For World Ocean Day: why we say Ocean and not 'oceans' ...

Banner image: Ciaran Wilmore, Light Breaker, Clogher Head, Kerry. Love Your Coasts Photography Competition 2025

By Mary Kate Hickey, Clean Coasts Communications Officer 

Here at Clean Coasts, we often are asked: Why do you say 'Ocean' and not 'oceans' when speaking about the vast body of water our volunteer groups strive to protect and care for? In honour of World Ocean Day, June 8th 2026, we are diving in to discuss the global Ocean, and the importance of caring for and protecting it!

But aren’t there five oceans?

You probably learned in school that there are five oceans on planet Earth, namely the Pacific, Atlantic, Indian, Arctic and the Antarctic or Southern Ocean. Continentally speaking, it makes sense to divide the Ocean based on the bodies of land it encompasses for a land dweller's perspective. However, have you ever looked at the Ocean from the perspective of a marine dweller? To them, there are no borders. In fact many marine species travel or migrate vast distances, beyond time zones, the equator, and throughout the Ocean in search of food, escaping warming waters due to climate change, and for breeding purposes. Our marine counterparts do not need to abide by any man-made borders, instead they perceive the vast body of water that covers our blue planet as one global Ocean.

Image: Michal Czubala, Whale Breach, Mullaghmore Sligo, Love Your Coasts Photography Competition 2025

The One Global Ocean

In dropping the “s” and taking the stance that there is only one Ocean, we affirm the theory that the Ocean is one singular living, interconnected system that we choose to care for and protect. These bodies of water are not isolated from each other but are rather one interconnected system.

Over 70% of the Earth's surface is covered by a body of water, with the Ocean holding over 95% of all global water and producing 50% to 80% of the oxygen on Earth*. The Ocean is vital to life on Earth as it also controls the climate by acting as a massive carbon sink and regulating global weather patterns.

*Oxygen in the Ocean is produced by photosynthesising plant-like organisms called phytoplankton, including algae and some bacteria. Although these wee powerhouses produce 50% of Earth’s oxygen, roughly about the same amount is consumed by marine organisms and as dead plants and animals decay in the ocean (NOAA).

In viewing our Ocean as an interconnected single system, it helps remove the cognitive distance placed on far off waters and reminds us that not only are our oceans connected to each other, but that we are also connected to our Ocean.

Connection of the Ocean, and to the Ocean

The Ocean not only provides food, employment and a lifestyle to coastal communities, it powers our climate, sustains all life on earth, spreads life and nutrients across the globe and connects us to a global community sans borders. Because these waters are one continuous system, marine life, nutrients, and unfortunately pollution are shared globally without prejudice. This means that our actions and inactions locally can lead to consequences, both positive and negative, in other far off parts of the world.

By acknowledging we share one Ocean, we remember the importance of our local actions and that we must care for and protect our waters for all of Earth's inhabitants.

Protecting our Ocean

From oxygen to recreational activities, and from climate regulation to employment, the Ocean provides a vast array of benefits to both human and animal life. Protecting and preserving the health of the global Ocean is essential for the survival of all life on our planet.

It is important for us all to recognise that pollution and climate change impacts in one region affect the entire planet, and that small positive actions can have a huge impact further down the line.

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