Steller sea lions, Vancouver Island, British Columbia, Canada

© Steve Woods Photography/Getty Image

Hello from the other side. World Oceans Day

You can't talk about life on Earth without talking about the ocean. This year, World Oceans Day is being celebrated in Nice, France, just ahead of the UN Ocean Conference starting tomorrow. Officially recognised by the United Nations since 2008, it began as an idea at the 1992 Global Forum, a parallel event at the United Nations Conference on Environment and Development. This year's theme is 'WONDER: Sustaining What Sustains Us'. It highlights how the ocean supports life as we know it—influencing weather, food chains and economies.

Off the coast of Vancouver Island in Canada, Steller sea lions glide through chilly waters, as seen in today's image. These marine mammals are heavy—females average 260 kilograms, while males are more than 500 kilograms. Males are noticeably larger than females and are known for their loud roars, thick necks and flatter snouts. Their deep vocalisations include belching, growling and snorting to warn others and communicate underwater. Males get loud to defend turf, while moms and pups use unique calls to find each other in a crowded rookery. Despite their size, they're preyed on by orcas and large sharks. These sea lions are considered near-threatened, with populations declining in parts of Alaska. Ocean conservation keeps them—and countless other mammals—afloat.