19 resultados para competitiveness, labour costs, productivity, relative prices, comercial flows
em Publishing Network for Geoscientific
Resumo:
The data set shows energy consumption per hour of work (in MJ/hour), and labour productivity (in USD/hour) in the PS economic sector (Energy & Mining + Industry + Construction) for the period 1970-2009 and for the following countries: Germany, Spain, USA, Canada, Italy, UK, France, Japan. The intention is to look at the relationship between energy consumption as a driver of improvements in the productivity of labour. This is of particular relevance for the discussion of reducing working time in the context of the 'degrowth' debate, as it is done in the article to which this data is a suplement.
Resumo:
Pollen productivity estimates (PPE) are used to quantitatively reconstruct variations in vegetation within a specific distance of the sampled pollen archive. Here, for the first time, PPEs from Siberia are presented. The study area (Khatanga region, Krasnoyarsk territory, Russia) is located in the Siberian Sub-arctic where Larixis the sole forest-line forming tree taxon. Pollen spectra from two different sedimentary environments, namely terrestrial mosses (n=16) and lakes (n=15, median radius ~100 m) and their surrounding vegetation were investigated to extract PPEs. Our results indicate some differences in pollen spectra between moss and lake pollen. Larix and Cyperaceae for example obtained higher representation in the lacustrine than in terrestrial moss samples. This highlights that in calibration studies modern and fossil dataset should be of similar sedimentary origin. The results of the Extended R-Value model were applied to assess the relevant source area of pollen (RSAP) and to calculate the PPEs for both datasets. As expected, the RSAP of the moss samples was very small (about 10 m) compared to the lacustrine samples (about 25 km). Calculation of PPEs for the six most common taxa yielded generally similar results for both datasets. Relative to Poaceae (reference taxon, PPE=1) Betula nana-type (PPEmoss: 1.8, PPElake: 1.8) and Alnusfruticosa-type (PPEmoss: 6.4, PPElake: 2.9) were overrepresented while Cyperaceae (PPEmoss: 0.5, PPElake: 0.1), Ericaceae (PPEmoss: 0.3, PPElake <0.01), Salix (PPEmoss: 0.03, PPElake <0.01) and Larix (PPEmoss <0.01, PPElake: 0.2) were under-represented in the pollen spectra compared to the vegetation in the RSAP. The estimation for the dominant tree in the region, Larixgmelinii, is the first published result for this species, but need to be considered very preliminary. The inferred sequence from over- to under-representation is mostly consistent with results from Europe; however, still the absolute values show some differences. Gathering vegetation data was limited by flowering season and low resolute satellite imagery and accessibility of the remote location of our study area. Therefore, our estimate may serve as first reference to strengthen future vegetation reconstructions in this climate-sensitive region.
Resumo:
On the basis of their respective eruptive environments and chemical characteristics, alkalic dolerite sills from the northern Pigafetta Basin (Site 800) and tholeiitic pillow lavas from the Mariana Basin (Site 802) sampled during Ocean Drilling Program Leg 129 are considered to represent examples of the widespread mid-Cretaceous volcanic event in the western Pacific. Both groups of basic rocks feature mild, low-grade, anoxic smectite-celadonite-carbonate-pyrite alteration; late-stage oxidation is very limited in extent, with the exception of the uppermost sill unit at Site 800. The aphyric and nonvesicular Site 800 alkalic dolerite sills are all well-evolved mineralogically and chemically, being mainly of hawaiite composition, and are similar to ocean island basalts. They are characterized by high contents of incompatible elements (for example, 300-400 ppm Zr), well-fractionated rare earth element patterns ([La/Yb]N 18-21) and HIMU isotopic characters. They probably represent deep-sea, lateral, intrusive off-shoots from nearby seamounts of similar age. The olivine-plagioclase +/- clinopyroxene phyric tholeiitic pillow lavas and thin flows of Site 802 are nonvesicular and quench-textured throughout. Relative to normal-type mid-ocean ridge basalt, they are enriched in large-ion-lithophile elements, exhibit flat (unfractionated) rare earth element patterns and have distinctive (lower) Zr/Nb, Zr/Ta, La/Ta, and Hf/Th ratios. Overall they are compositionally and isotopically similar to the mid-Cretaceous tholeiites of the Nauru basin and the Ontong-Java and Manihiki plateaus. The Site 802 tholeiites differ from the thickened crustal segments of the oceanic plateaus, however, in apparently representing only a thin veneer over the local basement in an off-axis environment.
