Geology of Glaciers and Icebergs
The term glacier means ice in Latin. The process by which glaciers are formed is known as glaciation. They are essentially rivers of slow moving, very dense ice. Glaciers form on land when snow accumulates on a surface year after year. They are usually in a place that slopes downward allowing them to move slowly down under their own weight. Instead of melting, the snow crystals compress first into granules and then into more solid ice as the pressure from increased weight presses down. During this process much of the air trapped between the snow particles escapes.
There are several types of glaciers. The most common in Antarctica are Outlet, Piedmont, Valley, Hanging and Tidewater. Outlet glaciers, as their name indicates flow out from large ice sheets. Piedmont glaciers are those that spill out on to a plain. Valley Glaciers flow down valleys and are constrained on both sides by steep valley walls. Hanging glaciers flow down a mountainside and end at a certain point, typically a cliff. Tidewater glaciers are those that continue to flow down until they reach the sea. Tidewater glaciers are the type that calve off icebergs.
Color Spectrum of visible light
Carcass Island, Falkland Islands
The leopard seals, named for the spotted pattern on their undersides, are a large, almost reptilian-looking predator. An individual can be identified by the spot pattern on the left side of their face. These seals can grow to twelve feet in length (females being larger than males) and are very agile, strong swimmers. Their primary food source is penguins. They hunt their prey in the water and shake the penguin violently after grabbing them to nearly skin them before eating.
Hourglass dolphins are an Antarctic species. Adults are about six feet long and weigh just under 250 pounds.
This is from a Bowhead whale (Alaska) and is about twelve feet long. It was harvested as part of the native Alaskan subsistence whale hunt.
Penguins and seabirds are present on and around all of the Antarctic Peninsula, South Georgia and the Falkland Islands. There are eight species of penguins in the Antarctic. We were fortunate to see and photograph five of them (Chinstrap, Gentoo, King, Macaroni, and Magellanic). We missed out on Rockhopper and Adelie because landings in areas they inhabit were not possible due to very rough sea conditions. Emperor penguins are found on the ice sheets of the continent, well south of the area visited.
Blonde morph (Leucistic) Antarctic fur seal
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Tabular berg A57a measuring about 11 miles long and 5 miles wide. It comes out of the water about 150 feet. Icebergs normally have about twelve percent of their height above the water line so this berg goes down over 1100 feet. A quick calculation show us the volume of ice being over 12 cubic miles, weighing in at around 55 billion tons. This tabular berg broke off Larsen C Ice Shelf in 2008 and we saw it in the Bransfield Strait on the north side of the Antarctic Peninsula.
A section of an iceberg calved from a glacier, with very old, highly compressed blue ice on South Georgia
Sunset in the Gerlache Strait, Antarctic Peninsula
Note that the females are the more colorful animals in these two species.
Fur seals are eared seals with a pointy nose and large flippers enabling them to move fast through water and on land. They primarily feed on krill. Many species of fur seals were nearly hunted to near extinction in the early and mid-1800’s for their fur, which is very dense with about 70,000 hairs per square inch. Today the population has rebounded. Males are two to three times heavier than females. Some pups can be aggressive and will occasionally “charge” people.
The other types of marine mammals in the Antarctic are cetaceans. There are two suborders of cetaceans found here, those without teeth and toothed whales. The toothless whales are filter feeders that use rows of baleens to filter food from the water. They open their large mouths with expandable throats, take in large quantities of sea water then squeeze the water out through the baleen filter. The overlapping baleens are very efficient filters and quantities of small prey are trapped (krill and small schooling fish). The whale then uses its muscular tongue to push the food back to the throat for swallowing. There are several species of baleen whales in the region. We were able to photograph Humpback, Fin and the Blue Whale.
Area around Stanley, the largest city in the Falklands
Ice that is fairly young has snow on the surface and quite a bit of air still trapped in the ice structure. This allows the ice to reflect almost all incident light and therefore appear white. (White light is made up of all the colors in the spectrum.) Older ice that has undergone significant pressure over a prolonged amount of time is more highly compressed with almost all the air forced out. This type of ice structure absorbs the longer wavelength (red – orange light) and reflects the shorter wavelength (blue-green). Since only the shorter wavelengths are reflected, the ice appears blue or green.
Tidewater Glacier, Elephant Island, Antarctica
Nearly a 12-foot wingspan requires two joints in the wing to allow compact, folded wings.
The other suborder of Cetaceans found here are the toothed whales. This suborder includes dolphins, porpoises, and killer whales (orcas) as well as sperm and beaked whales. We were able to photograph Type B orcas (mostly gray with white patches stained slightly yellow) and hourglass dolphins.
