Polar Seas Polar Seas • Polynyas are the active, open water areas surrounded by ice, where life congregates. • Because the water is cold, oxygen is rich. • Summer Season – Increased light availability – Phytotplankton blooms – Upwelling is frequent due to high winds over low terrain
46
Embed
Polar Seas Polynyas are the active, open water areas surrounded by ice, where life congregates. Because the water is cold, oxygen is rich. Summer Season.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Polar SeasPolar Seas• Polynyas are the active,
open water areas surrounded by ice, where life congregates.
• Because the water is cold, oxygen is rich.
• Summer Season– Increased light availability– Phytotplankton blooms– Upwelling is frequent due
to high winds over low terrain
• Dominant phytoplankton - diatoms
• Dominant zooplankton - krill
• Short food chains yield high productivity and high population density.
• The number of species is low as food chains do not allow for diverse niches.
North Pole• Winter months (Dec-Jan) of 24
hrs of darkness• Summer months (June-July) of
24 hrs of daylight• Ocean ecosystem• Tall jagged icebergs• Average temperatures
• Most Pinnipeds (except the walrus) are covered with dense waterproof fur that was attractive to man.
• Since the Marine Mammals Protection Act of 1972, hunting is illegal. As a result, the shark has also experienced an increase in population because its food source is readily available.
OttersOtters• Smallest marine mammal• Not a pinniped because it
has 4 functioning limbs• High metabolic rate• Quickly die of
hypothermia when their fur is damaged
• Have no blubber
• 90% of the worlds’ otter population lived in the coastal waters from Prince William Sound to the Aleutian Islands
Exxon Tanker, Valdez Oil Spill
• More than 1500 otters killled
• Only a few hundred otters were saved.
• Dozens of orphaned otters were sent to zoos and aquaria
• Otter pups can’t swim so they float or rest on the mother’s stomach
• Males & females only socialize for a few days a year to mate
• Otters use tools such as rocks to break open abalone.
• Fisherman sometimes shoot otters because their appetites make them a competitor for abalone and fish.
• Declining abalone population is probably more often the result of over-fishing and the destruction of habitat.
• Otters help control the sea urchin population, who are destroying the kelp beds where the abalone live.
CurrentsCurrents are important
because they:- moderate climates- Mix nutrients &
oxygen- Transport larvae &
nekton
Currents are caused by:1. Spin of the earth on
its axis and the Coriolis effect
2. Ekman transport results in movement at a 90o angle to the wind
3. Warm air from equator flows toward the poles drives air circulation, makes wind
4. Continents deflect east-west water movement, but no air.
Gyre Currents• The characteristic
patterns of surface water currents.
• Northern hemisphere - the gyre is (right) clockwise
• Southern Hemisphere - the gyre is (left) counter-clockwise
Western Boundary Currents1. Located on the western
side of oceans.2. Currents bring warm
water from the equator3. High salinity4. Low oxygen content5. Nutrient poor,
infrequent upwelling6. Lower biomass
Eastern Boundary Currents• Located on the eastern
side of the ocean• Currents bring cold
water from the poles• Low salinity• High oxygen content• Nutrient rich due to
upwelling• High biomass
• Thermohaline currents are found on the ocean floor - “thermo”= temperature and “haline”= salinity/density
• Water slows down below the pycnocline (area defining water masses of different densities) to 1-2 meters/day
PenguinsPenguinsThere are 18 species of penguins,
who all belong to the Order Sphenisciformes, Class Aves.
Primary Habitat:- antarctica and surrounding
islands- Warm coastal areas of W.
South America- Southern Africa- Australia- New Zealand- Galapagos Islands
• The Emperor Penguin is the largest at 4 ft. and 90 pounds.
• The Blue Penguin is the smallest at 16 inches and 2 pounds
• Some Penguins have yellow crest feathers like the Macaroni, rockhopper, Royal and Fjordland.
• The Adelie is the common cartoon character with its black and white “tuxedo”.
• Penguins mate for life and can find their mate on crowded beaches among thousands of birds by its voice or call.
• Most penguins build nests of rocks, sticks, feathers, moss - whatever is available to lay their eggs.
• May migrate thousands of miles to spend summers in an ancestral rookery on Antarctica’s shores
• The King & Emperor penguins carry their eggs on their feet.
• In some species, the male cares for the egg all winter, tucked in a brood pouch kept 80o warmer than the temperatures outside.
• Penguins lay 1-2 eggs and a few species may raise two chicks if food supply is good. Others only care for the second “B” egg which is larger.
• Both parents help feed the chicks by regurgitation.
• On warms the egg or chick while the other feeds.
• Some may go over 3 months between feeding turns.
• If the hunting mate fails to return with food, the remaining parent will be forced by hunger to abandon the chick
• Penguins eat:- Krill- Fish- Squid
• Penguins may be eaten by: - Seals- Birds- Killer whales
Body Structure• Bones are not hollow -
makes swimming & diving easier.
• The Emperor can dive to 900 ft.
• Penguins CAN’T fly• Short wings are used like
paddles in the water.• Dense feathers & thick
fat keep them warm• Skin contains 70
feathers per square inch
• They molt their feathers• Do not enter the water when
molting.• High metabolism - overheating is
a problem.• Walk with their wings out to the
side to cool off.
• Streamlined bodies aid in fast swimming (15 mph)
• They travel long distances by “porpoising” or swimming like a porpoise with jumps and plunges.
• Allows them to breathe without slowing down.
Auroras• Aurora Borealis
(Northern Lights)• Aurora Australis
(Southern Lights)• High energy particles
escaping from holes in the sun’s corona create solar wind. When the particles collide with the Earth’s Magnetosphere, the energy of the particles is turned into light
• Northern Hemisphere – can be seen best above the Hudson Bay during the equinox in March & October
• Auroras often last 20 minutes and have no regular pattern of occurrence.
• To see an aurora, the sky should be cloudless and relatively dark from ground lights.
El Nino & La Nina• Normally trade winds blow
warm surface water toward the Western Pacific.
• Warm water piles up in the Western Pacific about 1.5 ft. higher than the average ocean surface due to wind and Ekman transport.
• This causes the thermocline to rise near the surface in the Eastern Pacific.
• Cold, nutrient-rich water upwells from the thermocline to the surface waters off the coast of Peru - good for fishing.
• This image shows normal sea surface temperature in the Equatorial Pacific
• Notice the warm water in a pool in the Western Pacific Ocean
• El Nino describes unusual oceanic and atmospheric conditions.
• El Nino’s weaker trade winds blow warm water eastward, across the equatorial region of the Pacific.
• This depresses the thermocline across the Pacific and stop upwelling.
• Because warm water evaporates faster, the air fills with more water vapor and produces more rain.
• El Nino occurs primarily in the tropical Pacific Ocean but it affects global weather.
• La Nina - When too much westerly wind blows surface water near the Americas, it has an effect on the weather that is often opposite to El Nino