Intro to marine systems
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t/f the arctic ocean is shallow and very cold
false deep and cold!
water mass=
a large volume of water with unique properties of temp, salinity, and density that extends over 1000s of km
How do you measure a water mass?
CTD rosettes (CTD= conductivity, temp, depth)
All oceans are structured by water masses, and there are 3 water masses in the Canada Basin of the Arctic Ocean: 1 2 3
• Arctic/ polar water • Atlantic water • bottom water
Explain the process of brine rejection
as the surface of the ocean cools, ice forms and as the ice continues to develop, salt is ejected from the growing ice = brine rejection
brine rejection is a major process in driving the ocean ___
currents!
Northward flowing ___ water is the major means of head advection toward the arctic and strongly affects the ___-___ distribution
atlantic sea-ice
t/f Atlantic waters entering the Arctic ocean have always been close to the temperature they are today
false temps of atlantic water are unprecedentedly high compared to past 2000yrs, & are linked to arctic amplification of global warming
There are 3 components of an arctic marine habitat: 1 2 3
• ice-covered seas • open seas • benthic habitats
What is a floe? List 3-6 defining characteristics
A floe is a piece of sea ice (acts like a sailboat, the ridges act as sails!) • floe size • source (fresh/ salt water) • form (attached to land/ drifting) • development/ age • deformation • ice cover
Freeboard= Draft=
Freeboard= part of the ice floe above the water surface (w/o snow) draft= part of the ice floe below the water surface
What is the melt pond depth? Melt pond bottom Z coordinate?
melt pond depth= max depth of a melt pond on an ice floe melt pond bottom z coordinate= distance b/w the water surface and the bottom of the melt pond
multiyear ice is biologically ____ (productive or unproductive)? Why?
unproductive b/c there’s no light penetration
• sea ice expanded from the central arctic ocean for the first time __ million years ago • Sea ice expanded more in response to positive ice-___ feedback mechanisms
4 albedo
sea ice provides a series of specialized ___ for many species
niches
Over time, sea ice deforms. What are the progressions over time?
Rafted ice –> Pressure ridges –> weather ridge –> hummocks
____ ___ formation is essential for ringed seal lairs for giving birth to pups
pressure ridges
Polynya=
= area of open marine water at high latitude that remains ice free throughout the years (b/c of currents, tides, upwellings, winds)
2 reasons polynyas are important:
• important over-wintering areas for many species (rely on polynyas to breath etc, and utilize ice around them) • plays a major role in organization of marine life in the arctic
How many major polynyas are there in the circumpolar arctic?
6
Coastal polynyas (ie ___ heat polynyas) are driven by ____ ____
latent land winds
open ocean (ie __ heat) polynyas stay as open water b/c cold dense water sinks deeper, pushing up relatively ___ water
sensible heat warm
What’s a major source of the world’s bottom waters?
when salt is released (brine formation) from sea ice –> the cold saltier waters sinks, becoming bottom water
The community that occurs under sea ice is called ____
epontic eg. “epontic algae”