This is the 2811th most frequent Russian word.
североатлантический
"North Atlantic" or "related to the North Atlantic."
In this sentence, 'североатлантический' is an adjective describing 'альянс', indicating the geographical and thematic context of the alliance—related to the North Atlantic.
Североатлантический альянс играет важную роль в международной дипломатии.
The North Atlantic alliance plays an important role in international diplomacy.
Here, 'североатлантическое' qualifies 'течение', specifying the location and characteristic of the oceanic current associated with the North Atlantic.
Североатлантическое течение влияет на климат Европы.
The North Atlantic current affects the climate of Europe.
In this context, 'североатлантическую' is an adjective modifying 'флора и фауна', emphasizing that the flora and fauna being studied are characteristic of or located in the North Atlantic regions.