Table of contents for Our Oceans in Our Oceans

THE SMART MACHINE THAT CATCHES PLASTIC AT THE SOURCE Plastic particles have become ubiquitous in our seas. They have been spotted in remote areas of the poles and in the deepest ocean trenches. While a number of projects focus on removing plastics from the seas, tech start-up Ichthion has developed a system for extracting plastic waste from rivers. Rivers play a big part in the plastic problem in the oceans, because they sweep tonnes of waste from land out to sea. “What we’re doing hundreds of thousands of miles inland really does have an impact,” explains conservation scientist Dr Heather Koldewey, who recently took part in an expedition that tracked plastic waste along the River Ganges. Ichthion's Azure device sits on a river's surface and diverts floating objects towards the…

ANGEL SHARK The angel shark was once common from the North Sea to the Mediterranean. As it lives on the seabed, it is taken as bycatch by trawlers and has been almost completely wiped out. Now it only lives around the Canary Islands. TOTOABA Illegal fishing is driving the totoaba to extinction in its native range in the Gulf of California. Its swim bladder, an organ that regulates buoyancy, is worth up to £6,500 a piece in China to make into soup. WHALE SHARKS In 2016, the whale shark was listed as endangered by the World Conservation Union because its numbers have halved in the last 75 years. It only becomes sexually mature at between 20 and 30 years old, so populations take a long time to recover. COMMON SKATE…

Until about a century ago, it was thought that not much lived in the deep sea. With its average depth of around 3.5km, crushing pressures and permanent darkness, few people bothered looking there – what could hope to survive in such an environment? According to the US National Oceanic and Atmospheric Administration (NOAA), more than 80 per cent of the oceans are still completely unexplored. But today’s scientists have ditched the old ideas of a deep, empty ocean and flat, featureless seabed. They’re keen to take a closer look beneath the waves, and the latest generation of research equipment is opening up the depths like never before. New technology is helping scientists uncover the oceans’ vital role in global climate, and find bizarre creatures that offer clues about the origins…

Every time you pick up your smartphone, you hold in your hand a veritable periodic table of elements. Among the metals under the casing, there’s cobalt, nickel and indium, plus traces of 16 of the 17 so-called rare earth metals. They’re all dug up in mines dotted across the globe, from the Democratic Republic of Congo to the Philippines, Chile and China. One day, perhaps in the not too distant future, smartphones could contain metals that come not from land but from the deep sea. Mining the deep isn’t a new idea. For several decades, mining corporations have eyed up the mineral riches that lie in Davy Jones’s Locker. But it’s always been too expensive to operate machinery kilometres beneath the waves, and metal prices are too unsteady to make…

NAKED FRUIT & VEG Who needs their apples and bananas in a plastic packet? Take a canvas bag, and grab individual fruit and veg. Loose stuff is often cheaper, so you’ll save money, too! JUMBO SNACKS Multipacks contain lots of little plastic packets. So go for bigger, single packets of popcorn, crisps and nuts that you can reseal with a peg. Just promise not to pig out! ECO REFILL Grabbing a coffee on the way home? Use a reusable cup. If you prefer water, carry a reusable bottle and fill up on the fly. The Refill app helps you locate free refill stations. GLASS JARS Pick peanut buffer, spreads and sauces in glass jars and bottles that can be reused or recycled. Or, why not impress your colleagues and learn…

1 IT’S FINE TO KEEP GOLDFISH IN SMALL BOWLS Nope. While goldfish can survive in cramped conditions, it’s not good for them. To live to their full lifespan and size (they can reach 45cm), they need properly aerated, treated and filtered water. 2 EACH VARIETY OF GOLDFISH IS A DIFFERENT SPECIES Wrong again. All goldfish are the same species, Carassius auratus, a type of carp originally from East Asia that’s been selectively bred for hundreds of years. 3 YOU CAN’T TRAIN A GOLDFISH TO DO TRICKS Yes you can! Like training a dog with food rewards, you can teach goldfish to swim through hoops, slalom between posts and even push a mini football into a net. 4 GOLDFISH HAVE A THREE-SECOND MEMORY Wrong! Goldfish remember things for months. Feed your…

Hide and seek WEST PAPUA,INDONESIA A tiny Denise’s pygmy seahorse (Hippocampus denise) peeps out from its home in a sea fan (Annella sp.). It has the smallest home range of any fish and will stay on this gorgonian coral for the rest of its life. Measuring no more than 2.4cm, it’s too tiny to fend o! predators, so it has turned to camouflage instead, adapting its colour to blend in with the surrounding coral. Covering the seahorse’s body are small bumps, called tubercles, which further aid its clever disguise, mimicking the polyps that make up the sea fan. But don’t be fooled by its small size. This pygmy seahorse is a master of stealth, sneaking up to within one millimetre of its unsuspecting copepod prey before striking. It is unclear…

