Modern Benthic Foraminiferal Diversity: An Initial Insight into the Total Foraminiferal Diversity along the Kuwait Coastal Water

Deciphering the impact of decabromodiphenyl ether (BDE-209) on benthic foraminiferal communities: Insights from Cell-Tracker Green staining and eDNA metabarcoding

This study investigates the ecotoxicological effects of BDE-209, a persistent organic pollutant (POP) prevalent in Kuwait's coastal-industrial areas, on benthic foraminiferal communities. We conducted a mesocosm experiment in which we exposed benthic foraminiferal communities sampled from the coastal-industrial areas of Kuwait to a gradient of BDE-209 concentrations (0.01 to 20 mg/kg). The impact of exposure was assessed using live-staining and metabarcoding techniques. Despite the significantly different taxonomic compositions detected by the two techniques, our results show that BDE-209 significantly affects foraminiferal communities, with moderately high concentrations leading to reduced α-diversity and considerable taxonomic shifts in both molecular and morphological assemblages. At concentrations of 10 and 20 mg/kg, no living foraminifera were detected after 8 weeks, suggesting a threshold for their survival under BDE-209 exposure. The parallel responses of molecular and morphological communities confirm the reliability of both assessment methods. This study is the first to investigate the reaction of eukaryotic communities, specifically foraminifera, to POPs such as BDE-209, generating valuable insights that have the potential to enhance field studies and aid the refinement of sediment quality guidelines.

Benthic foraminifera as proxies for the environmental quality assessment of the Kuwait Bay (Kuwait, Arabian Gulf): Morphological and metabarcoding approaches

The rapid urbanization and industrialization of Kuwait and the consequent effluent discharges into marine environments have resulted in a degradation of water and sediment quality in the coastal marine ecosystems such as in the Kuwait Bay. This study investigates the ecological response of benthic foraminifera (protists) to environmental stress in the Kuwait Bay. The traditional morphological approach was compared to the innovative environmental DNA (eDNA) metabarcoding to evaluate the ecological quality status (EcoQS). Forty-six surface sediment samples were collected from selected stations in the Kuwait Bay. To detect the pollution gradient, environmental parameters from water (e.g., salinity, pH, dissolved oxygen) and sediment (e.g., grain-size, trace metals, total organic carbon, total petroleum hydrocarbons) were measured at each station. Although the foraminiferal assemblages were different in the morphological and molecular datasets, the species turnover was congruent and statistically significant. Diversity-based biotic indices derived from both morphological and metabarcoding approaches, reflect the environmental stress gradient (i.e., organic and metal contaminations) in the Kuwait Bay. The lowest values of EcoQS (i.e., bad to poor) are found in the innermost part (i.e., Sulaibikhat Bay and Ras Kazmah), while higher EcoQS values occur in the outer part of the bay. This study constitutes the first attempt to apply the foraminiferal metabarcoding to assess the EcoQS within the Arabian Gulf and presents its advantages compared to the conventional morphological approach.

Testing the applicability of random forest modeling to examine benthic foraminiferal responses to multiple environmental parameters

The main environmental variables controlling benthic foraminiferal distributions were identified and used to assess their influence on ecological indices developed as predictors of Ecological Quality Status (EcoQS) in marine ecosystems. Gradient forest and random forest models were applied to assess the predictive value of a selection of abiotic (environmental) and biotic (foraminifera) variables in a costal marine area in the central Adriatic Sea (Italy). This approach yields evidence that the predictor variables sand, silt, Pollution Load Index, and TN have the greatest influence on the distribution of benthic foraminifera in this area. In addition, we identify thresholds for the most important environmental variables that influence ecological indices. These findings contribute to efforts to determine how to best improve sediment quality and environmental stability for marine conservation. Further application of these approaches represents a useful tool for policymakers to survey the diversity of marine organisms and to improve the ability to protect and restore marine ecosystems by identifying predictors of diversity and identifying key thresholds in these predictors.

Benthic Foraminifera as Bio-indicators of Coastal Marine Environmental Contamination in the Red Sea-Gulf of Aqaba, Saudi Arabia

To assess heavy metals contamination in shallow marine environments using benthic foraminifera as bio-indicators. Forty-six species of foraminifera were found in 33 benthic samples from the Saudi Arabian coast of the Red Sea-Gulf of Aqaba. Forty-six species belonging to 27 genera and 10 families under the Textularina, Rotalina, and Miliolina suborders were recorded in the study area. The most common genera of the recorded fauna were Peneroplis (37.2%), Coscinospira (15.06%), Sorites (10.36%), and Quinqueloculina (7.76%). The influx of clastic sediments would dilute the abundance of foraminifera species, and It may be the main reason for the decrease in abundance Concentrations of Fe, Mn, Cu, Ni, Zn, Pb, Cr, Co, and Cd were measured in the four common species of benthic foraminifera (Sorites orbiculus, Peneroplis planatus, Peneroplis pertusus, and Coscinospira hemprichii) using inductively coupled plasma mass spectrometry. The average values of heavy metals in the study area show that Iron was the most abundant metal (3367 μg/g), followed by Mn (142 μg/g), Cu (30 μg/g), Zn (24 μg/g), Cr (21 μg/g), Ni (14 μg/g), Pb (7 μg/g), Co (4.6 μg/g), and Cd (0.82 μg/g). Iron concentrations recorded in the foraminiferal tests in the study area were lower than those from the Jeddah area of Saudi Arabia. Other metals were found at higher concentrations than those recorded off the Red Sea coast of Saudi Arabia and Egypt. The heavy metals concentrations in the study area may be attributable to terrestrial influx or anthropogenic activities. The increase of abundance of epiphytic foraminifers and the absence of opportunistic foraminifers show normal the environment in the study area.