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Nowadays, studying the macrophytes distribution climatic change reducing effect through land surface temperature is vital. 17 locations with 102 stands were randomly chosen to illustrate the vegetation physiognomy in Wadi Al-Sharaea, Makkah Province, Saudi Arabia. A total of 110 species from 77 genera and 33 families were detected during the field study, with the Poaceae family predominant. Therophytes were the dominant life form (38.2% of the total species), followed by chamaephytes (30.0%), and bioregional elements were the dominant chorotype. Remote sensing data were acquired to evaluate land surface temperature (LST), normalized difference built-up index (NDBI), and normalized difference vegetation index (NDVI) from 2002 and 2018. The study assesses the relationship between organic matter, plant diversity species, vegetation cover, and LST. Principal component analysis (PCA) was applied, and the obtained data showed that PCA1 and PCA2 represent about 25.29% and 16.34%, respectively. Cluster analysis was used to identify the commonality of the groups among the data from points clustered into four significant clusters. On the other hand, LST correlated with the distribution of some families, such as Caryophyllaceae, Boraginaceae, Euphorbiaceae, and Molluginaceae. The families that correlated to LST show the tolerance of these families to high temperatures. Results showed that Limeaceae, Poaceae, and Zygophyllaceae families grow in soil with high organic matter. These findings indicated fundamental advances in understanding the temperature response of organic matter and plant diversity. [ABSTRACT FROM AUTHOR]

In this study, the removal of methyl tertiary-butyl ether (MTBE) from contaminated groundwater using advanced oxidation technology was investigated. The UV/H2O2 treatment process was applied to remove MTBE from two Saudi groundwater sources that have different quality characteristics with regard to their contents of inorganic species such as chloride, bromide, sulfates and alkalinity. MTBE was spiked into water samples collected from the two sources to a concentration level of about 250μg/L. A 500mL bench-scale forced-liquid circulation photoreactor was used to conduct the experiments. Two different UV lamps were utilized: 15 Watt low pressure (LP) and 150 Watt medium pressure (MP). Results of the study showed that the UV/H2O2 process removed more than 90% of MTBE in 20 minutes when the MP lamp was used at an MTBE/H2O2 molar ratio of 1:200. The results also showed that groundwater sources with higher levels of radical scavengers such as alkalinity, bromide, nitrate and sulfate showed lower rate of MTBE removal. [ABSTRACT FROM AUTHOR]