The Ross Sea, a vast and isolated expanse of the Southern Ocean off Antarctica, is recognized for its exceptionally pristine conditions. Largely untouched by human activity, its icy waters and profound depths harbor an intact ecosystem. This offers a glimpse into a marine world free from widespread anthropogenic influence.
Characterized by extreme cold and abundant marine life, this unique area stands as a testament to the planet’s natural heritage. Understanding this region provides insights into polar ecosystems and the broader health of the global ocean.
The “Last Ocean” Defined
Positioned directly south of New Zealand, the Ross Sea is a deep embayment of the Southern Ocean. The immense Ross Ice Shelf, the world’s largest floating body of ice, forms its southern boundary. This ice shelf, roughly the size of France, plays a significant role in shaping the regional oceanography. Deep waters beneath the ice shelf contribute to the formation of Antarctic Bottom Water, a cold, dense water mass that drives global ocean circulation.
The Ross Sea’s unique oceanographic conditions, with extremely cold temperatures and high nutrient levels, are maintained by strong upwelling currents. These currents bring deep, nutrient-rich waters to the surface, fueling a productive food web. Scientists and conservationists often refer to the Ross Sea as the “Last Ocean” or “Earth’s Last Great Wilderness” due to its unparalleled ecological integrity.
Biodiversity and Unique Ecosystem
The Ross Sea teems with an extraordinary array of life adapted to its frigid environment. Adélie penguins and Emperor penguins thrive here, with large colonies nesting on its shores and sea ice. The Ross Sea is home to 38% of the world’s Adélie penguins and about 6% of the world’s Antarctic minke whales. Weddell seals, known for their deep-diving abilities, are also abundant. Several species of killer whales, including specialized ecotypes that prey on seals and penguins, navigate these icy waters.
The foundation of this rich ecosystem lies in the abundance of microscopic plant life, or phytoplankton, which flourish in the nutrient-rich surface waters during the austral summer. Antarctic krill (Euphausia superba), small crustaceans, graze on this phytoplankton, forming a massive biomass that serves as a primary food source for many larger animals. Unique fish species, such as the Antarctic toothfish and various notothenioid fish, possess natural “antifreeze” proteins in their blood, allowing them to survive in waters below freezing. This food web supports a diverse community, from tiny invertebrates to apex predators.
Protecting the Ross Sea: A Marine Protected Area
In 2016, the Ross Sea became the world’s largest Marine Protected Area (MPA) in international conservation. An MPA is a designated ocean area where human activities, particularly fishing, are restricted to protect marine life and habitats. For the Ross Sea, this designation covers 2.09 million square kilometers of ocean, with about 72% designated as a “no-take” zone, prohibiting all commercial fishing.
The Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR), an international body, was instrumental in establishing and overseeing the Ross Sea MPA. CCAMLR’s mandate is to conserve Antarctic marine life while allowing for rational use. The primary goals of the Ross Sea MPA include safeguarding biodiversity, allowing for scientific research on its undisturbed ecosystem, and managing the sustainable harvest of krill and toothfish in designated zones outside the no-take area. The MPA is divided into three zones, each with specific permitted and restricted activities. This protected status is set to remain in force until its review period in 2052, when it will be reviewed for renewal or modification.
Threats and the Future of the Ross Sea
Despite its protected status, the Ross Sea faces significant challenges, primarily from climate change. Rising ocean temperatures are a concern, potentially affecting sea ice formation, which provides habitat and foraging grounds for many species, including penguins, seals, and whales. Changes in temperature can also influence the growth, reproduction, and distribution of krill and fish, such as the Antarctic toothfish. Shifts in sea ice extent and thickness could also alter breeding grounds and migratory patterns for marine mammals and birds.
Ocean acidification, caused by the absorption of excess carbon dioxide from the atmosphere into seawater, poses another threat. This process reduces the ocean’s pH, making it more acidic and potentially hindering the ability of shell-forming organisms, like pteropods, to build their shells. These small organisms are an important food source for many Antarctic species, and their early life stages are most vulnerable. Ongoing international cooperation through CCAMLR and continued scientific monitoring are important for adapting to these changes and ensuring the long-term preservation of this remarkable wilderness.