Navigating a Microplastic Sea: How the Pacific Cupped Oyster (Magallana gigas) Respond to Microplastic Pollution in Lagoons.

Microplastic pollution poses an escalating concern, particularly in coastal lagoons rich in biodiversity. This study delved into the occurrence of microplastics (MPs) in Magallana gigas (formerly Crassostrea gigas) from the Orbetello and Varano coastal lagoons (Italy), also investigating the response of these filter-feeding organisms to various colors (P = pink; B = blue; W = white) of high-density polyethylene (HDPE) MP fragments. Oysters were exposed for 7 days under controlled conditions. Subsequently, the oysters underwent analysis for both MP presence and biochemical markers of oxidative stress. Diverse ingestion rates of HDPE were noted among oysters from the two lagoons, eliciting antioxidant responses and modifying baseline activity. The two-way ANOVA revealed the significant effects of treatment (control; HDPE_B; HDPE_P; HDPE_W), site, and the interaction between treatment and site on all biomarkers. Non-metric multidimensional scaling showed a divergent effect of HDPE color on biomarkers. Further investigation is warranted to elucidate the mechanisms underlying the influence of MP color, dose-dependent effects, and the long-term impacts of exposure. Comprehending these intricacies is imperative for devising effective strategies to mitigate plastic pollution and safeguard marine health.

One-year monitoring of potentially pathogenic microorganisms in the waters and sediments of the Lesina and Varano lagoons (South-East Italy).

In this study, two Mediterranean coastal lagoons (Lesina and Varano) of southern Italy, located in the north of the Apulia region, were investigated for the presence of Shiga toxin Escherichia coli (STEC) and potentially enteropathogenic Vibrio species in parallel with norovirus (NoV), hepatitis A virus (HAV), hepatitis E virus (HEV), and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This study aimed to evaluate the presence of potentially pathogenic bacteria and viruses in the water and sediments of these ecosystems. From March 2022 to February 2023, a total of 98 samples were collected: 49 water samples and 49 sediment samples. STEC strains were isolated in three samples (3.1%), of which one (2%) was water (stx1 and stx2 positive) and two (4.1%) were sediment (both stx2 positive) samples. Vibrio spp. were detected in twenty samples (20.4%), of which nine were water (18.4%) and eleven were sediment (22.4%) samples. The species detected included V. parahaemolyticus, V. cholerae, and V. vulnificus. NoV was detected in 25 (25.5%) samples, while none of the water or sediment samples were positive for HAV, HEV, and SARS-CoV-2. The results of this study provide an overview of the presence of potentially pathogenic microorganisms in areas influenced by anthropogenic pressure. Monitoring the circulation of these pathogens could be useful to evaluate the water flowing into the lagoons, in particular discharge waters (i.e., urban, agricultural, and livestock runoff), considering the presence of fish and shellfish farms in these sites.