Present-day plate interactions in Northeast Asia: North American, Eurasian, and Okhotsk plates

Based on seismicity and focal mechanisms, a separate Okhotsk plate is identified which includes most of the Sea of Okhotsk, Kamchatka Peninsula, and the Suntar-Khayata Mountains, in the northeastern USSR. Using slip vectors from the largest earthquakes in the region, we obtain a North America-Eurasia pole of rotation near the Lena River delta and a Okhotsk-North America pole off western Chukotka. The computed poles satisfy observed thrust faulting mechanisms in the northern Cherskii Mountains which are discordant with models proposed by previous workers. It is suggested that the Arctic rift propagated through northeast Siberia to the Pacific, separating the Okhotsk plate and causing a recent (<3Ma) change in location of the North America-Eurasia pole of rotation.     

Effects of the Black River (Cape,South Africa) on the distribution and survival of marine psammofauna

The physicochemistry of the Black River and adjacent marine beach, in terms of tidal, daily and seasonal fluctuations of temperature and salinity, presents a highly stressed environment exacerbated by canalization of the river mouth. Riverine pollution further stresses this environment, producing low densities and diversities of marine infauna adjacent to the river. No fauna were found in the river mouth where typical estuarine conditions exist only during high tide. Tolerance of the dominant marine species, Cerebratulus fuscus, to temperature, salinity and river water combinations showed that mortality was more rapid after exposure to river water dilutions than after exposure to distilled water dilutions. Computer-generated models suggested that this species should survive conditions closer to the river than were observed. This confirmed additional stress due to pollution carried in the river from urban and industrial drainage. Lower river water temperatures during winter appear to ameliorate pollution stress, enhancing survivability of the infauna.     

Thermal controls on biodegradation around the Peace River tar sands: Paleo-pasteurization to the west

Bitumens of the Alberta tar sands share a similar primary source rock, but exhibit varying levels of degradation. In the Peace River tar sands area, the wide range of API gravity and sulphur content in Lower Cretaceous reservoirs is investigated in terms of biodegradation processes, using detailed geochemical analyses, burial history modelling and charge/degrade modelling. Decreasing tar sand degradation to the west can be attributed to increasing reservoir temperatures which retard biodegradation. Gething oils west of the Peace River tar sands are derived from the same source, but are minimally degraded due to reservoir pasteurization at 80 °C shortly after charging. Long charge times, reservoir filling and possibly compositional or very low temperature degradation retardation have limited biodegradation of the Alberta tar sands despite long oil residence times and low reservoir temperatures.     

Variations in the composition of particulate organic matter in a time-series sediment trap

A time-series sediment trap was used to collect material for organic geochemical analyses as part of the Sediment Trap Intercomparison Experiment. The flux of particulate matter was more likely related to a change in current direction during the course of the experiment than to small-scale changes in surface productivity. Of the compounds measured, the n-alkanes reflected this change most dramatically, decreasing with the change in current direction.Amino acid and lipid components were measured in the samples. Amino acids made up 15–35% of the total organic carbon flux and 35–75% of the total organic nitrogen flux collected in the traps. Specific amino acids indicative of bacterial biomass or activity suggested that microbial growth occurred in the traps, probably as a result of incomplete poisoning by NaN₃. However, the effect of this growth on the bulk composition of particulate matter appeared to be minimal.The amino acid distribution of particulate organic material collected by large volume filtration (LVF) was not significantly different from the sediment trap material, except that the LVF material did not appear to be affected by bacterial growth.     

Regional Inequality in China: A Case Study of Jiangsu Province

The tremendous changes in China's development philosophy and regional economies during the last two decades have carved out selectively new locations of development across the nation. While politicians heatedly debate the acceptable levels of regional inequality, most scholarly studies focus on broad aggregate trends of inequality among provinces and groups of provinces, and pay little attention to identifying and conceptualizing sources and major agents of spatial change. This paper aims at revealing detailed spatial ramifications of the reforms, and at understanding the impacts of the state, local agents, and foreign investors on regional development. To this effect, we conduct a disaggregated and empirical study of Jiangsu, a coastal province experiencing dramatic economic and spatial restructuring. We show that local agents which favor rural industrial enterprises accelerated new growth in selected rural areas, in contrast to slower growth of older cities and state‐owned enterprises, resulting in a net decline of intercounty inequality. But the coalescence of state policy, local agents, and foreign investment has widened the historical gap between northern and southern Jiangsu, and is likely to accelerate intercounty inequality in the future. Our study demonstrates the utility of the “developments from above, below and outside” framework for analyzing key forces of regional growth in socialist transitional economies.     

