Lecture 13- Intro to Marine Systems Flashcards
What are Arctic Ocean Basins?
-Shelf waters shallow (200-400m) on shelf
-Off the shelf can be over 4000m in depth
Why does the arctic ocean differ from other oceans?
Because it has floating sea ice which can influence the stratification of the ocean
Arctic ocean currents affect _____
Global ocean circulation
Describe what happens between the pacific and arctic oceans
A narrow pathway therefore the pacific water enters but cannot exit. The pacific is warmer and brings in more nutrients, this is where it gets a lot of it nutrients from
Describe what happens between the atlantic and arctic oceans
The atlantic waters are able to come in and cycle with the arctic and go back out. The atlantic can bring in some warmer temperatures, but it has a higher salinity so salinity in the arctic is brought in from atlantic currents
What does the pacific and atlantic oceans provide to the arctic ocean?
-Pacific provides ocean heat and nutrients
-Atlantic provides most volume and subsurface heat
What does the introduction of freshwater do in the arctic ocean?
-Runoff from land is key in the development of sea ice
-Less salty water coming in, increases in lower density water because it has less salt in it, so it stays on the surface
-Changes ocean water stratification
What happens with the increase in amount of runoff from melting glaciers (freshwater)?
-Could cause changes in ocean currents
-Reducing mixing = reduced nutrients and get less water cycling because differences in salinity
What is the major source of freshwater into the arctic in Canada?
Mackenzie river
What are the three components of the northern seas?
1.Ice covered seas
2.Open seas (polynya)
3.Benthic habitats
Sea ice is very ____ and _____
-Variable
-Dynamic
What aspects of sea ice results in variability?
-Different forms
-Different floe size
Ice can be moved by ______
Wind, currents and tides
How is sea ice classified?
-Floe size
-Source (fresh or salt water)
-Form (attached or drifting)
-Development
-Deformation
-Cover of ice
The classification of sea ice can influence ____
What species can use the ice
What are the three forms of ice?
- Land fast ice
- Pack ice
- Leads (gaps in the ice)
What is land fast ice?
Ice thats attached to land and buffers shorelines from erosion
What is pack ice?
Free floating ice that varies in size and can combine or break apart
What is lead ice?
Narrow or wide gaps in the ice that allows whales to move through the sea ice
Describe the process of the formation in rough bottomed ice sheets
Starts with frazil ice, then have disruption in formation from waves which leads to pancake ice. Then the pancake ice starts to bump into each other more and you can start to get rafting or ridging and eventually get a rough bottomed ice sheet
Describe the process of the formation in smooth bottomed ice sheets
Starts with frazil ice, then have calm conditions that turns it into a soupy (water and ice) suspension called grease ice. Then they start to fuse into a flat continuous sheets called nilas. These nilas start to fuse together from rafting and eventually get smooth bottomed sheet ice
What is frazil ice?
When the water temperature starts to drop and get icicles forming in the water but they haven’t fused together or formed a sheet, just crystals
What is rafting?
The ice bumps into each other, when they collide you get a little bit pushed up and over time it forms little ridges
What is ridging?
More overlap with each other and form a much larger ridge
