Microbial Ecology of Qatar, the Arabian Gulf: Possible Roles of Microorganisms

Abstract

The Arabian Gulf ranks among the world’s most arid and warm regions; the land has high salinity levels with many Sabkhas and receives little precipitation. This region holds about one-third of the world’s oil supply. Qatar is the leading gas producer worldwide, which raises many concerns about the pollution of the sea, groundwater, and soil. Thus, the Arabian Gulf area has paid particular attention to environmental studies since the environmental status of this region imposed unique biological diversity, and microbial ecology has gained special importance following the identification of promising roles of microorganisms. This review article discusses the microbial ecology at the main habitats of the State of Qatar. We discuss important principles for successful ecological restoration and future perspectives of using biological approaches to solve many problems related to health, the economy, and agriculture. There are at least five microbial communities that have been recognized at the Qatari habitats: marine environment, salt marshes and mangrove forests, the arid lands (including dune communities), wetlands (including pond communities), and Rawdahs (including the Ghaf tree communities). Although, the environmental conditions of this region are almost the same, these habitats are compared with those at other countries of the Arabian Gulf whenever necessary, as each habitat has its own peculiar characteristics. Some case studies are presented to describe the biochemical characterizations of bacterial isolates from soils and leaf surface of native plants, including halophytes and xerophytes at these habitats. These studies rarely went beyond the general identification at species levels. There is a discussion about the possible roles of microorganisms at the rhizosphere, non-rhizosphere, and phyllosphere, and using plant exudates to control microbial activity. However, modern approach (culture-independent methods) addressing these topics has opened the door for deeper investigations, and to explore the roles played by microorganisms at these habitats. These methods have already begun during the last decade as serious step to solve many environmental issues. In the future, it is very likely that microorganisms will be used to tackle many pollution issues, as well as health, agricultural, and economic problems.

Possible Future Risks of Pollution Consequent to the Expansion of Oil and Gas Operations in Qatar

“…Pollution on mainland Qatar is affected by many activities, including natural, industrial, and anthropogenic activities, which negatively affect human health not only directly, but also through other sources, such as air pollution (as discussed above), intentional and unintentional oil spills and accidents, and pumping of industrial wastewater deep into the earth, thereby contaminating the groundwater (Al-Thani and Yasseen, 2020). The intrusion of polluted seawater into the mainland of the peninsula of Qatar could be a reason for the development of land pollution in Qatar in the future (Al-Thani and Yasseen, 2020;2021b). Thus, many concerns have been described about the accumulation of heavy metals in agricultural lands in Qatar in response to anthropogenic and industrial activities.…”

“…Thus, one possible measure to find a solution to water scarcity in the Arabian Gulf region in the future is to treat the industrial waste water with native microbial flora to degrade the organic components and reduce the negative impact of heavy metals. This could be used instead of the continually pumping of industrial wastewater deep into the earth, thus reducing the exposure of groundwater to pollution (Al-Thani and Yasseen, 2021a;2021b).…”

Soil Properties Correlate with Microbial Community Structure in Qatari Arid Soils

“…Qatar, despite being a relatively small country, harbors diverse habitats that range from terrestrial dunes, sabkhas, micronebkhas, rodahs, and wadis to marine environments, including mangrove forests ( 4 , 9 , 10 ). Limestone and gypsum cover the majority of the country’s surface, and about 88% of the country is a flat or gently undulating rocky desert ( 4 , 11 – 13 ).…”

“…Qatari soils generally have an alkaline pH (7.6 to 9.8) and low moisture content (0.2 to 8.8%) ( 4 , 10 , 22 ). Higher water holding capacity and organic carbon percentage are usually seen in rodahs and wadis than in sabkhas and sand dunes ( 4 ).…”

“…A number of studies focusing on cultured microbes from specific habitats in Qatar have been published previously. Al-Thani and Yasseen found that the most abundant cultured bacterial taxa in arid Qatari soils were Actinobacteria , Firmicutes , and Proteobacteria ( 10 ). Mangrove forest sediments in Qatar are dominated by cellulase-producing bacteria that are influenced by water temperatures ( 10 , 25 – 27 ), while Streptomyces are common in Qatari arid habitats, including rodahs (30 to 40% of total CFU) ( 22 ).…”