Tracking the hydro-climatic signal from lake to sediment: a field study from central Turkey

Palaeo-hydrological interpretations of lake sediment proxies can benefit from a robust understanding of the modern lake environment. In this study, we use Nar Gölü, a non-outlet, monomictic maar lake in central Turkey, as a field site for a natural experiment using observations and measurements over a 17-year monitoring period (1997–2014). We compare lake water and sediment trap data to isotopic, chemical and biotic proxies preserved in its varved sediments. Nar Gölü underwent a 3 m lake-level fall between 2000 and 2010. δ18Olakewater is correlated with this lake-level fall, responding to the change in water balance. Endogenic carbonate is shown to precipitate in isotopic equilibrium with lake water and there is a strong relationship between δ18Olakewater and δ18Ocarbonate, which suggests the water balance signal is accurately recorded in the sediment isotope record. Over the same period, sedimentary diatom assemblages also responded, and conductivity inferred from diatoms showed a rise. Shifts in carbonate mineralogy and elemental chemistry in the sediment record through this decade were also recorded. Intra-annual changes in δ18Olakewater and lake water chemistry are used to demonstrate the seasonal variability of the system and the influence this may have on the interpretation of δ18Ocarbonate. We use these relationships to help interpret the sedimentary record of changing lake hydrology over the last 1725 years. Nar Gölü has provided an opportunity to test critically the chain of connection from present to past, and its sedimentary record offers an archive of decadal- to centennial-scale hydro-climatic chang

Eastern Mediterranean hydroclimate over the late glacial and Holocene, reconstructed from the sediments of Nar lake, central Turkey, using stable isotopes and carbonate mineralogy

There is a lack of high-resolution records of hydroclimate variability in the Eastern Mediterranean from the late glacial and early Holocene. More knowledge of the speed of climate shifts and the degree to which they were synchronous with changes in the North Atlantic or elsewhere is required to understand better the controls on Eastern Mediterranean climate. Using endogenic carbonate from a sediment sequence from Nar Gölü, a maar lake in central Turkey, dated by varve counting and uranium-thorium methods, we present high-resolution (∼25 years) oxygen (δ18O) and carbon isotope records, supported by carbonate mineralogy data, spanning the late glacial and Holocene. δ18Ocarbonate at Nar Gölü has been shown previously to be a strong proxy for regional water balance. After a dry period (i.e. evaporation far exceeding precipitation) in the Younger Dryas, the data show a transition into the relatively wetter early Holocene. In the early Holocene there are two drier periods that appear to peak at ∼9.3 ka and ∼8.2 ka, coincident with cooling ‘events’ seen in North Atlantic records. After this, and as seen in other records from the Eastern Mediterranean, there is a millennial-scale drying trend through the Mid Holocene Transition. The relatively dry late Holocene is punctuated by centennial-scale drought intervals, at the times of 4.2 ka ‘event’ and Late Bronze Age societal ‘collapse’. Overall, we show that central Turkey is drier when the North Atlantic is cooler, throughout this record and at multiple timescales, thought to be due to a weakening of the westerly storm track resulting from reduced cyclogenesis in the North Atlantic. However, some features, such as the Mid Holocene Transition and the fact the early Holocene dry episodes at Nar Gölü are of a longer duration than the more discrete ‘events’ seen in North Atlantic records, imply there are additional controls on Eastern Mediterranean hydroclimate

Optimization of hollow fiber liquid-phase microextraction combined with GC-ECD for determination of organochlorine pesticides in orange juice

The hollow fiber protected liquid phase microextraction (HF-LPME) technique was evaluated for the extraction of organochlorine pesticides in orange juice prior to gas chromatography-electron capture detection (GC-ECD) analysis. At first, the effects of the HF-LPME experimental parameters on the enrichment factor were studied simultaneously using a 25-1 fractional factorial design. The HF-LPME variables of interest were extraction time, stirring speed, acceptor phase, salt (NaCl, w/v %) and pH. In the next step, a two-level plus centre point fractional factorial experiment was performed to evaluate the effects of three parameters, including the extraction time, stirring speed and pH of donor phase. The optimized HF-LPME conditions were as follows: an extraction time of 20 min, a stirring speed of 800 rpm, an acceptor phase of toluene, no salt and a source pH of 6. The extraction calibration plots were linear over the range of 0.25-10 ng mL-1 (r2: 0.9863-0.9995) and the limits of detection for ten pesticides studied were from 0.012 to 0.456 ng mL-1. Good enrichment factors were achieved (66-251-fold) with this method and good repeatabilities were obtained, with relative standard deviations below 19.9 %. © 2014, Chemical Publishing Co. All rights reserved

Studies on the adaptation of Azolla mexicana in the Aegean and the Mediterranean regions

WOS: 000220315300008Azolla (Azolla anabaena) is an aquatic fern plant that can be used as a green manure and organic matter resource in many countries where irrigation water is not a problem. A. mexicana is one of the azolla species adapted to the environmental conditions of Izmir (Turkey). The objective of this research was to determine the adaptation and agronomic potential of azolla plants to the Mediterranean climate regions. The research was conducted at three locations (Izmir and Aydin located in the Aegean region and Antalya located in the Mediterranean region of Turkey) in 1999, 2000 and 2001. Fresh azolla was planted in April, May, June and October at the rate of 300 g m(-2) at each application. The growing azolla plants were harvested 15 days after planting. The highest fresh yield (1481 g m(-2)) Was obtained in April at Izmir. The total N, P, and K values were between 2.93-3.31 %, 0.43-0.54 % and 1. 10-1.37 % at Izmir, Aydin, and Antalya, respectively. The shortest time to reach a two-fold increase was 3.53 days at Izmir based on the average of three years

Physiological and biochemical responses of Achillea millefolium group-related cultivar proa to different nitrogen regimes

In the present study the effect of different nitrogen amounts (0 g [N0 ], 0.45 g [N 1], 0.9 g [N 2] and 1.35 g N [N 3] per pot, corresponding to 0 kg·ha-1, 50 kg·ha-1, 100 kg·ha-1 and 150 kg·ha-1 N application in field conditions) and application times (at sowing, vegetative stage and pre-bloom stage) on the yield, relative water content, total nitrogen content and nitrogen use efficiency in plants of the Achillea millefolium group-related cv. Proa was investigated. Antioxidant activity, flavonoid content, rate and composition of the essential oils were also determined. Application of N2 increased the dry herbage and flos production, total nitrogen amount and nitrogen use efficiency, without affecting the essential oil rate while reducing the antioxidant activity. Higher amounts (N 3) of nitrogen maintained the dry herbage and flos yield at levels similar to N 2 but decreased the antioxidant activity and rate of the essential oil. The major component of the essential oil, chamazulene, was negatively (N 1,N2) or not influenced (N3) by the nitrogen application, while variable changes were registered in the content of the other components. The data point to the nitrogen regime being a subtle tool for regulating the performance of cv. Proa plants.Bulgarian Academy of Sciences: 108O290The authors thank the Research Fund of TUBITAK (The Scientific and Technological Research Council of Turkey) and BAS (Bulgarian Academy of Sciences) for their financial support (Project No. 108O290). -

Some agronomic and quality characteristics of two Achillea asplenifolia Vent. Populations

The genus of Achillea L. consists of herbaceous plants are generally distributed in the northern hemisphere. Achillea asplenifolia and Achillea collina are the most important group of A. millefolium due to their highly effective pharmacological properties. Both species, A. asplenifolia and A. collina are distributed in the Europen flora but they don’t exist in the Turkish flora. The present study aimed to determine some yield and quality characteristics of two populations, Achillea asplenifolia - 9602 and Achillea asplenifolia – 10403, belonging to Achillea asplenifolia Vent. collected from the flora of Bulgaria at Bornova and to select genotypes with high yield and quality. For this purpose a two years of field experiment was conducted in 2009 and 2010. Plant height (cm), green herbage yield (g/plant), drug herbage yield (g/plant), drug flos yield (g/plant) and essential oil content of populations were determined. Based on the results of two years of experiment minimum and maximum drug flos yield were 2 g/plant and 391.4 g/plant in Achillea asplenifolia - 9602. Essential oil rate ranged between 0.050-3.30%. Minimum and maximum drug flos yield of Achillea asplenifolia (10403) were 0 and 159.8 g/plant respectively and essential oil content ranged between 0-2.5%. A large distribution was found in both population of Achillea asplenifolia and especially population Achillea asplenifolia - 9602 was more remarkable and promising for selection studies. © 2016, Society of Field Crops Science. All rights reserved

Effects of different bone marrow stimulation techniques on avascular zone meniscal defects

Balta, Orhan/0000-0002-4398-827X; Eren, Mehmet Burtac/0000-0002-5888-8677WOS: 000451638900004PubMed: 30345770OBJECTIVES: In this study, we sought to investigate the effect of different amounts of Bone Marrow-Derived Mesenchymal Stem Cells (BMSCs), obtained by different BMSCs, on the healing of avascular zone meniscal defects. BACKGROUND: Treating avascular zone meniscal injuries has gained popularity. BMSCs contribute to the healing of avascular zone meniscal defects. The amount of BMSCs derived from different bone marrow stimulation techniques (BMSTs) varies, which could affect the therapeutic efficacy of this treatment. METHODS: Fifty-four skeletally mature female New Zealand White rabbits were used after local ethical committee approval. A full thickness, 1.5 mm diameter defect was produced in the inner two-thirds of the anterior portion of the medial meniscus avascular zone using a biopsy punch. Animals were enrolled into three different groups according to BMST (0.8 mm, 1.5 mm, and 4 mm). Medial menisci were harvested and prepared for histomorphometric, histologic and immune-histologic analyses. RESULTS: Larger bridging tissues across the defect were detected in the 1.5-mm and 4-mm groups at 4 weeks (p 0.05) CONCLUSION: The largest amount of BMSCs did not correlate with best quality and largest quantity of bridging tissue at the avascular zone in meniscal defects.Gaziosmanpasa University Scientific Research Projects Programme [51879863-33]The study was funded by the Gaziosmanpasa University Scientific Research Projects Programme (51879863-33)