Evaluación interdisciplinar de la presencia y distribución de las basuras marinas (macro-residuos flotantes, microplásticos y aditivos plásticos), y de sus impactos en vertebrados marinos

[spa] La basura marina está aumentando exponencialmente en los mares y océanos de todo el mundo. En los últimos años, se han reportado y documentado sus amenazas a la fauna marina y a los ecosistemas marinos en general. Por estas razones, se están fomentando medidas de mitigación y campañas de monitoreo para determinar cuáles son las zonas de acumulación de basura marina y evaluar la eficacia de las medidas propuestas. Sin embargo, todavía falta información para determinar los niveles basales de basura marina y mejorar las metodologías de monitoreo. El objetivo general de la presente tesis es estudiar la basura marina de manera interdisciplinar para tener una visión más amplia de sus potenciales efectos sobre los vertebrados marinos. En el primer capítulo, se investigan los macro-residuos flotantes mediante fotografía aérea desde drones y los macro-residuos flotantes y megafauna marina desde avionetas y se desarrolla un modelo de aprendizaje profundo para detectar y cuantificar los macro-residuos flotantes en las imágenes aéreas. Los resultados revelan que las técnicas de teledetección son igual o incluso más efectivas que las técnicas visuales para detectar macro-residuos flotantes y megafauna marina, y el modelo de aprendizaje profundo, instalado en una aplicación web, alcanza una efectividad del 81%. En el segundo capítulo, se utilizan tres especies potencialmente bioindicadoras (la boga (Boops boops), el rorcual común (Balaenoptera physalus) y el lobo marino antártico (Arctocephalus gazella)) para determinar la ocurrencia de microplásticos. Los resultados revelan la ocurrencia de microplásticos en el 46% y 52% de bogas de la costa catalana y rorcuales comunes del Atlántico Norte, respectivamente. Por lo contrario, no se encontraron microplásticos en los excrementos de lobo marino antártico, resultado que sugiere que las aguas del Estrecho de Bransfield presentan niveles muy bajos de contaminación plástica. En el tercer capítulo, se determina la concentración de aditivos plásticos en muestras de tejido de vertebrados marinos, para analizar su relación con las concentraciones de microplásticos e investigar los procesos de bioacumulación y biomagnificación de estos contaminantes. Los resultados muestran que las bogas del Mediterráneo presentan niveles considerables, pero no preocupantes, de ésteres organofosforados en sus tejidos musculares y que estas concentraciones no están relacionadas con la ocurrencia de microplásticos en sus tractos gastrointestinales. Además, los resultados muestran que los rorcuales comunes del Atlántico Norte presentan ésteres organofosforados y ftalatos en sus tejidos musculares y, aunque parece que los niveles no sean preocupantes para la viabilidad de sus poblaciones, una exposición a largo término podría desencadenar una toxicidad crónica. Además, parece ser que los ésteres organofosforados no se bioacumulan ni biomagnifican, y que los ftalatos no presentan diferencias intra-poblacionales ni temporales en rorcual común. En conjunto, los resultados de esta tesis proporcionan información de utilidad para mejorar los programas de monitoreo de basuras marinas y datos que pueden ser usados como referencia de los valores basales de macro-residuos flotantes, microplásticos y aditivos plásticos.[eng] Marine litter is increasing exponentially in the seas and oceans of the world. In recent years, its threats to marine fauna and marine ecosystems in general have been reported and documented. For these reasons, mitigation measures are being adopted and monitoring programmes are being set in place to determine accumulation zones and evaluate the effectiveness of adopted measures. However, the information needed to determine baseline levels of marine litter and to improve and standardize monitoring methodologies is still poor. The general objective of this thesis is to investigate marine litter through an interdisciplinary approach to gain a broader perspective of its potential effects on marine vertebrates. In the first chapter, floating marine macro-litter is investigated using aerial photography from drones; floating marine macro-litter and marine megafauna are observed with a combined visual- and photographic-based approach from aircraft, and a deep learning model is developed to detect and quantify the floating marine macro-litter in aerial images. Results reveal that remote sensing techniques are as effective or more effective than visual techniques in detecting floating marine macro-litter and marine megafauna, and the deep learning model, installed in a web application, achieves an accuracy of 81%. In the second chapter, three potential bioindicator species (i.e., the bogue (Boops boops), the fin whale (Balaenoptera physalus) and the Antarctic fur seal (Arctocephalus gazella)) are analysed to determine the occurrence of microplastics. Results reveal the occurrence of microplastics in 46% of the bogues sampled from the Catalan coast and in 52% of the North Atlantic fin whales, respectively, while no microplastics are found in Antarctic fur seal scats, suggesting that the waters of the Bransfield Strait have very low levels of plastic contamination. The third chapter aims to determine the concentration of plastic additives in samples of marine vertebrate tissues, analyse its relationship with the occurrence of ingested microplastics and investigate the processes of bioaccumulation and biomagnification of these pollutants. Results show that the levels of organophosphate esters in the muscle of the bogues from the Mediterranean Sea are considerable but not of concern and do not relate to the occurrence of microplastics in the fish gastrointestinal tracts. In addition, organophosphate esters and phthalates are detected in the muscle of North Atlantic fin whales, and although their levels do not seem of concern for the viability of the fin whale population, long-term exposure may lead to chronic toxicity. Finally, phthalate concentrations do not show intra-population or temporal differences in fin whales and organophosphate esters do not appear to bioaccumulate throughout the whale life-span and/or biomagnificate through the food web. The results of this thesis provide relevant information to improve marine litter monitoring programs as well as useful data to produce reference baseline values of floating marine macro-litter, microplastics and plastic additives

