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1.
We conducted a laboratory experiment to quantify nutrient (nitrogen and phosphorus) limitation of macroalgae collected along
a gradient in water column nutrient availability in Upper Newport Bay estuary, a relatively nutrient-rich system in southern
California, United States. We collectedEnteromorpha intestinalis and water for use in the experiment from five sites ranging from the lower end of the estuary to the head. Initial algal
tissue N and P concentrations and molar N∶P ratios—as well as water column NO3 and total Kjeldahl nitrogen (TKN)—increased along a spatial gradient from the lower end toward the head. Water column soluble
reactive phosphorus (SRP) varied among sites as well but did not follow a pattem of increasing from the seaward end toward
the head. Algae from each site were assigned to one of four experimental treatments: control (C), nitrogen enrichment (+N),
phosphorus enrichment (+P), and nitrogen and phosphorus enrichment (+N+P). Each week for 3 wk we replaced the water in each
unit with the appropriate treatment water to mimic a poorly flushed estuary. After 3 wk, the degree of nutrient limitation
ofE. intestinalis varied spatially with distance from the head of the estuary. Growth ofE. intestinalis collected from several sites increased with N enrichment alone and increased further when P was added in combination with
N This indicated that N was limiting and that when N was sufficient, P became limiting. Sites from whichE. intestinalis exhibited nutrient limitation spanned the range of background water column NO3 (12.9±0.4 to 55.2±2.1 μM) and SRP (0.8±0.0 to 2.9±0.2 μM) concentrations. Algae that were N limited had initial tissue N
levels ranging from 1.18±0.03 to 2.81±0.08% dry weight and molar N∶P ratios ranging from 16.75±0.39 to 26.40±1.98. 相似文献
2.
North-western Anatolia has been actively deformed since Pliocene by the right-lateral North Anatolian Fault (NAF). This transform fault, which has a transtensional character in its western end due to effects from the Aegean extensional system, is a major control on the regional geomorphologic evolution. This study applied some geomorphic analyses, such as stream longitudinal profiles, stream length-gradient index, ratio of valley floor width and valley height, mountain front sinuosity, hypsometry and asymmetry factor analyses, to an area just east of the Sea of Marmara in order to understand the tectonic effects on the area’s geomorphological evolution. The active and fastest northern branch of the NAF lies within a topographic depression connecting Sea of Marmara in the east to the Adapazar? Basin in the west. This depression filled with early Pleistocene and younger sediment after a series of pull-apart basins opened along the NAF. North of this depression lies the Kocaeli Peneplain, whose southern edge the NAF uplifted. Meandering streams on the central peneplain were incised possibly due to baselevel changes in the Black Sea. South of the depression, an E-trending mountainous area has a rugged morphology. Based on geomorphic analyses, uplifted Pliocene sediment, marine terraces, and recent earthquake activity, this area between northern and southern branches of the NAF is actively uplifting. The geomorphic indices used in this study are sensitive to vertical movements rather than lateral ones. The bedrock lithology that played an important role on the area’s geomorphologic evolution also affects the geomorphic indices used here. 相似文献
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A simple parameter estimation procedure, designated as integration-based estimation (IBE), was introduced to determine the hydraulic properties of an aquifer using slug test models subjected to certain flow geometries such as radial and spherical flows. The basic idea behind the proposed IBE approach is to link an integration value at pre-defined normalized head levels for field data with that of a theoretical type curve. The IBE method removes the need for the implementation of the classical graphical matching process which would be ineffective to acquire aquifer parameters for non-ideal aquifer conditions. As the second aspect of this study, a new decision tool was suggested to determine the suitable slug test model to be utilized for the site data since diagnosing the flow character properly is of crucial importance for following a convenient analysis procedure. The estimation performance and limitation of the proposed IBE method were tested for several slug test scenarios including radial and spherical flow models with a number of synthetically generated data sets as well as a field application. Results reveal that the IBE together with the identification methodology not only is able to retrieve aquifer parameters as reliable as the existing techniques in the literature but also diagnoses the flow character precisely as demonstrated in this study. 相似文献
5.
Ufuk Utku Turuncoglu Nellie Elguindi Filippo Giorgi Nicolas Fournier Graziano Giuliani 《Climate Dynamics》2013,41(7-8):1731-1748
We present a validation analysis of a regional climate model coupled to a distributed one dimensional (1D) lake model for the Caspian Sea Basin. Two model grid spacings are tested, 50 and 20 km, the simulation period is 1989–2008 and the lateral boundary conditions are from the ERA-Interim reanalysis of observations. The model is validated against atmospheric as well as lake variables. The model performance in reproducing precipitation and temperature mean seasonal climatology, seasonal cycles and interannual variability is generally good, with the model results being mostly within the observational uncertainty range. The model appears to overestimate cloudiness and underestimate surface radiation, although a large observational uncertainty is found in these variables. The 1D distributed lake model (run at each grid point of the lake area) reproduces the observed lake-average sea surface temperature (SST), although differences compared to observations are found in the spatial structure of the SST, most likely as a result of the absence of 3 dimensional lake water circulations. The evolution of lake ice cover and near surface wind over the lake area is also reproduced by the model reasonably well. Improvements resulting from the increase of resolution from 50 to 20 km are most significant in the lake model. Overall the performance of the coupled regional climate—1D lake model system appears to be of sufficient quality for application to climate change scenario simulations over the Caspian Sea Basin. 相似文献
6.
