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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
261

Property Law in Roman Egypt in the Light of the Papyri: Safeguarding Women's Economic Interests

Sturym, Melina 08 1900 (has links)
This study looks at the role of women in the economic environment of Roman Egypt in the light of the papyri. By examining marriage and inheritance documents from the first three centuries, the study shows that marital and inheritance laws and customs in Roman Egypt were made to protect women’s interests when it came to ownership and possession of property, which is one of the main reasons why women played such a prominent role in Egypt’s economic environment.
262

Fish as ecological indicators in Mediterranean freshwater ecosystems

Benejam Vidal, Lluís 22 December 2008 (has links)
Podeu escriure el text directament o arrossegar-lo des d'un altre documentL'objectiu d'aquesta tesi és contribuir a l'ús dels peixos continentals com a indicadors de l'estat ecològic a la conca Mediterrània. En el primer treball es va detectar que encara que tots els índex biològics estaven correlacionats significativament, els peixos integren i expressen els estressos de manera i a una escala diferents, aportant una informació complementària als altres índexs. Al segon article es van estudiar els cabals de sis conques catalanes. S'ha mostrat que els règims hídrics estan alterats amb una tendència a la disminució del cabal i del nivell dels aqüífers. S'ha detectat quatre mètriques de peixos que es troben significativament afectades en zones més castigades per manca d'aigua degut a l'activitat humana. Es discuteix la necessitat de conèixer en profunditat el règim hídric de cada conca abans d'utilitzar els índex biològics. Al tercer article es va detectar que la composició d'espècies capturades va variar significativament al llarg del buidat amb un augment de l'alburn (A. alburnus) a les aigües pelàgiques durant els dies de pitjor qualitat de l'aigua, confirmant que l'alburn és més tolerant a la mala qualitat de l'aigua que la madrilleta vera (R. rutilus) i suggereix el seu potencial com a bioindicador. La condició d'aquestes dues espècies va canviar significativament al llarg del buidat de manera molt estreta amb la qualitat de l'aigua. Al quart capítol es va estudiar la biologia dels peixos d'un embassament altament contaminat (Flix). El percentatge de DELT anomalies i la presència de paràsits externs era major en la zona impactada que als punts de control i els valors més alts de pes eviscerat i pes del fetge estaven als punts de control. Les respostes van ser diferents per cada espècie i la carpa va ser la que va mostrar més clarament els impactes. / Podeu escriure el text directament o arrossegar-lo des d'un altre documentThe aim of this thesis is to contribute to the use of freshwater fish as ecological indicators in the Mediterranean basin. In the first article we found that although most biological indices were correlated, fish reflected different ecological aspects due to their particular features. In the second article the stream flow regimes of six Mediterranean basins were studied. A decrease of streamflow and aquifer levels was detected, despite no observed decrease of rainfall precipitation. Of the thirty metrics tested to detect sites impacted by water abstraction, we detected four significant fish metrics. Furthermore, the role of biotic indices when the river is artificially dry is discussed. In the third article we found that species composition in the pelagic zone varied significantly during the drawdown with higher proportion of bleak (A. alburnus) during the days of worst water quality, confirming that bleak is more tolerant than roach (R. rutilus) to poor water quality. The weight-length relationship of roach and bleak also varied significantly during the drawdown with close relationship between water quality and fish condition. In the fourth article the condition and fecundity of freshwater fishes were assessed in a highly polluted reservoir (Flix reservoir). We have shown significant increases of DELT anomalies and ectoparasite prevalences and decreases in condition and fecundity of several freshwater fish at the impacted area. The responses to the pollutants were species-specific and common carp was the species that showed more markedly the effects.
263

Mesoscale variability of the northern current in the gulf of lions and the role of bottom topography

