Rationale: Sea ice is one of the most important components of the Barents Sea climate system. It plays a crucial role for many species and ecosystem processes and has a strong impact on regional economies and local communities

Rationale: The air temperature influences ice conditions and shows the warming and the cooling in the region. The summer Barents Sea air temperature correlates to the ice conditions in the region. The winter temperature correlates to the sea surface temperature (SST)

Rationale: Oceanographic conditions play a key role in the functioning of the Barents Sea ecosystem. The temperature in the Barents Sea is dependent on the advection of heat through the southwestern opening and defines the distribution of various important species as well as the extent of the seasonal sea-ice cover. Hence, monitoring oceanographic properties is important for the management of the ecosystem of the Sea

Rationale: Water masses properties and volume transports play a key role in the functioning of the Barents Sea ecosystem. Due to unique properties of water masses, the Barents Sea is rich in marine life, being one of the most productive fishing grounds in the world. Monitoring of water mass properties and volume fluxes is of major importance for management and sustainable use of resources of the Sea

Rationale: The ocean has taken up between 30 to 50% of the human induced CO₂. This has led to a pH decrease and a decrease in carbonate ion concentration ([CO₃^-2]). There is a large natural seasonal and interannual variability. Long-term monitoring is required to discern the change due to increased CO₂ and its impact on OA state

Rationale: State of the bottom substrate defines he quality of the benthic community life as well as the levels of pollutants such as heavy metals, oil etc. which are important in the planning of environmental research and security measures to ensure the safety of oil rigs.

Rationale: Phytoplankton is the first link of all trophic chains in marine ecosystems and only the primary producer in the open water. Its diversity, abundance, biomass and production will be important for how much energy is available for other trophic levels

Rationale: In the Barents Sea ecosystem, zooplankton forms a link between phytoplankton (primary producers) and fish, mammals and other organisms at higher trophic levels. It is thus important to monitor this group to better understand ecosystem dynamics

Rationale: Benthos is one of the main components of marine ecosystems. It is stable in time, characterizes local situation, and is able to show the ecosystem dynamics in retrospective. The changes in community structure and composition reflect natural and anthropogenic factors

The procaryotic bacteria and archaea, as a result of their diversity and unique types of metabolism, are involved in the cycles of virtually all essential elements. Bacteria play an important role in for example the microbial loop, i.e. a trophic pathway in the marine microbial food web where dissolved organic carbon (DOC) is returned to higher trophic levels via the incorporation into bacterial biomass, and coupled with the classic food chain formed by

Rationale: The importance of ice-related ecosystems is significant. Ice algae is the prime food source for the majority of the ice fauna, thus fuelling the ice-related part of the ecosystem, and the significance increases further north due to lower pelagic production. The sympagic–pelagic–benthic coupling is of great importance in the Arctic. Reduced sea ice, especially a shift towards less multiyear sea ice, will affect species composition as well as biomass and production

Rationale: The rationale between the use of fish and shrimp biomass is to include sub parameters that are important parts of the Barents Sea ecosystem. The stock developments of keystone species as capelin and cod and young herring are tightly connected and important for the dynamics between these stocks on each other as well as zooplankton, other fish stocks, sea mammals and sea birds

Rationale: Next to climate changes, introduced species represent the largest threat to biodiversity and habitat destruction in the world. Alien species may expel native fauna and cause serious changes in the ecosystem functionality. Exotic species are commonly dispersed by human activities, and ballast water and biofouling are thought to be the most important vectors in the marine environment.

Rationale: The purpose of the indicator is to identify changes in the seabird community in the Barents Sea. Distribution and abundance of seabirds at sea is sensitive to changes in the ecosystem in open waters. The indicator reflects both changes in population size and changes in habitat use.

Rationale: Seabirds constitute important components of the Barents Sea ecosystem. They form an important link between the marine and terrestrial ecosystems by bringing nutrients from sea to land. As predators covering many niches, seabirds can be used as indicators of health of the marine ecosystem at large.

Rationale: Monitoring the dynamics of non-ice associated marine mammals in the Barents Sea area is essential for understanding overall ecosystem dynamics and as a basis for assessing and mitigating impacts of human activities on the marine fauna.

Rationale: Ice associated marine mammals are expected to be severely affected by declining sea ice extent. It is thus of great importance to monitor their population dynamics.

Rationale: A healthy ecosystem is based on biodiversity. To maintain it, vulnerable and endangered species must be consistently monitored. They are important in terms of genetic, scientific, educational and esthetic value. They experience direct impact from anthropogenic activity as well as from the changing environmental conditions that affect their distribution and population numbers.

Rationale: This indicator is based on the vector of biomasses of the demersal species caught during the ecosystem survey in the demersal trawl. Following the widely accepted paradigm that diverse communities are more stable through time, and therefore more able to sustain either human or climate driven change, our approach can classify these sub-areas along a “resilience-to-change” gradient.

Rationale: Fishing can remove large part of key commercial stock from the ecosystem, thereby influencing directly and indirectly the other ecosystem components. Normalized fishing mortalities shows if a stock is harvested sustainable (according to given international reference levels). Landings show how much biomass is removed and IUU fishing, Ghost fishing and dumping show unwanted human harvest of key ecosystem components

Rationale: POPs, heavy metals (in particular Hg is of concern) and radionuclides are transported on a regional/ hemispheric/global scale. The Arctic is a sink region for these pollutants, where they may accumulate in biota and affect other parts of the ecosystems.

Rationale: Contaminant levels in biota show the levels of contaminants (radionuclides, heavy metals and POPs) at different trophic levels in marine food webs. When monitored over several years it would also be possible to determine spatial and temporal trends.