[OANNES Foro] 3D ocean map tracks ecosystems in unprecedented detail

[Mario Cabrejos]

Nature 541, 10-11

(05 January 2017)

doi:10.1038/541010a

 

Tool to divide water masses into precise categories can help in conservation
planning.

3D ocean map tracks ecosystems in unprecedented detail

 
<http://www.nature.com/news/3d-ocean-map-tracks-ecosystems-in-unprecedented-
detail-1.21240?WT.ec_id=NATURE-20170105&spMailingID=53127731&spUserID=MjA1NT
E2ODQxMAS2&spJobID=1080713024&spReportId=MTA4MDcxMzAyNAS2#auth-1> Alexandra
Witze

03 January 2017

http://www.nature.com/news/3d-ocean-map-tracks-ecosystems-in-unprecedented-d
etail-1.21240?WT.ec_id=NATURE-20170105
<http://www.nature.com/news/3d-ocean-map-tracks-ecosystems-in-unprecedented-
detail-1.21240?WT.ec_id=NATURE-20170105&spMailingID=53127731&spUserID=MjA1NT
E2ODQxMAS2&spJobID=1080713024&spReportId=MTA4MDcxMzAyNAS2>
&spMailingID=53127731&spUserID=MjA1NTE2ODQxMAS2&spJobID=1080713024&spReportI
d=MTA4MDcxMzAyNAS2

 

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."

Esri launched a web portal for the EMU data in September, and has been
presenting the concept at conferences since then. Wright described it on 16
December in San Francisco, California, at a meeting of the American
Geophysical Union.

EMUs can help to reveal why marine animals live where they do. In the
eastern tropical Pacific Ocean the mapping shows a complex interplay between
oxygen-rich and oxygen-poor waters. The boundary of the low-oxygen zone
shifts towards the surface in some spots and dips deeper in others. That
variation affects the locations of economically important tuna fisheries,
says Patrick Halpin, a marine ecologist at Duke University in Durham, North
Carolina. "It's an interesting thing to look at in three dimensions, fairly
unique and gratifying."

Such data could guide the United Nations' effort to designate a series of
ecologically or biologically significant marine areas to focus future
conservation efforts, Halpin notes. Looking at the distribution of EMUs
could help officials to pinpoint the boundaries of those areas, or to make
sure they are designating enough waters to capture all the biogeographic
diversity.

And the South African National Biodiversity Institute is interested in using
EMUs to update data on open-ocean and deep-sea habitats for the country's
next national biodiversity assessment, due in 2019, says Heather Terrapon, a
spatial analysis coordinator at the institute in Cape Town. Nations that do
not have the money to gather their own data sets could use the free EMU data
and visualizations to manage their marine resources, says Peter Harris, a
marine geologist at the environmental information-management centre
GRID-Arendal in Arendal, Norway.

"It's like total world domination in ecosystem mapping."

The creation of the EMUs is the second step in a project that started with
similar mapping on land. The intergovernmental Group on Earth Observations
asked Roger Sayre, an ecologist at the US Geological Survey in Reston,
Virginia, to lead a team to categorize terrestrial eco-systems. The
researchers, including some at Esri, combined information on geology and
vegetation to generate nearly 4,000 'ecological land units'. One example
might be warm, wet plains, on metamorphic rock, with mostly deciduous
forest.

Next, the team moved their focus from land to the oceans. "It's like total
world domination in ecosystem mapping," says Sayre, who heads the EMU
project with Wright.

They began with 52 million data points in the World Ocean Atlas maintained
by the US National Oceanic and Atmospheric Administration. These include
information on chemical and physical parameters gathered every 27 kilometres
to create a 3D grid. The team added other data such as the shape of the sea
floor and used statistical techniques to group the results into categories.

The resulting EMUs include the deep, very cold, low-oxygen waters that
encompass roughly one-quarter of the world's oceans. Others are much
smaller, such as the upper waters of the Red Sea, or the dilute estuaries of
several Northern Hemisphere rivers.

For now, the EMU maps rely on data averaged over five decades. Looking at
conditions over shorter periods of time, such as seasons, would provide more
helpful detail, says Frank Muller-Karger, a biological oceano-grapher at the
University of South Florida in St Petersburg who has been comparing EMUs
with weekly maps of coastal changes made using satellite imagery. And to
monitor change over decades, the EMU team would need to recalculate its maps
every five years or more.

The EMU developers say that future iterations of the system could tackle
such issues. For now, they are hoping to expand on the land and marine units
by creating new categories for coastal and freshwater ecosystems.

 



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