Concentration, distribution, and risk assessment of polychlorinated biphenyl compounds in surface sediments of the Persian Gulf and the Oman Sea.

This study involved analyzing 76 sediment samples from the Persian Gulf and Oman Sea. The concentration of 18 prevalent PCB congeners was determined. Results indicated that the highest concentration of PCB-52, reaching 636.

Exploring latitudinal gradients and environmental drivers of amphipod biodiversity patterns regarding depth and habitat variations.

Amphipods are known as umbrella species in conservation biology that their protection indirectly protects other species. Recent hypotheses suggest a bimodal latitudinal global species richness pattern for amphipods, irrespective of species' depth or habitat type. Phylogeographic hypotheses suggested two distinct procedures for amphipod diversification: ecological radiation and Pangea fragmentation.

Analysis of PAHs content, source identification and ecological risk assessment in surface sediments from the Caspian Sea.

The concentrations of Polycyclic Aromatic Hydrocarbons (PAHs) in surface sediments were investigated in the southern Caspian Sea. The results revealed that the total PAHs in sediments varied from 6.53 to 170.

Environmental impacts of fish cage cultures in the southern Caspian Sea.

In the last two decades, cage culture industries have developed in Iranian seas, supplying a portion of the needed protein and contributing to food security. In this paper, environmental impacts of cage culture are investigated, focusing on the physical, hydrodynamical, chemical, geological, and biological oceanographic aspects at the Abbas Abad fish farm in the southern Caspian Sea. Multidisciplinary field measurements were conducted from fall 2018 to late summer 2019 in different oceanographic aspects.

Distribution, environmental risks, and conservation challenges of chemical pollutants in Persian Gulf marine protected areas.

This study investigates the occurrence and distribution of chemical pollutants, including total petroleum hydrocarbons (TPHs), organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), anionic surfactants, and total organic carbon (TOC), in the Marine Protected Areas (MPAs) waters in the northern Persian Gulf. Water samples were collected from five MPAs during the winter and summer of 2022. The study identified significant seasonal variations, with higher pollutant levels recorded in winter compared to summer.

Polychlorinated biphenyls (PCBs) in the Persian Gulf and Gulf of Oman: baseline report on occurrence, distribution, and ecological risk assessment.

In the present study, 18 polychlorinated biphenyl (PCB) compounds were measured in marine sediments collected from 49 offshore stations in the Persian Gulf and the Gulf of Oman in 2019. After the last oceanographic cruise in 2006, no study has been performed on the offshore sediments of this region, and this is the first study on the PCBs in this area. The total amount of PCB compounds in the sediment samples ranged from 74.

Surface microplastics dynamics in the Persian Gulf and Arabian Sea using numerical modelling and CYGNSS satellite estimations.

Microplastics have long-term negative effects on marine environment. One of the most significant threats of microplastics is their ability to absorb chemicals which enhances the transfer of pollutants. These pollutants eventually enter the tissues of living organisms e.

Suspended particulate matter in the Gulf of Oman: Spatial variations in concentration, bulk composition, and particulate metals controlled by physical and biogeochemical processes.

The present work aims to assess the biogeochemical and physical sources of variation in the spatial distribution of suspended particulate matter (SPM), its major biotic and abiotic components, particulate metals, and the Redfield (N:P) stoichiometry of particles in a poorly understood basin of the Gulf of Oman. Particulate samples were collected in February 2022 from the Gulf of Oman aboard the R/V Persian Gulf Explorer, revealing surface SPM concentrations ranging from 140 to 1145 μg/l. The elemental composition of crustal-type elements in the surface offshore region confirmed the input of lithogenic components by aeolian dust from the surrounding deserts.

Antibiotics in surface waters of the south caspian sea: Occurrence, spatial distribution and ecological risks.

Marine environments play a crucial role in absorbing land-based pollutants. While the presence of pharmaceuticals in various marine settings worldwide is well-documented, there is a lack of data regarding pharmaceutical occurrence in the south Caspian Sea. This study examined the presence and spatial distribution of 14 antibiotics in the surface waters of the south Caspian Sea during summer of 2020.