Flexas Sbert, Maria del Mar 11 July 2003 (has links)
The Northern Current flows cyclonically contouring the continental slope in the NW Mediterranean. At the entrance of the Gulf of Lions this current is about 20 -- 30 km wide and flows along the deepest half of the continental slope, i.e. over the 1000 to 2000 m isobaths approximately. Surface speeds are of 30 -- 50 cm s^{-1}. In the MATER HFF experiment (March -- May 1997) mesoscale variability of the Northern Current is observed from current meter records, SST images and hydrographic data. The HFF experimental box is 20 x 40 km, covering the upper half of the slope (i.e. covering from 250 m to 1250 m depth isobaths). Current meter and satellite data show that the site is embedded in a region of significant Northern Current meandering and eddy activity. From SST images, meander wavelengths are estimated larger than 60 km, embracing smaller structures. These flow patterns affect upper-layer waters down to at least 650 m depth. Current meter data distinguish two narrow energetic bands centred at 3.5 days and 7.5 days, respectively, in agreement with previous studies.Baroclinic instability is viewed as a possible mechanism to explain the generation of the Northern Current meanders. The analytical model of Tang (1975) predicts the development of unstable waves of wavelength (> 60 km) and periods compatible with the 7.5 day band recorded with current meter devices. The higher frequency band of 3.5 days is out of the frequency range predicted by the classical baroclinic instability theory and it is discussed as a restriction of quasi-geostrophic theory.Barotropic instability is studied using a laboratory model of a -westward' jet flowing over the lower half of the continental slope, which considers dynamic similarity with the Northern Current. The laboratory model is cross-validated with a corresponding numerical model. Jet instabilities of currents similar to the Northern Current (i.e. westward jets) occur at the edges of the jet, showing a clear meandering tendency over the mid-slope. Westward currents of Ro = 0.1 -- 0.2 develop instabilities of wavelengths (50 -- 75 km) similar to those observed from SST images, with periods (3.3 -- 3.8 days) compatible with the 3.5 days period band recorded with HFFE current meters.The laboratory and numerical experiments have reproduced westward jets (as the Northern Current), but also eastward jets, in order to have a full approach to better understand the role of the bottom topography on barotropic instabilities. The slope current instabilities are successfully explained by the Marcus and Lee theory (1998) of jets on a beta plane. This theory is valid for westward flows with Ro > 0.1 and for eastward flows with Ro > 0.2 (jets of the so-called Regime II flows in this thesis), and it states that the instabilities of each shear layer of the barotropic jet take the appearance of a Kelvin-Helmholtz-like pattern, associated with a Rossby wave (of topographic origin in our case). According to this theory, the differences between eastward and westward jets rely on the disposition of the Rossby waves --at the centre of the current in eastward flows and at the edges of the jet in westward currents. Jets over a sloping bottom with small Rossby numbers (Ro < 0.1 for westward jets; Ro < 0.2 for eastward jets) show a flow pattern (the so-called Regime I in this thesis) that has common characteristics for eastward and westward flows. In these -small'-Ro flows, Kelvin-Helmholtz-like instabilities dominate, whereas Rossby waves are too weak to produce any major difference between jets flowing in eastward or westward direction. This occurs when the topographic influence, assumed proportional to the Ro number of the jet, is small.The differences between eastward and westward slope currents observed in this work (and similar observations of jets on a beta-plane from previous works) are explained in this thesis by a simple scheme based on conservation of potential vorticity, considering there are two main components in balance: the shear-induced vorticity and the topographically induced vorticity. The signs of these two components are determined by the relative direction of the flow with respect to the inclination of the bottom topography. Once the critical Rossby number is overpassed so that the topographic effects are important (Ro > 0.1 for westward jets; Ro > 0.2 for eastward jets), conservation of potential vorticity tends to enhance vortices at the centre of eastward jets --eastward jets show meandering at the jet core. In westward jets, potential vorticity conservation is responsible of enhancing vortices at each edge of the jet. Thus, westward jets (as the Northern Current) are broad and meandering occurs at the jet edges.In Ro > 0.1 westward flows (i.e. Regime II westward jets) a topographic Rossby wave appears over the shelf break. This result is likely observed because of the specific topography used in this work --a continental slope and a continental shelf separated by a shelf break, producing a strong change in ambient potential vorticity. Numerical simulations reveal that this Rossby wave is triggered by the slope current. This topographic Rossby wave is a robust pattern, since it is independent of the position of the current over the slope, the shape of the velocity shear profile of the jet, and the jet width. Although this type of wave could not be inferred from the HFFE field data, it could be a focus of study in further field experiments. It also needs further analytical consideration. The general conclusion extracted from this thesis that tries to explain the mesoscale variability associated to the Northern Current is that both baroclinic and barotropic instability could explain part of the oceanic observations. As a consequence, mixed barotropic-baroclinic instability (which occurs at wavelengths which are between those corresponding to pure barotropic and pure baroclinic instability) is thought to play an important role on the observed mesoscale variability. The resulting wavelength would depend on the relative strength of both mechanisms.
264

