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Clift P.D.,University of Aberdeen | Clift P.D.,CAS South China Sea Institute of Oceanology
Geophysical Research Letters

Surface erosion is the most significant process responsible for the recycling of continental crust into the upper mantle, and controls both exhumation in mountain belts and the long-term global climate via chemical weathering. Earlier studies have highlighted the importance of climate instability since the onset of Northern Hemispheric Glaciation (∼3 Ma) as being the primary influence causing high erosion rates since that time. Here I show that synchronous pulses of erosion and exhumation occurred across Eurasia, in North America and in Africa starting after 33 Ma, with a prominent peak around 16 Ma. Correlation of these erosional events with changes in global climate suggests that they are controlled by surface processes. Because these climate events involve both cooling and warming periods the importance of increased seasonality is emphasized as being the key factor in controlling global erosion and exhumation throughout the Cenozoic. Copyright © 2010 by the American Geophysical Union. Source

Cai J.-X.,CAS South China Sea Institute of Oceanology
Journal of Geodynamics

Ductile shear structure of the Guanging-Bobai fault belt in the SW part of the Qin-Hang belt, South China, has been investigated and interpreted in terms of radiometric dating data. A series of ductile shear zones occurs within the fault belt with deformation and metamorphic features indicative of formation under medium temperature and pressure conditions. The foliation such formed is steeply dipping and bears a gently plunging lineation, which along with the dextral kinematic indicators determines a broad NE-SW-trending dextral strike-slip regime responsible for the development of these shear zones. Field overprinting relationships indicate that this dextral shear is pre-dated by the Indosinian (P2-T) NNE-verging thrusting and post-dated by the Yanshanian (J2-K2) SE-verging thrusting, and thus occurred during a transitional period between the two orogenies. 40Ar-39Ar radiometric dating on muscovite from mylonites further constrains timing of the dextral shear to the Early Jurassic (187-193Ma). Based on the coeval tectonic framework of eastern Asia, we propose here that the dextral strike-slip system was initiated by the far-field oblique stress field from the incipient subduction of the Izanagi oceanic plate. An offset continental margin of the South China plate may have been created in response to this transcurrent movement along the fault belt, dissecting and displacing not only a relict Caledonian foreland basin, but also an Indosinian magmatic belt. © 2012 Elsevier Ltd. Source

Traditionally Cocholodinium and Gymnodinium sensu lato clade are distinguished based on the cingulum turn number, which has been increasingly recognized to be inadequate for Gymnodiniales genus classification. This has been improved by the combination of the apical groove characteristics and molecular phylogeny, which has led to the erection of several new genera (Takayama, Akashiwo, Karenia, and Karlodinium). Taking the apical groove characteristics and molecular phylogeny combined approach, we reexamined the historically taxonomically uncertain species Cochlodinium geminatum that formed massive blooms in Pearl River Estuary, China, in recent years. Samples were collected from a bloom in 2011 for morphological, characteristic pigment, and molecular analyses. We found that the cingulum in this species wraps around the cell body about 1.2 turns on average but can appear under the light microscopy to be >1.5 turns after the cells have been preserved. The shape of its apical groove, however, was stably an open-ended anticlockwise loop of kidney bean shape, similar to that of Polykrikos. Furthermore, the molecular phylogenetic analysis using 18S rRNA-ITS-28S rRNA gene cistron we obtained in this study also consistently placed this species closest to Polykrikos within the Gymnodinium sensu stricto clade and set it far separated from the clade of Cochlodinium. These results suggest that this species should be transferred to Polykrikos as Polykrikos geminatum. Our results reiterate the need to use the combination of apical groove morphology and molecular phylogeny for the classification of species within the genus of Cochlodinium and other Gymnodiniales lineages. Source

Yu K.F.,CAS South China Sea Institute of Oceanology
Science China Earth Sciences

This paper reviews both the recent and longer-term (Holocene) ecological history of coral reefs in the South China Sea (SCS). (1) Local ecological monitoring since the 1960s shows that the coral reefs in the South China Sea have declined dramatically, reflecting the rapid decrease of living coral cover and the great loss of symbiotic zooxanthellae. Collectively, this has led to a significant decrease of annual CaCO 3 production. Heavy anthropogenic activities and global warming are recognized as major triggers of the observed coral reef degradation. Observations show that the modern coral reefs in the SCS are a source of atmospheric CO 2 in summer. (2) Coral reefs of the SCS have been widely used to reveal longer-term environmental variations, including Holocene high-resolution sea surface temperature (SST) and abrupt climate events, millennial-scale El Niño variations, millennial- and centennial-scale sea level oscillations, strong and cyclic storm activities, East Asian monsoon intensities, variation in seawater pH, and recent seawater pollution. (3) Coral reefs of the southern SCS have experienced repeated episodes of bleaching over the last 200 years due to high SST and intense El Niño events; coral reefs of the northern SCS suffered high levels of mortality during several abrupt winter cold-water bleaching events during the middle Holocene warm period. On average, recovery after the middle Holocene cold-bleaching took 20-30 years; recovery following other middle Holocene environmental stresses took approximately 10-20 years. Such findings have significantly contributed to the understanding of the present ecological pressures faced by the coral reefs in the SCS, the histories of Holocene climate/environment changes, and the long-term models of coral reef responses to various past environmental changes. © 2012 Science China Press and Springer-Verlag Berlin Heidelberg. Source

A Gram-negative, poly-3-hydroxybutyrate-accumulating rod bacterium, strain GYP-2(T), was isolated from a pool of marine Spirulina platensis cultivation, Sanya, China. Growth was observed at 10-45 °C and pH 6-10 in the presence of 1-10 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that the new isolate belonged to Gammaproteobacteria and displayed 93.8-95.3 % 16S rRNA gene sequences similarities to members of the genera Thalassolituus, Oleibacter, and Oceanobacter, but house-keeping gene gyrB (encode DNA gyrase beta subunit) demonstrated that the new isolate was distantly related to Thalassolituus, Oleibacter, and Oceanobacter species (only 77-83 % gene gyrB sequences similarities).The G+C content of genomic DNA was 55 mol%. The major respiratory quinone was Q-9, while that for Oceanobacter kriegii LMG 6238(T) was Q-8. Major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, and phosphatidylethanolamine. On the basis of its physiological, chemotaxonomic, and molecular properties, strain GYP-2(T) is suggested to represent a novel species of a new genus in Gammaproteobacteria, for which the name Bacterioplanes sanyensis gen. nov., sp. nov. is proposed. The type strain is GYP-2(T) (=CGMCC 1.12392(T)=KCTC 32220(T)). Source

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