Monitoring macroplastic ingestion by birds and marine mammals in northeastern Patagonia, Argentina

Diatom and macroinvertebrate communities dynamic: A co-occurrence pattern analysis on plastic substrates

Wetlands are habitats that provide numerous ecosystem services, but are often understudied and threatened by anthropogenic pollution, particularly plastic pollution. Macroplastics are a significant component of plastic litter that have high biological impacts but are often understudied. Previous studies have highlighted negative impacts on biota, but there is a lack of information about the communities of micro and macro organisms that settle on macroplastic litter. In this context, we investigated the colonization patterns and community structures of diatoms and macroinvertebrates on virgin substrates composed of two different plastic polymers, polystyrene and polyethylene terephthalate, located at two different depths in a protected wetland in Central Italy over a period of 10 months. The results show that diatom community is not highly structured by competitive forces and aggregation patterns emerges. In contrast, macroinvertebrate community appears to be randomly structured, without the presence of patterns following specific assembly rules. Randomness in macroinvertebrates assemblages could highlight the presence of different niches available for settlement of different taxa. Combined matrix analyses show that diatoms and macroinvertebrates co-occur, and their community assemblages are sometimes structured, while they appeared to be randomly assembled at other times. Whenever non-randomness of diatoms and macroinvertebrates co-occurrences was detected, it suggested aggregation. Moreover, the possible predatory relationship between different macroinvertebrates taxa should be investigated, as it could reveal important scenarios in the establishment of macroinvertebrate structured communities on plastic litter, including taxa that exploit different ecological niches. This could lead to an enrichment of the biological community within areas impacted by plastics.

What do small cetaceans tell us about trace elements pollution on the Argentinean coast? Franciscana dolphin as a biomonitor

Trace elements (TEs) constitute the oldest emerging pollutants globally, most occur from natural sources, but a few are derived from anthropogenic sources. Marine mammals are considered bioindicators of ecosystem contamination. The aims of this review is compile reports on essential and nonessential TEs occurrence in small cetaceans from Argentinean waters; and to review the existing information on the concentration of TEs in the Franciscana dolphin, a biomonitor species of the Argentine coastal marine ecosystem. We searched reports where levels of TEs were present in small cetaceans from and eight species were analysed: Pontoporia blainvillei, Tursiops truncatus gephyreus, Kogia breviceps, Delphinus delphis, Lagenorhynchus obscurus, Lagenodelphis hasei, Cephaloryhchus commersonii and Ziphius cavirostris. Essential TEs like Zn, Cu, Mn, Cr, Fe, Co, Ni, Mo, Se, As, Au, Ag, Sn, and nonessential TE as Pb, Cd, Hg, As was considered. The reports compiled in this article analysed kidney, liver, muscle and occasionally brain, skin, lung and spleen, covering a temporal range of 30 years, from 1982 to 2016. Of data analysis, we identify knowledge gaps, species of small cetaceans for which the concentration of trace metals is not yet known and areas on the Argentine coast where there are no reports that analyse them. The most recent information corresponds to the 2010 decade, and in those subsequent publications, the samples were taken at that time. This emphasizes the importance of reviewing this data, in order to compare old and new datasets, create contamination timelines and evaluate possible increases or decreases of contaminants in different study areas. The information recopilated will serve as valuable baselines to detect the future impact of increasing human, even natural, activities on marine ecosystems in the South Atlantic Ocean.

Multi-dimensional visualization of ingestion, biological effects and interactions of microplastics and a representative POP in edible jellyfish

Due to their ubiquity and potential risks, microplastics (MPs) and nanoplastics (NPs) are concerning environmental issues. Yet there are still significant knowledge gaps in understanding the tissue-specific accumulation and dynamic change of MPs and NPs in the aquatic organism and how these micro/nano-scale emerging contaminants interact with other environmental pollutants such as persistent organic pollutants (POPs). Here, in vivo imaging systems (IVIS), radioisotope tracing, and histological staining were innovatively used to reveal the fate and toxicity of fluorescently-labeled MPs/NPs and 14C-labeled 2,4,4'-trichlorobiphenyl (PCB28) in edible jellyfish Rhopilema esculentum. These contaminants' ingestion, biological effects, and interactions were visualized at cellular, tissue, and whole-body multidimensional levels. Both MPs and NPs were shown to be preferentially accumulated in the mouthlets of oral arms, and most ingested MPs/NPs were present in the extracellular environment instead of being internalized into the mesoglea. Moreover, the presence of MPs or NPs in the seawater significantly inhibited the bioaccumulation of PCB28 in the jellyfish tissue, thus alleviating physiological alteration, gastric damage, and apoptosis caused by PCB28. This study provides a multi-dimensional visualization strategy to display the distribution and biological effects of typical pollutants in marine organisms and offers new insights for understanding the impacts of MPs/NPs and POPs on marine ecosystems.