Plastic Debris Research Articles

Literature-based database to inform policy making on marine plastic pollution in ASEAN+3

The ASEAN+3 countries urgently need to present actual data on the state of their marine plastics pollution, so that they can respond to the criticisms of being the top-5 global sources of marine plastics based on modeled predictions, as well as to develop effective response policies based on sound data. While the research outputs on marine plastic pollution have increased spectacularly across these countries, their overall resource capacity to access the data remains lacking. This study describes a robust framework developed to use >700 peer-reviewed research publications from the region that can inform policy-making. First, detailed metadata fields were developed for this database focused on extracting information from the publications that are relevant to regional policy questions being asked to adequately respond to the threats posed by marine plastics. Second, the curation of research publications in this database greatly depended on a team of regional researchers, who were apt in the subject matter and a native language speaker. The latter was critical in the capture of non-English articles to boost the quality of database. Some of the key findings from the broad analyses included the rapid increase in research efforts on marine plastics between 2014 and 2021, which coincided with the growing concerns of this environmental crisis, the dominant publication language was English despite the diversity of countries, and the dominant research topic appeared to be of policy response measures. Overall, the database produced adequate and immediate data, where policy-makers can leverage for urgent actions. For example, the output on the status of marine plastic pollution is ever-increasing, but the region could start to focus on knowledge gaps (e.g., sampling in critical sensitive habitats like seagrasses and coral reefs). Finally, this study presented a comprehensive summary of the current state of marine plastic pollution and knowledge gaps (e.g., technical capacity and equipment) of the region that can facilitate discussions among target audience including the governments as well as international and regional regulating bodies, the research community and plastic waste management professionals.

Plastic debris beaching on two remote Indian Ocean islands originates from handful of Indonesian rivers

Abstract Large amounts of plastic waste from non-local sources (>200 tonnes) wash up on Christmas Island and the Cocos Keeling Islands, two remote Indian Ocean islands, every year. Local communities on these islands organize beach clean-ups regularly to tackle this problem and, because their waste systems cannot handle the enormous amounts of plastic, predominantly incinerate the collected waste. However, as long as plastic waste keeps entering the ocean, beach clean-ups alone cannot be sustained. The first crucial step to solving this problem is to determine the main sources of plastic waste to the islands. In this study, we simulate the transport of floating plastic waste to determine the main riverine sources of plastic reaching the islands. We find that the majority of simulated plastic waste comes from just 4 Indonesian rivers: the Solo, Brantas, Ci Tanduy, and Wai Sekampung. We suggest that further numerical and field studies, as well as potential river clean-up efforts focus on these rivers to stop plastic waste inundating Christmas Island and the Cocos Keeling Islands.

Plastic Debris in the Aquatic Environment: An Emerging Substratum for Antimicrobial Resistant (AMR) Biofilms.

Plastic pollution has quadrupled over the past years and has become a global concern due to its direct impact on life forms. The present study analysed whether the plastic debris in aquatic environments could act as the substratum for the antimicrobial-resistant (AMR) bacteria to form biofilm for survival. We have collected various plastic debris (n = 32) from six sites of the Periyar River, the drinking water source for the entire city and one of the most polluted rivers in Kerala (India). The chemical composition of plastics was screened via FTIR analysis and found that they comprised two types, viz., polyethylene and polypropylene. Bacteria isolated from the samples were screened for the AMR characteristics towards eight different classes of antibiotics. All isolates showed 100% resistance towards colistin and obtained the MAR index value of 0.1-0.4 range. Six representative bacterial isolates with high multiple antibiotic resistance (MAR) index were selected and identified by 16sRNA sequencing as Lysinibacillus mangiferihumi, Bacillus pumilus, Bacillus safensis, Bacillus cereus, Bacillus altitudins and Bacillus pumilus. In vitro biofilm formation was experimented on the purchased plastic samples in artificial media and river water using two selected strains, Bacillus pumilus and Bacillus cereus. Significant variations were observed in biofilm growth in different media (P < 0.05) regardless of plastic types (P > 0.05). The extracellular polymeric substances (EPS) and the characteristic holes on the surface morphology were visualized in SEM analysis, thus indicating the conditioning of the plastics by the isolates for biofilm formation.

