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111.
The concurrent development of a cool-carbonate Miocene clinoform system and the tropical reef which developed on its shelf in the North Carnarvon Basin is studied. The study, based on seismic interpretation and geometrical analysis, seeks to investigate how the architecture of the clinoforms develops in relation to the advance of the reef-margin, providing a proxy for discussing contemporaneous shoreline versus shelf-edge development. The progradation of the reef and shelf-edge often display a closely mirrored development, although the reef twice advances an order of two to three times the concurrent advance of the shelf-edge. The forced regression of the second advance, as compared to the normal regression during the first, is observed in proportionally higher input of sediment towards advance of the shelf-edge and toe, along with a gentler slope. The inability of the shelf-edge to keep pace with the reef-margin (and by proxy the shoreline) during lower accommodation/sedimentation is a result of the increased volume of sediment required to match reef-margin advance beyond the shelf-edge. Increased accommodation/sedimentation ratios promote higher trajectories where the volumes on shelf and slope are more balanced and the development more closely matched. The observed matched development of reef and shelf-edge during both limited and increased slope sedimentation, suggest that accommodation is the dominant control on the location and trajectory of both ‘shoreline’ and shelf-edge, and that excess sediment is deposited along the slope. 相似文献
112.
Rafał Iwański Anna Odzimek Lasse B.N. Clausen Vijay Kanawade Ingrid Cnossen Niklas J.T. Edberg 《Acta Geophysica》2009,57(3):760-777
The first red sprite events scientifically observed from Poland on 20/21 July 2007, during the two-week SPARTAN Sprite-Watch
2007 campaign, are analysed in the context of the meteorological conditions over Poland and the Czech Republic at that time.
The phenomena were detected and recorded from the IMWM High-Mountain Meteorological Observatory at Mount Śnieżka using a low-light
television CCD camera. Meteorological conditions over the south-west Poland were monitored on the basis of information from
the Polish and Czech meteorological radar and lightning detection systems and also from satellite infra-red difference images,
indicating the development of thunderstorm clouds over central Europe. Four sprite events detected in the night-time of 20/21
July indicate that in this region sprites are produced by massive storm cells built on warm fronts which are supplied by warm
and humid tropical air masses during local summer thunderstorm season. 相似文献
113.
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115.
This study evaluates the sensitivity of Washington State’s freshwater habitat of Pacific Salmon (Oncorhynchus spp.) to climate change. Our analysis focuses on summertime stream temperatures, seasonal low flows, and changes in peak and base flows because these physical factors are likely to be key pressure points for many of Washington’s salmon populations. Weekly summertime water temperatures and extreme daily high and low streamflows are evaluated under multimodel composites for A1B and B1 greenhouse gas emissions scenarios. Simulations predict rising water temperatures will thermally stress salmon throughout Washington’s watersheds, becoming increasingly severe later in the twenty-first century. Streamflow simulations predict that basins strongly influenced by transient runoff (a mix of direct runoff from cool-season rainfall and springtime snowmelt) are most sensitive to climate change. By the 2080s, hydrologic simulations predict a complete loss of Washington’s snowmelt dominant basins, and only about ten transient basins remaining in the north Cascades. Historically transient runoff watersheds will shift towards rainfall dominant behavior, undergoing more severe summer low flow periods and more frequent days with intense winter flooding. While cool-season stream temperature changes and impacts on salmon are not assessed in this study, it is possible that climate-induced warming in winter and spring will benefit parts of the freshwater life-cycle of some salmon populations enough to increase their reproductive success (or overall fitness). However, the combined effects of warming summertime stream temperatures and altered streamflows will likely reduce the reproductive success for many Washington salmon populations, with impacts varying for different life history-types and watershed-types. Diminishing streamflows and higher stream temperatures in summer will be stressful for stream-type salmon populations that have freshwater rearing periods in summer. Increased winter flooding in transient runoff watersheds will likely reduce the egg-to-fry survival rates for ocean-type and stream-type salmon. 相似文献
116.
Hedwig Roderfeld Eleanor Blyth Rutger Dankers Geir Huse Dag Slagstad Ingrid Ellingsen Annett Wolf Manfred A. Lange 《Climatic change》2008,87(1-2):283-303
The EU project BALANCE (Global Change Vulnerabilities in the Barents region: Linking Arctic Natural Resources, Climate Change and Economies) aims to assess vulnerability to climate change in the Barents Sea Region. As a prerequisite the potential impact of climate change on selected ecosystems of the study area has to be quantified, which is the subject of the present paper. A set of ecosystem models was run to generate baseline and future scenarios for 1990, 2020, 2050 and 2080. The models are based on data from the Regional Climate Model (REMO), driven by a GCM which in turn is forced by the IPCC-B2 scenario. The climate change is documented by means of the Köppen climate classification. Since the multitude of models requires the effect of climate change on individual terrestrial and marine systems to be integrated, the paper concentrates on a standardised visualisation of potential impacts by use of a Geographical Information System for the timeslices 2050 and 2080. The resulting maps show that both terrestrial and marine ecosystems of the Barents region will undergo significant changes until both 2050 and 2080. 相似文献
117.
The capelin is a small pelagic fish that performs long distance migrations. It is a key species in the Barents Sea ecosystem
and its distribution is highly climate dependent. Here we use an individual based model to investigate consequences of global
warming on capelin distribution and population dynamics. The model relies on input on physics and plankton from a biophysical
ocean model, and the entire life cycle of capelin including spawning of eggs, larval drift and adult movement is simulated.