Huseyin Ozdemir Alper Unal Tayfun Kindap Ufuk Utku Turuncoglu Zeynep Okay Durmusoglu Maudood Khan Mete Tayanc Mehmet Karaca 《Theoretical and Applied Climatology》2012,108(1-2):31-38
The Anatolian Peninsula is located at the confluence of Europe, Asia, and Africa and houses 81 cities of which 79 of them have population over 100,000. We employed some criteria to select the cities from the 81 cities. After accomplishing all the criteria, eight cities were remaining for the study. Nonparametric Mann–Kendall test procedure was employed for the urban and rural stations of these cities to detect the long-term change in temperature trends. Statistical analysis of daily minimum temperatures for the period between 1965 and 2006 suggest that there is no statistically significant increase in rural areas. In contrast to the findings of the previous studies, however, all the urban sites and difference between urban and rural pairs show significant increase in temperatures, a strong indication for the existence of urban heat island (UHI) affect over the region. Regional Climate Model was also utilized to assess the changes in temperature by the end of century for the region. The findings suggest that an increase of up to 5°C is possible. Climate change effects enforced with UHI have the potential to cause serious problems for the entire region and hence needs to be studied thoroughly. 相似文献
7.
Mustafa Erdik Karin Sesetyan Mine Demircioglu Ufuk Hancilar Can Zulfikar Eser Cakti Yaver Kamer Cem Yenidogan Cuneyt Tuzun Zehra Cagnan Ebru Harmandar 《Acta Geophysica》2010,58(5):855-892
The almost-real time estimation of ground shaking and losses after a major earthquake in the Euro-Mediterranean region was performed in the framework of the Joint Research Activity 3 (JRA-3) component of the EU FP6 Project entitled “Network of Research Infra-structures for European Seismology, NERIES”. This project consists of finding the most likely location of the earthquake source by estimating the fault rupture parameters on the basis of rapid inversion of data from on-line regional broadband stations. It also includes an estimation of the spatial distribution of selected site-specific ground motion parameters at engineering bedrock through region-specific ground motion prediction equations (GMPEs) or physical simulation of ground motion. By using the Earthquake Loss Estimation Routine (ELER) software, the multi-level methodology developed for real time estimation of losses is capable of incorporating regional variability and sources of uncertainty stemming from GMPEs, fault finiteness, site modifications, inventory of physical and social elements subjected to earthquake hazard and the associated vulnerability relationships. 相似文献
8.
A 16-mo long monitoring study was carried out in Upper Newport Bay estuary (UNB), Orange County, California, to quantify the
macroalgal community of a southern California estuary. Quarterly sampling began December 1996 at 8 stations along the main
channel and tidal creeks ranging from the head to the lower end of UNB. At each station, two strata (one at high and one at
low elevation) were surveyed. Macroalgal species abundance (% cover and biomass) and algal tissue nitrogen (N) and phosphorus
(P) were measured. The algal community changed from sparse macroalgal cover during winter 1996 to larger patches dominated
byEnteromorpha intestinalis in spring 1997. The community was characterized by a thick cover of macroalgae comprised ofE. intestinalis andUlva expansa in summer 1997 andU. expansa andCeramium spp. in fall 1997. UNB returned to sparse macroalgal cover by spring 1998. In summer and fall 1997, biomass ofE. intestinalis andCeramium reached over 1,000 g wet wt m−2 each, andU. expansa biomass exceeded 700 g wet wt m−2. Tissue N was high inE. intestinalis andU. expansa collected from UNB (≈3% dry wt) and higher inCeramium (≈3.5% dry wt). Tissue P in all three algae ranged from 0.24–0.28% dry wt. Tissue N∶P (molar) ratios inE. intestinalis andU. expansa ranged from 16.4 to 30.0 and inCeramium from 21.8 to 40.1. A field experiment was conducted in whichE. intestinalis was used as a bioassay of N and P availability. Algal tissue was cultured under known conditions and samples were deployed
throughout the estuary and left for 24 h. Tissue N of algae from these bags showed a nominal increase in N with proximity
to the primary nutrient input to the system, San Diego Creek (p=0.0251; r2=0.200). Our data indicate that UNB is already a highly eutrophic estuary, but macroalgal blooms in UNB may increase if more
N is added to the system. 相似文献
9.
Development of ground-shaking maps for the Sultanate of Oman 总被引：1，自引：1，他引：0
10.
Assessing radial transmissivity variation in heterogeneous aquifers using analytical techniques 
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下载免费PDF全文 Pumping tests are one of the most commonly used in situ testing techniques for assessing aquifer hydraulic properties. Numerous researches have been conducted to predict the effects of aquifer heterogeneity on the groundwater levels during pumping tests. The objectives of the present work were as follows: (1) to predict drawdown conditions and to estimate aquifer properties during pumping tests undertaken in radially symmetric heterogeneous aquifers, and (2) to identify a method for assessing the transmissivity field along the radial coordinate in radially symmetric and fully heterogeneous transmissivity fields. The first objective was achieved by expanding an existing analytical drawdown formulation that was valid for a radially symmetric confined aquifer with two concentric zones around the pumping well to an N concentric zone confined aquifer having a constant transmissivity value within each zone. The formulation was evaluated for aquifers with three and four concentric zones to assess the effects of the transmissivity field on the drawdown conditions. The specific conditions under which aquifer properties could be identified using traditional methods of analysis were also evaluated. The second objective was achieved by implementing the inverse solution algorithm (ISA), which was developed for petroleum reservoirs to groundwater aquifer settings. The results showed that the drawdown values are influenced by a volumetric integral of a weighting function and the transmissivity field within the cone of depression. The weighting function migrates in tandem with the expanding cone of depression. The ability of the ISA to predict radially symmetric and log‐normally distributed transmissivity fields was assessed against analytical and numerical benchmarks. The results of this investigation indicated that the ISA method is a viable technique for evaluating the radial transmissivity variations of heterogeneous aquifer settings. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献