Yazar "Tan, Ibrahim" seçeneğine göre listele

Listeleniyor 1 - 3 / 3
  • [ X ]
    Öğe
    Comparative assessment of eutrophication in the southern Black Sea using TRIX, BEAST, and NEAT
    (Elsevier, 2025) Tan, Ibrahim; Atabay, Hakan; Aslan, Ertugrul; Mantikci, Mustafa; Taskin, Ergun; Kurt, Guley; Beken, Colpan Polat
    This study is among the few that seek to provide an integrated assessment of eutrophication in the coastal region of the Southern Black Sea. Three methods were compared to evaluate eutrophication in the southern Black Sea coastal waters: the Black Sea Eutrophication Assessment Tool (BEAST), the Nested Environmental Status Assessment Tool (NEAT), and the Trophic Index (TRIX). TRIX was not able to effectively differentiate between different levels of eutrophication in the southern Black Sea. Regardless of the assessment method used BEAST and NEAT, all the results indicated that the water quality in the southern Black Sea is either moderate or below. The BEAST and NEAT methodologies demonstrated a stronger correlation with eutrophication-related parameters compared to the TRIX approach. The BEAST assessment typically presented a worst-case scenario compared to NEAT. River-influenced coastal water bodies (CWBs), such as Sakarya (KAR02), Yes,il & imath;rmak (KAR07), and K & imath;z & imath;l & imath;rmak (KAR10) had poor or bad status. Samsun province (KAR08), which has been pressure from both domestic and industrial activities, has been determined to be in a bad status. The study also highlights the critical need for site-specific indicators, reference values, and long-term data for effective assessment tools. The results provide evidence to support managers and decision-makers in monitoring and achieving good environmental status.
  • Küçük Resim
    Öğe
    First bloom report of Polykrikos hartmanni (Dinophyceae) in the coastal waters of İzmir Bay, Aegean Sea (Eastern Mediterranean)
    (Univ Autonoma Metropolitana-Iztapalapa, 2025) Sabanci, Fatma Colak; Sahin, Fatih; Garate-Lizarraga, Ismael; Erba, Edanur; Tan, Ibrahim
    Background. Harmful algal blooms have increased in frequency, intensity and distribution in the last decades around the world. This increase has also been observed for the waters of the Mediterranean Sea. In November 2023, several reddish patches were observed in & Idot;zmir Bay (Aegean Sea); the dinoflagellate Polykrikos hartmannii was the causative agent. Goal. The purpose of this study was to report for the first time a bloom of this species in & Idot;zmir Bay. Methods. During the bloom, surface samples of seawater were collected using 1 liter plastic bottles at eleven sampling stations and fixed with Lugol for cell counting, which were performed under an OLYMPUS BX-50 microscope, using 1 ml Sedgewick-Rafter chambers. Samples were collected for live analysis and correct identification of the responsible species. Results. The moderate bloom occurred in November 2023 was caused by Polykrikos hartmannii. During the bloom two-celled chains were the predominant species, with single cells occurring less frequently. The highest cell abundance (4.8 x 104 cells L-1) was observed at station 29 in the inner bay. Cell sizes were 29.7 - 34.6 pm long, and 39.6 - 44.5 pm wide. Conclusions. Living samples allowed correct identification of P. hartmannii. Cells tend to become round or disrupted when preserved with Lugol's solution. This may be why this species has not been previously reported. The maximum abundance of P. hartmannii was recorded in & Idot;zmir Bay at a water temperature of 14.84 degrees C and a salinity of 38.02 %o, coinciding with highest values of nutrients. The bloom occurred in the shallowest area with limited water circulation and significant riverine inflow.
  • [ X ]
    Öğe
    Integrated assessment of eutrophication in the southern Black Sea waters, using the Nested Environmental Status Assessment Tool
    (Pergamon-Elsevier Science Ltd, 2023) Tan, Ibrahim; Atabay, Hakan; Evcen, Alper; Kurt, Guley; Taskin, Ergun; Beken, Colpan Polat
    This research deals with the land-based pressures on the southern Black Sea coast (Turkey), with the objective of assessing their eutrophication impacts. In this context, reference values of some of the eutrophication indicators were calculated, and eutrophication assessment was carried out for this area using the holistic approach NEAT (Nested Environmental Status Assessment Tool). In addition, correlations between NEAT results of coastal regions and pressure-impact analysis methods were investigated. In the determined Spatial Assessment Unit (SAU) areas, 9 indicators were evaluated according to the SAU surface, both with and without weighting by their size the overall assessment of the Turkish Black Sea coast is good (0.70) and moderate (0.57) environmental status, for non-weighting and weighting by SAUs, respectively, with a high confidence level. With this study, we concluded that the sensitivity of the assessment tool needs to be increased. Despite these results, an appropriate number of indicators to represent the water column should be added. It is important to include the phytoplankton variable in the evaluation in future studies. In addition, this study, which uses NEAT allows identifying problematic environmental areas that require attention and action from managers and policymakers.