The role of energetic flow structures on the aeolian transport of sediment and plastic debris

The role of energetic flow structures on the aeolian transport of sediment and plastic debris

Critical review on unveiling the toxic and recalcitrant effects of microplastics in aquatic ecosystems and their degradation by microbes.

Production of synthetic plastic obtained from fossil fuels are considered as a constantly growing problem and lack in the management of plastic waste has led to severe microplastic pollution in the aquatic ecosystem. Plastic particles less than 5mm are termed as microplastics (MPs), these are pervasive in water and soil, it can also withstand longer period of time with high durability. It can be broken down into smaller particles and can be adsorbed by various life-forms. Most marine organisms tend to consume plastic debris that can be accumulated easily into the vertebrates, invertebrates and planktonic entities. Often these plastic particles surpass the food chain, resulting in the damage of various organs and inhibiting the uptake of food due to the accumulation of microplastics. In this review, the physical and chemical properties of microplastics, as well as their effects on the environment and toxicity of their chemical constituents are discussed. In addition, the paperalso sheds light on the potential of microorganisms such as bacteria, fungi, and algae whichplaya pivotal role in the process of microplasticsdegradation. The mechanism of microbial degradation, the factors that affect degradation, and the current advancements in genetic and metabolic engineering of microbes to promote degradation are also summarized. The paper also provides information on the bacterial, algal and fungal degradation mechanism including the possible enzymes involved in microplastic degradation. It also investigates the difficulties, limitations, and potential developments that may occur in the field of microbial microplastic degradation.

“Strategic Environmental Assessment” Oriented to Marine Litter (SEAmarlitt): a New Approach to Diagnose Management and Governance in Brazil

Objective: Develop and present a Strategic Environmental Assessment (SEA) approach focused on marine litter. Theoretical Framework: SEA is a set of analytical and participatory approaches designed to integrate environmental and sustainability considerations into public policy decision-making. The development of new SEA approaches has allowed its use in different sectors and geographic areas. The creation of the “United Nations Decade of Ocean Science for Sustainable Development” contributed to the development of SEA focused on marine litter. Method: The methodology applied is qualitative and was developed from two analysis methods: composition of the conceptual model to select the Elements of the Methodological Structures; and conceptual modeling to construct the conceptual model of the new SEA approach. Results and Discussion: It was possible to develop a conceptual model of the SEA approach oriented to marine litter (SEAmarlitt) composed of three groups and 13 classes, where each class represents an element of the conceptual model. Research Implications: The next challenge is to operationalize SEAmarlitt by applying its conceptual model to coastal regions of Brazil. This phase is crucial to test its efficiency and validate the model. Originality/Value: This study presents SEAmarlitt, an unprecedented methodological approach to SEA in Brazil focused on marine litter.

Seasonal biophysical interactions in tidal marsh evolution: insights from a synchronized dataset in Jiangsu, China

IntroductionTidal marsh wetlands provide essential and valuable services to the wider interconnected marine and coastal environment, although the complex intertwined processes in morphological evolution remain insufficiently understood owing to synchronized data scarcity, limiting the development of numerical models and management strategies.MethodsThis study investigated the hydrodynamic, biological, sediment and morphological processes on the Doulong tidal wetlands, Jiangsu, China, using a one-year field dataset that captured spatial and seasonal variations.Results and discussionOur results indicate that biophysical interactions among multiple processes could result in some overlooked sedimentary behaviours and bio-morphological patterns in tidal marsh wetlands. Firstly, the dominance of alongshore currents caused a rapid alongshore expansion of saltmarsh patches, by which the marsh edge achieved seaward advancing, markedly different from the widely reported cross-shore expansion. Secondly, results showed that the particle size of sediment near the marsh edge coarsened when plants withered and then fined when plants grew, indicating that the seasonal variation trend of sediment grain size in saltmarshes was opposite to the trend of vegetation biomass. Thirdly, the interaction between vegetation and stranded marine debris formed banded debris zones within the saltmarsh, where debris bands could cause a biomass reduction of up to 58%, disrupting the commonly-observed parabolic biomass-elevation relationship. Meanwhile, the seasonal variation of vegetation and hydrodynamics could alter the debris positions and hence result in the formation of multiple parallel debris bands. Overall, this study provides a synchronized dataset and elucidates specific bio-morphological relationships and processes that have thus far not been systematically documented, enhancing the comprehensive understanding of tidal marsh wetland evolution.

