Biomonitoring of Trace Metals in the Coastal Waters Using Bivalve Molluscs

Several environmental contaminants including toxic trace metals are being discharged into the coastal environment causing serious threat to marine organisms and posing public health risk. Marine bivalves (mussel, oyster, and clam) have been successfully used as sentinel organisms for monitoring contaminant levels, including trace metals, in coastal waters around the globe. Chemical analyses measure the contaminants present in the biota but do not necessarily reveal potential biological effects. Therefore, the need to detect and assess the effects of contaminants, especially at low concentrations, has led to the development of molecular markers of contaminant effects called biomarkers. Owing to their short time of response, biomarkers in marine bivalves are used as early warning signals of biological effects caused by environmental pollutants. Research into the development and application of accurate biomarker-based monitoring tools for the environmental contaminants has been intensified in several developed countries

Macrobenthic Community Structure in the Northwestern Arabian Gulf, Twelve Years after the 1991 Oil Spill

The biota in the Arabian Gulf faces stress both from natural (i.e., hyper salinity and high sea surface temperature), and human (i.e., from oil-related activities) sources. The western Arabian Gulf was also impacted by world's largest oil spill (1991 Oil Spill). However, benthic research in this region is scarce and most of the studies have been conducted only in small areas. Here, we present data on macrobenthos collected during 2002–2003 from the open waters and inner bays in the northwestern Arabian Gulf aimed to assess the ecological status and also to evaluate the long-term impact, if any, of the 1991 Oil Spill. A total of 392 macrobenthic taxa with an average (±SE) species richness (S) of 71 ± 2, Shannon-Wiener species diversity (H′) of 4.9 ± 0.1, and density of 3,181 ± 359 ind. m−2 was recorded from the open water stations. The open waters have “slightly disturbed” (according to AZTI's Marine Biotic Index, AMBI) conditions, with “good-high” (according to multivariate-AMBI, M-AMBI) ecological status indicating the absence of long-term impacts of the oil spill. Overall, 162 taxa were recorded from inner bays with average (±SE) values of S 41 ± 9, H′ 3.48 ± 0.39, and density 4,203 ± 1,042 ind. m−2. The lower TPH (Total Petroleum Hydrocarbons) stations (LTS, TPH concentrations <70 mg kg−2) show relatively higher S, H' and density compared to the higher TPH stations (HTS, TPH concentrations ≥100 mg kg−2). In the inner bays, AMBI values indicate slightly disturbed conditions at all stations except one, which is moderately disturbed. M-AMBI values indicate good status at LTS, while, high, good, moderate, and poor status at HTS. The “moderately disturbed” conditions with “moderate-poor” ecological status in some locations of the inner bays specify a severe long-term impact of the oil spill

Anthropogenic-induced acceleration of elemental burial rates in blue carbon repositories of the Arabian Gulf

Since the discovery of oil in early 1900, the Arabian Gulf has experienced a continuous and fast coastal development leading to increase the human pressures on the marine environment and its enrichment with various pollutants. The present study attempts to describe the historical changes of trace elements in the sediments of vegetated coastal habitats in the western Arabian Gulf. 210Pb–dated sediment cores collected from seagrass, mangrove and saltmarsh habitats were analyzed to evaluate historical variations in concentrations and burial rates of 20 trace elements (Al, As, Ba, Ca, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, P, Pb, S, Sr, V and Zn). The highest correlations (Spearman correlation coefficients ≥0.51) were found between crustal elements (Al, Fe, Co, Cr, K, Na, Mg, Mn, Ni, V, and P), suggesting a common crustal source in the Gulf. The increased concentrations of these crustal elements in modern marine sediments of the Arabian Gulf seem to be linked to increased mineral dust deposition in the area. Over the last century, both elemental concentrations and burial rates increased by factors of 1–9 and 1–15, respectively, with a remarkably fast increase occurring in the past six decades (~1960 – early 2000). The considerable enrichment of trace elements in the Arabian Gulf during the last decades is most likely due to an increase in anthropogenic pressures, including industrial, urban and agricultural development. Our study demonstrates that sediments in vegetated coastal habitats provide long-term archives of trace elements concentrations and burial rates reflecting human activities in the Arabian Gulf

Better model transfers require knowledge of mechanisms

No abstract available

Outstanding Challenges in the Transferability of Ecological Models.

Predictive models are central to many scientific disciplines and vital for informing management in a rapidly changing world. However, limited understanding of the accuracy and precision of models transferred to novel conditions (their 'transferability') undermines confidence in their predictions. Here, 50 experts identified priority knowledge gaps which, if filled, will most improve model transfers. These are summarized into six technical and six fundamental challenges, which underlie the combined need to intensify research on the determinants of ecological predictability, including species traits and data quality, and develop best practices for transferring models. Of high importance is the identification of a widely applicable set of transferability metrics, with appropriate tools to quantify the sources and impacts of prediction uncertainty under novel conditions