Eighteen Things We’ve Learned About the Oceans in the Last Decade

In the past 10 years, the world’s oceans have faced new challenges, revealed new wonders, and provided a roadmap for future conservation

Octopus Moms
Thousands of brooding octopuses were discovered in 2018 on the ocean floor off the coast of California. Phil Torres and Geoff Wheat

As the end of the decade approaches, marine scientists and conservationists are reflecting on what we have learned about the seas, and what the next decade may hold for the world’s watery realms. So the Smithsonian’s Ocean Portal team has combed through years of studies, discoveries and expeditions to bring you some of ocean science’s most notable moments of the last ten years.

With the threats of climate change and ocean acidification, it can be easy to dwell on the bad and the ugly, and this past decade had its fair share of depressing news. But despite the doom and gloom, the ocean still manages to delight with the unexpected, and ocean conservation efforts have progressed, too. Here are the decade’s most significant events and research findings associated with the world’s oceans.

Polluted Seas

Straws are not the only things that make their way to the ocean as trash, and a variety of pollutants can impact ocean species and ecosystems.

Plastic Bottle
NOAA estimates that about 8 million metric tons of plastic enter the oceans every year. Sebnem Coskun / Anadolu Agency via Getty Images

Engulfing Oil

The decade began with tragedy on the ocean. On April 20, 2010 the Deepwater Horizon oil rig exploded, killing 11 people and spewing over 130 million gallons of oil into the Gulf of Mexico. The oil leaked 5,000 feet below the surface of the ocean and moved quickly to the ocean floor, its surface, and the beaches and marshes of the Gulf coast.

BP (formerly British Petroleum), along with the rig operator, Transocean, have paid upwards of 60 billion U.S. dollars in settlements, claims and other funds, including 1 billion to fund two ongoing research programs. The result has been an unprecedented amount of research on the impacts of the spill on species, ecosystems, the economy and human health. Researchers have found that some species and ecosystems still see effects from the spill ten years later, while others were fairly resilient. As more areas of ocean are opened to drilling, this information will be incredibly valuable for resource managers and disaster responders.

Drowning in Plastic

Oil isn’t the only thing polluting the ocean. The “Great Pacific Garbage Patch” (first described in 1988) made headlines early this decade as research expeditions gathered information about the abnormally high concentration of trash swirling in the North Pacific Gyre. The patch is not actually a “giant island” of garbage, but rather conglomerations of thousands of pieces of small, sometimes even microscopic, pieces of plastic and other trash.

Large pieces of marine debris—ranging from motorcycles to boats to barges—also traveled across the Pacific to the West Coast of the United States after a 9.0 earthquake and tsunami struck Japan in 2011. Pieces of debris from the disaster have brought along invasive species, which are still making their way across the ocean in 2019. Efforts abound to clear the ocean of trash—both the controversial Ocean Cleanup Project and Mr. Trash Wheel got their start in the past ten years. Plastic bag and straw bans have also exploded around the world with the realization that stopping trash from reaching the ocean starts at the source.

In Hot Water

This decade has been the hottest ever recorded, and the ocean bears the brunt of the increased heat. Impacts range from algal blooms to dead coral and beyond.

Coral Bleaching
Coral bleaching threatens reefs across the world. Near the Society Islands of French Polynesia, major coral bleaching occurred in 2019. Alexis Rosenfeld via Getty Images

The Blob & and Beyond

“The Blob” may conjure images of a monster fit for a sci-fi horror flick, but in the ocean it’s a different kind of horror. In 2014, water temperatures from Alaska to California skyrocketed to over 5 degrees Fahrenheit beyond the annual average. Scientists dubbed this large pocket of hot water “the blob,” and in 2019 a similar temperature spike announced its return (though the recent blob of hot water seems to be fading). The first heat wave caused intense algal blooms that shut down crab and clam fisheries, killed malnourished sea lion and seal pups, diverted whale feeding into busy and dangerous shipping routes, and devastated many Pacific fisheries.