Resumo:
Native Cu occurs in amygdules, fractures and groundmass of tholeiites from Ocean Drilling Program Site 642 on the Vøring Plateau. Similar occurrences have been reported in other tholeiites of the early Tertiary North Atlantic Volcanic Province drilled at Deep Sea Drilling Project Sites 342 on the Vøring Plateau and 553 on the Rockall Plateau. The flows containing the native Cu have distinctive alteration patterns characterized by the combination of reddened flow tops, distinctive pastel coloration of the upper parts of the flows, relative abundance of celadonite, and the presence of native Cu. These associations suggest that subaerial weathering and subsequent seawater-basalt interaction are related to the occurrence of native Cu. An additional factor may be the increase in compatibility of Cu in silicates and Fe- Ti oxides that may accompany sub-solidus oxidation of basaltic flows. Native Cu occurrences in Site 642 tholeiites have some striking similarities to the large native Cu deposits in the Precambrian basalts of the Keweenaw Peninsula, Michigan, that are suggestive of similar mineralization processes.
Resumo:
Pebble-sized basaltic and glassy clasts were extracted from seamount-derived volcaniclastic debris flows and analyzed for various trace elements, including the rare earths, to determine their genetic relationships and provenance. All the clasts were originally derived from relatively shallow submarine lava flows prior to sedimentary reworking, and have undergone minor low-grade alteration. They are classified into three petrographic groups (A, B, and C) characterized by different phenocryst assemblages and variable abundances and ratios of incompatible elements. Group A (clast from Hole 585) is a hyaloclastite fragment which is olivine-normative and distinct from the other clasts, with incompatibleelement ratios characteristic of transitional or alkali basalts. Groups B and C (clasts from Hole 585A) are quartz-normative, variably plagioclase-clinopyroxene-olivine phyric tholeiites, all with essentially similar ratios of highly incompatible elements and patterns of enrichment in light rare earth elements (chrondrite-normalized). Variation within Groups B and C was governed by low-pressure fractionation of the observed phenocryst phases, whereas the most primitive compositions of each group may be related by variable partial melting of a common source. The clasts have intraplate chemical characteristics, although relative to oceanic hot-spot-related volcanics (e.g., Hawaiian tholeiites) they are marginally depleted in most incompatible elements. The source region was enriched in all incompatible elements, compared with a depleted mid-ocean-ridge basalt source.
Resumo:
Tropical climate is variable on astronomical time scale, driving changes in surface and deep-sea fauna during the Pliocene-Pleistocene. To understand these changes in the tropical Indian Ocean over the past 2.36 Myr, we quantitatively analyzed deep-sea benthic foraminifera and selected planktic foraminifera from >125 µm size fraction from Deep Sea Drilling Project Site 219. The data from Site 219 was combined with published foraminiferal and isotope data from Site 214, eastern Indian Ocean to determine the nature of changes. Factor and cluster analyses of the 28 highest-ranked species distinguished four biofacies, characterizing distinct deep-sea environmental settings. These biofacies have been named after their most dominant species such as Stilostomella lepidula-Pleurostomella alternans (Sl-Pa), Nuttallides umbonifer-Globocassidulina subglobosa (Nu-Gs), Oridorsalis umbonatus-Gavelinopsis lobatulus (Ou-Gl) and Epistominella exigua-Uvigerina hispido-costata (Ee-Uh) biofacies. Biofacies Sl-Pa ranges from ~2.36 to 0.55 Myr, biofacies Nu-Gs ranges from ~1.9 to 0.65 Myr, biofacies Ou-Gl ranges from ~1 to 0.35 Myr and biofacies Ee-Uh ranges from 1.1 to 0.25 Myr. The proxy record indicates fluctuating tropical environmental conditions such as oxygenation, surface productivity and organic food supply. These changes appear to have been driven by changes in monsoonal wind intensity related to glacial-interglacial cycles. A shift at ~1.2-0.9 Myr is observed in both the faunal and isotope records at Site 219, indicating a major increase in monsoon-induced productivity. This coincides with increased amplitude of glacial cycles, which appear to have influenced low latitude monsoonal climate as well as deep-sea conditions in the tropical Indian Ocean.
