A New Global Seafloor Geomorphic
Features Map - Applications for
Ocean Conservation and
Management
Miles Macmillan-Lawler, Peter Harris, Elaine Baker, Jonas Rupp
GRID-Arendal, Geoscience Australia, Conservation International
Why Map Seafloor Geomorphology?
• Seafloor geomorphology can be mapped at
global scale using existing data
• Is a useful surrogate for biodiversity at the global
scale. i.e Seamounts have a different suite of
species to Abyssal Plains
• Support improved management of the marine
environment (eg MSP, feature inventories)
• Can be built upon using other physical and
biological data
Heezen and Tharp, 1960’s
Interpretation of seafloor
morphology – drawn by hand!
Global Map 1977
From Agapova et al.
(1979)
Improved digital bathymetry now available!
• SRTM30Plus v7 + other data
• Features defined based on shape, slope, rugosity and TPI etc.
• Combination of automated algorithms and expert interpretation
• Minimum feature size mapped ~10 square kilometres
Geomorphic Feature Interpretation
How do we map seafloor geomorphic features?
bathymetry contours
Slope TPI
IHO Categories
Global Seafloor Geomorphic Features Map
Some interesting statistics
• 131,192 separate polygons
• 10,234 seamounts and guyots
• Passive margin continental shelf width nearly 3x that of active margins
• Polar submarine canyons are twice as large
• Large rift valley segments are associated with slow spreading rates
Application of the GSFM for management
• Pacific – PACIOCEA & EPOG
• Global MPA representativeness
• VME identification
• CCZ assessment
PACIOCEA project area
Features in the PACIOCEA project area
features in the PACIOCEA project area
What summarises the PACIOCEA project
area
• Small amount shelf and slope
• Large amount of abyssal habitats, esp hills and
mountains
• Escarpment, seamount, guyot, ridge trough
trench and plateau all represented above global
average
Classification of seamounts and guyots and
canyons
• Seamounts and guyots important features for
biodiversity.
• PACIOCEA project area contains 2784
seamounts, 93 guyots.
• Classified based on geomorphometric and
physical parameters
Seamount and guyot classificationParameter Classes Relevance
Height Small (< 2000 m)
Large (> 2000 m)
Larger seamounts cover more depth ranges and thus
potentially more species habitats
Peak Depth Shallow – photic (< 50 m)
Shallow – mesophotic (50 – 150 m)
Medium – fishable depths (150 – 2000 m)
Deep (> 2000 m)
Seamounts that extend into the photic or mesophotic
zones will support different species that those that do
not. Shallow seamounts (less than 2000m) may be
exposed to fishing pressures using current fishing
techniques.
Seamount type Seamount
Guyot
Guyots have a truncated peak and may offer different
habitat at the peak depth range than an equivalent
height seamount.
Salinity No significant variation (not used) No variation observed in the deep waters of this region
Dissolved oxygen Low (<1 ml/l)
Adequate (>1 ml/l)
Low dissolved oxygen (< 1ml/l) can inhibit some
organisms
Temperature Cold (<4 degrees)
Cool (4-12 degrees)
Warm (>12 degrees)
The temperature range 4-12 degrees Celsius represents
the temperature range for the cold water coral Lophelia
pertusa
Maximum
Bottom Current
Weak (< 0.125 ms-1)
Strong (> 0.125 ms-1)
Stronger maximum bottom currents are likely to lead to
greater disturbance and promote a different suite of
species.
Physical Data
Seamount and guyot classification
• 28 different categories of seamount
• Only 9 categories have 50 or more seamounts
Seamount and guyot classification
Global MPAs – WDPA
August 2013 version
By 2020, at least 17 per cent of terrestrial and inland water areas and 10 per cent of coastal and marine areas, especially areas of particular importance for biodiversity and ecosystem services, are conserved through effectively and equitably managed, ecologically representative and well-connected systems of protected areas and other effective area-based conservation measures, and integrated into the wider landscape and seascape.
CDB - Aichi Target 11
• 3% of the oceans in
MPAs
• 97% of MPAs in EEZs
• Majority of MPAs
small
• Majority of area from
few large MPAs
Global Status of MPAs
What features are represented in MPAs
Abyssal Plains – Globally 0.7 % in MPAs
Cape Verde
Abyssal Plain
Seamounts – Globally 2.9 % in MPAs
Kelvin seamount in
northwest Atlantic
Trenches – Globally 8.5 % in MPAs
Japan Trench
Less than 3% of MPAs are in ABNJ
TrenchesSeamountsAbyssal Plains
Representation in MPAs
Globally what’s in and what’s not?
• Feature representation ranges from 0.5 and
8.5%
• Deep water features poorly represented
• Representation of features varies in the different
oceans
• Features in ABNJ poorly represented
