE Tenerife). Seven campaigns were conducted from November 2007 to June 2010 and temporal variations were found, as well as differences among sampling stations. The polychaete H. carunculata obtained its highest abundance in sediments beneath fish cages throughout the study period. Thus, the assemblages of this omnivorous species were favoured by the presence of fish cages.