Diversity, distribution, and density of marine mammals along the Saudi waters of the Arabian Gulf: update from a multi-method approach

Despite the important role of marine mammals in marine ecosystems and the imperative for their conservation, there is still a great lack of information on the diversity, distribution, and density of these animals in the Saudi waters of the Arabian Gulf. To fill this gap, an integrative data-collection approach including fishermen’s questionnaires, opportunistic sighting reports, and directed boat-based surveys, was undertaken between 2016 and 2020, leading to the first scientific report of marine mammal diversity, distribution, and density in the region. The results of the different approaches carried out during the study confirmed a high diversity of cetaceans on the west coast of the study area, with bottlenose dolphins (Tursiops aduncus), humpback dolphins (Sousa plumbea) and dugongs (Dugong dugon) as the most common species. While the two dolphin species were found to be widely distributed in both coastal and offshore waters, D. dugon appears to occur exclusively in coastal waters in the southern part of the study area, mainly in the Gulf of Salwah. The presence of both species of dolphins increased during the summer months and in the vicinity of the numerous oil and gas facilities in this region. The distribution of the observed dolphins was found mostly within a 10–20 km radius around each facility. Other cetacean species observed less frequently in the area include Bryde’s whale (Balaenoptera edeni), killer whale (Orcinus orca), common dolphin (Delphinus delphis) and finless porpoise (Neophocaena phocaenoides). Regarding the density of marine mammals in the region, boat-based surveys confirmed the results of fishermen’s questionnaires and reports of opportunistic sightings, with bottlenose and humpback dolphins being the most abundant species. These results provide a baseline for policies oriented to the conservation of mammals in the Saudi waters of the Arabian Gulf.info:eu-repo/semantics/publishedVersio

Cytotoxic and apoptotic evaluations of marine bacteria isolated from brine-seawater interface of the Red Sea.

BACKGROUND: High salinity and temperature combined with presence of heavy metals and low oxygen renders deep-sea anoxic brines of the Red Sea as one of the most extreme environments on Earth. The ability to adapt and survive in these extreme environments makes inhabiting bacteria interesting candidates for the search of novel bioactive molecules. METHODS: Total 20 i.e. lipophilic (chloroform) and hydrophilic (70% ethanol) extracts of marine bacteria isolated from brine-seawater interface of the Red Sea were tested for cytotoxic and apoptotic activity against three human cancer cell lines, i.e. HeLa (cervical carcinoma), MCF-7 (Breast Adenocarcinoma) and DU145 (Prostate carcinoma). RESULTS: Among these, twelve extracts were found to be very active after 24 hours of treatment, which were further evaluated for their cytotoxic and apoptotic effects at 48 hr. The extracts from the isolates P1-37B and P3-37A (Halomonas) and P1-17B (Sulfitobacter) have been found to be the most potent against tested cancer cell lines. CONCLUSION: Overall, bacterial isolates from the Red Sea displayed promising results and can be explored further to find novel drug-like molecules. The cell line specific activity of the extracts may be attributed to the presence of different polarity compounds or the cancer type i.e. biological differences in cell lines and different mechanisms of action of programmed cell death prevalent in different cancer cell lines

Haloferax profundi sp. nov. and Haloferax marisrubri sp. nov., Isolated from the Discovery Deep Brine-Seawater Interface in the Red Sea

Two extremely halophilic archaeal strains, designated SB29T and SB3T, were isolated from the brine-seawater interface of Discovery Deep in the Red Sea. Cells of both strains were pleomorphic (irregular polyhedrals, ovals, and rods) and stained Gram-negative; colonies were pigmented pink. The sequence similarity of the 16S rRNA gene of strain SB29T with that of its most closely related validly described species (Hfx. sulfurifontis DSM 16227T) and that of strain SB3T with its closest validly described relative (Hfx. denitrificans ATCC 35960T) was 98.1% and 98.6%, respectively. The incomplete draft genomes of SB29T and SB3T are 3,871,125 bp and 3,904,985 bp in size, respectively, and their DNA G + C contents are 60.75% and 65.64%, respectively. The highest ANI values between the genomes of SB29T and SB3T and the most closely related genomes in GenBank were determined as 82.6% (Hfx. sulfurifontis ATCC BAA-897T, GenBank accession no. GCA_000337835.1) and 92.6% (Haloferax denitrificans ATCC 35960T, GenBank accession no. GCA_000337795.1), respectively. These data indicate that the two new isolates cannot be classified into any recognized species of the genus Haloferax, and, therefore, two novel species of the genus Haloferax are proposed: Haloferax profundi sp. nov. (type strain SB29T = JCM 19567T = CGMCC 1.14960T) and Haloferax marisrubri sp. nov. (type strain SB3T = JCM 19566T = CGMCC 1.14958T)