Phallusia nigra-mediated vanadium removal from brine: Assessment and optimization.

The rejected brines from desalination plants contain significant amounts of heavy metals. In this study, we evaluated the effectiveness of Phallusia nigra Savigny, 1816 (P. nigra) in removing vanadium from the rejected brines of desalination plants through the bioaccumulation process.

Origin and comprehensive risk assessment of heavy metals in surface sediments along the Caspian Sea.

Metal concentrations (Cu, Zn, Cr, Fe, As, Pb, Ni, V, and Co) in surface sediments were determined in the southern Caspian Sea. Sediment pollution was investigated using geochemical index such as Enrichment Factor (EF) and ecological risk indices like modified Hazard Quotient (mHQ) and Toxic Risk Index (TRI). The highest calculated geochemical index was observed in sediments near the cities of Chalus and Ramsar, which are highly polluted due to human activities.

A note on the silent decline of the Caspian environment.

The Caspian Sea, the world's largest enclosed water body, experiences significant transformations in its physico-chemical properties and a decline in bioresources due to extensive anthropogenic activities. These activities include the discharge of diverse pollutants and bio-physical alterations such as over-fishing, hunting, and physical alterations to rivers. While acute manifestations such as a fall in the Caspian water levels and wetland desiccation are more overt, the pervasive impact of human activities contributes to a likely irreversible decline in environmental quality that we aim to spotlight in this discussion in order to facilitate its restoration.

Spatial and seasonal variations in suspended particulate matter concentration and composition in the Persian Gulf: From dust deposition and sediment resuspension to biological production in the regulation of the particulate trace elements.

The present document is intended to fill the knowledge gap on spatiotemporal variation of suspended particulate matter (SPM) concentration and composition by collecting samples from 26 stations during two contrasting seasons of summer and winter. The horizontal distribution of surface SPM is characterized by hotspots (up to 4.0 mg/l) along the river estuaries which sharply declined to <1 mg/l in the offshore region.

Distribution of hydrogen sulfide, nitrogen and phosphorous species in inshore and offshore sediments of the south Caspian Sea.

This study aimed to geochemically investigate the sediments of the south Caspian Sea at different depths in summer and winter 2020. Sampling was conducted in 5 transects along the south coastline of the Caspian Sea and sediment grain size, hydrogen sulfide, Oxidation-reduction potential (Eh), total nitrogen, nitrite, nitrate, ammonium, total phosphorus, organic and inorganic phosphorous were measured. Eh values showed significant differences between seasons and between different transects (p < 0.

Temporal variations of biofouling assemblages of a coral reef ecosystem during a monsoon period.

Coral reefs are highly biodiverse ecosystems, enriched by a range of biofouling species. Temporal variations in biofouling can affect ecosystem stability, but these diverse coral-associated communities remain underexplored in some regions. In the present study, biofouling assemblages of coral reefs in the Chabahar Bay were investigated during a summer monsoon at three deployment periods.

Future precipitation and near surface air-temperature projection using CMIP6 models based on TOPSIS method: case study, Sistan-and-Baluchestan Province of Iran.

Based on surface air temperature and precipitation, the current study examines the climate fluctuations over Sistan-and-Baluchestan Province, Iran's second-largest province. This area suffers from insufficient direct observations and a lack of climatic investigation. Three datasets were utilized including in situ data, gridded data (1984-2013), outputs of historical runs (during 1984-2013), and projections under the SSP5-8.

Heavy metal and persistent organic pollutant profile of sediments from marine protected areas: the northern Persian Gulf.

Marine protected areas (MPAs) are one of the policy tools to support marine biodiversity conservation and sustainable use of marine resources. The distribution, sources, and ecological risk assessment of persistent organic pollutants (POPs), including polycyclic aromatic hydrocarbon (PAHs), total petroleum hydrocarbons (TPHs), polychlorinated biphenyls (PCBs), and heavy metals (HMs) in sediments of MPAs in the northern Persian Gulf, were evaluated for the first time in this study. The ΣPAHs ranged from 4.

