An array of new technologies and methods are leading to rapid progress in oceanography — the physics and chemistry of the ocean. Automated sensor arrays are enabling us to trace systems of currents and nutrient flows in unprecedented detail. Deep-sea exploration is revealing how the ocean interacts with the solid Earth, notably in hydrothermal vents, where mineral-rich water spews up from beneath the seabed. The ocean is becoming understood as a vast engine of currents and chemical flows that is inextricably linked to wider Earth-system processes such as plate tectonics and the climate.²

This understanding is crucial because of the sheer power of the ocean. As global average temperatures continue to rise, the ocean is responding in complex ways: sea ice is melting and retreating, currents are slowing and shifting their paths, and stored heat is moving. Our growing understanding of oceanography will enable us to identify the most significant and pressing risks, and to devise ways to mitigate them.

Likewise, our knowledge of marine biodiversity is progressing rapidly, driven by technologies like eDNA and metagenomics. At the same time, our understanding of marine ecosystems and the services they provide is also increasing, enabled by uncrewed vehicles and other tools for large-scale ocean observation.

This knowledge is crucial to the well-being and prosperity of society. We already know that non-sustainable human activities pose multiple threats to key marine ecosystems in the deep sea and in coral reefs, seagrass meadows and the Arctic sea-ice biota. Our improving understanding of those ecosystems offers an opportunity to find better ways to conserve them — and thus to protect the natural services they provide, ranging from food provision to climate regulation.

The ocean can also offer opportunities, when managed sustainably. While the impact of large-scale industrial implementations is not yet understood and thus must be developed with great caution, the emerging “blue economy” sectors may provide renewable energies, store carbon (marine carbon-dioxide removal or mCDR), provide food or harvest and utilise marine genetic resources.

KEY TAKEAWAYS

The ocean is a major and vital part of the planet’s ecosystem, generating 50 per cent of oxygen, absorbing 90 per cent of excess heat and capturing 25 per cent of carbon dioxide. However, much of the detail of its characteristics, contributions and changing properties are not yet understood. The field of Oceanography aims to inform our understanding of the physics and chemistry of the ocean, such as currents, helping us to model and forecast the effects of a changing climate and the potential for tipping points to cause major change. Researchers are still gathering new information on Ocean biodiversity, including microbial marine life and plants and animals living in the water and on and in the seafloor, of which 90 per cent of species are yet to be discovered. Research is also uncovering the details of Ecosystem function. The services that the diverse deep-sea ecosystems, as well as plankton, seagrass and corals in shallower seas, bring to the ocean system remain largely unexplored, and further insights will be vital to conservation efforts. This information is required to enhance our understanding of Human impact and ocean stewardship to facilitate better outcomes for the ocean environment and dependent life in the face of climate change and other challenges.