2025-12-31
Hichem Belhadj, Dominique Aubert, Nacéra Dali Youcef, Nabil Touzout
Trace metals are among the most hazardous pollutants in marine environments due to their bioaccumulative properties and their high toxicity. The present study aims to assess the level of metallic contamination in Ghazaouet Bay (northwest Algeria) by analysing 10 trace metals (Mo, Zn, Cu, Mn, V, Ni, Co, Cr, Cd and Pb) in 2 seaweeds ( Enteromorpha linza and Corallina officinalis ) and in a marine gastropod ( Patella ferruginea ) collected respectively from three polluted sites (A, B and C). The metal pollution index (MPI) revealed significant contamination, particularly for V, Cr, Mo, Cd and Pb in algae and for Cd and Pb in limpets. The highest MPI values for E. linza, C. officinalis and P. ferruginea were recorded at station C, while station A appeared the least polluted site. Health risks associated with the consumption of these organisms were assessed using the target hazard quotient (THQ) and the hazard index (HI). Although all THQ and HI values remained <1, indicating a low overall risk, the relatively high HI for C. officinalis (0.695) and E. linza (0.416) raises moderate concerns, especially due to Pb and Cd levels exceeding Centre d’Étude et de Valorisation des Algues (CEVA) standards. These results highlight the need for continual monitoring of metallic contamination of these marine food resources.
2025-12-31
Aurellia Devina Putri, Pramaditya Wicaksono
Seagrasses absorb CO 2 for photosynthesis and convert it into new biomass. This study aims to assess the correlation between seagrass aboveground biomass (AGB) growth and percent cover, map and analyse AGB growth using Sentinel-2 imagery and estimate CO 2 uptake by multispecies seagrass meadows on Menjangan Besar Island. Correlation analysis revealed a strong relationship between AGB growth and percent cover at the community level ( r = 0.64) and for Enhalus acoroides ( r = 0.60), and a very strong relationship for Thalassia hemprichii–Cymodocea rotundata assemblages ( r = 0.89). AGB growth mapping was conducted using random forest (RF) regression, resulting in root mean square errors (RMSE) of 60.8, 125.6, 94.2 and 94.9 gDW · m −2 · year −1 for E. acoroides, T. hemprichii–C. rotundata, E. acoroides–T. hemprichii , and bare substrate (BS) classes, respectively. The corresponding coefficients of determination ( R 2 ) were 0.87, 0.67, 0.70, and 0.78. The total seagrass AGB growth on Menjangan Besar Island was estimated at 672.21 MgDW · year −1 , with an average of 331.7 gDW · m −2 · year −1 The estimated total CO 2 uptake by seagrass meadows was 197.85 MgCO 2 · year −1 , with an average of 97.6 gCO 2 · m −2 · year −1 .
2025-12-31
Pervin Vural Bilgen, Sefa Acarlı, Selçuk Berber, Pinar Celik, Semih Kale
Protein content was lowest in April 2018 and highest in May 2018 for Ruditapes decussatus (Linnaeus 1758), and was lowest in September 2017 and highest in December 2017 for Ruditapes philippinarum (Adams, Reeve 1850). Amino acid content is particularly important to determine such variations every month to develop consumption strategies for these species. Leucine was the most abundant amino acid in both species, followed by isoleucine, arginine, methionine, and serine. Leucine plays a critical role in protein synthesis and muscle repair. Leucine levels were consistently high throughout the year for both species, but the recommended optimal consumption periods are all months except September and April for R. philippinarum , and all months except spring for R. decussatus . Arginine is essential for children, and it has been shown to enhance growth hormone synthesis. Arginine concentrations were high in winter and spring for R. philippinarum and autumn for R. decussatus . Methionine levels were highest in spring for R. philippinarum , autumn for R. decussatus . The essential amino acid to non-essential amino acid ratio was >1 for both species throughout the year, indicating high protein quality.