Exploring the Depths: A Census of Marine Life

The ocean, covering 70% of our planet, is often called "Planet Ocean." It's a realm of immense productivity, responsible for half of Earth's new life and oxygen production. It teems with biodiversity, much of which remains a mystery. A decade-long international program, the Census of Marine Life, aimed to shed light on this underwater world.

Unveiling the Ocean's Secrets

Coordination, Cooperation, Collaboration

The Census of Marine Life was a massive undertaking, involving 2,700 scientists from over 80 countries. They embarked on 540 ocean expeditions, investing $650 million to study the distribution, diversity, and abundance of marine life.

A Decade of Discovery

The census revealed spectacular new species, from the shoreline to the abyss. The limiting factor wasn't the unknown diversity, but the scarcity of taxonomic specialists capable of identifying and cataloging these species. An estimated four to five new species are described every day in the oceans, and the actual number could be much higher.

The Shifting Baselines of Our Oceans

From Salting to Exhausting

Human exploitation of the oceans began heavily with the Romans, who developed salting techniques to store and transport fish over long distances, marking the start of industrial fishing. Relative to pre-human impacts, we've seen losses ranging from 65% to 98% in major groups of marine organisms.

Changing Oceans and Environmental History

Trophy fish catches off the coast of Florida show a drastic change over time. Fish caught in the 1950s were significantly larger than those caught in the 1980s, and by 2007, the catch was almost laughable in size. This decline highlights the loss of productivity in our oceans.

New Tools for Ocean Exploration

New tools to count all the fish in the sea

Remotely Operated Vehicles (ROVs): These tethered vehicles act as our eyes and hands on the sea floor, allowing us to sample habitats far from the surface and light.

Acoustics: Sound waves are used to detect objects like fish. By sending out sound waves and measuring the reflections, scientists can estimate fish populations with remarkable precision.

Satellite Tags: These tags track animals as they move through the oceans. For animals that surface to breathe, data can be sent back to shore, providing valuable information about their location.

Pop-Up Tags: These tags collect data about light and the time of sunrise and sunset. They then pop up to the surface and relay the data back to shore, helping to identify important areas for ocean conservation.

Genetic Bar Coding: This tool uses a specific gene (CO1) to unambiguously identify species, even if they look similar. It has been used to uncover mislabeling of fish in markets and restaurants.

Ocean Biogeographic Information System (OBIS): This open-access database contains all the data from the census, allowing users to plot the distribution of species and their occurrence in the oceans.

Hotspots, Coldspots, and Truckstops of Marine Life

Blue highways, hotspots, coldspots, truckstops

Coastal organisms are most diverse in the tropics, while oceanic organisms are more diverse at intermediate latitudes. This data can be used to prioritize areas for ocean conservation on both global and regional scales.

The Diversity of Ocean Life

Despite the vastness of the ocean, new species are still being discovered. A three-kilogram lobster eluded scientists until recently, and a three-meter-long golden V kelp was also a new discovery. The Jurassic shrimp, thought to be extinct for 50 years, was found thriving off the coast of Australia.

The Unknowns

Even after the census, much remains unknown. It's estimated that we know only about 9% of the species in the ocean, with 91% still waiting to be discovered. A single drop of seawater can contain 160 different types of microbes, and the oceans may contain as many as a billion different types.

The Importance of Global Collaboration

The ocean is interconnected, and marine organisms move freely across international boundaries. Global collaboration is essential to address the pressures facing our oceans, such as ocean acidification and warming, and to preserve the spectacular beauty and productivity that remains.

Conclusion

The Census of Marine Life has illuminated the wondrous discoveries, vast unknowns, and spectacular adaptations of ocean life. Whether you're a yak herder in the mountains of Chile, a stockbroker in New York City, or a resident of Edinburgh, the oceans matter, and as the oceans go, so shall we.