Ocean heat waves from 2014 to 2017—driven by the combination rising ocean temperatures due to climate change and a strong El Nino—also led to mass coral bleaching. This phenomenon occurs when corals expel their symbiotic algae and the corals turn bone white. Though the bleaching in the Great Barrier Reef received extensive media coverage, reefs across the globe were affected with about 75 percent of coral reefs experiencing some level of bleaching between 2014 and 2017, and 30 percent of those corals dying. The Northern Line Islands in the South Pacific lost over 98 percent of their corals to bleaching, and the Hawaiian Islands experienced the worst bleaching ever recorded.

Raging Storms and Melting Ice

Hot water does more than kill corals (and other marine organisms). It also results in more intense storms. In 2012 Hurricane Sandy caused $70 billion worth of damage, the costliest storm ever in the United States—until Hurricanes Harvey and Maria came along in 2017. Like Harvey over Houston, Hurricane Dorian stalled over the Bahamas, subjecting Grand Bahama island to over 24 hours of high-intensity winds in 2019. These deadly and damaging hurricanes will continue to pummel coastlines and islands as temperatures rise. Most communities and governments are simply not prepared.

Farther north, the Inupqiat of Alaska have over 100 names for various types of sea ice, and all of its forms are melting due to human-caused warming. The Arctic sea ice extent—the measure of how much the Arctic Ocean is covered by ice—has been tracked since 1978 by satellite. The sea ice expands and shrinks with the seasons, but the seasonal minimum and maximum have both declined, and in the past decade we’ve experienced record lows. The lowest amount of sea ice was in 2012, and not far behind were 2007, 2016 and 2019. Not only is this ecosystem important to native people who live in these regions and the ecosystems that thrive there, but the entire globe relies on the regular forming and reforming of ice in the north.

Deep Dives

While the oceans are in dire straits, this decade also had stories of discovery and exploration where, as always, the deep seas played a starring role.

Mariana Trench
The remotely operated vehicle (ROV) Deep Discoverer exploring the Mariana Trench at a depth of 6,000 meters in 2016. NOAA

Deeper Than Ever Before

Designing a submersible that can dive nearly seven miles (35,787 ft) beneath the ocean’s surface is like sending an astronaut to the moon. In 2012, filmmaker James Cameron did just that. In the custom-built Deepsea Challenger, Cameron descended to the bottom of the Mariana Trench, the second crewed dive to the deepest point of the sea and the first solo dive. Protected by a nine-and-a-half-inch-thick glass window and a hull reinforced by special foam, Cameron’s sub withstood a crushing pressure of about 16,00 pounds per square inch—more than 1,000 times the pressure experienced at sea level. This one dive was part of a larger expedition that discovered amazing biodiversity in the deep sea, including gigantic sea bugs that grow to almost a foot long. Cameron’s record was beaten this year by American explorer, Victor Vescovo, who managed two trips to the depths of the Marianna Trench in just one year.

In 2018 a new deep ocean zone was described. Dubbed the rariphotic zone, it ranges from 130 meters to at least 309 meters (427 to 1,014 feet). Meaning “scarce light,” researchers must rely on submersibles and remotely operated vehicles to explore the region.

Ancient Sharks

The deep sea is full of slowly growing and old creatures, and this decade saw another aging record broken. In 2016 we learned that the Greenland shark is the oldest vertebrate (an animal with a backbone) on the planet, reaching an unimaginable age of about 400 years old. The old shark far surpasses the next oldest vertebrate, the bowhead whale, which only lives to 211 years. Scientists aged the shark using radioactive molecules embedded within the animal’s eyes, taking advantage of the fact that unlike most bodily structures, the crystal structure of the eye lens remains intact from the moment of its creation in the womb. The largest shark studied, a 16-foot behemoth, was estimated at 392 years old.

Early Microbes

The deep sea is also home to some microbes that long ago were key players in the origin of complex life. These organisms are similar to bacteria but actually distantly related. Called archaea, the microbes may be the ancestral link between complex and single-celled life. In 2015, scientists discovered an interesting archaea in the muck surrounding a deep-sea hydrothermal vent system named Loki’s Castle. Now named Lokiarchaea, after the mischievous Norse god, this microbe shares about 100 genes for cellular functions with complex life.