Water and sediment characteristics influence the distribution of ghost shrimps (axiidea) in the Persian and Oman Gulfs.

Ghost shrimps (Crustacea: Decapoda) demonstrate remarkable levels of niche selection and habitat diversity. Due to their cryptic life style, interactions between ghost shrimp assemblages and environmental parameters that potentially shape their local distribution are poorly understood. In the present study, ghost shrimp assemblages from the Persian Gulf (PG) and the Gulf of Oman (GO) were investigated to assess the main drivers determining their assemblage structure along a wide niche type and at a large geographic scale.

A spatiotemporal study on contamination and bioaccumulation of heavy metals in sediment and cyprinid fish (Capoeta razii) from Telar River, Iran.

The concentrations of heavy metals (Cr, Cd, Ni, and Pb) were investigated in sediment and cyprinid fish (Capoeta razii) from Telar River, Iran in spring, summer, and autumn. Mean concentration of metals in fish and sediment over the seasonal sampling was as follows: Cr > Ni > Pb > Cd. Metal deposition in sediment was higher than their bioaccumulation in fish tissue.

Occurrence and spatial distribution of microplastics in the intertidal sediments along the Oman Sea.

Microplastics (MPs) have been found in marine systems more frequently. We aim to analyze the MPs abundances, distribution, and characteristics in the intertidal sediments along the Oman Sea. Samples were collected from 7 locations with three replicates.

Pseudaeginella makranensis sp. nov., a new species of caprellid (Crustacea: Amphipoda) from the Iranian coasts of Gulf of Oman.

Pseudaeginella makranensis sp. nov. is described from the Iranian coast of the Oman Sea.

Distribution of microplastics in upstream and downstream surface waters of the Iranian rivers discharging to the southern Caspian Sea.

Microplastic pollution in the riverine ecosystems has caught many attentions in the scientific literatures. However, little information is available about the abundance and distribution of microplastics of the rivers discharging to the Caspian Sea. The aim of this study was to assess the spatial and seasonal distribution of microplastics in the surface waters of thirteen rivers discharging to the southern Caspian Sea.

Secondhand and thirdhand smoke: a review on chemical contents, exposure routes, and protective strategies.

Secondhand smoke (SHS: a mixture of sidestream and mainstream smoke) and thirdhand smoke (THS: made up of the pollutants that settle indoors after smoking in closed environments) are a significant public health concern. SHS and THS contain various chemicals which can be released into the air or settle on surfaces. At present, the hazards of SHS and THS are not as well documented.

Retrieval and validation of the Secchi disk depth values (Z) from the Sentinel-3/OLCI satellite data in the Persian Gulf and the Gulf of Oman.

In this study, the Secchi disk depth (Z) values as an indicator of seawater clarity/transparency were estimated using the ESA (European Space Agency) Sentinel-3A and Sentinel-3B OLCI (S3/OLCI) satellite data in the Persian Gulf and the Gulf of Oman (PG&GO). To do so, two procedures were evaluated including an existing methodology developed by Doron et al. (J Geophys Res: Oceans 112(C6) 2007 and (Remote Sens Environ 115:2986-3001 2011) and an empirical model proposed in this research formed by employing the blue (B) and green (B) bands of S3/OLCI data.

Satellite-Based Monitoring of Eutrophication in the Earth's Largest Transboundary Lake.

The world's large lakes and their life-supporting services are rapidly threatened by eutrophication in the warming climate during the Anthropocene. Here, MODIS-Aqua level 3 chlorophyll- data (2018-2021) were used to monitor trophic state in our planet's largest lake, that is, the Caspian Sea that accounts for approximately 40% of the total lacustrine waters on Earth. We also used the in situ measurements of chlorophyll- data (2009-2019) to further verify the accuracy of the data derived from the MODIS-Aqua and to explore the deep chlorophyll- maxima (DCMs) in the south Caspian Sea.