Resumo:
During the culmination of the phytoplankton spring bloom in the Fladen Ground area in April-Mai 1976, gross primary production was between 1500 and 2000 mg particulate C m**-2 day**-1, at a crop density (mainly diatoms of the genus Chaetoceros) of about 1500-3500 mg C m**-2. Estimates of the C:chlorophyll a ratio in living cells were much lower than those reported in the literature, possibly because part of what is measured as "chlorophyll a" by the common fluorometric method is associated with particles that are not reported as cells. Most of the dark 14C fixation during the bloom's climax was due to abiotic processes. Excretion of 14C-labeled carbohydrates did not account for a significant fraction of the total photosynthetic rate. The low crop after the bloom period, in June, corresponded with nutrient depletion of the euphotic zone. The low photosynthetic efficiency in June may have been a gross underestimate. The presence of relatively high concentrations of chlorophyll derivatives signifies that the algal crop was consumed by heterotrophs, but at a lower rate in April/May than during the June cruise when particularly high molar ratios of phaeophorbide a and phaeophytin a relative to chlorophyll a were found. The high respiratory rate relative to autotrophic production in June manifested itself also in high dark 14C fixation values. The high concentration of phaeophorbide a in the upper 40 m and its scarcity below this depth during the spring bloom climax in April/May implies that copepod grazing at that time took place principally in the euphotic zone. The remarkably high concentration of chlorophyllide a in the surface layer during the bloom period indicates that the part of the crop that was destroyed by the grazers while eating was occasionally as high as the part that was actually ingested.
Resumo:
We used piston cores recovered in the western Bering Sea to reconstruct millennial-scale changes in marine productivity and terrigenous matter supply over the past ~180 kyr. Based on a geochemical multi-proxy approach, our results indicate closely interacting processes controlling marine productivity and terrigenous matter supply comparable to the situation in the Okhotsk Sea. Overall, terrigenous inputs were high, whereas export production was low. Minor increases in marine productivity occurred during intervals of Marine Isotope Stage 5 and interstadials, but pronounced maxima were recorded during interglacials and Termination I. The terrigenous material is suggested to be derived from continental sources on the eastern Bering Sea shelf and to be subsequently transported via sea ice, which is likely to drive changes in surface productivity, terrigenous inputs, and upper-ocean stratification. From our results we propose glacial, deglacial, and interglacial scenarios for environmental change in the Bering Sea. These changes seem to be primarily controlled by insolation and sea-level forcing which affect the strength of atmospheric pressure systems and sea-ice growth. The opening history of the Bering Strait is considered to have had an additional impact. High-resolution core logging data (color b*, XRF scans) strongly correspond to the Dansgaard-Oeschger climate variability registered in the NGRIP ice core and support an atmospheric coupling mechanism of Northern Hemisphere climates.
Resumo:
This study tests the hypothesis that the late Miocene to early Pliocene constriction and closure of the Central American Seaway (CAS), connecting the tropical Atlantic and East quatorial Pacific (EEP), caused a decrease in productivity in the Caribbean, due to decreased coastal upwelling and an end to the connection with high-productivity tropical Pacific waters. The present study compared paleoceanographic proxies for the interval between 8.3 and 2.5 Ma in 47 samples from south Caribbean ODP Site 999 with published data on EEP DSDP Site 503. Proxies for Site 999 include the relative abundance of benthic foraminiferal species representing bottom current velocity and the flux of organic matter to the sea floor, the ratio of infaunal/epifaunal benthic foraminiferal species and benthic foraminifer accumulation rates (BFARs). In addition, we calculated % resistant planktic foraminifers species and used the previously published % sand fraction and benthic carbon isotope values from Site 999. During early shoaling of the Isthmus (8.3-7.9 Ma) the Caribbean was under mesotrophic conditions, with little ventilation of bottom waters and low current velocity. The pre-closure interval (7.6-4.2 Ma) saw enhanced seasonal input of phytodetritus with even more reduced ventilation, and enhanced dissolution between 6.8 and 4.8 Ma. During the post-closure interval (4.2-2.5 Ma) in the Caribbean, paleoproductivity decreased, current velocity was reduced, and ventilation improved, while the seasonality of phytodetrital input was reduced dramatically, coinciding with the establishment of the Atlantic-Pacific salinity contrast at 4.2 Ma. Our data support the hypothesis that late Miocene constriction of the CAS at 7.9 Ma and its closure at 4.2 Ma caused a gradual decrease in paleoproductivity in the Caribbean, consistent with decreased current velocity and seasonality of the phytodetrital input.