Depth-stratified community zonation patterns on Gulf of Alaska rocky shores     

Brenda Konar  Katrin Iken  & Matthew Edwards 《Marine Ecology》2009,30(1):63-73

Vertical zonation patterns have been considered ubiquitous in intertidal ecosystems but questions remain about their generality for individual taxonomic groups and over broad spatial scales, and whether they continue into adjacent shallow subtidal habitats. Taxon richness, invertebrate abundance, and macroalgal biomass were examined in the summer of 2003 along a vertical gradient in the rocky intertidal and shallow subtidal habitats around Kodiak Island, Kachemak Bay, and Prince William Sound, all within the Gulf of Alaska. Replicate samples of benthic organisms were taken in the high (～ 7 m), mid (～ 4 m) and low (～ 0 m) intertidal (relative to MLLW), and at 1, 5, 10 and 15 m water depths at three sites in each region, and identified to the lowest possible taxonomic level. Our primary goals were to assess (1) how estimates of taxon richness, invertebrate abundance, and macroalgal biomass vary among intertidal heights and subtidal depths and (2) how general these patterns are when considered across the Gulf of Alaska. Our results show that when all invertebrates were considered together, most of the variation in taxon richness was accounted for by differences among depths (i.e. intertidal heights and subtidal depths) (～ 51%), and among replicate samples within each depth (～ 26%). Little to none of the variation was accounted for by differences among sites within each region (～ 1%) or among regions themselves (～ 0%). When considered across the Gulf of Alaska, total taxon richness and organism abundance were greatest in the low intertidal/shallow subtidal and decreased with increasing height/depth. When separated by phylum and examined together with macroalgae, variation in abundance and/or biomass among depths was significant and accounted for most of the variability. Differences among regions and sites within each region were not significant and accounted for little to none of the variance. Because the pattern of zonation varied among sites within each region, it reduced the generality of a single zonation pattern for the Gulf of Alaska. Likewise, when community composition was compared among depths, geographic regions and sites within each region using multivariate analyses, vertical zonation patterns were evident at a regional scale, but high variability in these patterns among sites within each region reduced the generality of these patterns.  相似文献   

Routine analysis of sediment pore water of high ionic strength     

Peter Herzsprung  Elke Bozau  Olaf Büttner  Anja Duffek  Kurt Friese  Matthias Koschorreck  Martin Schultze  Wolf v. Tümpling  Katrin Wendt‐Potthoff 《洁净——土壤、空气、水》2006,34(6):593-607

Pore water of sediments plays an important role in aquatic systems as mediator and as the reactive zone between the sediment and surface water. Sediment pore waters with high ionic strength from acidified pit lakes were investigated to obtain information about the influence on the lake water quality. The analysis of soluble reactive phosphorus, nitrate, ammonium, silica, dissolved organic carbon, ferrous iron, sulfate, chloride, sodium, potassium, calcium, magnesium, manganese, and total dissolved iron was predetermined as the dataset required for evaluation of water quality. The data collection procedure was optimised by designing a methodology for stabilisation, dilution of pore water samples and adaptation of analytical methods. The developed methodology was evaluated with respect to the effort required in the laboratory under routine conditions. In the first round of analyses, 72% of 638 individual analyses from a random selection of pore water profiles were found to be within the calibration ranges. Remedial actions to handle the remaining 28% of invalid analytical results are exemplified. Differences between comparative analyses of some ions by continuous flow analysis, ion chromatography, and atomic emission spectroscopy were evaluated. The majority of results measured by ion chromatography differed on a highly significant level from results measured by atomic emission spectroscopy. Possible reasons, originating from the extreme sample matrix, are discussed. Finally, the designed methodology and the results of the method comparison are used to recommend the selection of analytical methods under specific conditions.  相似文献   

Climate Protection Strategies: International Allocation and Distribution Effects     

Gernot Klepper  Katrin Springer 《Climatic change》2003,56(1-2):211-226

In international climate policy discussions, one of the centralissues for medium- to long run climate protection strategiesis the uncertainty about the costs and the distributional effectsof specific unilateral or multilateral emission reductions. Thispaper looks at the world-wide effects of climate protection strategieson the allocation of resources, on economic growth in differentregions, and on the regional welfare effects. The analysis isbased on a global recursively dynamic, multi-region, multi-sectorcomputable general equilibrium model parameterized accordingto the ICLIPS (Integrated Assessment of Climate Protection Strategies)integrated assessment model. The simulations show that nationalclimate policies will have important international repercussions.It is therefore important to consider international allocationeffects in the analysis of national climate protection strategies.The welfare costs of greenhouse gas emission reductions risemore than proportionally with lower emission targets. The analysisof the carbon leakage rate indicates that most of the leakagerapidly disappears if emission reduction moves towards an efficientdistribution of emission targets.  相似文献   

Copper and zinc content of periphyton from two rivers as a function of dissolved metal concentration   总被引：5，自引：0，他引：5  

Renata Behra  Rolf Landwehrjohann  Katrin Vogel  Bettina Wagner  Laura Sigg 《Aquatic Sciences - Research Across Boundaries》2002,64(3):300-306

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Ocean iron fertilization: Why further research is needed     

Kerstin Güssow  Alexander Proelss  Andreas Oschlies  Katrin Rehdanz  Wilfried Rickels 《Marine Policy》2010