Elemental Stoichometry in Nutrient Pools in Oligotrophic Marine Ecosystems

Lucea Sureda, Anna 23 January 2004 (has links)
Amb aquest treball es preté comprovar la universalitat de la relació estequiomètrica de Redfield i recercar patrons consistents de les desviacions d'aquesta raó promig en ambients oligotrofics. Per tal de dur a terme aquest propòsit s'han desenvolupat relacions estequiomètriques en el compartiment particulat i dissolt orgànic i inorgànic per el C, N, P i Si.La estequiometria dels nutrients a l'oceà s'ha examinat al Mar Mediterrani i a l'Oceà Atlàntic subtropical, mentre que la zona costenera del Mar Mediterrani ha servit per estudiar aquestes relacions sota l'influència d'aports terrestres. En el segon capítol de la tesi es descriuen patrons meridionals del fluxe de nitrogen i fósfor vers la capa biogènica de l'Oceà Atlàntic Central. La raó promig entre el fluxe difusiu del nitrogen inorgànic dissolt (DIN) i del fósfor (DIP) es mostra similar a la raó de Redfield al llarg de l'Oceà Atlàntic Central, però tendeix a valors per sota dels establerts per Redfield a la part sud del trajecte i superiors a la raó de Redfield al centre del gir sudtropical. La raó N:P del fluxe difusiu i la raó N:P dels nutrients dissolts inorgànics en la capa biogènica es troben fortament correlacionats, mentre que no existeix cap correlació amb els valors de la raó N:P de les aigües intermitges. Els resultats trobats en aquest capítol de la tesi indiquen que la recirculació vertical de nutrients a la capa biogènica de l'oceà Atlàntic Central és capaç d'operar amb raons estequimètriques que difereixen de Redfield i per tant els components biogènics i biolítics s'adapten a les variacions locals de la raó de Redfield. La hipòtesis que existeixen raons estequiomètriques previsibles en la reserva oceànica de material dissolt orgànic que es troben en equilibri amb la reserva del material particulat orgànic i dissolt inorgànic, es corrobora en el tercer capítol d'aquesta tesi. La majoria del carboni orgànic present en aigües oligotrofiques del Mediterrani estratificat es troba en forma d'orgànic dissolt, mentre que el POC (carboni orgànic particulat) representa un percentatge menor. El nitrogen i fósfor orgànic dissolt que comprenen el 50-80% del "pool" total de P i N a la capa biogènica, decreix en percentarge a la capa biolítica. S'ha comprovat una distribució uniforme del nitrogen disolt total (TDN). L'increment en el percentatge de N inorgànic disolt i el decreixement en percentatge de N orgànic dissolt amb la fondària, és un indicador clar de l'equilibri dinàmic que existeix entre les reaccions bioquímiques entre les reserves oceàniques. Mitjançant un sistema de balanços, s'estableix un intercanvi de nutrients (exportació-importació) entre els pools dissolt orgànic i dissolt inorgànic en el sistema. S'ha comprovat que el fluxe de nitrogen orgànic dissolt (DON) excedeix al fluxe difusiu de nitrogen inorgànic i per tant els aports atmosfèrics i terrestres són importants en aquesta regió.En el quart capítol de la tesi es descriu el lligam existent entre el component pelàgic i els component del bentos d'una àrea litoral del Mar Mediterrani, és a dir un compartiment anabolic que produeix matèria orgànica i un de catabolic que actúa com agent oxidant de la reserva de matèria orgànica del sistema. El compartiment pelàgic es mostra heterotrofic. Al mateix temps, existeix una contribució important de material terrestre als sediments. Per contra, el compartiment bentònic és autotrofic on el dèficit en la producció grossa es compensa amb l'excés de producció neta del sistema. Mitjançant la quantificació simultànea dels fluxes anuals de sedimentació per al C, N, P i Si així com dels fluxes sediment-aigua de les espècies orgàniques i inorgàniques dissoltes, s'ha establert un sistema de balanços de matèria del sistema. El compartiment bentonic es configura com a sumider o exportador de matèria orgànica, degut als aports terrestres de carboni en el sistema.Els patrons de distribució de nutrients derivats dels resultats dels capítols anteriors es comproven mitjançant un experiment d'addició de nutrients. En el capítol cinquè d'aquesta tesi s'estudien els canvis en la distribució de nutrients en les diferents reserves nutricionals d'un sistema quan es troba sotmès a aports controlats de nutrients. S'ha comprovat que, mentre el tamany relatiu de la reserva de nutrients inorgànics dissolts no varia amb l'increment de nutrients en el medi. Hi ha una tendència a l'increment del tamany relatiu de la reserva del material particulat, paral.lela a un decreixement simultani de la reserva de material dissolt orgànic. Aquest experiment