Global stability and bifurcations in a mathematical model for the waste plastic management in the ocean

The use of plastic is very widespread in the world and the spread of plastic waste has also reached the oceans. Observing marine debris is a serious threat to the management system of this pollution. Because it takes years to recycle the current wastes, while their amount increases every day. The importance of mathematical models for plastic waste management is that it provides a framework for understanding the dynamics of this waste in the ocean and helps to identify effective strategies for its management. A mathematical model consisting of three compartments plastic waste, marine debris, and recycle is studied in the form of a system of ordinary differential equations. After describing the formulation of the model, some properties of the model are given. Then the equilibria of the model and the basic reproduction number are obtained by the next generation matrix method. In addition, the global stability of the model are proved at the equilibria. The bifurcations of the model and sensitivity analysis are also used for better understanding of the dynamics of the model. Finally, the numerical simulations of discussed models are given and the model is examined in several aspects. It is proven that the solutions of the system are positive if initial values are positive. It is shown that there are two equilibria E0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E^0$$\\end{document} and E∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E^*$$\\end{document} and if BR<1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\mathcal {B}}}{{\\mathcal {R}}}<1$$\\end{document}, it is proven that E0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E^0$$\\end{document} is globally stable, while when BR>1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\mathcal {B}}}{{\\mathcal {R}}}>1$$\\end{document}, the equilibrium E∗\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$E^*$$\\end{document} exists and it is globally stable. Also, at BR=1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\mathcal {B}}}{{\\mathcal {R}}}=1$$\\end{document} the model exhibits a forward bifurcation. The sensitivity analysis of BR\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${{\\mathcal {B}}}{{\\mathcal {R}}}$$\\end{document} concludes that the rates of waste to marine, new waste, and the recycle rate have most effect on the amount of marine debris.

Spatial and temporal patterns of floating litter in shallow habitats: Insights from high-tourism tropical areas in Northeastern Brazil

We investigated the composition, quantity, distribution and potential sources of floating litter in the subtidal zones of tropical beaches. Marine sampling sites were selected based on the presence (protected/sheltered) or absence (non-protected) of reefs. Plastic was the most abundant material, and the presence of floating litter from land-based sources was confirmed, which was likely associated with domestic and tourism-related activities, owing to irregular waste disposal. Marine debris was more abundant during the rainy season, and marine beaches had more floating litter than estuarine beaches. Coastal reefs served as a barrier, impeding the transport of marine litter by coastal currents, explaining the greater abundance of floating litter on protected/sheltered marine beaches. Thus, three mechanisms seemed to drive the amount of floating litter in the subtidal zone of the tropical beaches: 1) the availability of floating litter in the water, 2) coastal hydrodynamics favoring the accumulation of floating litter, and 3) a beach’s capacity to retain floating litter. Our study demonstrates that marine litter is an important pollution source in sensitive areas that play a key role as nurseries for marine life, especially in beaches close to reef formations.

Unaccounted plastic: Estimating waste generation from marine vessels in Bangladesh

Solid waste mismanagement induces the release of a significant amount of plastic waste into the ocean, particularly in countries with poor solid waste management systems, such as Bangladesh. Nevertheless, the total plastic input of Bangladesh by multiple sources is still unknown. Waste input from land-based sources within 50 km coastline of this country is documented. However, the quantity of plastic entering the oceans from multiple sources, such as marine vessels, is still unknown and not documented. Passengers and goods are transported via marine vessels operating in Bangladesh's Inland Water Transport sector, which has the potential to generate a substantial quantity of plastic debris that remains unaccounted for. This study represented the initial attempt to quantify the amount of debris produced by passenger-carrying marine vessels in riverine systems. The estimated total amount of plastic waste generated per day per route from marine vessels stands at 76.6 kg. The total weight of plastic waste from all pathways was 436.3 kg, resulting in an estimated annual plastic waste generation of 157,068 kg. This yearly input is 0.6 % of Bangladesh's total mismanaged waste input into the Bay of Bengal, which is 0.79 million metric tonnes. The lack of implementation of regulatory measures and ineffective waste management systems can be pointed out as the main reason behind these plastic inputs. This paper identifies the current gaps in waste management practices for riverine plastic waste and is a forerunner to creating a baseline for unified policy formulation for the government.

