marine map

3D ocean map tracks ecosystems in unprecedented detail

Oceanographers are carving up the world’s seas like the last of the holiday turkey. A new 3D map sorts global water masses — from deep, frigid circumpolar waters to the oxygen-starved Black Sea — into 37 categories.

The map groups together marine regions of similar temperature, salinity, oxygen and nutrient levels. It has been available for only a few months, and researchers are still working through how they might use it. But its international team of developers hopes that the map will help conservationists, government officials and others to better understand the biogeography of the oceans and make decisions about which areas to preserve. It could also serve as a data-rich baseline for analysing future ocean changes.

Many existing systems also attempt to classify variations in the ocean, such as lists of large marine ecosystems or the Longhurst biogeographical provinces that are defined by the rate at which ocean life consumes carbon. But these are often limited to surface or coastal ecosystems. The latest effort, known as the ecological marine units (EMUs), is the most detailed attempt yet to cover the global ocean in three dimensions.

“What’s often missing is all that’s between the surface of the ocean and the ocean bottom,” says Dawn Wright, chief scientist of Esri, a geographic information-systems company in Redlands, California, that helped to develop the 3D map. “That’s what our project will hopefully bring to the table.”

This ecological marine unit (EMU) map shows variations in water conditions off the coast of Ireland. Keith VanGraafeiland & Sean Breyer/Esri

Irish mosaic

The Sentinel-1A satellite takes us over to Ireland, in this multi-temporal colour composite of land coverage across the island.

With a coastline of 7500 km, Ireland is home to some 4.8 million people and a wealth of history and tradition.

Stretching 486 km from north to south and 275 km across, Ireland is washed by abundant rainfall all year, coating the country in omnipresent emerald-green grasslands.

The coastal mountain fringes in the west, northwest and east are composed mainly of granite, while old red sandstone predominates in the south. Many lakes, large bog areas and low ridges make up the very scenic lowland, as seen throughout the image.

This image was stitched together from 16 radar scans by the satellite during May 2015, and gives us an idea of the island’s land cover and use.

Different colours show changes that occurred within the 12 days’ coverage.

The blues across the entire image represent strong changes in bodies of water or agricultural activities such as ploughing.

The yellows represent urban centres, with the capital city of Dublin very distinct on the far middle right. An interesting feature is the many yellow ‘spots’ scattered throughout the entire island, visible even more clearly when zooming in. These clusters all represent farmhouses.

Vegetated fields and forests appear in green. The reds and oranges represent unchanging features such as bare soil or possibly rocks that border the forests, as is clear on the left side of the image, along the tips of the island.

Sentinel-1A has been in orbit since 3 April 2014. It is a polar-orbiting, all-weather, day-and-night radar imaging mission for land and ocean services, monitoring the marine environment and mapping water and soil surfaces, among other major applications. Its sister, Sentinel-1B, is scheduled for launch on 22 April.

Copyright

Contains modified Copernicus Sentinel data [2015], processed by ESA