contribueix a verificar el paper del DOM (matèria dissolta orgànica) com a principal reserva nutricional en sistemes oliogotròfics. / The stoichiometric ratios are powerful tools to model basic biogeochemical patterns of the sea when the fluxes of a single element are known. It is, therefore essential to understand the full implications of variable stoichiometries to predict the effect of the living components of the ocean on biogeochemical processes. Here, the stoichiometry between C, N, P and Si in different chemical pools (particulate and dissolved organic and dissolved inorganic matter) were examined in contrasting oceanic and littoral ecosystems, and the changes in nutrient partitioning in response to nutrient inputs was tested through experimental research. In the Central Atlantic Ocean, the average ratio between dissolved inorganic nitrogen and phosphorus in the estimated vertical diffusive fluxes was similar to the Redfield ratio, but tended to be above the Redfield ratio at the center of the South subtropical gyre. The N:P supply ratio and the N:P ratio of dissolved inorganic nutrients in the biogenic layer were strongly correlated, but were not positively correlated to that in the intermediate waters. The vertical nutrient conveyor belt of nutrients in the upper waters operates relatively independently of the underlying waters in the Central Atlantic, so that both the biogenic and the biolythic components should be able to adapt to local variation about the Redfield ratio.In the stratified NW Mediterranean Sea, the stoichiometry between dissolved inorganic, organic and particulate organic matter pools indicated an excess nitrogen relative to phosphorus, particularly in the biolythic layer, as well as a general silicate deficiency relative to both N and P. Most (> 80 %) of the organic carbon was present as dissolved organic carbon, with POC representing a minor percent of total organic C throughout the water column. The increasing C/N ratio of DOM with depth indicates that N is recycled faster than C in the DOM. There exists a dynamic equilibrium between the biological transformations between these pools with depth, with a dominance of DON production in surface waters and remineralization in the underlying layers, from which dissolved inorganic nitrogen is re-supplied to the biogenic layer. Alocthonous N inputs must be important in the region since the downward DON flux exceeded the diffusive DIN supply. The coupling between anabolic and catabolic compartments of a littoral area in the NW Mediterranean Sea are characterized. The pelagic compartment was heterotrophic, supported by significant allochthonous inputs of land material, whereas the benthic compartment was autotrophic, with the excess net benthic community production balancing the deficit in pelagic community production, leading to a system in metabolic equilibrium. Sedimentary inputs of phosphorus and silicon were compensated by sediment release of phosphate and silicate, whereas nitrogen was lost or accumulated in the sediment compartment. Carbon inputs to the benthic compartment also exceeded requirements, due to the allocthonous subsidies to the system, so that the benthic compartment stored or exported organic carbon.Experimental nutrient additions lead to a parabolic change in C/N and C/P ratios in the dissolved organic matter with increasing nutrient inputs. The relative size of the dissolved inorganic nutrient pools did not vary, but there was a tendency towards an increase in the relative size of the particulate pool at the expense of a decrease in the relative importance of DOM as a reservoir of N, P and C, with increasing nutrient inputs.The relative importance of different nitrogen pools was examined in relation to the total nutrient stoichiometry of the oligotrophic system. The ratio of dissolved inorganic nutrients reported in the research presented is indicative of a general deficiency in nitrogen compared to the global ratios reported in literature. The dissolved organic matter was highly depleted in P relative to N and C at all locations investigated and the resulting POC:PON ratio (11.7) of this study in the particulate pool deviates greatly from the literature values which approximates Redfield value (5.5-6). The shift of the dominance of DON towards PON at TOC/TN values higher than 20 on the oligothrophic areas of the study, gives evidence of increasing carbon export fluxes in a system dominated by particulate pool and points to the effect of the biota on the gradient-driven export to sinking carbon fluxes in the ocean.
265

The Use and Knowledge of Olive Oil and Other Lipids in a Collegiate Student Population

