Have you ever enjoyed playing in the snow or making snowmen in the wintertime? The winter season is our coldest season. However, some of the coldest days we have here in Indiana have the same temperature of some of the warmest days in other areas of the world. Check it out! The average temperature of the Arctic Ocean, even in the summer months, is not much more than freezing! The Arctic Circle is the area north of the latitude 66º 33 N. The Arctic climate is extremely cold, as you might imagine. It is also very dry, receiving only 100-200 mm of precipitation a year. Much of it is permanently covered in a layer of ice called the permafrost, making it a harsh environment. At some points, the ice can be 6-9 feet thick! In general, it is typically cloudy and not as windy as the Antarctic southern pole area. www.weather.nps.navy.mil In the Arctic Circle, the ocean and ice are primarily surrounded by land, which inhibits the melting of the ice and the circulation of water. The tides can be very varied, tending to be greater in the east and south, up to 3-15 feet. They can be as low as 1.5 feet in the north and west. A strong current in the Arctic Ocean, called the Arctic Ocean Gyre, moves from west to east, in a counter-clockwise direction. Very important to the stability of all ocean water is thermohaline circulation, which moves cold, salty water throughout the world s ocean in a slow, steady moving conveyor belt. Average depth: Total Area: 12,000 feet 5.4 million square miles 5Two of the main currents in the Arctic region are the North Atlantic Current (in red) and the Transport Current (in blue). These help to circulate the cold Arctic water and also cause an upwelling of nutrients with which to sustain life. www.whoi.edu/oceanus/viewarticle.do?id=9206
The food web is one important tool oceanographers use to analyze the complexity of an ecosystem. Here is an example food web for an ecosystem similar to the Arctic. This one comes from the continent of Antarctica, in the southern hemisphere. Already, you can see that with just 10 animals, there are many complex relationships. The arrows show the transfer of energy. So, for example, when the killer whale eats the penguin, the penguin s energy is transferred to the killer whale. www.gould.edu.au/foodwebs/antarcticc.htm All energy originates from the heat produced by the rays of the sun. So, at the very bottom of the food chain are the producers, mostly plants, which make their own energy through a process, called photosynthesis. This energy is transferred to animals when the plants are eaten. This energy continues through the hierarchy until it reaches the primary consumers, at the very top. Notice that although both penguins and fish eat krill, penguins also eat fish. Also, the organisms at the bottom of the food chain have many more predators than those towards the top. This is a simplified web. This is an example of a producer in the Arctic. Single-celled algae are a major contributor to the energy production in the Arctic Ocean. Here is a picture of a killer whale, one of the Arctic region s top consumers. Source of algae photo: www.arctic.noaa.gov/essay_krembsdeming.html Source of killer whale photo: www.hickerphoto.com/surfing-orca-whale-2727-pictures.htm
The Arctic Ocean is a very harsh environment in which to live. This explains why although there are few species that live there, those who do, have high populations. As mentioned, photosynthesizing organisms produce the energy needed in an ecosystem. Plants have a hard time in the Arctic Ocean because during the winter months there are a few hours, at most, of sunlight a day in the Arctic Circle. In addition, there is a thick cover of ice on the water preventing sunlight from permeating it. In the spring time when the amount of daily sunlight rises, there is also a growth in productivity. Algae and microscopic phytoplankton are the main producers in the Arctic. In addition to plants, the Arctic Ocean and its surrounding shoreline are home to several diverse species, including birds, fish, and marine mammals. The Arctic is home to several species of birds who migrate for the rougher seasons. One of these birds, pictured on the left, is called the ivory gull. http://collections.ic.gc.ca/arctic/species/ivophoto.htm It is a scavenger it will feed on any dead or decaying carcasses it finds, and also small fish. The