Polar Environments Flashcards
The artic?
Tree line. 30% ice surrounded by land. Substantial terrestrial food - land mammals, herbivore and insectious bird’s. Not geo isolated, glacial refugees. Extensive ice-free coastal zone in summer. Relatively high faunal and floral diversity.
Antarctic?
No trees. Larger land - 97% ice. Surrounded by the southern ocean. No terrestrial food, and mammals or birds. Low fauna and floral diversity. Isolated no glacial refugees - limited ice free in summer
The tundra climate?
Cold throughout the whole year very dry like desert. Permafrost. Inhospitable for life. Summer (6-10 weeks) brief of milder climate when the sun shines almost 24 hours a day. Rarely gets above 7-10 degrees but warmth melts top of permafrost, creating bogs and shallow lakes that don’t drain and are locked up.
Deep rooted plants can’t get water.
Winter temperatures don’t reach above -7 and av -30 -35 24hour darkness. Exceptionally Windy and photosynthesis slow
Permafrost?
Covers a large extent of artic- getting more sparse going away from poles. Region of green under water which is sub store of carbon etc (the essentials) as stuff produced tends to stick around. When the permafrost melts methane is released. Activation of dissolved carbon - positive feedback of climate change.
Tundra flora
No trees, no deep rooted plants, small shrubs in windy area. Also end up under the snow - best protection. Evergreen shrubs etc.
Tundra fauna
Severe climate therefore low species number. Low mean densities. Low temp means high quality for insulation, increase metabolic rate. Snow means life below snow for small animals.
Large favour soft/thin snow.
Short summer means birds migrate, breeding cycles compressed, large little size. Species low but numbers are high. Food web is simple as a lot will migrate - insects primary herbivores. Productivity can be enormous.
Artic ocean
Highly seasonal, low overall productivity, thick multi-year ice has low light levels. 2-5 m thick.
Need to travel away from the ice to get productivity
Stable ocean with restricted inflow and outflow and vertical mixing
Sub artic bering sea and Norwegian seas 100x more productive than high artic due to light level and mixing
Southern ocean
Highly seasonal. High overall productivity. Thin one year has good light levels. Good vertical mixing in dynamic stormy ocean, free exchange with world oceans. Best mixing in well lit surface areas and where upwelling of nutrients occurs e.g. the Scotia sea.
The richest parts, summer phytoplankton yield of vegetable matter is higher than good mid latitude agricultural land.
Southern ocean food web
Krill is the most abundant herbivore and the primary food - source for much of the food web. Krill alone have a biomass greater than that of every human on the planet and an annual production of 150, 000,000 tonnes, double the world’s fish production.
Keeping warm. - cold and warm blooded
Cold blooded animals tend to adjust to the ambient temperature by avoidance of freezing, glycoprotein production and metabolic rate adjustments.
Warm blooded : thermoregulation, heat exchange mechanisms, size and shape adaptions.
Also adopt life styled that enhance their chances of survival - shelter, response to food and light availability, energy efficiency, strategies, reproductive, migrations.
How is the polar region affect by climate change
Ice season shortened by nearly 90 days and perennial sea ice is no longer a feature of this environment. This is accelerating. Python plankton blooms decreased by 12%. Net productivity is decreased. Declines in Polar species related to decreasing sea cover, effects on prey availablity
Affect of climate change overall on species
Disrupting the life strategies of resident species leading to changes in community structure and ultimately altering the nature of local, regional food webs.
Affect of climate change on permafrost?
Permafrost carbon thawing. Contains twice as much carbon as in atmosphere. Could increase climate change.
1700 billion tons of carbon in northern permafrost zone. More deeper as well, will break down rapid upon thaw. Happening over decades but getting faster, will incur additional costs to society.
Sources
How do polar marine ecosystems respond to rapid climate change? ( o schofield, hw. Ducklow, dg. Martinson etal, 2010)
Climate change and the permafrost carbon feedback ( eag. Shucar, ad McGuire ET Al, 2015)