Benyazza, Samir 21 May 2010 (has links)
Purpose: Evidence suggests that olive oil consumption is associated with a decreased prevalence of cardiovascular disease and certain cancers. The purpose of this study was to assess the intake and knowledge of olive oil and other lipids in a collegiate population. Methods: Using an IRB-approved protocol, volunteered college students (N=56) from the college of Health and Human Sciences at Georgia State University completed a questionnaire on lipid and knowledge and eating behavior. Results were assessed to determine if students were able to accurately answer questions on the contents of different lipids, and also to determine the consumption behaviors of different lipids. Statistical comparisons were made between undergraduate and graduate students, and between students in different academic majors (nutrition, nursing, respiratory therapy, social work, criminal justice, and other). Results: It was hypothesized that eating behaviors would overemphasize unhealthy lipids. Lipids assessed included: olive oil, butter, canola oil, peanut oil, corn oil, margarine, sunflower oil, and soybean oil. There were no statistically significant differences between the ratios of consumed lipids labeled as ‘good’, and lipids labeled as ‘bad’. There were also no statistically significant differences in the presence of ‘good’ to ‘bad’ lipids in the subjects’ kitchens. Therefore, the results of this study were not able to disprove the null hypothesis. Nevertheless, using a Likert scale response scheme, there was a difference (p=0.041) between academic majors in the consumption of canola oil (an oil high in monounsaturated fatty acid), with Nursing majors reporting the highest consumption (X=3.73; SD=1.61) and Respiratory Therapy majors reporting the lowest consumption (X=1.89; SD=1.53). There was no statistically significant difference between graduate and undergraduate students in the presence of lipids in the kitchen. It was hypothesized that subject knowledge of lipid constituents would be poor. The majority of subjects either failed to respond correctly to the constituents of different lipids or reported that they did not know. Based on this result, the study is able to reject the lipid knowledge null hypothesis. There were clear differences in subgroup knowledge of commonly consumed lipids. Most notably, 100% of nutrition students responded correctly to the constituents of olive oil. Conclusions: This study focused on a group of college students in the College of Health and Human Sciences. One might assume that such a population would be sensitive and knowledgeable about key dietary factors that may influence disease risk. Nevertheless, these findings indicate that, except for isolated exceptions, the eating behaviors and lipid knowledge of these students in not at a level that could be considered health promoting. This suggests that, even with students in the health sciences, personal health classes are likely to be beneficial in reducing disease prevalence.
266

An Analysis of the Surface Area of the Western Roman Empire until CE 476

Roncone, Laura Antonia January 2012 (has links)
In 1968, Rein Taagepera created growth curves of four empires by measuring the surface area of each and plotting his data on a graph of area versus time. He used his growth curves to analyse the development of empires quantitatively, as he considered surface area to be the best measurable indicator of an empire’s strength. His growth curve of the Roman Empire, in particular, has been referenced numerous times by scholars researching the decline and fall of complex civilizations to support their individual analyses of the collapse of Rome. While this thesis surveys only the territories of the Western Roman Empire, many of the parameters used by Taagepera have been either borrowed or adapted in order to define, measure, and graph the surface area of the Western Empire as precisely as possible. This thesis also adds further precision and validity to Bryan Ward-Perkins’ theory that surface area can be used to analyse and quantify the collapse of a complex society accurately. In order to demonstrate the extent to which differing circumstances and outcomes of provincial history impacted the total surface area of the Western Roman Empire, it was essential to include not only an overview of Rome’s extensive history, but also to establish the chronology, as it related to the Roman Empire, of each individual province, territory, and client kingdom within the Western Empire. Detailed chronologies of Noricum and Britannia have been included to serve as case studies as they comprise a broad range of distinct characteristics and so represent typical western provinces. My research of the history and geography of the Roman Empire has generated a comprehensive inventory that includes all the pertinent onomastic and chronological data needed to measure the surface area of each of Rome’s western provinces and client kingdoms. When plotted on a graph of area versus time, my data not only produced an accurate representation of the actual surface area of the Western Roman Empire, but also one that facilitates temporal analyses of territorial fluctuations at any given point in the Empire’s history until the fall of the Western Empire in CE 476.
267

Adapting And Testing A Community Classification System For Mediterranean Turkey Using Satellite Imagery

