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31.
Trine Bekkby Frithjof E. Moy Tone Kroglund Janne K. Gitmark Mats Walday Eli Rinde 《Marine Geodesy》2013,36(4):379-390
Mapping the seabed along the Norwegian coast is costly and time consuming. Hence, finding a modeling method to separate rocky seabed from other substrate types will provide digital maps that may be used to develop cost-effective sampling designs to predict species and habitat distribution. Our approach was to use geophysical data that were quantitative and objectively defined, generalized additive models (GAMs), and Akaike information criterion (AIC) to develop statistical models and select among them. We found that slope, terrain curvature, wave exposure, and depth predicted rocky seabed occurrence with a high degree of certainty. 相似文献
32.
Gabriele Procaccini Sven Beer Mats Björk Jeanine Olsen Silvia Mazzuca Rui Santos 《Marine Ecology》2012,33(4):522-527
In March 2011, the Ecophysiology and Genetics Working Groups of the European Science Foundation COST Action ES 0906, entitled Seagrass Productivity: From Genes to Ecosystem Management, organized an exploratory workshop entitled “Linking Ecophysiology and Ecogenomics in Seagrass Systems”. The goal of the workshop was to discuss how to integrate comparative gene expression studies with physiological processes such as photosynthetic performance, carbon and nitrogen utilization and environmental adaptation. The main questions discussed for integrative research related to mechanisms of carbon utilization, light requirements, temperature effects and natural variation in pH and ocean acidification. It was concluded that the seagrass research community is still in the nascent stages of linking ecophysiology with genomic responses, as carbon and nitrogen metabolism of seagrasses have not been sufficiently well studied. Likewise, genomic approaches have only been able to assign meaningful interpretations to a handful of differentially expressed genes. Nevertheless, the way forward has been established. 相似文献
33.
Mats P. Björkman Elke Morgner Robert G. Björk Elisabeth J. Cooper Bo Elberling & Leif Klemedtsson 《Polar research》2010,29(1):75-84
Recent climate change predictions suggest altered patterns of winter precipitation across the Arctic. It has been suggested that the presence, timing and quantity of snow all affect microbial activity, thus influencing CO2 production in soil. In this study annual and seasonal emissions of CO2 were estimated in High-Arctic Adventdalen, Svalbard, and sub-Arctic Latnjajaure, Sweden, using a new trace gas-based method to track real-time diffusion rates through the snow. Summer measurements from snow-free soils were made using a chamber-based method. Measurements were obtained from different snow regimes in order to evaluate the effect of snow depth on winter CO2 effluxes. Total annual emissions of CO2 from the sub-Arctic site (0.662–1.487 kg CO2 m–2 yr–1 ) were found to be more than double the emissions from the High-Arctic site (0.369–0.591 kg CO2 m–2 yr–1 ). There were no significant differences in winter effluxes between snow regimes or vegetation types, indicating that spatial variability in winter soil CO2 effluxes are not directly linked to snow cover thickness or soil temperatures. Total winter emissions (0.004–0.248 kg CO2 m–2 ) were found to be in the lower range of those previously described in the literature. Winter emissions varied in their contribution to total annual production between 1 and 18%. Artificial snow drifts shortened the snow-free period by 2 weeks and decreased the annual CO2 emission by up to 20%. This study suggests that future shifts in vegetation zones may increase soil respiration from Arctic tundra regions. 相似文献
34.
Ghislain Dubois Benjamin Sovacool Carlo Aall Maria Nilsson Carine Barbier Alina Herrmann Sébastien Bruyère Camilla Andersson Bore Skold Franck Nadaud Florian Dorner Karen Richardsen Moberg Jean Paul Ceron Helen Fischer Dorothee Amelung Marta Baltruszewicz Jeremy Fischer Françoise Benevise Valérie R. Louis Rainer Sauerborn 《Chemie der Erde / Geochemistry》2012
Through their consumption behavior, households are responsible for 72% of global greenhouse gas emissions. Thus, they are key actors in reaching the 1.5 °C goal under the Paris Agreement. However, the possible contribution and position of households in climate policies is neither well understood, nor do households receive sufficiently high priority in current climate policy strategies. This paper investigates how behavioral change can achieve a substantial reduction in greenhouse gas emissions in European high-income countries. It uses theoretical thinking and some core results from the HOPE research project, which investigated household preferences for reducing emissions in four European cities in France, Germany, Norway and Sweden. The paper makes five major points: First, car and plane mobility, meat and dairy consumption, as well as heating are the most dominant components of household footprints. Second, household living situations (demographics, size of home) greatly influence the household potential to reduce their footprint, even more than country or city location. Third, household decisions can be sequential and temporally dynamic, shifting through different phases such as childhood, adulthood, and illness. Fourth, short term voluntary efforts will not be sufficient by themselves to reach the drastic reductions needed to achieve the 1.5 °C goal; instead, households need a regulatory framework supporting their behavioral changes. Fifth, there is a mismatch between the roles and responsibilities conveyed by current climate policies and household perceptions of responsibility. We then conclude with further recommendations for research and policy. 相似文献
35.
The IVS Intensive sessions are single-baseline, 1-h VLBI sessions carried out everyday in order to determine Universal Time
(UT1). We investigate different possibilities to improve the results of such sessions. We do this investigation by extracting
2-h single-baseline sessions from the CONT08 data set. These are analysed like normal Intensives, and the results are compared
to the results of the analysis of the full CONT08 data set. We find that tropospheric asymmetry is the major error source
for the single-baseline sessions. It is possible to improve the accuracy of the estimated UT1 either by using accurate a priori
tropospheric gradients or by estimating gradients in the data analysis. 相似文献
36.
A field experiment was conducted to investigate how water-based drill cuttings and sediment type influence colonization of soft bottom communities. Bottom frames with trays containing defaunated sediments were placed at the seabed for 6 months to study colonization of macrofauna. Two different sediments (coarse and fine) were used, and 6 or 24 mm layer of water-based drill cuttings were added on top of these sediments. Some of the sediments were controls with no additions. In the end of the experiment, the oxygen availability in sediment porewater and macrofaunal abundance were reduced in treatments with 24 mm drill cuttings compared to controls. Tube-building annelids were particularly sensitive to drill cuttings. However, these responses were only minor, and notably, the drill cuttings initiated a weaker faunal response than sediment type and site of the bottom frame. Sediments capped with water-based drill cuttings thus showed a rapid colonization of macrofaunal communities. 相似文献
37.
Jenny A. U. Nilsson Srdjan Dobricic Nadia Pinardi Vincent Taillandier Pierre-Marie Poulain 《Ocean Dynamics》2011,61(10):1475-1490
The Mediterranean Forecasting System (MFS) has been operational for a decade, and is continuously providing forecasts and
analyses for the region. These forecasts comprise local- and basin-scale information of the environmental state of the sea
and can be useful for tracking oil spills and supporting search-and-rescue missions. Data assimilation is a widely used method
to improve the forecast skill of operational models and, in this study, the three-dimensional variational (OceanVar) scheme
has been extended to include Argo float trajectories, with the objective of constraining and ameliorating the numerical output
primarily in terms of the intermediate velocity fields at 350 m depth. When adding new datasets, it is furthermore crucial
to ensure that the extended OceanVar scheme does not decrease the performance of the assimilation of other observations, e.g.,
sea-level anomalies, temperature, and salinity. Numerical experiments were undertaken for a 3-year period (2005–2007), and
it was concluded that the Argo float trajectory assimilation improves the quality of the forecasted trajectories with ~15%,
thus, increasing the realism of the model. Furthermore, the MFS proved to maintain the forecast quality of the sea-surface
height and mass fields after the extended assimilation scheme had been introduced. A comparison between the modeled velocity
fields and independent surface drifter observations suggested that assimilating trajectories at intermediate depth could yield
improved forecasts of the upper ocean currents. 相似文献
38.
V. D. Mats D. Yu. Shcherbakov I. M. Efimova 《Stratigraphy and Geological Correlation》2011,19(4):404-423
Independent methods of geological and molecular-biological chronologies have made it possible to define generally corresponding
stages in the geological and biological evolution of the environments and communities of Lake Baikal since the Late Cretaceous,
i.e., during the last 70 myr. All the abiotic elements drastically changed during geological evolution, with destruction of
existing and formation of new natural complexes. Nevertheless, some specific zones retained relicts of former settings. The
resulting present-day natural complex includes elements of different ages and geneses. Similar to different natural zones
of the present-day Earth, which are populated by different biocoenoses, stages in the development of abiotic elements are
also characterized by different faunal and floral assemblages. Some taxa were replaced by others, and the resulting aqueous
biota of Lake Baikal includes different-age and ecologically different elements. The oldest groups of Baikal organisms appeared
approximately 70 Ma ago, although the largest proportion of the lake biota started forming 4–3 Ma ago in response to the most
drastic changes in the abiotic elements of the environment. The youngest taxa appeared 1.8 to 0.15 Ma ago, i.e., during the
period when superdeep lake environments and mountainous glaciations were developing. The chronological coincidence of main
stages in development of abiotic and biotic elements of the nature indicates their relationships. Particular transformations
of abiotic elements and the probable mechanism of their influence on the evolution of living communities are also considered. 相似文献
39.
