Post-glacial regional climate variability along the East Antarctic coastal margin—Evidence from shallow marine and coastal terrestrial records     

Elie Verleyen  Dominic A. Hodgson  Koen Sabbe  Holger Cremer  Steven D. Emslie  John Gibson  Brenda Hall  Satoshi Imura  Sakae Kudoh  Gareth J. Marshall  Andrew McMinn  Martin Melles  Louise Newman  Donna Roberts  Steve J. Roberts  Shiv M. Singh  Mieke Sterken  Ines Tavernier  Sergey Verkulich  Evelien Van de Vyver  Wim Van Nieuwenhuyze  Bernd Wagner  Wim Vyverman 《Earth》2011,104(4):199-212

We review the post-glacial climate variability along the East Antarctic coastline using terrestrial and shallow marine geological records and compare these reconstructions with data from elsewhere. Nearly all East Antarctic records show a near-synchronous Early Holocene climate optimum (11.5–9 ka BP), coinciding with the deglaciation of currently ice-free regions and the optimum recorded in Antarctic ice and marine sediment cores. Shallow marine and coastal terrestrial climate anomalies appear to be out of phase after the Early Holocene warm period, and show complex regional patterns, but an overall trend of cooling in the terrestrial records. A Mid to Late Holocene warm period is present in many East Antarctic lake and shallow coastal marine records. Although there are some differences in the regional timing of this warm period, it typically occurs somewhere between 4.7 and 1 ka BP, which overlaps with a similar optimum found in Antarctic Peninsula terrestrial records. The differences in the timing of these sometimes abrupt warm events in different records and regions points to a number of mechanisms that we have yet to identify. Nearly all records show a neoglacial cooling from 2 ka BP onwards. There is no evidence along the East Antarctic coastline for an equivalent to the Northern Hemisphere Medieval Warm Period and there is only weak circumstantial evidence in a few places for a cool event crudely equivalent in time to the Northern Hemisphere's Little Ice Age. There is a need for well-dated, high resolution climate records in coastal East Antarctica and particularly in Terre Adélie, Dronning Maud Land and Enderby Land to fully understand the regional climate anomalies, the disparity between marine and terrestrial records, and to determine the significance of the heterogeneous temperature trends being measured in the Antarctic today.  相似文献   

Removal of Natural Free Estrogens and their Conjugates in a Municipal Wastewater Treatment Plant     

Ze‐hua Liu  Yoshinori Kanjo  Satoshi Mizutani 《洁净——土壤、空气、水》2011,39(2):128-135

Removal of natural free estrogens and estrogen conjugates in a municipal wastewater treatment plant (WWTP) was investigated and analyzed by GC‐MS, in which estrogen conjugates were first transformed to their corresponding free estrogens with an acid solvolysis procedure before their analysis. Natural free estrogens, E1‐3‐sulfate (E1‐3S), and E3‐3‐sulfate (E3‐3S) were detected with high concentrations in both the influent and effluent of the primary settling tank (PS), while no estrogen glucuronides were detected in any of the monitored wastewater samples. Regarding their removal efficiencies, all were almost completely removed, except for E1 with only a minor decrease. The estrogenic/androgenic removal of the same WWTP was also evaluated with estrogen receptor (androgen receptor) (ER (AR))‐binding assays, in which the removal efficiencies for E2 equivalents (EEQ) or testosterone equivalents (TEQ) were 68.5 and 72.2%. In addition, the chemically calculated EEQ from natural estrogens were about 20.6–39.3% that of the ER‐binding assay, in which E3 contributed the biggest proportion in both the influent and PS, while the calculated value of E1 increased from only 6.7% in the influent to as high as 20.6% in the effluent.  相似文献   

New buoy observation system for tsunami and crustal deformation     

Narumi Takahashi  Yasuhisa Ishihara  Hiroshi Ochi  Tatsuya Fukuda  Jun’ichiro Tahara  Yosaku Maeda  Motoyuki Kido  Yusaku Ohta  Katsuhiko Mutoh  Gosei Hashimoto  Satoshi Kogure  Yoshiyuki Kaneda 《Marine Geophysical Researches》2014,35(3):243-253

