About the Deep Sea
Why explore the deep sea? In addition to being an exciting, relatively unexplored new frontier, the deep oceans have been an arena for ground-breaking science. Today, the deep sea is also becoming an important frontier in resource exploration with many nations starting to lay claims to large seafloor areas for mineral exploitation. Norway has vast deep, poorly studied ocean areas lying under Norwegian jurisdiction. What can be found there? How might Norway’s deep sea help Norway participate in the blue economy of the future?
The Deep Sea – an Introduction
Hidden below kilometers of water, the seafloor is the most dynamic part of the solid Earth. Along a 60 000 km long ridge and mountain chain, the oceanic crust is constantly being created by volcanic activity and the process of seafloor spreading. Here 90% of Earth volcanic eruptions occur. Over the last period of about 200 million years - a short time in Earth’s 4.6 billion years history – millions of volcanic eruptions have formed the seafloor we know today.
The ocean spreading ridges are a locus for the most vigorous and extensive interactions between water and rocks on Earth. This hydrothermal activity supports chemosynthetic ecosystems – ecosystems that rely on chemical energy rather that solar energy and photosynthesis!
Life in the Deep Sea
We now know that the deep sea harbours the greatest amount of biodiversity on Earth. Researchers have discovered that the process of chemosynthesis supports a deep biosphere that extends kilometers into the subsurface ocean sediments. Here we find organisms living under conditions that are at the limits for life. Temperatures approach 130°C and the chemical conditions are poisonous to most known life forms. These thermophilic or heat-loving organisms are changing our understanding of the roots of the evolutionary tree of life. It may be that the deep sea is the nearest modern analogue for the beginnings of life on Earth.
Revealing Earth’s History
Sediments accumulate on the seafloor slowly, at rates of a few millimeters per thousand years. Gradually, over time, the rough volcanic landscape becomes covered by hundreds of meters of sediments. When extracted in a sediment cover, these layers of sediments are like pages in a history book and can take us back in time – even to the start of the Jurassic period – 200 million years ago. Geologists can read the story the sediments tell us about changing oceans, volcanic eruptions, hydrothermal activity, glaciations, and about catastrophic events, when life on Earth almost went extinct.
The sedimented seafloor covers a major part of the globe. It is a complex and vital interface where geology and biology interact. This interaction extends deep into the subsurface. One of the challenges today is to decipher the information in the sediments to better understand this dynamic relationship.
Blue Growth – Bioeconomy
Life in extreme environments has extreme properties and already there is research showing that such life forms contain biomolecules that may be valuable for industrial processes and medical use. Such untapped biological and genetic resources may result in an important bioeconomy.
No one knows how “blue” the future will be, but we know that new knowledge is needed to fully understand the potential and the significance of the deep sea.
Nations are scrambling to claim areas of the seafloor for mineral and resource exploration, with deep sea mining already commencing in some regions in the coming years. However, although there are vast seafloor and subseafloor metal resources, it is unclear if the resources that are accessible are substantial enough to justify activities such as large-scale deep sea mining. The environmental impacts of such industrial activity are also unknown. Much research remains to be done!