How plastic litter sunk by biofouling recovers buoyancy - The role of benthic predation

Estimates suggest that the amount of plastic litter discarded in the ocean is several times greater than what remains floating at the sea surface, raising questions about the fate of this marine debris. Fouling-induced sinking of plastic litter is one of the proposed mechanisms responsible for this mass difference. While some of this ‘missing’ plastic mass may be explained by the effects of fouling, it has also been hypothesized that sinking litter may return to the surface after benthic organisms consume the biofouling. However, this hypothesis has never been tested. The present study evaluated the structure and biomass of the fouling community in response to benthic predation in both summer and winter seasons. Floating PVC plates were installed during winter and summer in central Chile (36°S) until the growing biofouling community caused them to sink. Plates were then moved to the seabed, where they were exposed to benthic predation, while control plates were maintained in a mesh cage impeding predator access. In summer, all plates recovered their buoyancy, while in the winter only 60 % recovered buoyancy. All caged control samples remained on the bottom in both seasons. The community structure differed both in the treatments and across the seasons, with plates that recovered buoyancy initially being dominated by Ulva sp. and Ciona robusta. Conversely, plates that did not refloat were mainly covered by species resistant to predation such as Pyura chilensis, Austromegabalanus psittacus, and Balanus laevis. Thus, fouling community structure influences how predation facilitates buoyancy recovery, because not all epibionts can be consumed by predators. While previous studies had shown how fouling organisms cause sinking of floating litter, this is the first study to provide experimental evidence that predation can reverse this process and allow litter to resurface and become again available as dispersal vectors for native and invasive species.

The Occurrence of Marine Debris and its Impacts on Coral Reefs in the Sempu Island Nature Reserve, Malang, Indonesia

The Occurrence of Marine Debris and its Impacts on Coral Reefs in the Sempu Island Nature Reserve, Malang, Indonesia

Formation mechanisms and biogeochemical response of coastal salinity front in the central eastern Arabian Sea

This study investigates the formation mechanisms and impact of a coastal salinity front observed in the central eastern Arabian Sea (EAS) coast, particularly off Mangalore (∼13°N), during the peak summer monsoon in August 2018. The interplay of intense monsoon rainfall, river runoff and coastal upwelling created a dynamic frontal zone characterised by distinct physical and biogeochemical properties in the central EAS. The study revealed that observed salinity fronts are formed due to the breaking of freshwater lenses by strong upwelled waters and the subsequent offshore transport of low-salinity plumes by prevailing current and Ekman transport. The high nutrient concentrations enhanced the chlorophyll a concentration 15–20 times higher (10.12 mg/m3) in the frontal zone compared to the non-frontal station. The dominance of diatoms in the frontal zone indicates herbivorous control in the coastal food web. Accumulation of plastic debris and foam-like particles in the frontal zone poses ecological risks and threatens aquatic life.

Assessment and removal of contaminants in ocean plastics for safe repurposing in a circular plastics economy

Assessment and removal of contaminants in ocean plastics for safe repurposing in a circular plastics economy

Citizen science supports national reporting of a Sustainable Development Goal indicator: A case study of plastic debris density on beaches

Global momentum to address plastic pollution has led to the development of national processes to monitor plastics into and within the environment. The Sustainable Development Goals (SDGs) provide guidance for reporting on plastic pollution, although compiling national estimates remains a challenge. Data availability remains a key barrier, which could be addressed through engagement with the citizen science community, which collects and maintains data at a resolution suitable for SDG reporting. Here, we demonstrate a process that uses citizen science monitoring of plastic debris on beaches to report on SDGs at the national scale. The study uses the Australian Marine Debris Initiative (AMDI) Database, which is composed of data submissions from over 1400 organisations across Australia. The AMDI was used to provide initial estimates of plastic debris density both nationally and across Natural Resource Management areas (NRMs). Before analysis, the database was filtered for data quality and alignment with guidance for SDG reporting (i.e., SDG Indicator 14.1.1b), resulting in the analysis of 3144 events across 538 sites between 2014 and 2019 (inclusive). The average density of plastic debris on beaches across Australia was between 0.155 and 0.279 counts m−2, with management relevant trends identified across NRMs. This study demonstrates the potential for the citizen science community to support SDG reporting and management processes, which could inform and enable actions to address plastic pollution.

