Marine environmental pressures

Page Last modified 08 May 2018
6 min read
The marine environment is a vital resource for life on Earth. Marine ecosystems perform a number of key environmental functions:
  • regulating the climate,
  • preventing erosion,
  • accumulating and distributing solar energy,
  • absorbing carbon dioxide, and
  • maintaining biological control.

Human society depends on the seas for survival. Seas are essential for the economic prosperity of human society, social well-being and quality of life. We all rely on the seas, so we have an obligation to use them wisely.

Oceans and seas are still perceived as the last wilderness of the world, but human influence has already reached them all, from the coasts and the sea surface to the deep sea floor. Multiple benefits and human uses of the seas are causing multiple, cumulative human pressures and related changes to oceans and seas, coastal marine habitats and marine ecosystems. Each human activity on land or at sea has direct and indirect impacts on the marine environment. It is therefore very important to understand the cumulative effects of human activities in view of natural changes in order to build a solid base for managing and safeguarding the benefits for current and future generations.

The main pressures affecting European seas result from:

  • fishing,
  • sea floor damage,
  • pollution by nutrient enrichment and contaminants,
  • the spread of non-indigenous species.

Marine litter and underwater noise are also of growing concern. These pressures are at the core of the MSFD but some have also been targeted by other dedicated EU policies (the Water Framework Directive, the related Habitat and Bird Directives and the common fisheries policy). The information reported under the MSFD, although incomplete, shows a low percentage of our seas where pressures are considered to be at an acceptable (good) level.

Pressure sources

Multiple pressures continue to be a significant presence in our seas and their combined effect is of growing concern:

  • Fishing pressure is reducing but decades of overfishing have affected ecosystem integrity.
  • Damage to sea floor habitats is likely to increase with growth in maritime activities.
  • Pollution by nutrient enrichment and contaminants remains an environmental challenge.
  • Non-indigenous species are spreading and their impacts are not fully assessed.
  • Marine litter and underwater noise are adding pressures but are still poorly understood.

Fishing pressure affects ecosystem integrity

Fishing is one of the greatest pressures in the marine environment. It reduces biodiversity by targeting commercial fish and shellfish and accidentally killing invertebrates, mammals, seabirds and turtles. It also modifies the structure and functioning of the ecosystems in which fisheries are embedded. Unsustainable fishing levels and practices have greatly damaged European fish stocks. In 2013, the 88 % of the assessed stocks in the Mediterranean and Black Seas were overfished.

Multiple activities threaten sea floor integrity

Sea floor damage mainly refers to changes in the structure and function in seabed habitats and their communities, therefore affecting sea floor integrity. It is caused by harvesting natural resources, which can be either biological (e.g. bottom-trawling) or physical (e.g. aggregates). To a lesser extent, it is also caused by energy production (e.g. oil and gas structures), coastal and port infrastructure (e.g. dredging) or telecommunications (sub-sea cables). Because these activities differ in terms of their extent, degree of impact or affected habitat types and associated communities, the overall magnitude of their impact differs.

The extent of sea floor pressure in some parts of Europe’s seas shows that managing it will become a major challenge. For example, in the German North Sea, some areas (3 x 3 nautical miles) have been annually fished for up to 433 hours using large-beam trawling, even inside Marine Protected Areas. The recovery time for seabed communities affected by bottom-trawling has been estimated to be between 7.5 and 15 years after one single pass of a beam trawl.

With the expected growth in maritime activities, the impact on the sea floor and its cumulative effects are likely to increase. In this respect, the development of seabed mining, a novel but strategic area for the EU’s Blue Growth strategy, will be important for sea floor integrity, especially in the deep sea due to the vulnerability of those ecosystems.

Non-indigenous species are spreading

The introduction of non-indigenous species is closely linked to the increasing globalisation of trade and travel. While many of these species become part of the ecosystem they are introduced into, only a few actually become invasive and end up generating negative impacts. When this happens, major ecological, economic or social effects threaten biodiversity and ecosystem services. Records show that more than 1 350 marine alien species have been introduced into European seas since the 1950s.

Contaminants in the marine environment

Contaminants are widespread in the marine environment, and they can be dissolved in water, stored in sediments or ingested by animals. Some of these substances occur naturally in low concentrations, and others are introduced by man. Contaminants toxic to plants and animals are liable to accumulate through the food web. Substances with endocrine-disrupting properties can impair reproduction in fish and shellfish. Evidence shows that regulatory levels for certain contaminants in seafood have been exceeded in European seas, exposing humans to contaminants through consumption.

Contaminants can be spread over large distances through repeated deposition and evaporation. The main sources for this dispersal are:

  • treated and untreated waste water,
  • agriculture,
  • shipping,
  • port activities,
  • aquaculture,
  • offshore oil exploration,
  • consumption of fossil fuels,
  • industrial activities.

Pollution with nutrients — eutrophication

Nutrients in marine waters derive from artificial fertilisers and manure used in agriculture, urban waste water, aquaculture and shipping. Member State reporting confirms these pathways. Whatever their origin, nutrients often cross national boundaries. Finding the right solutions requires continued regional cooperation.

Marine litter is accumulating, in particular plastic

Marine litter is a problem rooted in unsustainable consumption patterns and behaviours. Increasing amounts of litter, mostly coming from land-based sources, are ending up in the oceans, making this an emergent global problem. Plastic is the most abundant material in this waste, although the amount and type of litter varies regionally.

Human activities are generating underwater noise

Underwater noise has become an emerging environmental issue in the light of growing transport and industrial activities at sea. Whether emitted deliberately (e.g. military sonar) or as a by-product of other actions (e.g. shipping), manmade sound induces a range of behavioural reactions, and it can even cause death. Sound can reach very far underwater and its impacts can be felt at large distances (Marine Messages, EEA, 2014).

Protection strategies

The Marine Strategy Framework Directive (MSFD) constitutes the first EU legislation specifically devoted to the protection of the marine environment but it needs to be considered alongside other EU policies and legislation. Most notably, these are the Water Framework Directive (WFD), the Nature Directives (Habitats and Birds), the common fisheries policy (CFP) and the Maritime Spatial Planning Directive (MSPD). There are similarities in the objectives and implementation processes of the WFD and the MSFD, although both directives together should cover all relevant activities and pressures (marine based and land based) to guide progress towards good environmental status.

At the same time there are also strong synergies between the MSFD and the EU Nature Directives (Habitats and Birds), in that they all seek to conserve biodiversity. As a result, an important feature of the MSFD is the requirement to include spatial protection measures in programmes of measures to contribute to establishing coherent and representative networks of Marine Protected Areas that adequately cover the diversity of the constituent ecosystems.

The EEA works in the scope of EU marine environment policies and legislation. It assesses the pressures and impacts in Europe’s seas by collecting data on pressures and impacts, contaminants, eutrophication and biodiversity. The EEA combines existing information and indicators with a more quantitative and spatial approach. One of its important aims is to move towards a holistic, integrated assessment of the ecosystem health of Europe’s seas.

The EEA supports and informs policymakers and European citizens concerning marine environment status and trends for the future. We collect available marine data, converting it into state of the seas information through our thematic assessments, sharing our knowledge with European citizens, our stakeholders and policymakers and creating insights for healthy European seas.

Our generic tasks for marine areas are:

    • data flows/reporting, data management,
    • assessments supporting the implementation and development of EU policies,
    • information sharing and marine environment indicators,
    • networking for better communication, coordination and cooperation in the marine environment.

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European Environment Agency (EEA)
Kongens Nytorv 6
1050 Copenhagen K
Phone: +45 3336 7100