bird on the right is an Oldsquaw, and it dives for its food, which consists mostly of plankton and small bottom dwellers. There are also many other species of birds, including ducks, swans, loons, and shore birds. Zooplankton, like jellyfish, flatworms, and crustaceans feed on the algae living in the ice. Benthic creatures, organisms that live on the ocean floor, like sponges and anemones, eat the dead organisms which fall to the ocean floor. The way the ecosystem works, the larger pelagic organisms, ones who can propel themselves through the water on their own, consume the zooplankton and benthic animals. Below and to the left is a picture of several arctic sea stars, who live on the ocean floor. Below and to the right is a picture of a jelly fish, an example of zooplankton of the Arctic. These organisms both live in the depths of the ocean. http://oceanexplorer.noaa.gov/ explorations/05arctic/background/biodiversity /media/ctenodiscus crispatus.html http://oceanexplorer.noaa.gov/expl orations/05arctic/logs/july5/july5.h tml
In addition to smaller animals, there are also several large marine animals in the Arctic Ocean. To the right is a Greenland shark, sometimes called a sleeper shark, who eats mostly fish and sometimes smaller sea mammals. This shark lives at deep depths, and can reach almost 20 feet in length. Below is a picture of a mighty polar bear! These bears are amazingly well adapted to suit the cold environment they live in. They have a layer of http://www.arctickingdom.com/g alleries/animals/greenlandshark1.html blubber that is almost 5 inches thick for insulation. Just look at how massive this bear is! Their skin is black so that they can absorb as much warmth as possible and the thick fur they have is clear and hollow to provide yet more insulation. This bear swims through the cold water to find food, but it lives primarily on land. I The beluga whale, pictured below, is a marine mammal that spends all of its time in the water. It has all the characteristics of a mammal, but it is adapted to be able to live and survive in the water. They grow to about 15 feet in length and can weigh almost 2 tons! They are mammals, so they breathe air, but they live underwater. They accomplish this by using a blow hole, located on the top of their head to breathe and release air when they come back to the surface. Another unique characteristic about beluga whales is that they use echolocation to find their prey. The way this works is they emit a vocalization and wait to receive the echo of it bouncing off of a fish. They use this information to calculate instinctively where the fish are located. The community of belugas also has a very complicated communication system. ( http://www.polarworld.com/pb5pic.htm) Notice that both of these animals are light in color. Do you think that there are advantages to being light when you live in this type of environment? www.arctickingdom.com/galleries/animawww.arc tickingdom.com/galleries/animals/beluga2.html)
Polar Bear-Ursus maritimus. <http://www.blueplanetbiomes.org/polar_bear.htm> Woods Hole Oceanographic Institute. http://www.whoi.edu/oceanus/viewarticle.do?id=9206 Gould League. http://www.gould.edu.au/foodwebs/antarcticc.htm National Oceanic and Atmospheric Administration. http://www.arctic.noaa.gov/essay_krembsdeming.html http://oceanexplorer.noaa.gov/explorations/02arctic/background/education/media/arctic_c_events.pdf http://oceanexplorer.noaa.gov/explorations/05arctic/background/biodiversity/media/ctenodiscus_crispatus.ht ml http://oceanexplorer.noaa.gov/explorations/05arctic/logs/july5/july5.html Rainbow Productions. Rolf Hicker. http://www.hickerphoto.com/surfing-orca-whale-2727-pictures.htm Naval Postgraduate School. http://www.weather.nps.navy.mil Canadian Council on Ecological Areas. http://www.ccea.org/ecozones/abm/overview.html Canadian Arctic Profiles. http://collections.ic.gc.ca/arctic/species/ivophoto.htm Arctic Kingdom Marine Expeditions. http://www.arctickingdom.com/galleries/animals/greenlandshark1.html http://www.arctickingdom.com/galleries/animals/beluga2.html National Snow and Ice Data Center. http://nsidc.org/seaice/characteristics/difference.html Parks Canada. http://www.pc.gc.ca/progs/amnc-nmca/plan/arc_e.asp Wikipedia. http://en.wikipedia.org/wiki/greenland_shark Enchanted Learning http://www.enchantedlearning.com/subjects/whales/species/beluga.shtml