The attachement of limits for waste on the seabed It has ceased to be a generic aspiration and has become a regulated commitment in the European Union. With the agreement reached among the member states, Brussels is taking a significant step towards quantifying, with clear figures, how much waste can accumulate on the seabed before it is considered that the marine environment is seriously deteriorating.
This European regulatory advance is linked to a scientific concern of global scope: the ocean floor functions as final sink for marine pollutionespecially from the plastic pollution and other large wastes, without until now there being a homogeneous system to measure these wastes in a comparable way or a consensus on what levels are tolerable.
New thresholds for waste on the European seabed
The European Commission has announced that EU countries have agreed New limits on permitted waste on the seabedThese guidelines, conceived as an initial framework for monitoring pollution in European waters, represent the first time that specific quantitative thresholds have been defined for this type of waste.
In the areas where they are used drag studies To quantify the waste, the established criterion is that no waste is observed. increase in the amount of garbage over timeIn other words, at a minimum, levels must stabilize and not continue to grow, an objective that seeks to curb the cumulative trend of waste on the seabed.
In areas monitored by visual methods -for example, underwater cameras, remotely operated vehicles or autonomous systems-, the established reference is much more precise: No more than one waste item will be allowed per 1.000 square metersThis seemingly modest figure obliges Member States to strengthen both the spill prevention such as monitoring campaigns in coastal waters.
For now, official assessments will focus on waters up to 200 meters deepThis depth threshold defines the initial technical scope of the European monitoring system, starting from the most accessible and frequently used areas, with the idea of progressively extending it to deeper areas once the methodology is consolidated.
The purpose of these values is to turn the need into verifiable objectives reduce marine pollution, guiding national policies towards quantifiable goals and integrating the management of seabed waste into long-term environmental planning.
A critical environmental problem: from the surface to the bottom of the sea
Marine litter, and in particular plastic pollutionIt is considered one of the biggest environmental challenges for the oceans. This waste threaten species such as sea turtlesThey damage fragile ecosystems, harm coastal tourism and activities such as fishing and aquaculture, and pose a potential risk to the human health and well-being through the food chain and other exposure vectors.
Much of the waste seen on beaches or floating on the surface eventually ends up sunk to the seabedUntil recently, most of the information about this waste came from trash accidentally caught in nets during fishing. bottom trawlingHowever, technical differences between fishing gear and fishing grounds made the data difficult to compare between countries and seas, introducing a considerable margin of uncertainty.
This approach based on trawling was also limited and problematic: many areas of the seabed cannot and should not be monitored with nets, either because of their ecological sensitivity or by their geomorphological characteristics. Hence, the EU emphasizes the importance of new visual and image-based methods, capable of offering a more homogeneous and less invasive view of the state of the funds.
On a global scale, the ocean floor covers around 71% of the planet's surface and act as the final destination for a very significant portion of the waste generated on land and at sea. Recent research indicates that a considerable fraction of marine litter ends up deposited on the ocean floor. where it can remain for decadesto fragment progressively and affect organisms that live at the bottom.
Waste reaches the ocean through multiple pathways: large rivers that carry waste From the interior of continents, extreme events such as tsunamis or floods, losses and abandonment of fishing gear, as well as spills associated with industrial activity or maritime transport. All of this fuels a diffuse and difficult-to-trace problem, which complicates the definition and enforcement of specific limits.
From scattered data to image observation systems
To this day, the scientific community agrees that the ocean floor remains, to a large extent, unknown territorySome estimates indicate that there is only a visual record of around 0,001% of the funds at more than 200 meters in depth, although these areas represent approximately the 66% of the total area of the oceansOn such a fragmented basis, it is difficult to assess the true magnitude of the waste accumulation.
One of the major problems in establishing global or regional limits The problem lies in the lack of common standards for data collection and information management. Differences in methodologies, the definition of waste categories, or the sampled area hinder comparisons between studies and, consequently, the development of comprehensive analyses. coordinated policies that are based on solid evidence.
For this reason, various international scientific teams propose to put the bottom trawling with nets as the primary monitoring method and move towards strategies based almost exclusively on the direct observation and image captureThis approach is considered less harmful to ecosystems and more suitable for quantifying the presence of macro-waste (objects larger than 2,5 centimeters) in a comparable way between regions.
The platforms used for this type of observation include Remotely Operated Vehicles (ROVs), Autonomous Underwater Vehicles (AUVs), towed camera systems and modular devices of low costThanks to these technologies, it is possible to cover relatively large areas of the seabed, adjusting operating costs to the possibilities of each project or country.
The classification of the detected waste is based on hierarchical schemes developed by international organizations and in the increasing use of Artificial Intelligence to process large volumes of images. However, machine learning still faces difficulties stemming from a lack of sufficiently large databases and homogeneous labeling criteria.
Integration of the new boundaries into European marine strategies
In the EU context, the introduction of these thresholds for marine litter is part of the Marine Strategy Framework Directive (DMEM), which obliges Member States to achieve and maintain a good environmental condition of its marine waters. This regulation acts as a general umbrella for various policies related to environmental quality, including waste management.
To comply with the new limits, countries will need to incorporate specific measures in their marine strategiesThese guidelines already address issues such as biodiversity protection, reducing pollution from land and sea, and the sustainable use of resources. The amount of litter accumulating on the seabed will therefore become a key indicator within this set of objectives.
