Baseline distribution of petroleum hydrocarbon contamination in the marine environment around the coastline of Qatar

Levels of organic contaminants (TPHs, PAHs) were simultaneously determined in both abiotic (sediments, seawater) and biotic (Pinctada radiata oysters) samples at four sites along the coastline of Qatar (Arabian Gulf) in 2017-2018. TPHs and PAHs were more frequently detected in oyster tissues than sediment and seawater samples collected from the same areas. While levels of TPHs and PAHs in seawater and sediments were lower than previous local studies and worldwide studies, PAHs levels observed in pearl oyster tissue (25.9- 2240 μg/kg) were relatively higher than in previous studies in Qatar. In general, eight PAHs compounds were detected in oyster tissue, with benzo(a)pyrene displaying the highest concentration. The coast of Qatar could be affected by seasonal patterns of pollutants, where TPHs and PAHs levels increased in winter compared to summer. These results provide key information on the use of the pearl oyster as a bioindicator species and Qatar’s marine environment

Micromorphological and Anatomical Characteristics of the Genus Chrysophthalmum Schultz Bip. (Asteraceae) Growing in Turkey

The genus Chrysophthalmum (Asteraceae) is represented by five species in the world. Three species of this genus are naturally grown in Turkey. The species growing in Turkey are C. montanum (DC.) Boiss., C. dichotomum Boiss. and Heldr. and C. gueneri Aytac and Anderb. Except C. montanum; the other species are endemic for Turkey. In the present study, micromorphological and anatomical characteristics of these species by using light microscopy (LM) and scanning electronmicroscopy (SEM) have been comparatively presented for the first time. Themicromorphological studies are related to trichomes and cypsela. In anatomical studies, crosssections of the stem, and leaf have been examined. In addition, to show stomatal distribution and anatomy on adaxial and abaxial leaves, surface sections of the leaves have been taken and stomatal index calculated. The features of stems, leaves, trichomes and cypsela have been found to be significant to distinguish the species. Mesophyll structure, number of vascular bundles in midrib, presence or absence of sclerenchymatous fibers in leaf, trichome types, presence or absence of pappus in cypsela, presence or absence of hair on cypsela surface are important diagnostic characters. A diagnostic key based on combined leaf, trichome and cypsela characteristics of the Chrysophthalmum species has been given