Biodiversity patterns of plankton assemblages at the extremes of the Red Sea

Abstract

The diversity of microbial plankton has received limited attention in the main basin of the Red Sea. This study investigates changes in the community composition and structure of prokaryotes and eukaryotes at the extremes of the Red Sea along cross-shelf gradients and between the surface and deep chlorophyll maximum. Using molecular methods to target both the 16S and 18S rRNA genes, it was observed that the dominant prokaryotic classes were Acidimicrobiia, Alphaproteobacteria and Cyanobacteria, regardless of the region and depth. The eukaryotes Syndiniophyceae and Dinophyceae between them dominated in the north, with Bacillariophyceae and Mamiellophyceae more prominent in the southern region. Significant differences were observed for prokaryotes and eukaryotes for region, depth and distance from shore. Similarly, it was noticed that communities became less similar with increasing distance from the shore. Canonical correspondence analysis at the class level showed that Mamiellophyceae and Bacillariophyceae correlated with increased nutrients and chlorophyll a found in the southern region, which is influenced by the input of Gulf of Aden Intermediate Water.

Microbial planktonic communities in the Red Sea: high levels of spatial and temporal variability shaped by nutrient availability and turbulence

“…Bathycoccus was observed predominantly at the DCM, which seems to be typical of its distribution in other oceans 86, 87 and is likely to be linked to the increased availability of nutrients at this depth 86 . In contrast, Micromonas has a higher affinity to surface waters, particularly near the coast, in line with reports in other biogeographical studies 16, 64, 88, 89 . Meanwhile, Ostreococcus showed a more even distribution in the photic zone of the water column.…”

“…17 , Pearman et al . 16 and Kheireddine et al . 19 have a wide spatial coverage but are limited to a single temporal period while Touliabah et al .…”

“…Distinct gradients in temperature, salinity and nutrients are observed along its latitudinal axis. Temperature increases from north to south, salinity generally follows the opposite trend 30 , and nutrients are higher in southern regions compared with the north 13, 16, 31 . Satellite imaging in the main body of the Red Sea indicates a strong seasonality in surface chlorophyll a concentrations 32 .…”

“…11) gradients and to assess the effects of environmental patterns on their composition. In the Red Sea, the number of molecular studies investigating the diversity of the microbial component is extremely limited (e.g., refs 12–16). Other methods have investigated the planktonic diversity in the Red Sea including fingerprinting techniques 17 , microscopy and HPLC 18 .…”

Nutrient Limitation in Central Red Sea Mangroves

“…The nutrient concentrations used in the treatments were higher than in the water in a lagoon near Thuwal, where the (mean ± SE) concentrations of NO 2 were 0.062 ± 0.006 µmol L −1 and NO 2 +NO 3 were 0.181 ± 0.017 µmol L −1 (Banguera-Hinestroza et al, 2016). They were also higher than values found in coastal water from Duba (north) and Jazan (south) along the Saudi coast of the Red Sea (NO 3 = 2.351 ± 0.386 µmol L −1 and PO 4 = 0.239 ± 0.039µmol L −1 ; (Pearman et al, 2016).…”