Southern Humpback whales range in size up to 45 feet and weigh 30 tons. The estimated population in the Antarctic region is about 25,000.
Kelp goose pair on Carcass Island in the Falklands
The Shetland Islands, off the coast of Antarctica.
A berg broken off an ice sheet
This was near the Shetland Islands off the coast of Antarctica.
Blue-eyed shag (Antarctic cormorant)
View across Stromness Harbor, South Georgia
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Upland goose pair in the Falklands
Falkland Island thrush
This image shows three Valley Glaciers flowing into a Piedmont Glacier with two medial moraines
Andean condor spotted in a shag rookery on an island in the Beagle Strait in Tierra del Fuego
Wildlife in Antarctica and the surrounding region consists of marine mammals and birds. Of the one hundred known marine mammal species, twenty exist in the Southern Ocean. Although only twenty percent of the species types are here, the biomass they represent is closer to fifty percent of all marine mammals. The bird population varies depending on which location you consider. Penguins and seabirds are common on all three places we visited. South Georgia and the Falklands have a limited number of raptor and passerine species as well.
Marine mammals in the Southern Ocean are seals and Cetaceans.
Pinnipeds of the Southern Ocean – Taxonomy and Natural History
Pinnipeds, the general name given to seals and sealions, means fin-footed. Flippers, which evolved from fore and rear limbs, allow the animals to swim very well. Earless or true seals are awkward on land, moving in slug-like motions. Eared seals can rotate their rear flippers enabling them to walk, climb and run on land. Today pinnipeds are classified into two or three super families within the order Carnivora, the walrus being the animal that is somewhat confounding. In the three-family model, eared seals are in the family Otariidae and true or earless seals are in Phocidae. Walrus are the only living genus and species in the third family, Odobenidae. The two-family model puts walruses into the eared seal family Otariidae and genus Odobenus.
In the true seal or earless seal family we photographed southern elephant seals, Weddell seals, and leopard seals. In the eared seal family, we photographed South American, Antarctic and Falkland fur seals.
Southern elephant seals are larger than their northern cousins. Bulls can weigh in at 8000 pounds and be as long as five meters vs. about 6000 pounds and four meters in the north. Males and females are sexually dimorphic by size. Males are typically five to six times heavier than females. Their primary food source is squid. The can dive very deep to feed, off the coast of Tierra del Fuego a bull was documented diving more than a mile down.
Glaciers pick up rocks as they move. Water seeps down cracks (crevasses) to the bedrock under the glacier. When the water re-freezes it cracks the rocks and the resulting debris is absorbed by the glacier. The rock debris forms moraines. The most common types of moraines are terminal, recessional, lateral and medial. Terminal moraines are seen at the foot of a glacier. As the glacier moves down a valley and either melts or breaks off (calving) it leaves behind the rocks that were underneath. Recessional moraines are the rock fields left as a glacier recedes. Lateral moraines are made of the rock debris along the sides of the glacier. When two glaciers meet, such as when two valleys join in a Y shape, the resulting rock debris fields from their lateral moraines combine into a medial moraine, one seen as a stripe in the combined glacier.
The earliest known sighting of Antarctic mountains was in 1599 by a Dutch explorer Dirk Gerritsz when his ship was blown off course by a storm. He most likely saw the South Shetland Islands. British explorer James Cook did discover the South Sandwich Islands and South Georgia in the late 1770s. He reported the huge populations of fur-bearing and oil-producing pinnipeds. That report changed the course of Antarctic exploration as sealers now were the sailors that came down and eventually discovered the continent of Antarctica (1820). During the first part of the 1800’s fur seals were hunted nearly to extinction. The population rebounded but then in the second half of the 1800s the hunt resumed, again nearly driving them to extinction. Today, with no demand for their fur, their protected status since 1920, and the reduction of their predators and competitors for food (due to whaling), the population has more than rebounded. Whaling replaced the seal oil business in the early 1900s as many countries launched whaling fleets and built whaling stations in addition to fleet support stations in the Antarctic and South Georgia. Whale populations dropped to low numbers as the whale oil business boomed. Today few countries still hunt whales. With the reduced whale population, krill are much more abundant. This food source for fur seals has helped restore populations but may be at risk for depletion due to the over population of fur seals in places.
There are 53 signatories to The Antarctic Treaty. Twelve original countries who established this treaty in 1959 and seventeen countries that have demonstrated ongoing scientific research here make up its decision-making body. This treaty is a cooperative agreement to conserve, protect and facilitate scientific endeavors.
