The ocean covers over 70% of our planet’s surface and holds 97% of all Earth’s water. This dynamic system profoundly influences Earth’s habitability and supports a rich diversity of life. Its powerful currents connect distant regions, playing a pervasive role in global processes. The ocean’s scale and complexity highlight its importance to natural systems and human society.
The Ocean’s Role in Earth’s Systems
The ocean regulates Earth’s climate and supports its ecosystems. It acts as a carbon sink, absorbing approximately 25-30% of human-caused carbon dioxide emissions annually. This occurs through physical processes and biological carbon pumps, where microscopic marine organisms like phytoplankton take up CO2 during photosynthesis. Coastal ecosystems like mangroves and seagrass beds are effective “blue carbon” sinks, capable of sequestering carbon dioxide at rates up to four times higher than terrestrial forests.
The ocean is also a producer of oxygen, with phytoplankton generating an estimated 50-80% of the atmospheric oxygen through photosynthesis. These tiny organisms form the base of the marine food web, supporting diverse life. The ocean moderates global temperatures by absorbing and distributing solar energy via ocean currents. It holds around a thousand times more heat than the atmosphere and has absorbed about 90% of the excess heat generated by greenhouse gases.
The ocean is a reservoir of biodiversity, housing an estimated 80% of all life on Earth. While approximately 250,000 marine species have been identified, scientists estimate millions more remain undiscovered, particularly in the deep sea. Coral reefs, for example, are biodiverse ecosystems, supporting over 25% of marine biodiversity despite covering less than 0.1% of the ocean’s surface. The health of these marine ecosystems is directly linked to the stability of the global environment.
Economic Pillars from the Ocean
The ocean provides economic benefits, underpinning various industries and supporting livelihoods globally. Fisheries and aquaculture serve as a food source for billions, contributing to global food security. In 2022, global production reached a record 223.2 million tonnes, with 89% used for direct human consumption. This sector employed an estimated 61.8 million people in its primary production.
Maritime shipping and trade are central to global commerce, facilitating the movement of goods and resources across continents. Approximately 80% of international trade by volume, and over 70% by value, is carried by sea. In 2023, maritime trade volumes increased by 2.4%, reaching 12,292 million tons.
Coastal tourism and recreation are also economic drivers, drawing millions of visitors to coastal destinations annually. This industry generates revenue, creates jobs, and supports local businesses. For instance, in the European Union, coastal tourism generates approximately €183 billion in gross value added and employs over 3.2 million people.
The ocean also holds future economic potential in areas like renewable energy and marine biotechnology. Technologies such as offshore wind, tidal, and wave energy are being developed to harness the ocean’s power, offering sustainable alternatives to fossil fuels. Marine biotechnology explores marine organisms for novel compounds and processes, with applications in pharmaceuticals, biofuels, and advancements in aquaculture.
Ocean’s Impact on Human Health and Well-being
The ocean contributes to human health and overall well-being. Seafood provides nutritional benefits, being a rich source of proteins and essential nutrients. Fatty fish, such as salmon, herring, and mackerel, are abundant in omega-3 fatty acids like EPA and DHA, linked to a reduced risk of heart disease and supporting healthy brain and vision development. Health organizations suggest an intake of at least 250 to 500 milligrams of EPA+DHA per day, with the American Heart Association recommending two servings of oily fish per week.
Beyond nutrition, the marine environment is a source for pharmaceutical advancements. Scientists have discovered compounds from marine organisms, including sponges, mollusks, and microorganisms, with therapeutic properties. Examples include ziconotide, approved for chronic pain treatment, and eribulin, an anti-cancer agent derived from a marine sponge. These marine-derived compounds offer mechanisms of action and are being explored for treatments against cancer, viral infections, and neurodegenerative diseases like Alzheimer’s.
The psychological benefits of “blue spaces”—areas with natural water environments like oceans, lakes, and rivers—are recognized. Proximity to the ocean or engaging in ocean-related activities can impact mental health. Studies indicate that visits to and views of blue spaces can reduce stress and anxiety and improve mood. This connection suggests that access to coastal environments can serve as a natural therapeutic resource.
Frontiers of Ocean Discovery
The ocean represents a largely unexplored frontier that continues to yield scientific discoveries and drive technological innovation. Studying marine life and ocean processes provides insights across scientific disciplines, including biology, chemistry, and physics. Researchers are uncovering new species, with some estimates suggesting that only 10-25% of marine species have been described globally. Recent expeditions have documented hundreds of new deep-sea animals, including corals, sponges, and crustaceans, from depths up to 4,990 meters.
The discovery of biological compounds from marine organisms, particularly extremophiles—microbes thriving in harsh environments like deep-sea hydrothermal vents—holds potential. These organisms produce molecules that allow them to survive under extreme temperatures, pressures, or chemical conditions. Such compounds can inform advancements in fields from medicine and biotechnology to materials science, offering new enzymes, antibiotics, and other substances. The ongoing exploration of these deep-sea environments and their inhabitants continues to expand our understanding of life’s adaptability and the planet’s biological and chemical processes.