A new model is suggested for the history of the Baikal Rift,in deviation from the classic two-stage evolution scenario,based on a synthesis of the available data from the Baikal Basin and revised correlation between tectonic-lithological-stratigraphic complexes(TLSC) in sedimentary sections around Lake Baikal and seismic stratigraphic sequences(SSS) in the lake sediments.Unlike the previous models,the revised model places the onset of rifting during Late Cretaceous and comprises three major stages which are subdivided into several substages.The stages and the substages are separated by events of tectonic activity and stress reversal when additional compression produced folds and shear structures.The events that mark the stage boundaries show up as gaps,unconformities,and deformation features in the deposition patterns. The earliest Late Cretaceous-Oligocene stage began long before the India-Eurasia collision in a setting of diffuse extension that acted over a large territory of Asia.The NW-SE far-field pure extension produced an NE-striking half-graben oriented along an old zone of weakness at the edge of the Siberian craton.That was already the onset of rift evolution recorded in weathered lacustrine deposits on the Baikal shore and in a wedge-shaped acoustically transparent seismic unit in the lake sediments.The second stage spanning Late Oligocene-Early Pliocene time began with a stress change when the effect from the Eocene India-Eurasia collision had reached the region and became a major control of its geodynamics.The EW and NE transpression and shear from the collisional front transformed the Late Cretaceous half-graben into a U-shaped one which accumulated a deformed layered sequence of sediments.Rifting at the latest stage was driven by extension from a local source associated with hot mantle material rising to the base of the rifted crust.The asthenospheric upwarp first induced the growth of the Baikal dome and the related change from finer to coarser molasse deposition.With time,the upwarp became a more powerful stress source than the collision,and the stress vector returned to the previous NW-SE extension that changed the rift geometry back to a half-graben. The layered Late Pliocene-Quaternary subaerial tectonic-lithological-stratigraphic and the Quaternary submarine seismic stratigraphic units filling the latest half-graben remained almost undeformed.The rifting mechanisms were thus passive during two earlier stages and active during the third stage. The three-stage model of the rift history does not rule out the previous division into two major stages but rather extends its limits back into time as far as the Maastrichtian.Our model is consistent with geological, stratigraphic,structural,and geophysical data and provides further insights into the understanding of rifting in the Baikal region in particular and continental rifting in general. 相似文献
40.
Ghislain Dubois Benjamin Sovacool Carlo Aall Maria Nilsson Carine Barbier Alina Herrmann Sébastien Bruyère Camilla Andersson Bore Skold Franck Nadaud Florian Dorner Karen Richardsen Moberg Jean Paul Ceron Helen Fischer Dorothee Amelung Marta Baltruszewicz Jeremy Fischer Françoise Benevise Rainer Sauerborn 《Chemie der Erde / Geochemistry》2013
Through their consumption behavior, households are responsible for 72% of global greenhouse gas emissions. Thus, they are key actors in reaching the 1.5 °C goal under the Paris Agreement. However, the possible contribution and position of households in climate policies is neither well understood, nor do households receive sufficiently high priority in current climate policy strategies. This paper investigates how behavioral change can achieve a substantial reduction in greenhouse gas emissions in European high-income countries. It uses theoretical thinking and some core results from the HOPE research project, which investigated household preferences for reducing emissions in four European cities in France, Germany, Norway and Sweden. The paper makes five major points: First, car and plane mobility, meat and dairy consumption, as well as heating are the most dominant components of household footprints. Second, household living situations (demographics, size of home) greatly influence the household potential to reduce their footprint, even more than country or city location. Third, household decisions can be sequential and temporally dynamic, shifting through different phases such as childhood, adulthood, and illness. Fourth, short term voluntary efforts will not be sufficient by themselves to reach the drastic reductions needed to achieve the 1.5 °C goal; instead, households need a regulatory framework supporting their behavioral changes. Fifth, there is a mismatch between the roles and responsibilities conveyed by current climate policies and household perceptions of responsibility. We then conclude with further recommendations for research and policy. 相似文献