Institute of Marine and Coastal Research

Estuaries are dynamic but understudied nodes in the global plastic cycle where hydrodynamics and particle interactions govern microplastic fate. We applied high-sensitivity pyrolysis gas chromatography tandem mass spectrometry and elutriation-based settling velocity experiments to quantify polymer-specific concentrations and settling behavior across Gulf of America estuaries. Site-averaged concentrations were highest in Galveston Bay (0.82–19.8 μg L–1), particularly along the Houston Ship Channel, followed by Matagorda Bay (0.09–3.7 μg L–1), whereas other Gulf estuaries had lower concentrations (0.12–3.4 μg L–1). Polymer compositions differed among estuaries likely driven by specific point sources. Settling experiments revealed a continuum of velocities, from buoyant to >38 m d–1, with frequent deviations from density-based expectations due to aggregation, biofouling, and resuspension. Time-series observations at estuarine mouths showed ebb-dominant export, indicating temporary retention within estuaries followed by tide-modulated export to the coastal ocean. Comparisons with transport modeling confirmed that retention and export depended on both polymer properties and hydrodynamic forcing. These results demonstrated that estuaries act as semipermeable filters, intermittently trapping and remobilizing microplastics before exporting them to the shelf, with important implications for regional and global plastic budgets.

The increasing incidence of skin cancer, including melanoma, combined with the need for ultraviolet (UV) filters that are safe for human health and marine ecosystems, is driving the search for new photoprotective agents. Gadusol, a natural metabolite present in marine organisms, has been identified as a compound capable of absorbing UV radiation and exerting antioxidant functions. In this study, we investigated the photoprotective effects of gadusol on non-tumorigenic murine melanocyte cell line exposed to UVB radiation. Cell viability was assessed by trypan blue exclusion, and parameters of cell death, reactive oxygen species (ROS) generation, and proliferation were also analyzed. The results showed that gadusol (50 μM) did not exhibit cytotoxicity and, when administered during exposure to 15 and 30 mJ/cm2 of UVB, protected cells against reduced cell viability and viable cell count. Furthermore, gadusol also protected against apoptosis, attenuated ROS production, and maintained the proliferative rate at levels similar to the control, even under high UVB doses (30 mJ/cm2). We conclude that gadusol exerts effective photoprotective action, attenuating the effects of UVB radiation on melanocytes without compromising cell viability or proliferation. These findings reinforce the potential of gadusol as a safe, effective, and environmentally sustainable alternative for skin photoprotection applications.

Abstract This paper describes seasonal and annual Mid‐Holocene (MH) temperature in South America simulated by PMIP2, PMIP3, and PMIP4 experiments and compares with information extracted from paleoclimate proxies. The study is focused on seasonal and annual MH anomalies with respect to the pre‐Industrial (PI) climatology in PMIP2, PMIP3, and PMIP4 as well as MH anomalies with respect to the present‐day (PD) climate in PMIP3 and PMIP4 (PD was not part of PMIP2 experiments). Results show that the three PMIP generation of models agree on colder MH in austral autumn and warmer MH in austral spring with respect to the PI which is a consequence of insolation changes. With the inclusion of modern warming produced by anthropogenic forcing, PMIP3 and PMIP4 agree on colder MH with respect to the PD except over broad areas in austral spring in which the reduction of temperature from MH to PI in response to insolation changes has not been reversed by human‐induced warming yet. Comparisons of these model results against proxy‐based reconstructions is challenging over most of South America due to three main reasons: (a) proxy information is scarce or absent over broad areas; (b) there are marked discrepancies among paleorecords extracted from nearby sites; and (c) estimated proxy uncertainties imply wide ranges of values of the reconstructed anomalies. Comparisons between paleorecords and model outputs over areas with unequivocal proxy‐based signals of change show dissimilar results.

The Burmeister's porpoise ( Phocoena spinipinnis ) is a small cetacean endemic to South America, yet its diet is poorly known along Argentina's northern coast. We analyzed stomach ( n = 18) and intestinal ( n = 2) contents of 18 stranded or bycaught individuals collected from 1996 to 2024 between San Bernardo and Necochea (36°42′–38°33′S), Buenos Aires, Argentina. From the nine individuals with contents, 12 prey species were identified: 10 teleosts, 1 squid, and 1 crustacean. The striped weakfish ( Cynoscion guatucupa ) was the most important prey based on the index of relative importance (IRI% = 52.7), followed by Brazilian codling ( Urophycis brasiliensis ) (IRI% = 30.9). While the striped weakfish showed the highest frequency of occurrence (FO% = 27.8) and numerical abundance (NA% = 28.9), the Brazilian codling contributed most to biomass (BI% = 50.8). Teleost lengths ranged from 6.3 to 54.6 cm (23.7 ± 11 cm). All identified prey are of commercial interest, and 75% fall within commercial sizes. These results indicate a diet focused on demersal and pelagic coastal prey and suggest potential resource competition with local fisheries and sympatric predators. This is the first diet study for Burmeister's porpoise in northern Argentina and provides critical baseline data for its conservation.

Reducing waste in the fishing industry and adding value by implementing a circular economy is a key objective to establish a more sustainable use of the natural resources. This waste contains various bioactive molecules, such as collagen, which presents an increasing demand from the consumers. The narrownose smooth-hound (Mustelus schmitti) processing generates a large amount of residues. This study aimed to optimize the traditional collagen extraction process and evaluate alternative eco-friendly collagen extraction techniques using the narrownose smooth-hound skin as raw material. Results showed that the pre-treatment optimal conditions were 2 h of deproteinization followed by 6 h of defatting. Acid extraction required 72 h to achieve maximum yield. Likewise, the maximum yield for the enzymatic extraction was obtained using 10% v/v pepsin and 24 h of treatment. As an alternative technique, an enzymatic extraction was conducted using an endogenous enzyme obtained from the narrownose smooth-hound stomach. This method acquired higher yields than the acid control and slightly lower yields than the commercial pepsin control. On the other hand, an acid extraction assisted with sonication was evaluated, with no significant differences observed. All extracts obtained were characterized by SDS-PAGE, FTIR, UV-spectra, and amino acid profile, confirming the presence of type I collagen. This study offers a sustainable solution to reduce fishery waste, generating two value-added products, collagen and endogenous enzymes. PRACTICAL APPLICATIONS: Optimization of collagen extraction from fisheries waste. Enzymatic extraction showed higher yields than the acidic one. Endogenous enzymes of fishery waste are a viable alternative for collagen extraction. The extracts obtained have characteristics that suggest type I collagen.