We have developed a new system for real-time observation of tsunamis and crustal deformation using a seafloor pressure sensor, an array of seafloor transponders and a Precise Point Positioning (PPP ) system on a buoy. The seafloor pressure sensor and the PPP system detect tsunamis, and the pressure sensor and the transponder array measure crustal deformation. The system is designed to be capable of detecting tsunami and vertical crustal deformation of ±8 m with a resolution of less than 5 mm. A noteworthy innovation in our system is its resistance to disturbance by strong ocean currents. Seismogenic zones near Japan lie in areas of strong currents like the Kuroshio, which reaches speeds of approximately 5.5 kt (2.8 m/s) around the Nankai Trough. Our techniques include slack mooring and new acoustic transmission methods using double pulses for sending tsunami data. The slack ratio can be specified for the environment of the deployment location. We can adjust slack ratios, rope lengths, anchor weights and buoy sizes to control the ability of the buoy system to maintain freeboard. The measured pressure data is converted to time difference of a double pulse and this simple method is effective to save battery to transmit data. The time difference of the double pulse has error due to move of the buoy and fluctuation of the seawater environment. We set a wire-end station 1,000 m beneath the buoy to minimize the error. The crustal deformation data is measured by acoustic ranging between the buoy and six transponders on the seafloor. All pressure and crustal deformation data are sent to land station in real-time using iridium communication.  相似文献   

Long-term (36-year) observations on the dynamics of the fish-killing raphidophyte Chattonella in Harima-Nada,eastern Seto Inland Sea,Japan     

Tetsuya Nishikawa  Yutaka Hori  Satoshi Nagai  Kazutaka Miyahara  Yukinobu Nakamura  Kazuhiro Harada  Kuninao Tada  Ichiro Imai 《Journal of Oceanography》2014,70(2):153-164

Long-term changes of the fish-killing raphidophyte Chattonella spp. (Chattonella antiqua, Chattonella marina and Chattonella ovata) were examined in relation to environmental factors at 19 sampling stations in Harima-Nada, eastern Seto Inland Sea, Japan, for 36 years from 1973 to 2008. Long-term trends in the dynamics of Chattonella populations were considered to relate to environmental factors such as nutrient concentrations and water temperature. High nutrient levels during the period from the 1970s to the early 1980s have contributed to the high cell density and large-scale red tides of Chattonella spp. in Harima-Nada. However, nutrient levels exhibited a decreasing trend thereafter, and it is thought that Chattonella spp. cannot form large-scale blooms under the present conditions. After the mid-1990s, the occurrence period of vegetative cells of Chattonella spp. has been several weeks or 1 month earlier than that of the 1970s and early 1980s, and the appearance frequency of Chattonella spp. has increased in the northern coastal area, although the cell density and the spatial scale of the distribution have become lower and smaller than those in the previous decades. It is suggested that the timing of germination of Chattonella cysts has become earlier as a result of the increase in water temperature, and the chances of vegetative growth have also increased, especially at the northern coast where most of large rivers discharge into the Harima-Nada. In addition, the present results revealed that fewer diatoms were also one of the significant factors for the high abundance of Chattonella spp. in Harima-Nada.  相似文献   

Surface deformation related to the 2008 Wenchuan earthquake,and mountain building of the Longmen Shan,eastern Tibetan Plateau     

Bihong Fu  Pilong Shi  Huadong Guo  Satoshi Okuyama  Yoshiki Ninomiya  Sarah Wright 《Journal of Asian Earth Sciences》2011,40(4):805-824

