Marine coastal chemistry related to inland inputs in San Jorge gulf and the adjacent north coast.

Coastal regions are sectors where human activities impact the marine ecosystem, and if necessary control measures are not taken, they can generate negative consequences for health and ecosystem services. Within the framework of the Pampa Azul initiative and under the One Health paradigm, the interconnection between the terrestrial and marine environments of the San Jorge Gulf and the adjacent north coast has been studied. In November, 2022, a campaign was carried out aboard the R/V "Mar Argentino" at thirty-four stations near the coast. There, for the first time, simultaneously with in-situ measurements of physical variables, macronutrients (NO3-, PO4-3, Si(OH)4 and NH4+), particulate silica (BSi and LSi), trace metals in the particulate material (Cd, Cu, Cr, Fe and Pb) and the phytoplankton community were analyzed. The results showed a high nutrient dynamic, with a significant influence of natural stratification and anthropogenic condition due to the discharge of effluents off the cities of Comodoro Rivadavia and Caleta Olivia. Under natural conditions, NO3- and Si(OH)4 limited the surface primary production by 47 % and 41 %, respectively. Additionally, due to the anthropogenic contribution, NH4+ concentration reached 3 µM, increasing the proliferation of nanophytoplankton, among other consequences. As a result of nutrient dynamics, the uptake of Si(OH)4, the growth rate of diatoms and their production of BSi were decoupled. Furthermore, a significant correlation between LSi and Fe in particulate matter was evidenced, opening new lines of research that relate dust storms to primary productivity in this marine environment. The measured concentrations of trace metals do not appear to be a biological risk; however, contamination by Cd (37.6 µg g- 1 d.w.) and Cu (214.97 µg g- 1 d.w.) off Camarones poses a significant concern that must be addressed in the immediate future.

Microplastics in commercial seafood: Pleoticus muelleri as a case study in an estuarine environment highly affected by human pressure (Southwestern Atlantic).

Plastic pollution in seafood has become a worldwide safety concern due to its possible harm to humans. This is the first study which has investigated the length-weight relationship, growth patterns and condition factor, together with the concentrations of microplastics (MPs) and mesoplastics (MesoPs) in Pleoticus muelleri from the Bahia Blanca Estuary (BBE), Argentina. Forty-nine individuals were collected from three sampling stations in the BBE, and each abdominal muscle with the gastrointestinal tract was analyzed. P. muelleri showed an isometric growth pattern (b = 3.0054) with values of K similar among the individuals collected (ranged between 0.80 and 0.91), considering them in good condition compared to other crustacean species around the world. 96% of shrimp presented transparent or black synthetic fibers as prevalent types, with an abundance average of (3.0 ± 2.90) MPs/g w. w. And (0.053 ± 0.16) MesoPs/g w. w. as well as a dominant size range of 0.5-1.5 mm, in accordance with recent studies in the same area. The linear regression analysis showed that K was independent of the concentration of MPs ingested by P. muelleri, with R2 ranging between 0.024 and 0.194 indicating that MPs contamination does not affect the nutritional condition of shrimp. SEM/EDX detected the presence of elements like C, O, K, and Mg, tissue residues and fractures on the surface of the analyzed fibers. FTIR confirmed different types of polymers in shrimp related to textile fabrics probably from untreated sewage discharges from nearby cities. The results of this research provide useful information for a better understanding of MPs contamination in seafood, suggesting P. muelleri as a suitable species for monitoring MPs in estuarine ecosystems. Likewise, more research is required to know the effects of MPs on food safety in humans.