Home›Open Questions›How large is the deep sea, in square kilometers?Open QuestionsHow large is the deep sea, in square kilometers?Citation FormatsGeneral ReferenceGeneral Reference Citation TextNature Atlas. "How large is the deep sea, in square kilometers?." Accessed August 30, 2026. https://nature.interactiveatlas.org/open-questions-index/open-question-deep-sea-total-area.Copy General ReferenceAPA StyleAPA Style Citation TextNature Atlas. (n.d.). How large is the deep sea, in square kilometers?. Retrieved August 30, 2026, from https://nature.interactiveatlas.org/open-questions-index/open-question-deep-sea-total-areaCopy APA StyleBibTeXBibTeX Citation Text@misc{natureatlas-how-large-is-the-deep-sea-in-square-kilo, author = {Nature Atlas}, title = {How large is the deep sea, in square kilometers?}, year = {2026}, url = {https://nature.interactiveatlas.org/open-questions-index/open-question-deep-sea-total-area}, note = {Accessed August 30, 2026} }Copy BibTeXOpen QuestionCross-Tradition ConnectionsSourcesComments (0)Reader Challenges (0 open reader challenges)Open QuestionPublished figures for the total area of the deep ocean floor vary by more than 10 percent depending on the depth-contour definition used (commonly 200m) and the underlying bathymetric data set, ranging from roughly 300 to 335 million square kilometers in different sources; NOAA itself states the extent only as a share of the ocean (over 90 percent of the ocean is deep ocean) rather than a single agreed area figure, and less than 0.001 percent of the deep seafloor has ever been directly observed, which is part of why no more precise consensus figure exists.What would resolve this A single, standardized global bathymetric survey below the 200m contour, using one consistent methodology, of the kind not yet completed as of this writing (Seabed 2030 and similar mapping initiatives are working toward this but are not yet complete).OpenOceanography and bathymetric mappingHow Much of the Ocean Has Been Explored? (NOAA Ocean Exploration)Cross-Tradition ConnectionsQuestion OnDeep Sea, Ecosystems Well-attested Source How Much of the Ocean Has Been Explored? (NOAA Ocean Exploration)tier 1SourcesHow Much of the Ocean Has Been Explored? (NOAA Ocean Exploration)tier 1NOAA Office of Ocean Exploration and ResearchOcean fact: How much of the ocean has been explored?View the SourceComments (0)No comments yet. Be the first to share a thought.Sign in to join the discussion.Reader Challenges (0 open reader challenges)No disputes yet. Spotted an error or a better source? Open the first one.Sign in to dispute this or suggest a correction.View At A Past YearThe atlas records no dated fact of its own for this entry, so there is no other year to choose.Show This Year