All the Poles Provide
Bridget Hott
It was long speculated by mapmakers that a southern continent existed, but there was no proof until 1820, when the first humans saw what is now known as Antarctica. Up North, the first human didn’t step foot onto the North Pole until 1909 and the common belief was that the Arctic Ocean was a single ocean basin, which we know today it is not. For the next century and more, research expeditions nurtured the primal understanding of these other-worldly environments, and it wasn’t until the 1950s that modern scientific monitoring began to take place. As a result of this delayed start, there is still so much to learn about the polar seas, but already scientists are understanding just how crucial these ecosystems are on a global scale.
Polar scene. Photo: Unsplash
Carbon Sequestration - shaping global climate
The global ocean is responsible for sequestering a third of all atmospheric CO2, and the Southern Ocean accounts for half of that alone. All waters in the Southern Ocean below 60o latitude act as a link between the physical climate system and marine environments. How is this possible?
The overturning of the world ocean is driven by heat and salt displacement, and this overturning process is properly given the name thermohaline circulation (thermo- means heat, and haline- means salt). This circulation process is also known as the Global Conveyer Belt and it increases the ocean’s ability to absorb carbon by bringing cold water up from the deep.
For starters, the ice itself maintains the global climate, by cooling the atmosphere through the albedo effect. Sea ice reflects solar energy back into space, acting like a mirror that prevents heat absorption in the Earth. Unfortunately, as this ice melts, the now dark sea absorbs the incoming energy, which creates a positive feedback loop as warming oceans cause global temperatures to rise and more energy is absorbed.
Antarctica is also responsible for influencing the pattern of ocean circulation through a process known as the thermohaline circulation or the Global Conveyer Belt. This circulation is the magic behind heat being transported from the tropics out towards the poles, which increases the ocean’s ability to absorb CO2. All of this works because cold surface water high in salinity found at the poles sink down to the depths of the sea, forcing ocean currents into different locations, effectively moving heat around the globe. All of this water movement ends up having a huge impact of the global climate and is heavily influenced by different wind patters around Antarctica and what is going on with the Antarctic ice sheet, another reason a warming planet will have unforeseen consequences as natural processes are disrupted.
Even the smallest players influence these forces that regulate life on this planet. Salt cannot be accommodated into the atomic structure of ice, as water crystals form in freezing sea water, so it ends up getting pushed out and creating small pockets of saltier water within the ice. These pockets cut through the ice around them and into the unfrozen ocean water below, making the ocean saltier, and therefore, denser. And what happens to dense water? It sinks, pushing deep water aside and creating current flows. Now, the sea ice that has rejected this salt is freshwater and when it melts, it adds freshwater into the ocean and reduces the salinity, affecting flow rates and water distribution around the world.
Polar Bear on an iceberg. Photo: Unsplash.
Habitat and Fisheries
The polar regions are home to thousands of species, with 5,500 species in the Arctic alone and 235 that exists in both. All that these habitats may be, is thanks to the ice. Sea ice and ice sheets provide ample surface area that sustain life in these harsh environments. From activities like mating, breeding, resting, and feeding to dictating entire predator-prey relationships, ice in the polar oceans deserves one big round of applause.
Without sea ice, walruses and seals wouldn’t be able to rest near food sources while nursing their young, who reside in the pack ice for the first 6 months of their life. The sea ice provides spacious habitats, distance from shore-based predators, and shelter from the piercing wind.
Without sea ice, birds wouldn’t have a place to rest between long migrations. The ice edge is an extremely important habitat for birds and marine mammals that are less ice-adapted and cannot feed within the continuous fast-ice zone.
Without sea ice, species in the polar sea would have very little to eat. At the very base of the polar food web is the ocean’s favorite friend: algae. Algae in the poles grows on the underside of ice sheets and ice caps, and makes its way to the seafloor throughout its lifetime, supplying nutrients to a wide variety of species along the way. Ice algae is one of the most well adapted species on earth, being able to photosynthesize in very low light. These algae populations form the base of the polar food web and are primarily fed on by krill which go on to support polar ocean inhabitants, open ocean communities, and, inevitably, commercial fisheries. You can read up on the importance of fisheries here.
Fun fact: Aside from marine life, the Arctic also hosts 1700 plant species that sustain polar herbivores and form the base of the food web for many species in Arctic and subarctic regions.
A ship navigating through icebergs. Photo: Unsplash.
Cultural value & Research expeditions
Of course, the Arctic and Antarctic regions have immense value outside of their ocean’s. The Arctic is home to 4 million indigenous peoples and contain 40 different ethnic groups. This region saw a huge influx of immigrants during the mid-1900’s, who came in search of the bountiful natural resources the Arctic has to offer. Humans have resided here for thousands of years, which means they have incredible knowledge of the ice. Information about the sea ice and icescapes has been passed down for generations through stories, training, and shared experiences, most of which hasn’t even been touched by researchers, oceanographers, and climate specialists. Unfortunately, the survival and livelihoods of these people is increasingly threatened by melting sea ice through rising costs of maintenance and relocations, and knowledge of the ice is being lost as languages and traditions become weakened and forgotten.
On the other end of the world, Antarctica has no native people and only houses small communities of researchers, photographers, and on occasion, tourists. That doesn’t mean it doesn’t have cultural value. The Antarctic region, along with the Arctic, are extremely important areas for researching global climate systems, some of which can only be understood by studying polar climates. The ice here can tell the history of the atmosphere going back hundreds of thousands of years, and unique species can be studied in untouched environments.
Icebergs in the ocean. Photo: Unsplash
Conclusion
With all these life sustaining services, protecting the polar seas should be at the top of our to-do list. Fortunately, many organizations and institutions are already on it, with most groups focusing on blocking new leases for oil drilling. Allowing these practices would greatly disturb fragile habitats that are already quite close to collapse. To take part in protecting the polar seas from your own home, a simple web search for petitions will provide an abundance of options, here are a few to get you started: