Search Results (4)

Mediterranean biogeography is characterized as a global “hotspot” for climate change; understanding the impacts of these changes on local agricultural systems through high-resolution analyses has thus become a critical need. This study addresses this gap by evaluating the holistic effects of climate change on site-specific agriculture systems, focusing on the Eğirdir–Karacaören (EKB) and Beyşehir (BB) lake basins in the Lakes Region of Türkiye. This study employed machine learning modeling techniques to forecast changes in the yields of key crops, such as wheat, maize, apple, alfalfa, and sugar beet. Detailed spatial analyses of changes in agro-climatic conditions (heat stress, chilling requirement, frost days, and growing degree days for key crops) between the reference period (1995–2014) and two decadal periods projected for 2040–2049 and 2070–2079 were conducted under the Shared Socioeconomic Pathways (SSP3-7.0). Daily temperature, precipitation, relative humidity, and solar radiation data, derived from high-resolution climate simulations, were aggregated into annual summaries. These datasets were then spatially matched with district-level yield statistics obtained from the official data providers to construct crop-specific data matrices. For each crop, Random Forest (RF) regression models were fitted, and a Leave-One-Site-Out (LOSOCV) cross-validation method was used to evaluate model performance during the reference period. Yield prediction models were evaluated using the mean absolute error (MAE). The models achieved low MAE values for wheat (33.95 kg da⁻¹ in EKB and 75.04 kg da⁻¹ in BB), whereas the MAE values for maize and alfalfa were considerably higher, ranging from 658 to 986 kg da⁻¹. Projections for future periods indicate declines in relative yield across both basins. For 2070–2079, wheat and maize yields are projected to decrease by 10–20%, accompanied by wide uncertainty intervals. Both basins are expected to experience a substantial increase in heat stress days (>35 °C), a reduction in frost days, and an overall acceleration of plant phenology. Results provided insights to inform region-specific, evidence-based adaptation options, such as selecting heat-tolerant varieties, optimizing planting calendars, and integrating precision agriculture practices to improve resource efficiency under changing climatic conditions. Overall, this study establishes a scientific basis for enhancing the resilience of agricultural systems to climate change in two lake basins within the Mediterranean biogeography. Full article

As lakes contribute significant amounts of methane (CH₄) to the atmosphere, they account for a significant share of the global greenhouse gases (GHGs) budget. Since lakes are ecosystems where physical and biological processes influencing CH₄ formation are concentrated, the study focuses on atmospheric CH₄ column concentrations over lake areas. This study aims to analyze the temporal variation in atmospheric CH₄ column concentrations (XCH₄) over Lake Eğirdir and Lake Burdur in Türkiye in 2023 and 2025 as well as the relationship between XCH₄ and environmental parameters such as Water Surface Temperature (WST), Normalized Difference Chlorophyll Index (NDCI), and Floating Algae Index (FAI). The temporal variability of XCH₄ observed over both lakes showed statistically significant positive correlations with lake-area-averaged WST, NDCI, and FAI (Pearson r = 0.49–0.65, p < 0.01). This outcome indicates consistent temporal patterns between XCH₄ and environmental conditions at the lake scale. Furthermore, time-series graphs show that monthly average XCH₄ values in both lakes reached their highest levels during the summer and autumn months. During these periods, XCH₄ concentrations exceeded 1860 ppb in Lake Eğirdir and 1900 ppb in Lake Burdur. The areas of land use/land cover (LULC) classes surrounding the lakes were evaluated together with XCH₄, and relatively higher XCH₄ values were observed over agricultural areas, which constitute the dominant class in the basins of both lakes. The distribution of XCH₄ throughout the lake depth showed higher values in the shallow and mid-depth zones and lower values in the deeper areas beyond 20 m, indicating that the distribution of XCH₄ varies throughout lake depth. The results obtained underline the importance of remote sensing data in monitoring XCH₄ in lake ecosystems. Full article

Perfluoroalkyl and poly-fluoroalkyl substances (PFAS) are among the synthetic chemicals employed by various industries since the 1950s and the most critical persistent organic pollutants (POPs) that led to emerging concerns due to high persistency, toxicity, mobility, and environmental bioaccumulation. Although there are more than 5000 types of PFASs, perfluorooctanoic acid (PFOA) and perfluorosulfonic acid (PFOS) are the two chemicals whose employment is highly restricted and banned by the Stockholm Convention. In the present study, certain water resources in the Marmara Region, the most densely populated and industrial region in Turkey, and the waters of Turkey’s two largest drinking water reserves, Beyşehir and Eğirdir lakes, were investigated. The study was carried out in two seasons, spring and autumn. The lowest and highest PFOA concentrations were determined between 1.77 ± 0.1 and 6.71 ± 2.9 ng/L in all surface waters, and the highest PFOS concentrations were between <LOQ and 3.27 ng/L. PFOA concentrations were higher when compared to PFOS concentrations in all water sources, and PFOA and PFOS concentrations were lower in spring compared to autumn. In some commercially procured fish from water resources, 7.48 ng/g PFOS was detected in Küçükçekmece Lake pike, and 2.5 ng/g PFOA was identified in Eğirdir Lake trout. PFOA and PFOS were not detected in other fish tissues. Full article

Lakes are the most important freshwater resources for humans. It is stated that together with population growth, unplanned urbanization, excessive water consumption, industrialization, and unconscious irrigation, global climate change causes changes in the water levels and volumes of lakes. Lake Eğirdir in Turkey, which is important in terms of drinking and irrigation water use, was chosen as the study area. Lake Eğirdir water level (LWL) and water volume (LWV) values measured between 1988–2019 were used. Dependencies in the annual LWL and LWV were examined by autocorrelation analysis, and trend changes were examined by regression analysis, the Mann-Kendall rank correlation test, and the Şen innovation trend test. The research has shown a significant decrease since 2000 in LWL and since 1990 in LWV. The LWL has decreased by −1.272 to −3.514 m and the LWV has decreased by −72.980 to −1082.134 hm³ in approximately 32 years. The actions to be taken based on the values determined in this study will help protect the water resources of lakes. As a result of the tests used in our study, it was determined that there were decreases in both the water level and the volume of the lake. The climatic changes in the lake basin and the decrease in the water resources feeding the lake are shown as the biggest factor in these reductions. Full article