Beached and Floating Litter Surveys by Unmanned Aerial Vehicles: Operational Analogies and Differences

The abundance of litter pollution in the marine environment has been increasing globally. Remote sensing techniques are valuable tools to advance knowledge on litter abundance, distribution and dynamics. Images collected by Unmanned Aerial Vehicles (UAV, aka drones) are highly efficient to map and monitor local beached (BL) and floating (FL) marine litter items. In this work, the operational insights to carry out both BL and FL surveys using UAVs are detailly described. In particular, flight planning and deployment, along with image products processing and analysis, are reported and compared. Furthermore, analogies and differences between UAV-based BL and FL mapping are discussed, with focus on the challenges related to BL and FL item detection and recognition. Given the efficiency of UAV to map BL and FL, this remote sensing technique can replace traditional methods for litter monitoring, further improving the knowledge of marine litter dynamics in the marine environment. This communication aims at helping researchers in planning and performing optimized drone-based BL and FL surveys

Boops boops as a bioindicator of microplastic pollution along the Spanish Catalan coast

Microplastic pollution is a growing cause of concern for the marine environment, particularly in the Mediterranean Sea, which is considered to be one of the most polluted seas worldwide. In this study, the gastrointestinal tracts of 102 bogues (Boops boops), sampled from three areas off the Catalan coast (Spain) subject to different degrees of industrialization, were analysed to assess microplastic ingestion and thus estimate local levels of microplastic pollution. Microplastics were detected in 46% of samples analysed. As expected, the abundance and frequency of occurrence of ingested microplastics were higher off the most anthropized area of Barcelona. The majority of ingested microplastics were blue fragments ranging 0.1-0.5 mm, and the most common polymer type was polypropylene. The results of this study indicate the area off Barcelona as a possible area of concentration for microplastics, further supporting the use of B. boops as a bioindicator to assess microplastic pollution

Automatic detection and quantification of floating marine macro-litter in aerial images: introducing a novel deep learning approach connected to a web application in R

The threats posed by floating marine macro-litter (FMML) of anthropogenic origin to the marine fauna, and marine ecosystems in general, are universally recognized. Dedicated monitoring programmes and mitigation measures are in place to address this issue worldwide, with the increasing support of new technologies and the automation of analytical processes. In the current study, we developed algorithms capable of detecting and quantifying FMML in aerial images, and a web-oriented application that allows users to identify FMML within images of the sea surface. The proposed algorithm is based on a deep learning approach that uses convolutional neural networks (CNNs) capable of learning from unstructured or unlabelled data. The CNN-based deep learning model was trained and tested using 3723 aerial images (50% containing FMML, 50% without FMML) taken by drones and aircraft over the waters of the NW Mediterranean Sea. The accuracies of image classification (performed using all the images for training and testing the model) and cross-validation (performed using 90% of images for training and 10% for testing) were 0.85 and 0.81, respectively. The Shiny package of R was then used to develop a user-friendly application to identify and quantify FMML within the aerial images. The implementation of this, and similar algorithms, allows streamlining substantially the detection and quantification of FMML, providing support to the monitoring and assessment of this environmental threat. However, the automated monitoring of FMML in the open sea still represents a technological challenge, and further research is needed to improve the accuracy of current algorithms

