The EMODnet broad-scale seabed
habitat map for Europe
(View or download the map)
History
Building on the highly successful INTERREG IIIB-funded MESH and
BALANCE projects, phase 1 of
EMODnet Seabed Habitats (2009-2012) improved and
harmonised the broad-scale physical habitat map across the Celtic
Seas, Greater North Sea and Baltic Sea, as well as generating
the very first broad-scale map of the western
Mediterranean. In phase 2 (2013-2016), the coverage of
the maps was extended to all European seas and the
existing maps were improved. Updates and a further increase
in extent to the Barent Sea will take place in
the current phase (2017-2019). The map is also known
as EUSeaMap.
Overview of the current broad-scale
map coverage as of September 2016.
EUSeaMap provides the community with a comprehensive, free and
ready-to-use map, harmonising mapping procedures and fostering a
common understanding among seabed mappers in Europe. The EUSeaMap
broad-scale predictive mapping methods are repeatable and ensure
that the predictive maps can continue to be improved in the
future.
Benefits of a broad-scale habitat map
In order to most benefit from the potential offered by the
European marine basins in terms of growth and employment, and to
protect the marine environment, we need to know more about the
seafloor. European Directives, such as the
Marine Strategy Framework Directive (MSFD), call for a
full-coverage seabed habitat map of all European seas. In general,
habitat maps are very costly and time consuming to produce from
survey. The creation of a detailed habitat map involves surveying
the seafloor with sonar equipment and collecting samples or photos
of the seabed, before analysing and integrating these data types to
generate a map. It can take several years from planning a survey to
completing a detailed map. By contrast, broad-scale mapping of
seabed substrate at a low resolution combined with using modelling
techniques to classify habitats in terms of physical parameters is
an efficient way to meet the need for a full coverage habitat map
at a reasonable cost and a shorter time frame.
EUSeaMap products have been used for assessing and reporting the
status of European seas, designing ecologically coherent Marine
Protected Area networks, establishing monitoring programmes for
seabed habitats and informing marine planning.
More information and some examples of application of EUSeaMap
products is available in the in the documents section. The data layers,
confidence maps and thresholds produced by the project partners, are freely
available through the EMODnet Seabed Habitas interactive map.
Principles behind making broad-scale seabed habitat maps
It is possible to produce a ‘predictive map’ of expected
seabed-habitat types by combining a series of proxy measurements,
such as water depth and light levels amongst others, using
statistical analysis and Geographical Information System
modelling.
Principal drivers for seabed habitat distributions include the
type of seabed substrate (rock, mud, mixed sediment, etc.), depth,
light availability and the energy of water movements. To describe
the variation in environmental conditions with depth, EUNIS divides
subtidal habitats into zones: Infralittoral, Shallow Circalittoral
(or Circalittoral), Deep Circalittoral and Deep Sea. In this
project we further subdivide the Deep Sea zone into
bathyal and abyssal zones, following scientific literature and
recognising the diversity of these huge areas.
The division of marine sublittoral
habitats into biological zones (©MESH Atlantic Blue Box, 2013).
Another factor that can be fundamental in driving habitat types is
the degree of exposure to wave and water-current energy. For some
more enclosed basins other parameters, such as salinity, oxygen
levels and temperature of water at the seabed are also considered
to be fundamental for habitat mapping.
Generating the maps
During the first phase of EMODnet Seabed
Habitats (2009-2012), a consistent method was developed to
take into account the diverse range of seabed habitats found in
different regions.
The first step is to acquire the best-available spatial data for
several environmental variables. This includes data provided by
EMODnet Geology and
EMODnet Bathymetry. The
data are organised and harmonised into pixelated images divided
into classes. These data can be combined by ‘layering’ the data in
GIS to create a combined output describing the habitat.
Illustration of how a predictive habitat map can be created by
‘layering’ data in GIS.
The principal input layers are the type of seabed substrate and
the biological zones. Depending on the basin, layers of
hydrodynamic energy levels, salinity and/or oxygen are also
produced. For example the hydrodynamic energy layer is divided into
‘Low’, ‘Medium’ and ‘High’ classes.
Example of an input layer:
biological zones. Input layers are also useful per se and are
available online through the EMODnet Seabed Habitats interactive
map.
The EUSeaMap model was developed in ESRI™ ArcGIS ModelBuilder
and can be saved and executed multiple times, which ensures that
the systems are repeatable and easily updated when new layers or
methods are available.
As well as careful evaluation of contributing data, and refining
statistical methods for its interpretation, during the creation
of the maps it is necessary to define meaningful thresholds
for likely changes in habitats: in each input layer these are used
to define the boundaries between classes, where the change in the
physical conditions reaches a critical point that defines an
expected change in habitat type (at the map-scale adopted in
EUSeaMap, 250mx250m blocks). For example, the infralittoral zone is
the area of the seabed where photosynthetic algae is able to grow.
This is mapped by finding a threshold value of light at the seabed
that best fits observations of this limit in the field.
For more details about the methods used to create the
broad-scale habitat maps, see the documents page.