Spatiotemporal distribution of copepod populations in the Gulf of Gdansk (southern Baltic Sea)

In the present study, we used a 3D Coupled Ecosystem Model of Baltic Sea version 1 (3D CEMBSv1) coupled with a copepod model to examine the spatiotemporal distribution of two representative copepod populations in the Gulf of Gdansk (southern Baltic Sea) including Acartia spp. and Pseudocalanus minutus elongatus. The annual cycles simulated for 2000 under realistic weather and hydrographic conditions were studied with the three-dimensional version of the coupled ecosystem-copepod model in the south-eastern Baltic Sea. The paper presents the comparison of simulated and observed copepod development at two stations in the Gulf of Gdansk. A validation of influential state variables gives confidence that the model is able to calculate reliably the stage development of dominant species in the southern Baltic Sea. The number of generations was one for P. m. elongatus and 3?C5 for Acartia spp.. A mean of five generations for the latter species per year were estimated in the coastal region and ca. three generations at the Gdansk Deep (in the open sea). Food concentration and temperature as the main factors controlling the development of the investigated copepods as well as salinity as a masking factor (i.e. salinity modifies the rate of their development) in the case of Pseudocalanus minutus elongatus are included in the present study.     

Estimation of Shallow Geothermal Energy Resource in Canada: Heat Gain and Heat Sink

Maps of shallow depth (down to −250 m) temperature distribution across Canada show large variability, related mainly to surface climatic forcing. Very small changes of temperature with depth in the upper 250 m are related to heat gained by the subsurface due to recent global warming. Temperature data compiled from precise temperature logs in equilibrium wells, and temperature time series from a network of meteorological stations, allow calculation of the available heat energy for heating in the cold period and for cooling in peak warm months. Utilization of this energy resource has the potential for significant CO₂ reduction in Canada. The geothermal energy stored in the ground can be used, with the help of heat pumps, for heating, given very low winter temperatures. The amount of potential heat available is vast. In Canada, south of permafrost border, the integrated value of potentially available heat during the heating season down to −50 m is 1.1 E21 J (1100 quads).     

Crystallization of quartz dioritic magmas at 2 and 1 kbar: experimental results

Crystallization experiments were performed on quartz diorite (~55 wt.% SiO₂, 3.1–8.4 wt.% MgO) from the G?siniec Intrusion (Bohemian Massif, SW Poland) at 1?2 kbar, 750–850°C, various mole fractions of water and with fO₂ buffered by the NNO buffer. The two natural quartz diorites (leucocratic poikilitic quartz diorite - ‘LPD’ and melanocratic quartz diorite - ‘MD’) differ in whole rock and mineral composition with MD being richer in MgO and poorer in CaO than LPD, probably due to accumulation of mafic minerals or melt removal in MD. LPD represents melt composition and is used to reconstruct crystallization conditions in the G?siniec Intrusion. The crystallization history of LPD magma, deduced from experimental and natural mineral compositions, includes a higher pressure stage probably followed by emplacement at ~2 kbar of partly crystallized magma at temperatures ~850?800°C and quick cooling. The mineral assemblage present in LPD requires water contents in the magma of at least 5 wt% and oxygen fugacity below that controlled by the NNO buffer. The compositions of mafic minerals in the MD composition were equilibrated at temperatures below 775°C and at subsolidus conditions. The equilibration was probably due to the reaction between water-rich, oxidizing residual melt and the cumulatic-restitic mineral assemblage. MD is characterized by occurrence of the euhedral cummingtonite and increasing anorthite content in the rims of plagioclase. A similar reaction was reproduced experimentally in both LPD and MD compositions indicating that cummingtonite may be a late magmatic phase in quartz dioritic systems, crystallizing very close to solidus and only from water saturated magma.     

Large regional variability of recent climatic change driven sub-surface temperature changes as derived from temperature logs-central Canada example

International Journal of Earth Sciences - The analysis of the warming/cooling patterns from inversion of 94 well temperature logs for the study area of Central Canada shows very high variability...     

Composite surface temperature history from simultaneous inversion of borehole temperatures in western Canadian plains

Functional space inversions (FSI) of precise temperature logs from wells located in low conductivity clastic sediments of the western Canadian Sedimentary Basin show evidence of extensive, recent ground surface temperature (GST) warming. Simultaneous inversion of the data, as well as averaging of the individual site reconstructions, indicate that this high magnitude of GST warming exceeds over two times that of globally averaged GST's [Science 282 (1998) 279] and is significantly higher than that of surface temperature histories based on instrumental records and tree ring reconstruction in northern and western Canada [Holocene 7 (1997) 375; Science 278 (1997) 1251; Clim. Res. 12 (1999) 39].     

Finite element study of patterns of shear zones in granular bodies during plane strain compression

Numerical investigations of patterns of shear zones in granular bodies obtained during quasi-static plane strain compression tests were performed. The effect of a spatially correlated stochastic distribution of the initial void ratio and roughness of horizontal plates was analyzed. To describe a mechanical behavior of a cohesionless granular material during a monotonic deformation path in a plane strain compression test, a micro-polar hypoplastic constitutive model was used. FE calculations were carried out with both initially dense and initially loose cohesionless sand. A Latin hypercube method was applied to generate Gaussian truncated random fields of initial void ratio in a granular specimen. A weak correlation of the initial void ratio in both directions and its large standard deviation were assumed for all specimens. The horizontal boundaries were either ideally smooth or very rough. The FE results show similar patterns of shear zones as compared to experiments.