The technical work does not end with the definition of these initial thresholds. The Commission and the Member States plan to continue refining the criteria over the coming years, with the possibility of setting higher thresholds. additional limits for the most harmful types of waste from an ecological or health perspective, and to develop specific protocols for new waste categories that may appear with the evolution of human activities.
Likewise, the following is on the table: expansion of monitoring to deeper watersprogressively extending the spatial scope of the assessments. This extension into abyssal and bathyal zones is especially relevant for Europe, which has extensive deep areas in the Northeast Atlantic and the Mediterranean, where the pressure of human activity combines with a limited dispersal capacity.
The agreed threshold values have been developed by the Technical Group on Marine Debris within the framework of the DMEM and were supported by EU marine directors during a meeting chaired by the Danish Presidency of the CouncilUltimately, it is a political and technical agreement that seeks to provide States with a common frame of reference to guide their management measures.
Connection with the Zero Pollution Action Plan and other standards
The initiative to set limits on marine debris aligns with the Zero Pollution Action Plan of the EU, which aims to drastically reduce air, water, and soil pollution. This step complements previous decisions at the European level, such as the establishment of a threshold for coastal litter, which sets a maximum of 20 waste items per 100 meters of coastline.
In parallel, the Marine Strategy Framework Directive It is subject to a review process in which it is intended better protect the marine environment, simplify its implementation y reduce administrative burdenThis process runs parallel to the development of a possible Law of the Oceans within a future European Ocean Pact, which points to greater integration of marine policies in the medium term.
The review of the Framework Directive on Waste Management It will also analyze formulas for strengthen threshold values agreed and ensure their effective application in all Member States. The aim is to prevent seabed regulations from being isolated from the rest of the legislation on waste and the circular economy, and to ensure that sources of litter on land and at sea are addressed coherently.
At the international level, these initiatives are connected with the Sustainable Development Goals of the United Nations, especially with the ODS 14, aimed at conserving and sustainably using the oceans, seas, and marine resources. Limiting waste on the seabed is part of that agenda, as it is a tangible indicator of human pressure on ocean ecosystems.
The move towards quantified limits and harmonized control methods is interpreted as a form of moving from general statements to measurable actionFrom now on, it will be possible to assess more accurately whether waste prevention, reduction and management policies are working or whether stricter measures are needed.
Towards a global and coordinated system for monitoring the seabed
Beyond the European context, several recent studies published in specialized journals underline the need to move towards a global seabed debris monitoring systemThis will allow for the coordination of research and management efforts beyond national borders. The idea is to lay the foundation for a continuous and comparable observation network across all oceans.
This global approach is based on the multidisciplinary international collaborationWith the participation of experts in marine geology, biology, underwater technology, data science, and environmental policy, scientific workshops held in various countries have identified knowledge gaps, technical challenges, and standardization needs that currently hinder a complete understanding of the problem.
One of the pillars of the proposal is to prioritize the direct observation using imaging systems compared to destructive or incomparable methods such as trawling. The systematic capture of photographs and videos of the seabed would allow for the creation of robust historical series and facilitate the detection of waste concentration zones, also known as “hot spots”.
To design these observation campaigns, experts recommend carefully selecting the sampling sites depending on variables such as depth, distance from the coast, seabed morphology, the presence of submarine canyons or continental shelves, as well as the availability of ships and systems precise positioningAll of this is aimed at obtaining representative and comparable data in the long term.
In addition to obtaining images, emphasis is placed on the need to create shared databases and compatible formats that allow for the storage and processing of information generated in different projects, institutions, and countries. The use of open platforms would facilitate the work of researchers, public administrations, and potentially private companies interested in contributing their data.
Scientific, technological and public-private collaboration
The transition to more comprehensive monitoring of the seabed requires combining advanced technology and institutional cooperationUnderwater vehicles, high-resolution cameras, and massive data storage systems are only part of the equation; equally important is defining common procedures for the identification and classification of waste.
The application of artificial intelligence to image analysis Underwater imaging is emerging as a key tool for managing the enormous volume of data that a global observation system will generate. Computer vision algorithms can help recognize objects, distinguish between types of debris, and automatically estimate litter densities, although more annotated datasets with homogeneous criteria are still needed to train these models.
The most recent studies suggest leveraging the capacity of Private companies in sectors such as energy, telecommunications, or marine explorationwho already have equipment and visual records of the funds obtained during their routine activities. Sharing some of that information with the scientific community would allow expand the available database without duplicating efforts or costs.
In parallel, the importance of prioritizing is emphasized. preventive measures on land and at seafocused on reducing waste production, improving waste management, and preventing it from reaching the ocean. Experts warn that the mass removal of waste already deposited on the seabed should only be considered under very strict technical and environmental criteria, so as not to cause additional damage to the ecosystems that are intended to be protected.
According to the researchers, the frequent monitoring of the seabed This is essential for assessing whether mitigation strategies are working and for guiding cleanup interventions where they are feasible and safe. In this way, the established limits, both at the European and global levels, could be adjusted periodically based on the actual evolution of the pollution.
The establishment of limits for waste on the seabed The EU's efforts and the promotion of internationally coordinated observation systems point to a new scenario in marine litter management: one in which the oceans cease to be the planet's invisible dumping ground and become a space subject to measurable controls, with clearer rules and with increasing support from science, technology and cooperation between countries.
