Environmental DNA-based profiling of benthic bacterial and eukaryote communities along a crude oil spill gradient in a coral reef in the Persian Gulf.

Coral reef ecosystems in the Persian Gulf are frequently exposed to crude oil spills. We investigated benthic bacterial and eukaryote community structures at such coral reef sites subjected to different degrees of polycyclic aromatic hydrocarbon (PAH) pollution using environmental DNA (eDNA) metabarcoding. Both bacterial and eukaryote communities responded with pronounced shifts to crude oil pollution and distinguished control sites, moderately and heavily impacted sites with significant confidentiality. The observed community patterns were predominantly driven by Alphaproteobacteria and metazoans. Among these, we identified individual genera that were previously linked to oil spill stress, but also taxa, for which a link to hydrocarbon still remains to be established. Considering the lack of an early-warning system for the environmental status of coral reef ecosystems exposed to frequent crude-oil spills, our results encourage further research towards the development of an eDNA-based biomonitoring tool that exploits benthic bacterial and eukaryote communities as bioindicators.

Multiple benthic indicators are efficient for health assessment of coral reefs subjected to petroleum hydrocarbons contamination: A case study in the Persian Gulf.

The ever-increasing anthropogenic activities have adversely impacted coral reef ecosystems and their ecological functions. This calls for an urgent assessment of the health state of these valuable ecosystems to justify the need for mitigation and proper management efforts. In this contribution, we used multiple indicators to assess the impact of intense oil-related activities on coral reefs in two near-by impacted and non-impacted islands in the northwestern Persian Gulf. The efficacy of indices was assessed using estimations of the effect size (omega-squared), precision, and decision trees (Classification and Regression Tree (CART)). The results demonstrated that the combination of bioaccumulation of Æ©PAH in coral tissues, the percent of live coral cover, and the Sediment Constituent (SEDCON) Index were the most robust proxies reflecting the influence of human activities on reef's health. Based on sedimentary PAH concentration, the CART classified most of the indicators into two classes consisting of those in impacted and those in non-impacted locations, further supporting the feasibility of the employed indices. The findings of this study provided a warning of degradation in coral reefs of the island subjected to PAH pollution. This encourages decision-makers to execute routine monitoring and mitigation practices to maintain healthy reefs in the study areas.

Dispersal beyond geographic barriers: a contribution to the phylogeny and demographic history of Pristurus rupestris Blanford, 1874 (Squamata: Sphaerodactylidae) from southern Iran.

Pristurus rupestris is a member of Semaphore geckos with a wide distribution range. Recently, 14 candidate species of P. rupestris rupestris have been identified in the Hajar Mountains (Arabia), yet the knowledge on the Iranian counterparts is limited. The present study elucidates the phylogenetic position of the Iranian P. rupestris and investigates the hypothesis on its historical colonization from Oman to Iran and the associated islands. Therefore, 20 Iranian specimens along with 115 individuals from Oman were examined using two mitochondrial genes including the Cytochrome b and the 12S ribosomal RNA. The molecular phylogenetic analyses revealed that the individuals collected from Iran are well nested within the candidate Species 3 of P. r. rupestris, demonstrating a single population with high gene flow. Additionally, the molecular analyses showed that the genetic diversity within the Iranian Blanford's Semaphore geckos is low and that the candidate Species 3 experienced a recent expansion approximately 17 thousand years ago (Kya). The historical demographic analyses (BSP) showed a mild increase in the effective population size between 15-20 Kya. These time estimations coincide with the Last Glacial Maximum, when the Persian Gulf was almost dry, reinforcing the hypothesis that the species might have colonized southern Iran from Oman through the Persian Gulf. In addition, we propose P. r. iranicus to be synonymized with P. r. rupestris.