Automated FerryBox monitoring reveals the first recorded river induced crude oil seep transport to the Strait of Magellan in southern Patagonia

This study presents the first documented occurrence of a natural crude oil seep plume associated with river discharge along the Strait of Magellan in southern Patagonia in modern times. Between September and December 2022, hydrocarbon signals were detected using a crude oil sensor integrated into a FerryBox system that traversed the Strait of Magellan and several channels of southern Patagonia, covering approximately 510 km. The highest levels of crude oil signals were observed in the mid-basin of the Strait of Magellan. These signals exhibited a strong negative correlation with sea surface salinity, coinciding with the water discharge from the San Juan River. Notably, during periods of high river discharge, typically exceeding 15 m3 s-1, a distinct crude oil plume was detected moving towards the Magellan Strait. Conversely, when river discharge fell below this threshold, no noticeable crude oil signal was observed. As river discharge decreased and winds intensified during the austral summer, the crude oil signal gradually dissipated. This observation suggests that the dispersion of crude oil becomes limited during periods of low river discharge, as buoyant currents remain confined close to the coast. Historical records indicate that this seep has been releasing hydrocarbons into the Strait of Magellan for at least the past 120 years, implying a long history of chronic crude oil input into this relatively isolated region of the world. This finding shows the potential contribution to the understanding of marine ecosystems dynamics and potential pollutants in poorly studied regions through the use of automated monitoring FerryBox system, enabling both spatial and temporal high-resolution surveys.

The hotspots of entanglement for pinnipeds of the world

Pinnipeds represent one of the most vulnerable marine groups severely affected by entanglements. However, the lack of standardized data collection poses a challenge when comparing the impacts of fishing gear across various geographic regions. In this study, we employed Generalized Additive Models to predict entanglement incidents stemming from fishing-related activities for 13 pinniped species across the last four decades (1976-2017). The models incorporated reported entanglement numbers, fishing effort covariates based on different gear types, and floating plastic debris distribution for each species. Through this approach, we generated global hotspot maps that pinpoint regions of heightened vulnerability where pinnipeds are susceptible to entanglement in lost gear. The best-performing model highlighted both species characteristics and the presence of floating plastic debris as pivotal factors in predicting pinniped entanglements. Our analysis revealed entanglement hotspots in the North Pacific and Southeastern Australia. This demonstrates the efficacy of our methodology in identifying high-priority geographic areas.

Marine debris and associated organic pollutants in surface waters of Chiloé in the Northern Chilean Patagonia (42°-44°S)

We report the occurrence of plastics and associated persistent organic pollutants (POPs) in surface waters from Northern Chilean Patagonia. A total of 200 particles were found during the conducted survey. The highest number of particles found was 0.6 item m^-3. We found that 53 % of the collected particles corresponded to plastic, with an average of 0.19 ± 0.18 item m^-3. Microplastics (68 %) were the dominant size found in the area, followed by macroplastics (18 %) and mesoplastics (14 %). Most plastic particles were white (55 %) while others were <10 % each. Black and light blue represented 9 %; red, dark blue, and other colors 7 %; and green 6 %. Fragments were the most frequent shape of plastic debris (38 %), followed by Styrofoam (30 %) and fiber (27 %). Higher PBDE levels were found in the central zone, and those were higher than DDT, PeCB, HCB, and PCB levels. This study is the first report on POP occurrence in marine plastic debris from Chiloé Sea in the Northern Chilean Patagonia.

A decade later, reviewing floating marine debris in Northern Chilean Patagonia

Floating marine debris (FMD) were abundantly reported in the Northern Chilean Patagonia in 2009 where sea-based activities (mussel and salmon aquaculture) are responsible for most of them. Identifying the sources of FMD is important to take the necessary actions to diminish their abundance. In 2019 eleven transects were opportunistically conducted to evaluate the abundance, spatial distribution and composition of FMD in the same area, and to compare them with the previous study using the same methodology. FMD identified were classified into the same six categories from the previous study, however "Others" category were now the dominant one indicating that new pollutants have been increasing during the last decade. Inside the "others" category, plastics buoy and other floating devices, that normally are used by the salmon aquaculture, were the main items. Similarly than the previous study, styrofoam and domestic plastics were also the other most abundant items. In general, also, an increase in abundance compared with the previous study was found. The highest abundances were similarly found in the "Golfo de Corcovado" zone ranging from 50 to 230 items km^-2. Our results, as well as the previous study, confirm that sea-based activities are still responsible for the FMD found in the Northern Patagonia. To avoid the origin of this contamination it is urgent to implement public policies that effectively reduce FMD, and hold the aquaculture industries responsible.

Microplastic ingestion cause intestinal lesions in the intertidal fish Girella laevifrons

We exposed juvenile intertidal fish to different amounts of Poly(styrene-co-divinylbenzene) microplastics in their diet. We fed ten individuals with pellets containing 0.01 g, another ten fish with pellets containing 0.1 g of PS, and ten fish without plastic as control. After 45 days of treatment, the whole intestine was removed, and the histological evaluation started immediately. We evaluated inflammation due to leukocyte infiltration (Lk), circulatory disorders like Hypermeia (Hyp), and regressive changes in the intestinal tissue, assessing Crypt cell loss (Ccl) and Villi cell loss (Vcl). The severity of the lesions increased according to the microplastic concentration. In the fish group feeding on microplastics, we found that leukocyte infiltration and hyperemia were more severe in the higher exposure group compared to the lower exposure; and crypt cell loss and villi cell loss increased significantly due to Poly(styrene-co-divinylbenzene) microplastic physical abrasion.

First detection of plastic microfibers in a wild population of South American fur seals (Arctocephalus australis) in the Chilean Northern Patagonia

The dramatic increase of microplastics (plastic fragments <5 mm) in marine environments is a problem that has attracted public attention globally. Within the different types of microplastics, microfibres are the least studied (size <1 mm). We examined 51 female scats from a population in Northern Patagonia. Our results showed no presence of microplastic particles, however 67% of them showed a remarkable abundance of microfibers, which until now had only been reported in animals fed in captivity. As a result of this work we propose that the examination of scats from South American Fur Seal and also other pinnipeds could be an efficient tool to monitor environmental levels of microfibres and maybe microplastics in the environment due to the easy recognition of the animals and their scats.