On average, we each eat more than 20 kilograms of fish per year. Worldwide, between 1961 and 2016, fish consumption increased faster than meat consumption, and grew twice as fast as the human population. All of these fishy dinners have depleted marine fish stocks to a point where a third of global fish stocks are now classed as ‘overfished’, meaning that if we continue fishing at the same levels, these populations will decline. Most of the rest are being exploited at the maximum levels that can be sustained without long-term decline. Fishing also has negative impacts on non-food species in the ecosystem, and pollutes the waters with fishing waste. Temporary fishing bans may help to alleviate some of the worst impacts, but what would happen if we banned fishing altogether?…

“It feels like I’m somewhere I shouldn’t be,” says marine biologist Dr Jack Laverick, as he recalls being the first person to see part of a 100m-deep Caribbean reef. “This kind of exploration can give you tingles.” He’s one of a new breed of scientists who are venturing deeper than most scuba divers ever go. Divers can now descend into the ‘twilight zone’, from 50m down, where sunlight begins to run out. Few have visited these depths, but now rebreathers are making it possible. Although invented before scuba equipment, rebreathers have only recently become safe enough for use in research. Instead of bubbling exhaled air into the water they recycle it, scrubbing out carbon dioxide and topping up the breathable oxygen. Astronauts on space walks use similar apparatus while a team…

FANGS A LOT FANGTOOTH Two hundred metres is all that separates you from an alien world, right here on Earth. Descend that far into the ocean, and you enter the ‘twilight zone’ of the deep sea, where the Sun’s rays gradually fade away and animals play a deadly game of hide-and-seek with predators in the shadows. Dive down beyond 1,000 metres and you’re in the ‘midnight zone’, a vast darkness punctuated by flashes of light from life forms that hunt for food and seek mates here. It’s a world with terrifying teeth, like those of the fangtooth fish. But don’t let the fangtooth scare you: it’s about the size of a grapefruit. MICROSCOPIC MARVEL ZOOPLANKTON (RIGHT & BELOW RIGHT) Lots of different animals drift in the ‘inner space’ of the…

At the bottom of the Pacific Ocean between California and Hawaii, stretches the Clarion-Clipperton Fracture Zone (CCZ), a muddy plain measuring six million square kilometres that’s covered in trillions of polymetallic nodules. It’s a major focus for deep-sea mining prospecting. Dr Diva Amon was part of a team that catalogued a wealth of sea life in parts of the CCZ where scientists had never been before. “Just over half of all the animals that we brought up were completely new to science,” she says. Amon and her colleagues revealed this to be one of the most diverse places in the deep sea. The nodules themselves also form an important habitat. They’re the only hard surface available for deep-sea corals and sponges to grow on, and scientists have spied octopuses laying…

There was a time when many of us accepted a straw in our Friday-night cocktail without a second thought. But in October 2017, Blue Planet II hit our screens, opening eyes to the damage that plastic waste is causing to the world’s oceans. While conservationists and marine scientists had long been aware of the issue, it was this series that brought the problem hurtling into public consciousness. Since then, many of us have tried to restrict our use of single-use plastics, while governments have been urged to take action – in the UK alone, microbeads in toiletries have already been banned, and from October 2020 plastic stirrers and straws will be restricted. Currently, around 380 million tonnes of plastic are produced each year – a large proportion of it single-use –…

In 2007, Marc Collins Chen was working as the minister for tourism in French Polynesia when reports started to emerge that the Pacific islands would be under threat from rising sea levels in the coming decades. “There wasn’t consensus around when this would happen,” he says. “But there was a sense of doom.” Today, Chen is CEO of Oceanix, a company based in Hong Kong that’s developing concepts for floating cities. He’s now been working on the problem for 13 years. “If you’re a Pacific Islander and many of your islands are at sea level, you have to look at a solution,” he says. In 2019, Oceanix announced a collaboration with the Bjarke Ingels Group (BIG) and MIT’s Centre for Ocean Engineering, creating a concept for a city of 10,000…

A reef shark slides past, an arm’s length away, then another. And moments later a third. These sleek hunters pay me no attention and seem accustomed to having people nearby. Scuba divers like me flock to visit the sharks and other marine life flourishing around the remote islands of Palau in the western Pacific Ocean. This special place offers a glimpse of how things used to be before human activities began emptying the oceans. Palau remains a rare underwater wonderland, in part because the government takes marine protection seriously. In 2015, the country’s president, Tommy Remengesau Jr, declared 80 per cent of the nation’s waters off-limits to fishing. This is one of a new generation of marine reserves. More recently, in August 2016, Barack Obama, who was then the US…

