What you need to know about our astonish­ing ocean

When humans first visited the Moon and watched the Earth – our brilliantly blue planet – rise over the lunar horizon, it forever changed our world view. Astronomer Carl Sagan called the Earth as seen from the Voyager Spacecraft leaving the Solar System, the “Pale Blue Dot,” and writer Arthur C. Clarke famously wrote, "How inappropriate to call this planet Earth when it is quite clearly Ocean." When considering the role of the ocean on Earth, we should remember: The ocean is the defining feature of our planet.

In light of its key role on our planet, seven big ideas about the ocean were developed. These ideas are the Seven Principles of Ocean Literacy. They are key ideas about the ocean, agreed on internationally, that everyone should know.

1. Earth has one big ocean with many features

In January, 1992, a container ship on the high seas accidentally released 29,000 rubber ducks, beavers, turtles and frogs into the Pacific Ocean. Carried by ocean currents, the rubber animals reached the shores of Indonesia, Australia and South America later that year. They reached the west coast of North America beginning in 1994. Most amazingly, they crossed the Bering Strait into the Arctic Ocean, were transported across the Arctic by sea ice into the Atlantic Ocean, where they made landfall in 2003, 11 years later, in Iceland and the United Kingdom, and along the eastern seaboard of North America.

The toys’ journey illustrates how the ocean differs from land and forces us to change how we think. In an essay on the fragmented governance of our global ocean, ocean leaders Wendy Watson-Wright and J. Luis Valdés describe how the ocean’s inhabitants know no borders, and its various ecosystems are parts of one connected whole. Their statement references ocean governance expert Elisabeth Mann Borgese (once called "the mother of the oceans"), who reminds us that in the sea, “everything flows and everything is interconnected.”

2. The ocean and life in the ocean shape the features of the Earth

A 2022 article titled, “Hot news from two billion years ago: plankton actually moved mountains,” describes how researchers discovered that over 2 billion years ago, phytoplankton, single-celled algae at the base of the marine food web, allowed much larger mountains to form on Earth than would have been possible without them. When phytoplankton die they sink to the seafloor and, buried under the pressure of other sediments, form sedimentary rock high in graphite. And graphite, like when printing with a pencil, slides. The phytoplankton remains acted as a lubricant between great slabs of rock that resulted in higher mountain ranges; ocean life changed the shape of land on Earth.

3. The ocean is a major influence on weather and climate

In a 2022 article in the Guardian, thermodynamics researcher John Abraham writes, “If you want to know how fast climate change is happening, the answer is in the oceans.” Water has a thousand times the capacity of air to hold heat, so the vast majority of the excess heat created by climate change is being held by the ocean. The heat the ocean absorbed in 2021 compared to 2020, Abraham says is the same as seven Hiroshima atomic bombs going off every second all year. The ocean has many impacts on our climate; one of them is to buffer us from rapid and catastrophic change.

4. The ocean makes Earth habitable

Life as we know it requires water. Earth is often described by astronomers as a ‘goldilocks’ planet, because the conditions for our planet are just right for life. In particular, the Earth has an ocean, and is not so hot that the ocean evaporated, nor so cold that it in its entirety froze. The ocean is often called the ‘cradle of life’ because all life on Earth is thought to have evolved from life that began in the sea.

5. The ocean supports a great diversity of life and ecosystems

Coral reefs, the rain forests of the ocean, support an unbelievable diversity of life. Even though they cover just 0.1% of the ocean’s surface, they support the highest diversity of fish and invertebrate species on Earth. Just to count species of fish on a reef is a challenge. Fish can be hard to find – life on a reef requires being unseen, surprising prey and hiding from predators. Now, researchers are using DNA shed from the bodies of fish in ocean water around reefs to identify the species living there. Their data revealed 16% more fish species than previously accounted for in diving observations.

Ninety-nine percent of the habitable space on Earth is in the ocean. The largest animal that has ever existed, the blue whale, and the smallest microbes, all live in the sea. The ocean supports a great diversity of life, and we don’t even know yet how many species it holds in total - we are still counting.

6. The ocean and humans are inextricably connected

In 2014, Kimberly Orren and Leo Hearn founded Fishing For Success, a not-for-profit that helps to re-connect Newfoundlanders to their fishing roots. Located in the coastal town of Petty Harbour, just outside of St. John’s, Newfoundland, Fishing for Success brings groups out onto the water to learn the local traditional skills used to fish for cod. They partnered with the Association for New Canadians to bring female immigrants into nature, at sea, to connect with one another in a safe space, and to fish. Their youth program teaches fishing skills and has participants make art of their catch; brightly coloured imprints of the cod’s bodies.

Humans are connected to the ocean in tangible ways – through fishing, shipping and other uses of ocean resources, but also in more intangible ways – through our deep cultural and personal connections.

7. The ocean is largely unexplored

In 2018, a submarine called the Limiting Factor brought humans for the first time to the bottommost point of all five major ocean basins. In 2019, it was used to measure the depth of the Mariana Trench, the deepest point on Earth, at just under 11 km, it is two kilometers deeper than Mount Everest is high. In 2021, the Limiting Factor dove in the Philippine Trench to the site of the shipwreck of the USS Johnston, a World War Two ship, and at over 6 km of depth, found a small squid swimming just above the seafloor. A small bigfin squid, it became the deepest-dwelling squid known to science. Researchers and explorers make discoveries about our ocean every day, and there are uncountable discoveries still waiting to be made!

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There’s so much more to learn about each of the seven principles, if you’d like to ride the wave. “Knowing and appreciating these principles not only enhances our connection to the ocean but also allows us to be more mindful of our responsibility for maintaining a healthy, vibrant, nurturing ocean environment”, says Boris Worm, Scientific Director of Ocean School.

Let Ocean School take you on a journey to connect with the ocean, and check out the United Nations’ website dedicated to the Seven Principles of Ocean Literacy, to go to greater ocean knowledge depths.