Travel to and within the region
Travel to the Antarctic is subject to rules and regulations set up by IAATO, the International Association of Antarctic Tour Operators. This organization is dedicated to preserving and protecting Antarctica. Although voluntary and self-regulating, most tour companies are members of IAATO and the majority many who are not, abide by the organization’s guidance. One of the regulations that we found most interesting was the limit on the number of daily landings an expedition ship can do. If the ship has less than 200 people, up to three landings a day are permitted. If the passenger count is 200 to 399, one landing per day is permitted. If the number of passengers exceeds 400, NO landings are permitted. Most landings are via Zodiac watercraft and are wet, meaning you get out of the craft in water that can be several inches to perhaps a foot deep. Waterproof boots and pants are a requirement. One other thing we found both interesting and comforting was the bio security regimen. Cleanliness of boots, pants, backpacks and so forth was paramount. Reputable expedition teams work diligently to ensure no cross contamination between the landing sites or the outside world occurs.
Arriving at Grytviken, South Georgia
If we had to describe the Antarctic region in one word, it would not be cold but instead alive. We came to realize the abundance of life here. The smallest living things to the largest, from prey to predator, from the land to the ocean, this area provides lessons in how living is a matter of adaptation and interdependence.
Striated caracara on Carcass Island in the Falklands
South American fur seals
There are 5 types of Orca in the Antarctic. They are called types A, B, C and D with Type B having two varieties (small and large). The animals we saw and photographed were the large type B Orcas.
Antarctica, South Georgia and the Falkland Islands
The earth’s polar regions are unique and wonderous places. If you were to compare the Arctic and the Antarctica regions of the planet you would find many similarities as well as a significant amount of differences. While the Arctic is a large expanse of ocean, typically frozen, surrounded by land (North America, a bit of Europe and Asia), the Antarctic is a large land mass, a continent, covered in most places with thousands of feet of ice. This land mass is surrounded by the Southern Ocean (also known as the Antarctic Ocean). Both are cold, but Antarctica reaches the coldest temperatures on the planet. It is the highest, coldest and windiest continent as well as the driest. Both have unique indigenous life forms that have evolved to survive harsh climates. In the winter of 2019, we had the opportunity to spend a little over three weeks on an expedition to the Antarctic Peninsula when it was summer in the southern latitudes.
Image of an endangered Blue whale
We were lucky enough to see one, really lucky to even make the image. Blues used to number in the hundreds of thousands but whaling in the early twentieth century drastically reduced their numbers. Today about 2,300 exist in the southern hemisphere with between 5,000 and 12,000 worldwide. They can grow to 100 feet long and weigh about 200 tons making them the largest animal ever to live on the earth.
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Fin Whales are the second largest whale next to the Blue. Adults in the Southern Hemisphere are a bit smaller than their northern cousins but adults are still a respectable 70 feet long and weigh in at 70 tons. We were treated to a group of between 50 and 100 animals feeding.
All the areas we visited had large numbers of seabirds. We photographed shags (a type of cormorant), petrels (named after St. Peter because they look like they walk on water as they take off), albatross, skuas and gulls. On South Georgia and particularly on the Falklands, we were able to photograph several species of raptors, waterfowl, and passerine birds.
The face of Nordenskold (tidewater) Glacier at Cumberland East Bay on the north coast of South Georgia Island
Southern elephant seals sharing a section of beach with fur seals
The Dragon's Teeth on Astrolabe Island, Antarctica
Icebergs are technically the large chunks of ice that fall (calve) off the face of tidewater glaciers. The very large “icebergs” that come from large ice sheets are actually large pieces of sea ice and are technically called tabular bergs.
Hanging Glacier- King Haakon Bay, South Georgia
Antarctic fur seals
Weddell seals have a large body with a small head with large dark eyes. They feed exclusively on fish. A seal’ whiskers are like those of a cat and sense underwater vibrations, enabling them to find food. Weddell seals are a favorite food of killer whales. These whales hunt in groups and work to create waves to wash seals off ice flows.
Sheep farm on Carcass Island, Falkland Islands
An interesting fact from physics: water molecules resonate (vibrate) at about the same frequency as blue light, making reflection of blue light from an iceberg (with little air trapped within), the most common color.
Piedmont Glacier- King Haakon Bay, South Georgia
We left from Ushuaia, Argentina Tierra del Fuego on the tip of South America and sailed across the Drake Passage to the Antarctic Peninsula, then on to South Georgia Island and returned to South America by way of the Falkland Islands. While traveling we had chances to photograph both from the ship and during excursions on land. Each destination’s terrain was unique. The Antarctic Peninsula is an archipelago formed by mountain peaks, some rising several thousand feet above the sea. The mountains are snow covered for the most part with many glaciers. South Georgia is an island with incredible mountains, glaciers and coastal flats, while the Falkland Islands are more temperate and much less rugged with the terrain being hillier with large open areas.
Antarctica, South Georgia and the Falkland Islands