Spawning day and adult movement strategies are adapted by a genetic algorithm. Spawning has to take place in designated near-shore
spawning areas. The output generated by the model is capelin migration/distribution and population dynamics. We present simulations
with present day climate and a future climate scenario. For the present climate the model evolves a spatial distribution resembling
typical spatial dynamics of capelin with the coasts of Northern Norway and Murman as the main spawning areas. For the climate
change simulation, the capelin is predicted to shift spawning eastwards and also utilize new spawning areas along Novaya Zemlya.
There is also a shift in the adult distribution towards the north eastern part of the Barents Sea and earlier spawning associated
with the warming. 相似文献
118.
Baussant T Ortiz-Zarragoitia M Cajaraville MP Bechmann RK Taban IC Sanni S 《Marine pollution bulletin》2011,62(7):1437-1445
Mussels (Mytilus edulis) were continuously exposed to dispersed crude oil (0.015-0.25 mg/l) for 7 months covering the whole gamete development cycle. After 1 month exposure to 0.25 mg oil/l, the level of alkali-labile phosphates (ALP) and the volume density of atretic oocytes in female gonads were higher than those in the gonads of control females, indicating that oil affected the level of vitellogenin-like proteins and gamete development. Spawning of mussels was induced after 7 months oil exposure. Parental oil exposure did not affect subsequent fertilization success in clean seawater but this was reduced in 0.25 mg oil/l. Parental exposure to 0.25 mg oil/l caused both slow development and a higher percentage of abnormalities in D-shell larvae 2 days post-fertilization; reduced growth 7 days post-fertilization. These effects were greatly enhanced when larval stages were maintained at 0.25 mg oil/l. Similar studies are warranted for risk assessment prognosis. 相似文献
119.
Olenin S Elliott M Bysveen I Culverhouse PF Daunys D Dubelaar GB Gollasch S Goulletquer P Jelmert A Kantor Y Mézeth KB Minchin D Occhipinti-Ambrogi A Olenina I Vandekerkhove J 《Marine pollution bulletin》2011,62(12):2598-2604
Adverse effects of invasive alien species (IAS), or biological pollution, is an increasing problem in marine coastal waters, which remains high on the environmental management agenda. All maritime countries need to assess the size of this problem and consider effective mechanisms to prevent introductions, and if necessary and where possible to monitor, contain, control or eradicate the introduced impacting organisms. Despite this, and in contrast to more enclosed water bodies, the openness of marine systems indicates that once species are in an area then eradication is usually impossible. Most institutions in countries are aware of the problem and have sufficient governance in place for management. However, there is still a general lack of commitment and concerted action plans are needed to address this problem. This paper provides recommendations resulting from an international workshop based upon a large amount of experience relating to the assessment and control of biopollution. 相似文献
120.
Caroline Schmidt Claudia Hanfland Pierre Regnier Philippe Van Cappellen Michael Schl��ter Ulrich Knauthe Ingrid Stimac Walter Geibert 《Geo-Marine Letters》2011,31(4):259-269
Activities of the naturally occurring radium nuclides 228Ra, 226Ra, 224Ra and 223Ra were determined in waters of the open German Bight and adjacent nearshore areas in the North Sea, in order to explore the
potential use of radium isotopes as natural tracers of land–ocean interaction in an environment characterised by extensive
tidal flats, as well as riverine and groundwater influx. Data collected at various tidal phases from the Weser Estuary (228Ra: 46.3 ± 4.6; 226Ra: 17.1 ± 1.1; 224Ra: 26.1 ± 8.2 to 36.5 ± 6.1; 223Ra: 1.8 ± 0.1 to 4.0 ± 0.4), tidal flats near Sahlenburg (228Ra: 39.3 ± 3.8 to 46.0 ± 4.5; 226Ra: 15.5 ± 1.5 to 16.5 ± 1.7; 224Ra: 34.3 ± 2.2 to 85.3 ± 6.3; 223Ra: 3.6 ± 0.5 to 8.0 ± 1.2), freshwater seeps on tidal flats near Sahlenburg (228Ra: 42.1 ± 4.1; 226Ra: 21.3 ± 2.2; 224Ra: 5.1 ± 0.9; 223Ra: 2.6 ± 1.3) and also in permanently inundated parts of the North Sea (228Ra: 23.0 ± 2.3 to 28.2 ± 2.8; 226Ra: 8.2 ± 0.8 to 11.8 ± 1.2; 224Ra: 3.1 ± 1.0 to 10.1 ± 0.9; 223Ra: 0.1 ± 0.02 to 0.9 ± 0.05; units: disintegrations per minute per 100 kg water sample) reveal that, except for the fresh
groundwater, the potential end-members of nearshore water mass mixing have quite similar radium signatures, excluding a simple
discrimination between the sources. However, the decreasing activities of the short-lived 224Ra and 223Ra isotopes recorded towards the island of Helgoland in the central German Bight show a potential to constrain fluxes of land-derived
material to the open North Sea. The largest source for all radium isotopes is generally found on the vast tidal flats and
in the Weser Estuary. Future work could meaningfully combine this so-called radium quartet approach with investigations of
radon activity. Indeed, preliminary data from a tidal flat site with fresh groundwater seepage reveal a 222Rn signal that is clearly lower in seawater. 相似文献