The Seabed – our final frontier
Incredibly, we have m
apped the moon's surface better than we have surveyed the Earth's seafloor. In the 1870's the Italian astronomer Giovanni Shiaparelli famously looked upon Mars through a powerful telescope at Milan's Brera Observatory. He described the planets' surface in great detail and named features after ancient Mediterranean place names including Olympus Mons which is the highest volcano in our Solar Systems standing over 25km tall. Most famously of all he described 'canali' which is the Italian for channels. Unfortunately, the description was translated literally and before long many people believed the surface of Mars had 'canals' which were assumed to have been built by Martians. It effectively started the belief that aliens existed elsewhere in the Universe and led to the science fiction genre!
Satellite technology has rapidly evolved to produce extremely high resolution maps of the Moon, Venus and Mars. NASA's Mars Reconnaissance Orbiter (MRO) has been taking images of Mars for more than 10 years in such detail that features as small as a tennis courts can be identified. Limited atmosphere and the lack of water has enabled barrier free imaging of features on the moon at a resolution of about 100 metres (per pixel).
Satellite technology has also been used to map the Earth in phenomenal detail. However, while the imaging systems can pass through our atmosphere, they are only capable of penetrating the shallowest of coastal waters, so most of Earth's oceans remain completely unmapped. Seafloor features that we can see globally are inferred from satellite measurements of the height and shape of the sea surface, which bends due to gravitational effect of mountains and valleys on the ocean floor beneath. While this information is very valuable reconnaissance information sometimes revealing plate tectonic boundaries and underwater mountain ranges (e.g.mid ocean ridges and seamounts), it is simply too coarse to provide the vital information needed to manage, protect and secure our ocean resources.
To truly understand the shape of the ocean floor, and its impact on biodiversity distribution, ocean circulation, and in turn weather and climate change, we have to move towards ocean basin scale deployment of modern seabed mapping technology and survey approaches.
Using a combination of different types of vessel mounted sonar systems, maps of discrete areas of the seafloor have vastly improved in the last 20 years, in particular in jurisdictions where claims for territorial waters have been progressed. To support these claims some countries have undertaken large scale seabed mapping programmes, including Ireland, Portugal, and Norway.
As seabed mapping endeavours extend into the deep ocean, seabed features are more clearly defined. Detailed surface structures are revealed of underwater mountains (seamounts), volcanic craters, and ocean spreading centres, (mid ocean ridges), giving us a new understanding of this unexplored domain of planet earth, and how it affects the circulation of ocean currents, and the cycle of marine life.
In recent years offshore Ireland INFOMAR's national seabed mapping programme survey effort has focussed on the Celtic Sea's Biologically Sensitive Area, an important area for European fisheries and marine traffic south of Ireland. Under the jointly managed initiative, the Marine Institute's two national research vessels, the RV Celtic Explorer and the RV Celtic Voyager, supported closer to shore by the Geological Survey Ireland vessels R.V. Keary and R.V. Mallet, have gathered and created vital bathymetry and habitat mapping data and products for improved resource management and safety at sea.
With an eye to the future, both INFOMAR partner organisations are working through a value added exploitation sub-programme towards innovative integrated technology approaches to leverage outputs from drones, satellites, autonomous vehicles, as well as conventional vessel mounted survey systems, for better land to sea integrated mapping, resource management, and growth in Irish marine economy.
INFOMAR is jointly managed by Geological Survey Ireland and the Marine Institute, and is funded by the Irish Government through the Department of Communications, Climate Action and Environment.