Zeydanli, Ugur 01 February 2007 (has links) (PDF)
Throughout the past century, vegetation scientists have been studying plant communities to develop classification standards for global mapping purposes. In Turkey, although there are several vegetation classification schemes in use by botanists, foresters or geographers, none is widely accepted by all for vegetation mapping. In this study, a hierarchical, ecologically meaningful, physiognomic-floristic classification system was adapted and developed for terrestrial vegetation in Turkey. The system has eight hierarchical levels, with the alliance and the association as its lowest two floristic levels, and the classes are designed to be easily detected in the field or indirectly through remote sensing. To test of its utility, a supervised vegetation classification of the whole Mediterranean Region of Turkey was carried out using Landsat ETM images. The accuracy of the classification ranged between 55% and 69% depending on the level of hierarchy. A further test for its ecological utility was carried out by comparing identified vegetation classes with breeding bird communities derived from data gathered through field observations at 193 ecological communities at 83 sites. The proposed classification scheme has proven to be reasonably accurate when widely available satellite imagery is used and ecologically meaningful as shown by a high concordance with observed bird community patterns. It is suggested that this new system can be safely applied to other regions of Turkey for purposes of vegetation mapping, species habitat modeling, and nature conservation if proper image set and ancillary data is used.
268

Study On Posidonia Oceanica (l.) Delile, 1813 Seagrass Meadows In The Levant Sea

Celebi, Billur 01 May 2007 (has links) (PDF)
In this thesis, the distribution and state of Posidonia oceanica meadows along the Turkish coast of the north eastern Mediterranean was investigated. The study area was a unique site due to the presence of eastern geographical limit of Posidonia oceanica meadows in Mediterranean Sea. It was aimed to assess the possible reasons of the absence and/or regression in relation to environmental changes. The study was conducted from September 2004 to January 2007 in 5 main regions between Anamur/Mersin and Samandag/Hatay. The regions were determined according to the presence/absence of Posidonia oceanica meadows / 1 region including the boundary meadow at the geographical distribution limit, 1 region western and 3 regions eastern to that boundary meadow. To describe the hydrological characteristics of the study area temperature, salinity and light were measured as abiotic descriptors. Additionally sedimentological analysis was carried out to check the suitability of the substrate type for Posidonia oceanica colonization. The main differences between the regions were found in temperature and light conditions. Both, the recordings of temperature loggers at 10 and 15 meter depths and the sea surface temperature retrieved from satellite (NOAA-AVHRR) showed that the eastern stations with no Posidonia oceanica meadows were warmer than the western stations. Consequently in this study the maximum tolerable temperature limit for Posidonia oceanica growth was determined as 28.4&deg / C from the data collected by the temperature loggers placed to natural meadows near to the boundary meadow. Generally, the whole study area had a limiting light condition for seagrass growth due to low penetration depths of the 10% of surface irradiation. This was a generalized minimum light requirement for growth of seagrasses. Especially in Mersin and Iskenderun bays the minimum required light level did not reached deeper than 10 meter depths in coastal stations. The biological parameters of the Posidonia oceanica meadows were investigated under 3 complementary methods in the first two regions. The structural descriptors were measured in-situ. The lowest shoot density and leaf lengths were found to be in boundary meadow. This meadow had also the lowest depth limit among other stations. The functional descriptors were examined by the lepidochronological and phenological analysis in laboratory. Most of the measurements varied either with respect to depth or among stations according to the abiotic factors of the stations. The lepidochronological cycles obtained from sheath thicknesses were further correlated with abiotic descriptors via a mathematical model. Finally, the first transplantation experiment of Posidonia oceanica along Turkish coasts has been conducted in 2 regions where presently no meadows exist. The survival of cuttings in one station indicated the success of the methodology, while the failure in other stations provided information on the possible reasons of absence/degradation of natural meadows in the area. These included the destructive impact of bottom trawling, the high pressure of grazing (the potential causes of Lessepsian migration) and the long term changes in climate resulting in alterations of environmental conditions such as increasing temperature and reduced light penetration.
269

