43 research outputs found
The Avifauna of Küçük Menderes Delta (Turkey): An evaluation on seasonal pattern of birds
Abstract. We performed monthly point counts for occurrence of bird species in Küçük Menderes Delta between September 2007 and May 2008, for 3 seasons per year. During the observation period 120 bird species that belong to 10 orders and 41 families were recorded. Diversity index and analysis of similarity were applied to time series data. The results were classified using cluster analysis and were ordered using multidimensional scaling for determining seasonal pattern of bird species in delta. As a result, September and May are less similar than other months regarding the species composition. At the same time, there are differences among seasons
A bio-optical model for integration into ecosystem models for the Ligurian Sea
A bio-optical model has been developed for the Ligurian Sea which encompasses both deep, oceanic Case 1 waters and shallow, coastal Case 2 waters. The model builds on earlier Case 1 models for the region and uses field data collected on the BP09 research cruise to establish new relationships for non-biogenic particles and CDOM. The bio-optical model reproduces in situ IOPs accurately and is used to parameterize radiative transfer simulations which demonstrate its utility for modeling underwater light levels and above surface remote sensing reflectance. Prediction of euphotic depth is found to be accurate to within ∼3.2 m (RMSE). Previously published light field models work well for deep oceanic parts of the Ligurian Sea that fit the Case 1 classification. However, they are found to significantly over-estimate euphotic depth in optically complex coastal waters where the influence of non-biogenic materials is strongest. For these coastal waters, the combination of the bio-optical model proposed here and full radiative transfer simulations provides significantly more accurate predictions of euphotic depth
Balık çiftliklerinin denizel ekosisteme etkilerinin uzaktan algılama ile tespiti: Ildırı Körfezi
Çalışma alanı olarak seçilen Ildırı Körfezi akuakültür aktivitelerinin yoğunluğu ile bilinmektedir. Balık çiftliklerinin deniz ekosistemine olası etkilerini uzaktan algılama ve coğrafi bilgi sistemleri kullanımı ile değerlendirmek amacıyla, Şubat 2010 ve Şubat 2011 tarihleri arasında arazi çalışmaları gerçekleştirilmiştir. Etki, askıda katı madde, Secchi derinliği ve yüzey suyu sıcaklığı ile değerlendirilmiştir. ENVISAT üzerinde bulunan sensörlerden biri olan MERIS'ten elde edilen görüntüler askıda katı madde ve Secchi derinliği dağılımının belirlenmesinde kullanılmıştır. Bu çalışmada oluşturulan ampirik algoritma atmosferik düzeltme adımı sonrasında oluşturulmuştur. Analizler yapay sinir ağı ile uydu görüntülerinden üretilen veriler üzerine yoğunlaşmıştır. Coğrafi bilgi sistemleri sonuçları düzenlemek ve sunmak için kullanılmıştır. Elde edilen sonuçlar, bu çalışma sınırları içerisinde akuakültür aktivitelerinin çevresine açık bir etkisi yoktur. Mekansal çözünürlüğünün orta seviyede olması MERIS sensörüne ait görüntülerin Ildırı Körfezi'nde gerçekleştirilen akuakültür aktiviteleri için hasas olmadığı görülmüştür. Göreceli düşük çözünürlüğün yerel etkileri değerlendirmek konusunda yeterli olmamasına rağmen, bu çalışmanın ileride yapılacak çalışmalar için bir yol gösterici olacağını ya da arazi çalışmaları için bir tamamlayıcı olacağı düşünülmektedir. The Bay of Ildırı is one of the areas where the most intensive aquaculture activities have taken place along the Aegean coast of Turkey. In order to evaluate the possible impacts of aquaculture to the marine ecosystem by using remote sensing and geographic information systems, fieldworks performed in the bay between February 2010 and 2011. The impact is evaluated in terms of total suspended matter, Secchi depth and sea surface temperature. Images from MERIS sensor of the ENVISAT were used to determine distribution of Secchi depth and total suspended matter. Empirical algorithm performed after atmospheric corrections applying the analysis concentrated on the derivation of data from satellite imagery by artificial neural network technique. Geographical information system was used for data arrangement analysis and presentation purposes. Results show that as limitation of this study, there is no apparently impact of aquaculture activities to their environment in Ildırı Bay. Images of MERIS are not very sensitive because of its medium spatial resolution. Although it relatively lower resolution seems a problem to evaluate local impacts, the study will provide probably important input for further studies or will support as a complementary in field studies to increase understanding
Bio-optical trends of seas around Turkey: An assessment of the spatial and temporal variability