There is a small lab on Friday Harbor, San Juan Island, just off the US state of Washington. Here, marine biologist Dr Adam Summers spends much of his time painstakingly loading fish after fish into a CT scanner to produce detailed images that reveal their intricate skeletons and inner structures. The project began inauspiciously several years ago when Summers would pay covert night-time visits to local hospitals, begging to use their CT scanners during periods of downtime. “We would stuff dead sharks and rays and things into bags, so nobody could tell what they were,” he says. After amassing a library of several successful scans, he began sharing his results on Twitter. To his surprise he got a huge response, with many biologists asking him to scan their favourite fish.…

Tagging huge elephant seals on an Antarctic beach isn’t a job for the faint-hearted. Mature males weigh up to four tonnes, and can easily mistake a human for another seal looking for a fight. “Elephant seals don’t have good vision,” says Dr Horst Bornemann, a researcher from Germany’s Alfred Wegener Institute for Polar and Marine Research. “You want a team who can anticipate their behaviour and fend off advancing territorial males.” There’s a good reason for working with such colossal, bad-tempered animals in remote, sub-zero conditions, though. Southern elephant seals, the deepest-diving seal species, can dive below 2,000m for hours at time, so fixing small, electronic sensors to their heads can transform them into a fleet of researchers. These sensors gather data on the seals’ movements – how deep they…

Measuring 1.5m in length and weighing 180kg, OceanOne is quite unusual for a remotely operated underwater vehicle. Described as a ‘robo-mermaid’, it has a head, two cameras for eyes and a pair of fully articulated arms, complete with wrists and fingers. OceanOne acts as an underwater avatar, allowing people to feel like they’re diving to inaccessible depths while remaining safe and dry. A human pilot can see what the robot sees via stereoscopic cameras, and feel what it’s holding via sensors in the robot’s hands that transmit haptic feedback to a controller on the surface. To a certain extent, OceanOne can even think for itself. Onboard processors analyse camera footage and adjust the thrusters in the robot’s tail to make sure it doesn’t bump into anything. If sensors detect an unavoidable…

Polymetallic nodules LOCATION: Abyssal plains MAIN DEPOSITS: Clarion-Clipperton Fracture Zone and the Peru Basin in the Pacific DEPTH: 4,000-5,500m METALS: Manganese, nickel, cobalt, copper, plus traces of molybdenum, lithium and rare earth metals (REMs) KEY FEATURE: 5-10cm spherical rocks that grow as metals settle out of the water at a rate of a few millimetres per million years WHAT LIVES THERE: Octopuses, corals, sponges, brittle stars, sea cucumbers and maybe foraging whales Cobalt-rich crusts LOCATION: Seamounts MAIN DEPOSITS: Western equatorial Pacific DEPTH: 800-2,500m METALS: Manganese, cobalt, copper and nickel, plus traces of REMs KEY FEATURE: The metal-rich crusts grow around 1-5mm per million years WHAT LIVES THERE: Corals, sponges, starfish, sea urchins, long-lived fish Seafloor massive sulphides LOCATION: Hydrothermal vents MAIN DEPOSITS: Mid-ocean ridges, subduction zones DEPTH: 800-5,000m METALS: Copper,…

Nanoplastics smaller than a micrometre in size (one micrometre = one-thousandth of a millimetre) could be floating through the oceans and piling up on the seabed, but at the moment there’s no way of detecting them. Scientists are developing automated machines to trace the chemical signatures of these tiny plastics, so we should know more soon. Already there are fears that nanoplastics could cause even bigger problems than microplastics because they’re likely to hold more chemical contaminants on their relatively large surface area and there’s a possibility they could get inside living cells. In a lab study, when zebrafish were fed nanoplastics, the particles moved into the fishes’ blood and built up in their nervous systems. This changed their behaviour and possibly caused brain damage: the fish explored their surroundings…

Many people don’t think of fish as being intelligent. Fish brains are too small and they’re too distantly related to humans to be clever; they lack feelings; they can’t feel pain – at least that’s how they’ve been typecast. Their simpleminded reputation means that people still tend to treat fish differently from other animals, with far less concern for their welfare (just imagine if we slaughtered cows by drowning them in the sea). In the past, many scientists overlooked fish intelligence and didn’t bother testing for it. Those that did often used experiments that weren’t relevant for these animals, with senses so different from our own. But the science of fish cognition is catching up, and new studies are showing that fish are much smarter than previously thought. Signs of…