Automatic detection and quantification of floating marine macro-litter in aerial images: Introducing a novel deep learning approach connected to a web application in R

The threats posed by floating marine macro-litter (FMML) of anthropogenic origin to the marine fauna, and marine ecosystems in general, are universally recognized. Dedicated monitoring programmes and mitigation measures are in place to address this issue worldwide, with the increasing support of new technologies and the automation of analytical processes. In the current study, we developed algorithms capable of detecting and quantifying FMML in aerial images, and a web-oriented application that allows users to identify FMML within images of the sea surface. The proposed algorithm is based on a deep learning approach that uses convolutional neural networks (CNNs) capable of learning from unstructured or unlabelled data. The CNN-based deep learning model was trained and tested using 3723 aerial images (50% containing FMML, 50% without FMML) taken by drones and aircraft over the waters of the NW Mediterranean Sea. The accuracies of image classification (performed using all the images for training and testing the model) and cross-validation (performed using 90% of images for training and 10% for testing) were 0.85 and 0.81, respectively. The Shiny package of R was then used to develop a user-friendly application to identify and quantify FMML within the aerial images. The implementation of this, and similar algorithms, allows streamlining substantially the detection and quantification of FMML, providing support to the monitoring and assessment of this environmental threat. However, the automated monitoring of FMML in the open sea still represents a technological challenge, and further research is needed to improve the accuracy of current algorithms.Peer ReviewedPostprint (published version

Perfluoroalkyl substances in striped dolphins (Stenella coeruleoalba) from the NW Mediterranean Sea: Biomagnification and temporal trends (1990-2021)

Poly- and Perfluoroalkyl Substances (PFAS) are widely recognized as a class of pollutants known for their ability to bioaccumulate and biomagnify in the environment. In this study, the objective is to determine the biomagnification rates of PFAS in sexually mature striped dolphins and assess the temporal trends of PFAS concentrations over the past three decades (1990-2021) in the North-Western Mediterranean Sea. Thirteen out of the 19 targeted PFAS compounds were detected in the digestive content of the dolphins, while all 17 PFAS compounds were detected in the liver samples. Concentrations of PFAS in the digestive content ranged from 50 to 1611 ng/g, while the liver samples showed concentrations ranging from 268 to 7014 ng/g. The most prevalent compounds found in both types of samples were linear perfluorooctanesulfonic acid (n-PFOS) and perfluorooctanesulfonamide (FOSA), which were present in all samples. Additionally, perfluoroundecanoic acid (PFUnDA), perfluorotridecanoic acid (PFTrDA), and perfluorononanoic acid (PFNA) were also detected in significant quantities. Interestingly, the study found that long-chain PFAS compounds exhibited greater biomagnification rates compared to short-chain PFAS compounds in striped dolphins. This suggests a potential impact on the health of these marine mammals due to the accumulation of long-chain PFAS in their systems. The analysis of the samples indicated that half of the digestive content samples exceeded the Environmental Quality Standards (EQS) concentrations, indicating that the consumption of polluted prey may pose health risks for striped dolphins. When examining the temporal trends, the concentrations of most long-chain PFAS compounds showed an increase from 1990 to 2004-2009. However, concentrations appeared to stabilize during the period of 2014-2021, potentially reflecting the impact of country regulations and industry initiatives aimed at reducing PFAS pollution. These findings underscore the persistent presence of banned PFAS compounds in the marine ecosystem and highlight the need for ecological risk assessments and the development of management strategies to mitigate PFAS pollution in marine environments. In conclusion, this study provides valuable insights into the biomagnification rates of PFAS in striped dolphins and highlights the persistent nature of these pollutants in the North-Western Mediterranean Sea. The identification of specific PFAS compounds and their temporal trends contribute to the understanding of PFAS pollution and support future efforts in assessing ecological risks and implementing effective management strategies in marine ecosystems