Size-fractionated chlorophyll and physico-chemical variables at three coastal stations in Saudi waters of the Arabian Gulf between May 2016 and May 2018

Within the framework of the project “Sustaining Research Project, Marine Environmental Studies in the Arabian Gulf – Phase VI”, three coastal stations at Manifa, Khobar and Uqair were sampled monthly for size-fractionated chl a (micro-, nano- and picophytoplankton), as well as for total chl a, and for a range of physico-chemical variables. Sampling started in May 2016, this file includes the data from the first two years

Spatial and temporal variability in physicochemical factors of the Western Arabian Gulf in 2017 and 2018

Physicochemical data were collected in Saudi Arabian waters of the Arabian Gulf during summer 2017 and winter to early spring 2018. Temperature and salinity were measured in situ, using a YSI multi-parameter sonde. The photosynthetically active radiation was calculated from satellite measurements (MODIS Aqua). Concentrations of total suspended solids were measured by gravimetric analysis. Macronutrients (nitrite, nitrate, phosphate and silica) were analyzed using segmented flow analysis, while trace metals (copper, iron, molybdenum, nickel, vanadium and zinc) were analyzed by ICP-MS

Spatial and temporal variability in the phyto- and zooplankton community and important physicochemical factors of the Western Arabian Gulf in 2017 and 2018

Samples for phytoplankton and zooplankton abundance analysis, together with relevant physicochemical data, were collected in Saudi Arabian waters of the Arabian Gulf during summer 2017 and winter to early spring 2018. This study was part of the Sustaining VI project, jointly conducted by King Fahd University of Petroleum and Minerals and Saudi-Aramco. Phytoplankton samples were taken from surface waters, fixed with Lugol's iodine solution and analyzed in the laboratory using the Utermöhl sedimentation technique. Tintinnids were identified as part of the phytoplankton analysis as well. Zooplankton samples were collected through 10 minute horizontal tows of a bongo net with a mesh size of 300 µm. The net was equipped with a mechanical flow meter in order to subsequently calculate the filtered water volume and zooplankton abundances. In the lab, samples were analyzed following the method of Postel et al. (2000). Temperature and salinity were measured in-situ, using a YSI multi-parameter sonde. The photosynthetically active radiation was calculated from satellite measurements (MODIS Aqua). Concentrations of total suspended solids were measured by gravimetric analysis. Macronutrients (nitrite, nitrate, phosphate and silica) were analyzed using segmented flow analysis, while trace metals (copper, iron, molybdenum, nickel, vanadium and zinc) were analyzed by ICP-MS

Spatial and temporal variability in the phytoplankton community of the Western Arabian Gulf in 2017 and 2018

Samples for phytoplankton abundance analysis were collected in Saudi Arabian waters of the Arabian Gulf during summer 2017 and winter to early spring 2018. This study was part of the Sustaining VI project, jointly conducted by King Fahd University of Petroleum and Minerals and Saudi-Aramco. Phytoplankton samples were taken from surface waters, fixed with Lugol's iodine solution and analyzed in the laboratory using the Utermöhl sedimentation technique

Spatial and temporal variability in the zooplankton community of the Western Arabian Gulf in 2017 and 2018

Samples for zooplankton abundance analysis were collected in Saudi Arabian waters of the Arabian Gulf during summer 2017 and winter to early Spring 2018. This study was part of the Sustaining VI project, jointly conducted by King Fahd University of Petroleum and Minerals and Saudi-Aramco. Zooplankton samples were collected through 10 minute horizontal tows of a bongo net with a mesh size of 300 µm. The net was equipped with a mechanical flow meter in order to subsequently calculate the filtered water volume and zooplankton abundances. In the lab, samples were analyzed following the method of Postel et al. (2000)