US: In order to protect living marine resources from depletion, the USGS was given this task to form a public-private partnership with Esri, NOAA, academia, and non-profit organizations to produce the first ever detailed maps that group the entire global ocean into 37 distinct 3D ecosystems.
The groundbreaking work to produce the first-of-its-kind, objective, and true 3D global marine ecosystems maps is described in two recent USGS-led publications in the journal Oceanography and an AAG Special Publication.
The resulting ecosystem data and maps are available in a web-based app called the Ecological Marine Unit Explorer. This app, also available for cell phones here or here, organizes an incredibly rich collection of data and provides a convenient open-data platform to facilitate science and marine resource management.
“The web-based app and cell phone apps are examples of appropriate technologies for exploring Earth’s most remote places,” said Sayre. “They enable an improved global understanding of a vast but limited resource.”
An Ocean of Marine Ecosystems Data
To define marine ecosystems, the team began with more than 52 million data points in NOAA’s World Ocean Atlas. Each point includes values for six chemical and physical attributes that influence marine life — temperature, salinity, dissolved oxygen, nitrate, phosphate, and silicate. The values were averaged over 57 years to provide a baseline for comparisons.
The data points are located every 17 miles like a 3D net cast across the global ocean surface with 102 knots that extend down the water column to a depth of 3.5 miles. Details on the data and methods for identifying 37 ecosystems are available in the journal Oceanography.
Using the Ecological Marine Unit Explorer
From the web or phone apps, users will see a surface map of the ecological marine units. Shades of pink indicate warmer units, and blue designates colder units. Users can click on any point in the ocean to see a vertical cross section of the ecological marine units and data for all six attributes at any depth.
A series of 37 maps that depict the global lateral extent of each ecosystem at various depths is available here and in the companion AAG Special Publication.
The Big Picture of Marine Ecosystems
Although the ocean is vast, marine life is not uniformly distributed throughout it, and some ecosystems are more biologically rich than others.
Waters near the surface generally contain more oxygen, are warmer, and sunlit. Down from the surface, light begins to fade and oxygen depletion is common. About one third of the world’s ocean waters are deep, dark, very cold, and saline.
Map showing EMU 13
Map showing EMU 13, which dominates the deep Pacific and Indian Ocean basins but is nearly absent in the Atlantic. USGS/Esri map. Public domain.
Twenty–two of the 37 ecosystems are extensive and account for 99 percent of the ocean volume, while the remaining 15 are smaller, shallower, and occur near coasts. One very large ecosystem dominates the deep Pacific and Indian Ocean basins but is nearly absent in the Atlantic.