Bio-optical Properties Of The Turkish Seas

Orek, Hasan 01 March 2007 (has links) (PDF)
Optical properties of the seas surrounding Turkey (i.e. Mediterranean Sea, Black Sea and Aegean Sea) are investigated utilizing the data collected from years 2001-2005. Pigment, light (irradiance), absorption samples were collected and analyzed. SeaWiFS and MODIS satellite observations between years 1997-2006 has been collected, processed and analyzed. High temporal and spatial variability is observed in the optical properties of the three basins. The Mediterranean Sea and the Black Seas are the two typical examples of the Case I and the Case II waters, respectively. SeaWiFS and MODIS derived chlorophyll data obtained during the time period where the data were coexistent (2002-2004) gave consistent results. Thus, data from both sensors are used to establish temporal continuity. Optical classification of the water types based on the Jerlov model shows that the Mediterranean has clear (Type 1) and very clear water type characteristics and the Black Sea and the Marmara waters are turbid (Type 5). Absorption from yellow substance (or so-called CDOM) does not optically dominate the Mediterranean allowing accurate estimation of pigment concentrations by remote sensing methods. This study is further extended to analyze the main contributing phytoplankton groups to the bio-optical characteristics in the three basins. HPLC measurements show that the diatoms are the main group in the Black Sea ecosystem. Whereas in Mediterranean Cyanophyta dominates. Phytoplankton group compositions in the offshore and coastal regions of the Mediterranean do not show considerable difference. The main differences are the higher Prymnesiophyceae (nearly two times higher then the offshore) and lower Cyanophyta contribution in the coastal regions compared to offshore regions.
270

Annual Variations In Biochemical Composition Of Seston And Zooplankton Community In Mersin Bay-northeastern Mediterranean

Zenginer Yilmaz, Arife 01 November 2007 (has links) (PDF)
In this study, annual variations in biochemical composition of seston and zooplankton community were investigated to characterize the nutritional environment of zooplankton in the Mersin Bay, NE Mediterranean Sea. For this goal, seawater and zooplankton samples were collected at monthly intervals from two stations / one representing coastal and other representing open waters characteristics from November 2004 to January 2006. Seawater samples were collected with Niskin bottles from the sea surface. Zooplankton samples were collected both in the horizontal and vertical plane by towing a Nansen net (70 cm mouth diameter with 112 &micro / m mesh). Surface seston chl-a, lipid, protein and carbohydrate concentrations were measured by fractionating seawater into three different size groups, 0.7-2.7, 2.7-18 and &gt / 18 &micro / m representing pico, nano and micro particulates in the seston. Zooplankton biomass and abundance were determined at four size fractions: 112-200, 200-500, 500-1000 and &gt / 1000 &micro / m / dry and organic weights were measured by gravimetric method and major taxonomic groups of zooplankton was identified under stereo-microscope. The nearshore station was always more productive than the offshore station in terms of chl-a, particulate organic matter (POM: protein+lipid+carbohydrate), zooplankton abundance and biomass. Chl-a maxima occured in spring and autumn at both stations. Very low chl-a concentrations at the offshore station (0.02-0.35 &micro / g L-1) confirmed oligotrophic character of the Northeastern Mediterranean. The highest chl-a concentration (2.4 &micro / g L-1) was observed in March 2005 at the nearshore station due to the input of Lamas River nearby. POM varied from 42.1 &micro / g L-1 (in January 2006) to 1082 &micro / g L-1 (in March 2005) and 53.7 &micro / g L-1 (in January 2006) to 246 &micro / g L-1 (in May 2005) at the nearshore and offshore stations, respectively. The oligotrophy of this system was indicated by the extremely low particulate lipid, protein and carbohydrate concentrations (1-3 times lower than in more productive systems). The most evident characteristic of this oligotrophic environment was the dominance of pico-POM throughout the study period, accounting for 31&ndash / 65 % of the total carbohydrates, proteins, lipids and chl-a. The prt:cho ratio was generally lower than 1 (low in organic nitrogen). Carbohydrate was the dominant biochemical component at both stations. Zooplankton varied during the sampling period, and they showed two peak abundances, in spring and autumn, with small increase in summer. The higher biomasses of zooplankton were observed in summer and autumn in the entire water column, but in spring and autumn periods in the surface water. Zooplankton data showed that 200-500 and 112-200 &micro / m size fractions were dominant in abundance at both stations. However, 200-500 &micro / m size fraction was dominant in zooplankton biomass at nearshore, whereas &gt / 1000 &micro / m size fraction was at offshore station. Copepods were the most abundant zooplankton group and dominated the distribution of total zooplankton, followed by crustace nauplii, appendicularia, cladocera and pteropoda.

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