Seabirds as biovectors in the transport of plastic debris across ecosystem borders: A case study from the Humboldt Current Upwelling System

Seabirds have become biovectors of plastic pollutants between marine and terrestrial ecosystems, and transport of plastics to their nesting sites becomes relevant due to increasing levels of pollution. To determine the pathways by which plastic reaches their colonies, we analysed the abundance of plastics at the nesting sites of five seabird species (Humboldt penguin Spheniscus humboldti, Peruvian booby Sula variegata, kelp gull Larus dominicanus, grey gull Leucophaeus modestus, Markham's storm-petrel Hydrobates markhami) nesting in northern Chile. Seabirds were primarily grouped according to their nesting behaviour, but two species foraging in contrasting habitats (kelp gull and Markham's storm-petrel) were also compared directly. The abundance, type, and polymer of macro-, meso- and microplastics were analysed in the soil of colonies and control sites, and microplastic ingestion was evaluated for selected species. Densities of plastics in colonies of surface-nesting seabirds ranged from 0 to 21.4 items m−2 (mainly plastic bags and thin films), and 0.002 to 19.7 items m−2 (mainly hard fragments) in colonies of burrow-nesting seabirds. Mean microplastic loads in the stomachs of seabirds were between 3.7 ± 4.2 plastic items individual−1. Overall, the abundances of plastic items in all seabird colonies were low, suggesting a limited transfer of plastics from sea to land. For kelp gulls, the results indicate transfer of macroplastic items to colonies, reaching the colony via regurgitates, with landfills considered as the main plastic source. Our results suggest that contrasting nesting behaviour and foraging habitats among species can explain differential plastic accumulation in seabird colonies, but also other factors, such as wind, contribute to the accumulation of plastic debris in colonies. Proper management of sanitary landfills are key to reduce plastic contamination of coastal seabirds and their colonies.

Abundance of Marine Macrodebris on the Northern Coast of Jaffna Peninsula, Sri Lanka.

Marine plastic debris has emerged as a pressing concern along the northern coast of Jaffna, Sri Lanka, posing a significant threat to marine resources. A preliminary study was conducted to investigate the abundance and characteristics of marine plastic debris at four major fish landing sites in the northern coast of Jaffna, using the Clean Coast Index (CCI) and Plastic Abundance Index (PAI). The results revealed that the average abundance of marine debris and plastic debris were 1.71 ± 0.42 items/m2 and 1.66 ± 0.57 items/m2, respectively. The most common types of plastic debris represented plastic rope and net pieces (23.2%), followed by unidentified weathered plastic fragments (16.7%), beverage bottles (16.2%), bottle caps and lids (13%), and styrofoam (14.1%). The recognized sources of plastic debris were mainly fishing-based activities, recreation activities, transboundary sources, and unidentified sources. The fish landing sites were classified as exceptionally polluted, with a CCI exceeding 10 and a PAI value exceeding 8. Myliddy had the highest debris density, indicating substantial pollution levels, followed by Point Pedro, Mathagal, and Valveddithurai. These findings underscore the urgency of establishing a comprehensive plastic waste management framework for the northern coast of Jaffna and devising strategies to address buoyant debris within the northern Indian Ocean. Furthermore, this study carries significant implications for the local marine ecosystem, coastal communities, and Sri Lanka's broader environmental policies and practices.