Despite large uncertainties in the fertilization efficiency, natural iron fertilization studies and some of the purposeful iron enrichment studies have demonstrated that Southern Ocean iron fertilization can lead to a significant export of carbon from the sea surface to the ocean interior. From an economic perspective the potential of ocean iron fertilization (OIF) is far from negligible in relation to other abatement options. Comparing the range of cost estimates to the range of estimates for forestation projects they are in the same order of magnitude, but OIF could provide more carbon credits even if high discount rates are used to account for potential leakage and non-permanence. However, the uncertainty about undesired adverse effects of purposeful iron fertilization on marine ecosystems and biogeochemistry has led to attempts to ban commercial and, to some extent, scientific experiments aimed at a better understanding of the processes involved, effectively precluding further consideration of this mitigation option. As regards the perspective of public international law, the pertinent agreements dealing with the protection of the marine environment indicate that OIF is to be considered as lawful if and to the extent to which it represents legitimate scientific research. In this respect, the precautionary principle can be used to balance the risks arising out of scientific OIF activities for the marine environment with the potential advantages relevant to the objectives of the climate change regime. As scientific OIF experiments involve only comparatively small negative impacts within a limited marine area, further scientific research must be permitted to explore the carbon sequestration potential of OIF in order to either reject this concept or integrate it into the flexible mechanisms contained in the Kyoto Protocol.  相似文献   

Stability of thin reinforced concrete walls under cyclic loads: state-of-the-art and new experimental findings     

Angelica Rosso  João P. Almeida  Katrin Beyer 《Bulletin of Earthquake Engineering》2016,14(2):455-484

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Chronic exposure of adults and embryos of Pandalus borealis to oil causes PAH accumulation, initiation of biomarker responses and an increase in larval mortality     

Renée Katrin Bechmann  Bodil Katrine Larsen  Ingrid Christina Taban  Per Møller 《Marine pollution bulletin》2010,60(11):2087-2098

Adult shrimps (Pandalus borealis) and their embryos were exposed to an oil-water dispersion (OWD) at concentrations of 0.015, 0.06 and 0.25 mg/L using a continuous flow system. Lysosomal membrane stability was analysed in haemocytes using the neutral red retention assay and an alkaline unwinding assay was used to measure DNA damage in hepatopancreas tissue. Exposure to oil induced concentration and time dependent biomarker responses in adult shrimps together with the accumulation of PAH in their tissues. Oil exposure of shrimp embryos caused increased mortality in the resultant larvae, even if the larvae were kept in clean water after hatching. There were minor differences observed in larval stage development times in the first part of the experiments. The fatty acid composition of embryos exposed to oil was different to that of non-exposed larvae. PAH tissue concentration and biomarker responses correlated to the reduced survival of the shrimp larvae.  相似文献   

Earthquakes in Switzerland and surrounding regions during 2012     

Tobias Diehl  Nicholas Deichmann  John Clinton  Stephan Husen  Toni Kraft  Katrin Plenkers  Benjamin Edwards  Carlo Cauzzi  Clotaire Michel  Philipp Kästli  Stefan Wiemer  Florian Haslinger  Donat Fäh  Urs Kradolfer  Jochen Woessner 《Swiss Journal of Geoscience》2013,106(3):543-558

This report of the Swiss Seismological Service summarizes the seismic activity in Switzerland and surrounding regions during 2012. During this period, 497 earthquakes and 88 quarry blasts were detected and located in the region under consideration. With a total of only 13 events with M_L ≥ 2.5, the seismic activity in the year 2012 was far below the average over the previous 37 years. Most noteworthy were the earthquake sequence of Filisur (GR) in January with two events of M_L 3.3 and 3.5, the M_L 4.2 and M_L 3.5 earthquakes at a depth of 32 km below Zug in February and the M_L 3.6 event near Vallorcine in October. The epicentral intensity of the M_L 4.2 event close to Zug was IV, with a maximum intensity of V reached in a few areas, probably due to site amplification effects.  相似文献   

Decadal windstorm activity in the North Atlantic-European sector and its relationship to the meridional overturning circulation in an ensemble of simulations with a coupled climate model   总被引：1，自引：1，他引：0  

Katrin M. Nissen  Uwe Ulbrich  Gregor C. Leckebusch  Ivan Kuhnel 《Climate Dynamics》2014,43(5-6):1545-1555

The relationship between decadal variations in the North Atlantic meridional overturning circulation (MOC) and North Atlantic/Western European windstorm activity during the extended winter season is studied. According to an ensemble of three 240-year long simulations performed with the ECHAM5-MPIOM model, periods of high decadal windstorm activity frequently occur in the years following a phase of weak MOC (i.e. when the MOC starts to recover). These periods are characterised by a distinctive pattern in the mixed layer ocean heat content (OHC). A positive anomaly is located in the region 45°N?52°N/35°W?16°W (west of France). Negative anomalies are located to the North and South. The signal can be detected both in the heat content of the oceanic mixed layer and in the sea surface temperatures. Its structure is consistent with anomalously enhanced baroclinic instability in the region with the strong negative OHC gradient (30°W?10°W/45°N?60°N), which eventually produces a higher probability of windstorms.  相似文献   

Mixing efficiency from microstructure measurements in the Sicily Channel     

Vladoiu  Anda  Bouruet-Aubertot  Pascale  Cuypers  Yannis  Ferron  Bruno  Schroeder  Katrin  Borghini  Mireno  Leizour  Stephane  Ismail  Sana Ben 《Ocean Dynamics》2019,69(7):787-807

Ocean Dynamics - The dissipation flux coefficient, a measure of the mixing efficiency of a turbulent flow, was computed from microstructure measurements collected with a vertical microstructure...  相似文献