Pelagic Habitats Thematic Assessment

Human activities exert pressures which can affect pelagic habitats

Human activities with the potential to affect pelagic habitats include human-induced climate change, agriculture, waste treatment, dredging, shipping, fisheries, aquaculture, renewable energy generation, and offshore extraction of oil and gas. Among these activities, those associated with the most significant pressures impacting the state of pelagic habitats include human-induced climate change, agriculture, and waste treatment.

Trends for each OSPAR Region taken from the Human Activities Thematic Assessment:

The key human activities affecting pelagic systems are:

Human-induced climate change:
Human activities have caused changes in the atmospheric concentrations of greenhouse gases, for example from the burning of fossil fuels (for energy and transport), industrialised farming practices and deforestation. This human-induced climate change has affected pelagic systems through pressures in the physical and chemical ocean climate at multiple scales. See:  Climate Change Thematic Assessment , Ocean Acidification Other Assessment

Agriculture[Cultivation of living resources]:
Agricultural run-off can lead to changes in turbidity and the input of substances to the environment, including nutrients. In addition to the direct effects of terrestrial run-off, the increasing nutrient, dissolved, particulate, and detrital (organic and inorganic) inputs to the marine environment (including microorganisms and pathogens) can affect primary productivity and the structure of pelagic habitats. See: OSPAR Feeder Report 2021 - Agriculture

Waste treatment and disposal and Industrial uses [Urban and industrial uses]:
Industrial atmospheric emissions and direct discharges can lead to turbidity changes and the input of substances and nutrients to the environment, affecting pelagic habitats. In localised areas, nutrient run-off from industry and sewage can cause significant eutrophication impacts on pelagic habitats. See: OSPAR Feeder Report 2021 – Waste water

Restructuring of seabed morphol ogy, including dredging and depositing of materials [Physical restructuring of rivers, coastline or seabed (water management)]:
Dredging of the seabed can cause localised increases in nutrients and turbidity. See: Human Activities Thematic Assessment

Transport – shipping [Transport]:
Shipping contributes to greenhouse gas emissions and can introduce non-native species through ballast water discharge. See: OSPAR Feeder Report 2021 – Shipping and Ports

Fish and shellfish harvesting (professional, recreational) [Extraction of living resources]:
Removal of fish (and new fisheries for plankton, e.g., copepods) can alter balance in food webs (leading to trophic cascades), affecting plankton communities. Changes in the lower trophic levels induced by a disequilibrium in nutrients (e.g., nitrogen and phosphorus) can also alter this balance (bottom-up effects). Fishing vessels also contribute (alongside shipping) to greenhouse gas emissions. See: OSPAR Feeder Report 2021 - Fisheries

Aquaculture - marine, including infrastructure [Cultivation of living resources]:
Operational and production chemicals and nutrients have the potential to affect pelagic communities. Stocks will also contribute to changing balance within food webs. Moreover, parasites and diseases can propagate from highly dense structures. See: OSPAR Feeder Report 2021 - Aquaculture

Renewable energy generation (wind, wave and tidal power) including infrastructure [Production of energy], Extraction of oil and gas including infrastructure [Extraction of non-living resources], Offshore structures (other than for oil/gas/renewables) and Coastal defence and flood protection [Physical restructuring of rivers, coastline or seabed (water management)]:
Coastal development and the introduction of infrastructure to the marine environment can cause hydrological and hydrodynamic changes and thereby influence nutrient and plankton distributions. They also provide new substrate which meroplankton could potentially colonise. See: OSPAR Feeder Report 2021 – Offshore Renewable Energy Generation , OSPAR Feeder Report 2021 – Assessment of the impacts of the offshore oil and gas industry on the marine environment

Extraction of oil and gas, including infrastructure [Extraction of non-living resources]: and the consequent burning of fossil fuels contributes to greenhouse gas emissions. See: Human Activities Thematic Assessment , Offshore Industry Thematic Assessment