Summary: Until present, bio-optical characteristics and their variations in the eastern Mediterranean and Black Sea have rarely been studied. In order to characterize the basic features of bio-optical variables found in the seas surrounding Turkey, remotely sensed data sets covering the period between September 1997 and March 2017 were studied for the purpose of this research. Chlorophyll-a concentration (CHL), absorption coefficient by colored dissolved organic matter (CDOM) and particulate backscattering coefficient (BBP) were both evaluated to describe their recent linear and non-linear inter-annual patterns in the sub regions of the northern Levantine Sea (LS), the eastern Aegean Sea (AS), the Marmara Sea (MS) and the southern Black Sea (BS). The results determined a highly significant and decreasing trend of CHL in the Black Sea, whilst most other regions from the seas around Turkey displayed non-significant trends. The analysis indicated that the seas around Turkey can be clustered into two regions based on their bio-optical properties; one being the Black Sea and Marmara Sea, and the second cluster being the Aegean Sea and Levantine Sea. Keywords: Trend analysis, Chlorophyll-a, Colored dissolved organic matter, Particulate backscattering, Ecosystem dynamic
Feeding ecology and reproduction biology of Glaucostegus cemiculus (Geoffroy Saint-Hilaire, 1817) from the eastern Aegean Sea
Bengil, Fethi/0000-0003-0989-2829WOS: 000512766500030Though guitarfish are common bycatch and have an economical value in the Mediterranean Sea, there is still limited knowledge on blackchin guitarfishs, Glaucostegus cemiculus, their presence or any biological feature, with specific regard to those that inhabit the eastern Mediterranean coasts of Turkey. To explore this information gap, bio-ecological features, which are investigated in terms of stomach contents and reproduction, were examined from individuals obtained from Izmir Bay. A total of 122 individuals caught as by-catch were collected monthly between: July 2015-June 2016. Crustaceans were found to be the main prey item in their diets. Maturity stages were mainly immature, with the exception of two individuals: an immature 2-developing female and mature 3b-active male. Knowledge retrieved from present studies on bio-ecological features contributes to closing the current information gap on endangered blackchin guitarfish in the eastern Aegean Sea. Such studies also provide a platform for essential discussion on the various ways in which effective r monitoring strategies for the species could be implemented and managed; particularly in the Turkish coast of the eastern Mediterranean. (C) 2019 Elsevier B.V. All rights reserved.Rufford Foundation [17514-1, 20115-2, 23747-B]This study was funded as part of three the Rufford Foundation projects, numbered 17514-1, 20115-2 and 23747-B. the authors would also like to thank Ayla YILDIRIM for English proofing
Assessing the impact of aquaculture farms using remote sensing: an empirical neural network algorithm for Ildiri Bay, Turkey
The potential impact of aquaculture on Ildiri Bay, Turkey, was assessed using remote sensing data collected over 37 d between September 2009 and February 2011. The dataset was improved by applying a local empirical neural network (NN) algorithm. Impact was evaluated in terms of total suspended matter (TSM) and Secchi disk depth (SDD) as effective variables showing changes in underwater light fields in each defined subarea. Subareas were farm sites with their peripheries (impact zones) and the whole study area for 2 different regions within the bay. Real-time datasets of TSM and SDD were obtained for 7 different days within the same period. To create an NN algorithm, the full swath of geo-located products (with 300 m resolution) from the MERIS sensor aboard ENVISAT was used along with in situ data. The NN algorithm showed good performance, with an accuracy of 97.46% for TSM and 99.58% for SDD. No significant (F-s > 0.05) impact on the environment was observed; however, the time series analyses of similarities and anomalies showed that the impact zones have different temporal characteristics compared to the whole bay and vice versa. The highest particle concentrations and lowest light penetration occurred in the spring and summer. Water circulation patterns were identified as the major force determining the distribution and hence the source of particles and were also applied to reflect the particle loads introduced by feeding activity performed in aquaculture facilities. The influence of dissolved organic carbon to TSM and SDD indicates that the contribution of colored dissolved organic matter is another important variable for effective monitoring of aquaculture activity in the bay