Soon after the discovery of Lokiarchaea, similar microbes with complex cell functions began cropping up. Together they form the Asgard archaea, and their emergence has sparked a contentious debate among microbiologists. Currently, all life is divided into either bacteria, archaea, or eukaryote (complex life), but the discovery of the Asgard archaea suggests that archaea and eukaryotes could be lumped into one group. It also means that an ancient Asgardian ancestor potentially gave rise to all complex life—everything from orangutans to bread mold.

Hidden Reefs

At the mouth of the Amazon River, a massive deep-sea coral reef sits below a plume of mud and silt. The size of West Virginia, this reef is likely six times the size initially estimated when it was first surveyed in 2016. Even scientists were shocked by its existence and amazed by the breadth of diversity found living on and among the corals.

Then in 2018 scientists were shocked once more. During a deep-sea submersible dive off the coast of South Carolina, researchers stumbled upon another massive coral reef half a mile below the ocean’s surface. This discovery upended previous notions of where a coral reef could exist. Most reefs form near the coast, but the Carolina reef was found 160 miles from the nearest shore. Now scientists are anxious to continue the search for deep-sea reefs across the globe. With the recent ramp up in offshore dredging, the need to find these hidden oases before they are destroyed is greater than ever before.

Mystery Deaths

Another impact of warming water is an increase in ocean disease. Several mysterious illnesses this decade impacted ecosystems, and we also learned more about the event that killed 96 percent of ocean life over 250 million years ago.

Sea Star Wasting
The leg of this Pisaster ochraceus sea star in Oregon is disintegrating as a result of sea star wasting syndrome. Elizabeth Cerny-Chipman, courtesy of Oregon State University via Wikicommons under CC BY-SA 2.0

Going Viral

Humans aren’t the only animals that carry disease. Ocean diseases are a growing threat to several species, and ecosystems have become less resilient due to warming waters, pollution and other stressors.

In 2013 a mysterious disease swept through sea star populations on the U.S. Pacific Coast, devastating the animals which essentially disintegrated before scientists’ eyes. Dubbed sea star wasting syndrome, the disease did not discriminate by species, and the most heavily affected species, the sunflower star, was almost completely wiped out from the west coast of the U.S. Although a virus was identified as the cause for some of the mortality, the broader scope of the scourge seems likely to have been caused by a confluence of events and conditions that made the disease particularly deadly.

Another mysterious disease began to impact coral reefs off the coast of Florida in 2014. Today, over 20 coral species are known to be susceptible to the infection, and the disease has spread south and across the Caribbean. Some corals are able to resist the illness, leading scientists to search for a way to help fend off the disease. Antibiotics and probiotics are key players, but using them in the open ocean is tricky business.

The Great Dying

The deaths we have documented over the past decade, as bad as they were, were nothing compared to what happened over 250 million years ago during the Permian period, when about 96 percent of ocean creatures died in an event known as the “Great Dying.” It was the largest extinction event in Earth’s history, even eclipsing the impact event that killed off the dinosaurs. The cause was once heavily debated, but in 2018 we learned that the likely culprit of the die-off was a major increase in global temperatures due to volcanic activity. As the planet warmed, the ocean began to lose oxygen. Essentially, ocean life suffocated. As our present-day Earth continues to warm, this study serves as a cautionary tale for what life in our oceans may look like one day, as the ocean has already lost 2 percent of its oxygen in the last 50 years.

Fun With Cephalopods & Whales

Whale watches and other eco-tourism opportunities abound, but we still have much to learn about these amazing (and often elusive) creatures.

Here Be Monsters: Giant Squid Filmed in America's Backyard

Glimpses of Giant Squid

Tales of a terrorizing kraken are considered far-fetched today, but seafarers of the past who believed in the tentacled beast were likely inspired by a real but elusive deep-sea creature. For over 2,000 years, the giant squid was only known by floating carcasses and the sucker scars it left behind on sperm whales. This decade, the squid was finally seen in its natural habitat for the first time.

To catch the giant squid in action, scientists used Crittercams, remotely operated vehicles, and even dove in submersibles. Nothing seemed to do the trick. Then in 2012 Japanese scientists tried coaxing out a squid with luminescent lures that mimicked the pulsing lights of jellyfish, a method that led to the million-dollar shot. Fast forward to 2019 and another squid was filmed off the coast of Louisiana by the National Oceanic and Atmospheric Administration. The emergence of its eight probing arms from the dark is both eerie and beautiful—a reminder that the ocean still has many wonders waiting to be revealed.

