Ecological Marine Units

GIS provides a better understanding of ocean ecosystems

Public-private partnership led by USGS & Esri

Ecological Marine Units are published in the journals Nature and Oceanography.

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Esri Partners

Exploring Ecological Marine Units

Redefining the notions of the ocean to teach, conduct research, and collaborate for marine science advancement.

A healthy ocean can reduce poverty, combat hunger, limit the impacts of climate change, and improve the global economy. To achieve these ideals and support ocean sustainability, it is necessary to have a baseline method for understanding of the ocean’s ecosystems and a framework to detect change. Ecological Marine Units (EMUs) are baseline 3D mapped ecosystems of the ocean that have been classified through statistical clustering. They are published in the peer-reviewed journal Oceanography.

EMUs greatly benefit the design of marine protected areas (MPAs). Their use is also valuable for scientific research and classroom instruction.

The problem

The health of the ocean is fundamental to Earth’s survival, yet 95 percent of it remains a mystery. With so little of the ocean explored in detail, authoritative data and the insights it yields are lacking, limiting the extent to which vital marine ecosystems can be managed properly. In a world of accelerating climate change and population demands, a better understanding of the ocean is necessary to reduce the risk of critically damaging or exhausting marine resources.

A fish hiding in colorful coral reef

The solution

The Group on Earth Observations (GEO), a consortium of over 100 nations with an intergovernmental protocol related to Earth observation, commissioned a global map of EMUs to support the wise use of ocean resources to gain environmental resilience. Rigorous statistical clustering produced 37 distinct 3D volumetric regions of ocean properties most likely to drive ecosystem responses. With this in hand, conservation-minded organizations, academic institutions, or citizen scientists can gauge positive or negative trends and use data to make informed decisions that preserve marine environments. 

A scuba diver swimming with hundreds of orange fish above a colorful coral reef

How EMUs work

EMUs come from an unprecedented 3D point mesh framework of 52 million global measurements of six key ocean variables over a 50-year period at a horizontal resolution of 1/4˚ by 1/4˚ (~27 km x 27 km at the equator), over 102 depth zones. Multivariate statistical methods clustered the data into EMUs which were then verified by leading oceanographers. The result is a standardized, rigorous, and ecologically meaningful set of units which may be used as a basemap beneath an organization’s own GIS data for climate change impact studies, conservation priority-setting, economic and social valuation, and marine spatial planning.

A 3D map showing wave heights diminishing as they come into contact with landmass