Barau's petrel, Pterodroma baraui, as a bioindicator of plastic pollution in the South-West Indian Ocean: A multifaceted approach

Marine plastic pollution is well described by bioindicator species in temperate and polar regions but remains understudied in tropical oceans. We addressed this gap by evaluating the seabird Barau's petrel as bioindicator of plastic pollution in the South-West Indian Ocean. We conducted a multifaceted approach including necropsies of birds to quantify plastic ingestion; GPS tracking of breeding adults to identify their foraging areas; manta trawling of plastic debris to measure plastic pollution at sea and modelling of plastic dispersal. We developed a spatial risk index of seabird exposure to plastic ingestion. Seventy-one percent of the analysed birds had ingested plastic. GPS tracking coupled with manta trawling and dispersal modelling show that adults consistently foraged at places with high level of plastic concentration. The highest ingestion risk occurred in the northwest of Reunion Island and at latitude 30°S. Our findings confirm that Barau's petrel is a reliable bioindicator of plastic pollution in the region.

Enhancing Underwater Object Detection and Classification Using Advanced Imaging Techniques: A Novel Approach with Diffusion Models

Underwater object detection and classification pose significant challenges due to environmental factors such as water turbidity and variable lighting conditions. This research proposes a novel approach that integrates advanced imaging techniques with diffusion models to address these challenges effectively, aligning with Sustainable Development Goal (SDG) 14: Life Below Water. The methodology leverages the Convolutional Block Attention Module (CBAM), Modified Swin Transformer Block (MSTB), and Diffusion model to enhance the quality of underwater images, thereby improving the accuracy of object detection and classification tasks. This study utilizes the TrashCan dataset, comprising diverse underwater scenes and objects, to validate the proposed method’s efficacy. This study proposes an advanced imaging technique YOLO (you only look once) network (AIT-YOLOv7) for detecting objects in underwater images. This network uses a modified U-Net, which focuses on informative features using a convolutional block channel and spatial attentions for color correction and a modified swin transformer block for resolution enhancement. A novel diffusion model proposed using modified U-Net with ResNet understands the intricate structures in images with underwater objects, which enhances detection capabilities under challenging visual conditions. Thus, AIT-YOLOv7 net precisely detects and classifies different classes of objects present in this dataset. These improvements are crucial for applications in marine ecology research, underwater archeology, and environmental monitoring, where precise identification of marine debris, biological organisms, and submerged artifacts is essential. The proposed framework advances underwater imaging technology and supports the sustainable management of marine resources and conservation efforts. The experimental results demonstrate that state-of-the-art object detection methods, namely SSD, YOLOv3, YOLOv4, and YOLOTrashCan, achieve mean accuracies (mAP@0.5) of 57.19%, 58.12%, 59.78%, and 65.01%, respectively, whereas the proposed AIT-YOLOv7 net reaches a mean accuracy (mAP@0.5) of 81.4% on the TrashCan dataset, showing a 16.39% improvement. Due to this improvement in the accuracy and efficiency of underwater object detection, this research contributes to broader marine science and technology efforts, promoting the better understanding and management of aquatic ecosystems and helping to prevent and reduce the marine pollution, as emphasized in SDG 14.

Extraction and identification of plastic debris in Sargassum spp. from the beaches of Cancun and Cozumel, Mexico

The beaches of the Mexican Caribbean have been affected by the arrival of pelagic sargassum since 2011, which has caused economic losses in the area. This research consisted on the evaluation and identification of recovered plastic particles (Rpp) from pelagic sargassum collected at eleven beaches in Cancun and Cozumel. The Rpp were extracted manually before and after washing the sargassum, as well as by filtering the water used to wash it. The Rpp were classified by their size and color using optical microscopy; obtaining that these corresponded to secondary shape plastics and are mostly white in color (35.56 %). They were classified as microplastics (90 %), mesoplastics (9 %) and macroplastics (1 %). Also, Rpp were analyzed by Fourier transform infrared spectroscopy (FTIR) and compared with FTIR spectra of standard plastics, namely, polyethylene (PE), polypropylene (PP) and polystyrene (PS); It was found that the Rpp corresponded to PE (47 %) and PP (41 %). Finally, to corroborate wear or changes in the morphology of the Rpp, they were evaluated by environmental scanning electron microscopy; and wear, fractures and holes were observed on the surface of the particles; this result could be attributed to mechanical wear by ocean waves, as well as exposure to solar radiation for long periods.