Octopus Gardens

Octopuses are famously cryptic and solitary beings, so it was quite the shock when scientists came across an expanse of around 1,000 octopus moms tending their broods together on the sea floor. Now dubbed “octopus gardens,” a nod to the Beatles song, these octo-mom gatherings are likely taking advantage of the volcanic activity in the area. In 2018, deep-sea explorers found not one but two of these gardens, countering initial doubts that it was a case of octopus confusion.

Diving Whales

Whales often grab our attention—their massive size, wailing songs, and nurturing social behavior are relatable yet mysterious. We’ve managed to learn a lot more about these animals in the past ten years, including how they made the transition from land to sea, when they became the behemoths we know today, and why they aren’t even bigger. Some of the huge mammals are also deep divers, and just this month scientists calculated that blue whales' hearts beat only twice per minute when they are diving.


Ocean science is not all discouraging, and to highlight the success stories of the seas, 2014 saw the creation of a hashtag to highlight successful marine conservation efforts.​.

Sea Turtle
Green turtle Chelonia mydas/ swimming over coral reef with soft corals. Georgette Douwma via Getty Images

Upping Ocean Protections

Today, more ocean is protected than at any other time in history. Somewhere between 5 and 7.5 percent of the ocean is protected with a wide variety of management levels. While this may not sound like much, it equates to over 27 million square kilometers, 14 million of which were added since 2010. In the last decade substantial, new or expanded protected areas were established in Hawaii, the Cook Islands and the Pitcairn Islands in the middle of the Pacific Ocean, among many other places. The UN goal is to protect ten percent of the ocean by 2020.

More protected areas are needed on busy coastlines and to preserve a wide variety of habitats. Enforcement is also crucial to see positive impacts, which include benefits to fisheries and nearby fishers, increased ecosystem resilience and greater marine biodiversity.

Reptile Recovery

Turtles have it tough. The leading cause of sea turtle deaths in the last 50 years has been commercial fisheries bycatch—hundreds of thousands snared in fishing gear every year. But the implementation of turtle excluder devices in U.S. shrimp fisheries in the 1980s may finally be making an impact. In 2019, loggerhead sea turtles laid a record number of nests along the southeast coast of the United States. And in Hawaii, a record number of green sea turtles were recorded swimming around the island. Marine plastic is now a major threat to sea turtles, but this one collaborative action likely made a major difference, offering hope for the conservation of these marine reptiles.

Aiding the Revival of Corals

The increasing stresses induced by climate change and human development are taking their toll on coral reefs around the world, but an army of scientists are determined to develop new ways to save the critical ecosystems. In Florida, researchers found that if coral are broken into tiny pieces and then spread in close proximity, the individual pieces grow quicker than the larger mature coral and eventually fuse together. The large, fused coral is then better able to weather stressors due to its size.

Smithsonian scientists were also able to revive coral larvae that were flash frozen, a method that will enable the preservation of endangered corals. This new technique uses lasers, gold particles, and antifreeze to thwart ice crystal formation when the larvae are warmed. As ocean temperatures rise, scientists hope preserving coral will give them more time to adapt to the changing world.

An Ocean of Energy

In the future, will we turn to the ocean to power our lives? It’s possible. In 2017 a 30 megawatt wind farm—the first operational offshore wind farm in the United States—was connected to the mainland grid from off the coast of Rhode Island. The world’s largest offshore wind farm began operations in 2019 in the North Sea, and more energy can be found amidst the waves. In fact, the Department of Energy funded 25 million dollars in research for marine energy devices.

Ten More Years of Ocean Science

At the National Museum of Natural History, curators and researchers celebrated the tenth anniversary of the Sant Ocean Hall and the amazing ocean science happening across the Smithsonian. The United Nations Decade of Ocean Science for Sustainable Development will begin in 2021 to support ocean health with science-informed policy and action. And in 2020, the Smithsonian is celebrating a year of Earth Optimism to share stories of conservation success and inspire hope with events in Washington, D.C. and around the world.

Get the latest Science stories in your inbox.