You are here

Surface area and the seabed area, volume, depth, slope, and topographic variation for the world's seas, oceans, and countries

TitleSurface area and the seabed area, volume, depth, slope, and topographic variation for the world's seas, oceans, and countries
Publication TypeJournal Article
Year of Publication2010
AuthorsCostello, MJ, Cheung, A, De Hauwere, N
JournalEnviron. Sci. Technol.Environ. Sci. Technol.Environ. Sci. Technol.
KeywordsGIS and oceanography

Depth and topography directly and indirectly influence most
ocean environmental conditions, including light penetration and
photosynthesis, sedimentation, current movements and
stratification, and thus temperature and oxygen gradients.
These parameters are thus likely to influence species distribution
patterns and productivity in the oceans. They may be
considered the foundation for any standardized classification
of ocean ecosystems and important correlates of metrics
of biodiversity (e.g., species richness and composition, fisheries).
While statistics on ocean depth and topography are often
quoted, how they were derived is rarely cited, and unless
calculated using thesamespatial resolution the resulting statistics
will not be strictly comparable. We provide such statistics
using the best available resolution (1-min) global bathymetry,
and open source digital maps of the world’s seas and oceans
and countries’ Exclusive Economic Zones, using a standardized
and seabed area, volume, and mean, standard deviation,
maximum, and minimum, of both depth and slope. All the source
data and our database are freely available online. We found
that although the ocean is flat, and up to 71% of the area has
a circular features that may be seamounts or sea-hills as well
as prominent mountain ranges or ridges. However, currently
available global data significantly underestimate seabed slopes.
The 1-min data set used here predicts there are 68,669
seamounts compared to the 30,314 previously predicted using
the same method but lower spatial resolution data. The
ocean volume exceeds 1.3 billion km3 (or 1.3 sextillion liters),
and sea surface and seabed areas over 354 million km2. We
propose the coefficient of variation of slope as an index of
topographic heterogeneity. Future studies may improve on this
database, for example by using a more detailed bathymetry,
and in situ measured data. The database could be used to classify
ocean features, such as abyssal plains, ridges, and slopes,
and thus provide the basis for a standards based classification
of ocean topography.

Short TitleEnvironmental Science & TechnologyEnvironmental Science & Technology
Alternate JournalEnvironmental Science & Technology