Así detectamos y contamos la basura que flota en el mar

Los residuos marinos se definen como cualquier material sólido persistente que ha sido manufacturado o procesado y después, desechado, perdido o abandonado en el medio marino o costero. Están presentes en todos los mares y océanos del mundo y amenazan todo tipo de fauna marina, desde invertebrados, peces y tortugas hasta mamíferos marinos

Transplacental transfer of plasticizers and flame retardants in fin whales (Balaenoptera physalus) from the North Atlantic Ocean

Marine mammals are one of the groups of animals most affected by marine pollution including that by organic compounds which, besides bearing recognised harmful effects to adults, they may also affect foetuses through placental transfer. In this study we analysed samples of fin whale (Balaenoptera physalus) females and their foetuses collected in the western Iceland summer feeding grounds in 2018. Three different families of organic pollutants: organophosphate esters (OPEs); halogenated flame retardants (HFRs); and short chain chlorinated paraffins (SCCPs), were analysed and their placental transfer investigated. HFRs were detected in 87.5% of females and 100% of foetus samples with concentrations that ranged between nd-15.4 and 6.37–101 ng/g lipid weight (lw), respectively. OPEs were detected in all samples, both from females (85.8–567 ng/g lw) and foetuses (nq-1130 ng/g lw). SCCPs were detected in 87.5% of female samples and 100% of foetal samples with concentrations that ranged between nd-30.9 and nq-574 ng/g lw, respectively. For OPE compounds, a significant negative correlation was observed between the logarithm maternal transfer ratio and their log Kow, indicating that a high lipophilicity reduced placental transfer rate. Interestingly, the decabromodiphenyl ethane (DBDPE) was the compound with the highest log Kow but also the one that was transferred the most from mothers to foetuses, calling for in-depth research on this pollutant. These results constitute the first evidence of mother-calf transfer of plasticizers and flame retardants in fin whales. Further investigations are needed to determine their potential effects on this species and other groups of animals.During the conduct of this study, one of its authors, Gísli Arnór Víkingsson, sadly died unexpectedly. Serve this article as a last tribute to his memory. This study was supported by the Spanish Ministry of Science and innovation (grant CEX 2018-000794-S and project PID2020-119712GBI00) (MCIN/AEI/10.13039/501100011033), by the Ministry of Economic Affairs and Digital Transformation (project CGL2015-70468-R (MINECO, FEDER, UE)), and by the Generalitat de Catalunya (Consolidated Research Group 2017 SGR 1404 - Water and Soil Quality Unit 2017 SGR 1404).Peer reviewe

Assessment of bisphenols and phthalates concentrations in Mediterranean striped dolphins (Stenella coeruleoalba)

International audienc

Ingestion of synthetic particles by fin whales feeding off western Iceland in summer

In this study we aim to assess the daily ingestion rates of synthetic particles by the fin whales (Balaenoptera physalus) that feed off the western coast of Iceland. To do so, we collected and analysed samples from the stomach content of 25 fin whales, consisting solely of northern krill (Meganyctiphanes norvegica). The particles found consisted of fibres and fragments, mainly blue, black and red, with an average size of 1.2 ± 1.3 mm. To confirm the synthetic nature of these particles, we used Micro-Fourier Transform Infrared Spectroscopy and comparison with a polymer library. The mean concentration of synthetic particles in the krill samples found in the stomachs of whales was 0.057 particles per gram, a value much lower than that previously reported for particle uptake by krill. From this concentration in krill, we estimated that the daily intake of synthetic particles for the North Atlantic fin whale would be ranging from 38,646 ± 43,392 to 77,292 ± 86,784 particles per day. Although at this level it is not possible to assess the impact of synthetic particles and their associated chemicals on the North Atlantic fin whale population, concentrations of these contaminants are likely to increase in the future, potentially causing adverse effects on whales and other marine mammals