The 12 May 2008 M_s 8.0 Wenchuan earthquake, China, was one of largest continental thrusting events worldwide. Based on interpretations of post-earthquake high-resolution remote sensing images and field surveys, we investigated the geometry, geomorphology, and kinematics of co-seismic surface ruptures, as well as seismic and geologic hazards along the Longmen Shan fold-and-thrust belt. Our results indicate that the Wenchuan earthquake occurred along the NE–SW-trending Yingxiu–Beichuan and Guanxian–Anxian faults in the Longmen Shan fold-and-thrust belt. The main surface rupture zones along the Yingxiu–Beichuan and Guanxian–Anxian fault zones are approximately 235 and 72 km in length, respectively. These sub-parallel ruptures may merge at depth. The Yingxiu–Donghekou surface rupture zone can be divided into four segments separated by discontinuities that appear as step-overs or bends in map view. Surface deformation is characterized by oblique reverse faulting with a maximum vertical displacement of approximately 10 m in areas around Beichuan County. Earthquake-related disasters (e.g., landslides) are linearly distributed along the surface rupture zones and associated river valleys.The Wenchuan earthquake provides new insights into the nature of mountain building within the Longmen Shan, eastern Tibetan Plateau. The total crustal shortening accommodated by this great earthquake was as much as 8.5 m, with a maximum vertical uplift of approximately 10 m. The present results suggest that ongoing mountain building of the Longmen Shan is driven mainly by crustal shortening and uplift related to repeated large seismic events such as the 2008 Wenchuan earthquake. Furthermore, rapid erosion within the Longmen Shan fold-and-thrust belt occurs along deep valleys and rupture zones following the occurrence of large-scale landslides triggered by earthquakes. Consequently, we suggest that crustal shortening related to repeated great seismic events, together with isostatic rebound induced by rapid erosion-related unloading, is a key component of the geodynamics that drive ongoing mountain building on the eastern Tibetan Plateau.  相似文献   

Particle size effect on the saturation of methane hydrate in sediments – Constrained from experimental results     

Hailong Lu  Tatsuji Kawasaki  Toshiyasu Ukita  Igor Moudrakovski  Tetsuya Fujii  Satoshi Noguchi  Tadaaki Shimada  Masaru Nakamizu  John Ripmeester  Chris Ratcliffe 《Marine and Petroleum Geology》2011,28(10):1801-1805

Except for those occurring at seafloor, most of natural gas hydrate form in sediments and are subject to the influence of sediment. Among these factors, the particle size effect on hydrate saturation level in sediment have been studied with a series of silica sands with various sizes, and the results obtained clearly indicate that particle size does play an important role in affecting the saturation level of hydrate in sediments. The proton relaxation times of water confined in the same series of silica sands, which were determined with NMR measurement, show logarithmic relationship with particle size. By comprehensive consideration of the results of hydrate saturation and water proton relaxation times, the particle size effect observed is tentatively explained by the water availability for hydrate formation in sediments.  相似文献   

Three lecideoid lichens new to Svalbard, Norway     

T. Inoue  S. Kudoh  M. Inoue  M. Uchida  H. Kanda 《Polar Science》2011,4(4):588-592

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Effects of the Chemical Compositions of Salars de Uyuni and Atacama Brines on Lithium Concentration during Evaporation   总被引：2，自引：0，他引：2  

Yasumasa Ogawa  Hiroshi Koibuchi  Koichi Suto  Chihiro Inoue 《Resource Geology》2014,64(2):91-101

During Li recovery from salar brines, Li concentration is typically increased to about 60,000 mg L^?1 by evaporation. We investigated the concentration changes of Li, Na, K, Mg, Cl, SO₄, and B during evaporation of both natural Uyuni and artificial Atacama brines. The Uyuni brine exhibited a maximum Li concentration of 6810 mg L^?1 at 31 days of evaporation, at which point the majority of the Na and K in the brine was removed. The Li concentration decreased with further evaporation due to precipitation as Li₂SO₄, such that the level at the 56 day mark was approximately 4130 mg L^?1. In contrast, the artificial Atacama brine showed no pronounced Li precipitation, even after 54 days, at which point the Li concentration was 21,800 mg L^?1. The initial concentrations of Na and K in the Atacama brine were higher than those in the Uyuni brine, and the Atacama solution still retained K after 54 days of evaporation. The order of precipitation of cation species during the evaporation of both brines was: Na, followed by K, Mg, and Li. Thus, Li precipitation in the Atacama brine might be prevented due to the more favored precipitations of Na and K, such that significant Li removal did not occur in this brine.  相似文献   

Fragmentation of star-forming clouds enriched with the first dust     

Raffaella Schneider  Kazuyuki Omukai  Akio K. Inoue  Andrea Ferrara 《Monthly notices of the Royal Astronomical Society》2006,369(3):1437-1444

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Attenuation law of normal disc galaxies with clumpy distributions of stars and dust     

Akio K. Inoue † 《Monthly notices of the Royal Astronomical Society》2005,359(1):171-182

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