人口高密度较发达农业区的经济发展与人口迁移--以广东省高州市为例

农村剩余劳动力外了是我国人多地少、以农业为主要经济部门地区的普遍现象。在经济发展水平较高地区,又有欠发达区农村劳动力的补偿性流入及妇女的婚姻迁入。文中以对劳动力外出和妇女的婚姻迁入都极为活跃的高州市的实际调查为例,分析自然资源条件和经济结构对人口迁移的影响。     

Further investigations on why POC concentrations differ in samples collected by Niskin bottle and in situ pump

Particulate organic carbon (POC) concentrations measured in bottles are often higher than those measured by in situ pumps when samples are taken concurrently. In previous work, we suggested that differential collection of zooplankton might explain this systematic discrepancy in POC between these small volume (bottle) and large volume (in situ pump) techniques. We have now further quantified the carbon contributed by zooplankton collected in the >70-μm particulate fractions from both bottles and pumps at sites in the Mediterranean Sea and Long Island Sound. Our results show that zooplankton abundance and lipid concentrations from zooplankton are one order of magnitude higher in the bottles than in the pumps, supporting the idea that part of the pump–bottle difference is due to collection of more zooplankton by the bottles. Particle washout off the 70-μm mesh used in the in situ pump may cause loss of some particles as well. However, zooplankton in the >70-μm fraction from the bottles contributed only about 1–2 μM POC, which cannot explain the up to 20 μM POC differences observed in this study. Thus, the mechanisms leading to such a large POC difference are still unclear and need to be further investigated. POC concentrations measured using microquartz filters were similar to those using glass fiber filters, suggesting that filter types cannot explain the higher POC observed in bottles, where glass fiber filters are normally used. Furthermore, we investigated several different pump inlet designs to determine how these might affect the ability of pumps to collect and retain large (>70 μm) particles, including zooplankton. The comparison among different pump inlets suggests that inlet design affects the efficiency and retention of large particles and that a sealed filter holder with a narrow right-angle tubular opening is the most efficient at catching/retaining zooplankton.     

Precipitation and temperature space–time variability and extremes in the Mediterranean region: evaluation of dynamical and statistical downscaling methods

This study evaluates how statistical and dynamical downscaling models as well as combined approach perform in retrieving the space–time variability of near-surface temperature and rainfall, as well as their extremes, over the whole Mediterranean region. The dynamical downscaling model used in this study is the Weather Research and Forecasting (WRF) model with varying land-surface models and resolutions (20 and 50 km) and the statistical tool is the Cumulative Distribution Function-transform (CDF-t). To achieve a spatially resolved downscaling over the Mediterranean basin, the European Climate Assessment and Dataset (ECA&D) gridded dataset is used for calibration and evaluation of the downscaling models. In the frame of HyMeX and MED-CORDEX international programs, the downscaling is performed on ERA-I reanalysis over the 1989–2008 period. The results show that despite local calibration, CDF-t produces more accurate spatial variability of near-surface temperature and rainfall with respect to ECA&D than WRF which solves the three-dimensional equation of conservation. This first suggests that at 20–50 km resolutions, these three-dimensional processes only weakly contribute to the local value of temperature and precipitation with respect to local one-dimensional processes. Calibration of CDF-t at each individual grid point is thus sufficient to reproduce accurately the spatial pattern. A second explanation is the use of gridded data such as ECA&D which smoothes in part the horizontal variability after data interpolation and damps the added value of dynamical downscaling. This explains partly the absence of added-value of the 2-stage downscaling approach which combines statistical and dynamical downscaling models. The temporal variability of statistically downscaled temperature and rainfall is finally strongly driven by the temporal variability of its forcing (here ERA-Interim or WRF simulations). CDF-t is thus efficient as a bias correction tool but does not show any added-value regarding the time variability of the downscaled field. Finally, the quality of the reference observation dataset is a key issue. Comparison of CDF-t calibrated with ECA&D dataset and WRF simulations to local measurements from weather stations not assimilated in ECA&D, shows that the temporal variability of the downscaled data with respect to the local observations is closer to the local measurements than to ECA&D data. This highlights the strong added-value of dynamical downscaling which improves the temporal variability of the atmospheric dynamics with regard to the driving model. This article highlights the benefits and inconveniences emerging from the use of both downscaling techniques for climate research. Our goal is to contribute to the discussion on the use of downscaling tools to assess the impact of climate change on regional scales.