Ocean facts and stats

As a marine conservation charity we have an innate love for our ocean. Discover just some of our favourite facts and stats about the ocean - guaranteed to give you a new found respect for the deep blue sea.

The ocean still holds many mysteries

There is still so much that we have yet to discover in our ocean, especially when it comes to the deep abyss. In fact, we invest more in space exploration than we do in exploring the deep sea. This means we have only truly mapped out approximately 25% of the ocean floor compared to all of the observable universe.

The deepest part of the ocean is actually getting deeper

Scientists believe that the Mariana Trench, the deepest part of the ocean, is gradually getting deeper (by less than a few millimetres per year). However, the Pacific Ocean, where the trench is located, is actually shrinking at a rate of 2–3 centimetres annually. This means that in millions of years the entire Pacific Ocean and the trench might disappear altogether to make up a new supercontinent depending on how Earth’s tectonic plates shift.

Some anglerfish have been found to live up to roughly 4,000 meters deep near the Mariana Trench. However, the very bottom of the Mariana Trench is over 10,000 meters deep!

Credit: Superjoseph via Shutterstock

Underwater microphones pick up a lot of eerie-sounding noises underwater

Although the ocean seems quiet it is actually extremely noisy, our ears just can’t hear the low frequency noises that travel under the sea. Using underwater microphones we have begun to truly understand just how loud it can be and, in the process, have also picked up rather spooky recordings.

Though they conjure up thoughts about undiscovered giant sea creatures living in the deepest darkest parts of the ocean, the answer to what is making the noise often has a much less mysterious answer which ranges from underwater icequakes to whale sounds. Answering what makes these noises has also helped marine conservation. Recordings of ‘biotwang’ in 2014, which we now know were made by Bryde’s whales, have resulted in these sounds being used to help map the population and migration patterns of this elusive whale.

The recording above is of The Bloop. It was recorded in 1997 by NOAA which, while eerie, was later determined to be caused by icequakes, or ice cracking and breaking away from glaciers in Antarctica.

Sperm whales are recorded as the loudest marine animals with clicks that can reach 230 decibels. That’s louder than a jet engine!

The ocean is a lifesaver

Without the ocean, life on Earth would not have even been possible. All life originally came from the sea and it was roughly 1 billion years after life first appeared that the first land-dwelling organisms evolved. This means the ocean has been a consistent home to life on our planet for a very long time.

The ocean is a massive carbon sink

There are about 2,000 gigatonnes of carbon stored on land. In comparison, the ocean holds a massive 37,700 gigatonnes of carbon. That’s over 18 times more! Most of this carbon stays locked in the ocean for thousands of years which helps prevent excessive buildup of carbon dioxide in the air. This means the ocean is one of the most important allies in the fight against climate change.

It is thought that 35 times more CO2 is absorbed by seagrass than by rainforests making seagrass a vital asset in preventing climate change.

Credit: Laura McConnell

244 million tonnes of carbon are locked away within the top 10cm of the UK and Isle of Man seabed.

The ocean receives the equivalent energy of 7 Hiroshima bombs every second

It might sound extreme but the ocean absorbs a phenomenal amount of thermal energy from the sun. The ocean then transports it to the poles, moderating temperatures across the globe and making the planet hospitable so that the equator isn’t too hot and the poles aren’t too cold for life to exist. However, the energy that the ocean is absorbing is unfortunately increasing due to a mixture of global warming and natural climate change.

In 2024, over 90% of coral which makes up the Great Barrier Reef was affected by a global bleaching event caused by increased temperatures, reminding us of the fragility of these unique animals and the urgency to protect them.

The Gulf stream alone transports 550 trillion calories of heat energy across the North Atlantic every second.

The ocean can be pretty gross!

When people talk about the ocean, they usually mention how beautiful and majestic the creatures that swim in it are. However, just like anywhere else on Earth, there are some creatures that can be pretty disgusting.

Starfish eat by pushing their stomachs outside their bodies

Though it is one of the most recognisable sea creatures, starfish have a rather disturbing way of eating. They love to eat things like mussels by opening up the shells a little bit before pushing out their stomach through their mouth. That way they can digest food with tough exoskeletons and consume things that would otherwise not fit inside their mouth or be too difficult to eat. Starfish might seem cute to us but, for bivalves, they are a major threat. In fact, in some ecosystems, starfish can act like apex predators and keep population numbers of other species in check.

A common starfish captured around Shetland Islands, Scotland.

Credit: Billy Arthur

There's a parasite that replaces a fish’s tongue

The tongue-eating louse (Cymothoa exigua) is a type of isopod (part of the crustacean family) which has an uncanny way of living. It will enter a fish through their gills, move to the base of the fish’s tongue, latch on to it and begin to suck the blood and feed on the fish’s tongue until the tongue withers away. It will then move itself inside the fish’s mouth to act as its new tongue. It will remain there stealing food that the fish swallows. If its host does die though, the tongue-eating louse will simply detach itself and look for a new host to swim into and start the process all over again. Interestingly, it's the only parasite that is known to fully replace an organ in a host’s body.

Whales shoot snot out when they exhale

A whale’s blowhole is basically their version of a nose so it is no surprise that when they shoot water out of it, what we are actually seeing is a whole lot of mucus, water vapour and other gross particles being blown out from the whale. Basically when a whale is blowing through their blowholes, it is to force anything in their airways out. Researchers will often collect whale snot to help monitor the health of the whale and the ocean ecosystem in general. One way they collect it is by piloting special drones called snotbots to hover near a whale’s blowhole as the whale exhales.

Some whales have been known to shoot this gross concoction up to 10 feet high.

The ocean needs our help

The ocean is becoming increasingly more acidic

In the past 200 years alone, ocean water has become 30% more acidic. This is faster than any known change in ocean chemistry in the last 50 million years. It is being caused by the increased amount of carbon dioxide caused by burning fossil fuels, deforestation and industrial processes. Unfortunately, this is having an effect on ocean life.

Coral reefs are finding it increasingly difficult to build their calcium-based skeletons and the armor of shellfish are growing slower, weaker and thinner due to the acidity. In some places, their shells are actually dissolving. As species that play major parts within ocean ecosystems, creatures that rely on them for food or shelter are also being affected, meaning the entire ocean's biodiversity is at risk.

The United Kingdom's ocean habitats are severely underprotected

Although the UK has 377 Marine Protected Areas (MPAs), which covers over a third (38%) of UK seas, only 38 of the designated MPAs have bans in place that stop the use of bottom-towed gear across the whole of the site. Although there are several MPAs that have partial bans in place. This has had a devastating effect on the marine life and marine habitat.

Overfishing is a major concern

Though the ocean may seen infinite, the Marine Stewardship Council's 2024 report highlighted that 37.7% of monitored marine fish stocks were being overfished in 2021. Concerningly, that was 2.3% more than was recorded in 2019. By overfishing specific species, more pressure is being placed on the animals that rely on them as part of their natural food chain and on the fish themselves to reproduce. Also with less fish to catch, livelihoods are also becoming more difficult to maintain for fishing communities. This particularly affects the global South, where communities are dependent on fish for its nutrition source.

It is estimated that over 1000 cetaceans such as dolphins, porpoises and whales are killed each year in UK fisheries alone.