Ice Ice Baby

Another cool shot from NASA's Earth Observatory:


The image has 6MB worth of detail so you can really zoom in! This is a shot of the Sea of Okhotsk (which is between Siberia and Kamchatka for all the Risk players in the room). Cold arctic outbreaks, like those that put the Canadian prairies in deep freeze from time to time, cause intense cooling sessions over this sea. When the ice - which must be almost 100% pure fresh water for it to keep its crystalline form - removes fresh water from the sea, the enhanced saltiness of the water left behind is actually enough to cause that water to sink. This heavy water will sink to the bottom of the sea, and then cascade down into the deep ocean, like a slow motion water-fall. (Interestingly the same thing happens in the Mediterranean Sea because evaporation removes water but leaves salt behind.)

A neat feature of the image is that you don't really see clouds until the wind (which is blowing offshore) gets past the ice and starts blowing over the water.

you are here...

In response to themikestand's request about our whereabouts in this post...

That yellow dot on the Atlantic coast is approximately Halifax (my version of here). North is to the right in the picture. West is to the top of the picture.

The yellow dot near the horizon is where I do my field work.

The red dot is the Bay of Fundy.

The green dot is Cape Breton. (Those white parallel clouds are internal waves that formed as wind blows over the highlands.)

More coccolithophores!

This follows up on yesterday's post. Only this time, the photo is a little closer to home.

(from Emiliania Huxleyi's home page)

A world within a world

This shot was taken by a NASA satellite.

It, along with probably thousands of fascinating images, are available at NASA's EarthObservatory site. Each shot has a great explanation of what it is you're looking at.

Personally, I love the ones like this. Swirls within the ocean visualized by phytoplankton. Undersatnding the dynamics is complicated because the lifespan of the eddies is different from the lifespan of the phytoplankton that make them dramatically visible. Nonetheless, you can see the ocean being "stirred" (I can trace lines in and around the swirls) as well as the ocean being "mixed" (where did that swirl go, anyway?) You will see the same thing if you stir your coffee and then put milk in it.

Incidently, these phytoplankton are probably a specific kind called coccolithophores and more specifically, Emeliania Huxleyi. This is what they look like under the microscope:

Now here is where things get kind of fascinating, I think. The top figure has a scale bar 10 kilometres. The bottom one has a scale of microns. There are 1 billion microns in a kilometre.
--
1 billion! To put that number in perspective, if you had 1 billion pennies, you'd need more than forty 40-foot containers to store them. So think of how many of these little guys must be in that picture.

Also, those little plates on the the coccoloilthophore are called coccoliths. They are made of calcium carbonate (CaCO₃) and, to make a long story short, it is thought that the export of the their shells into the sediments is a way to extract CO₂ from the atmosphere. So if the ocean is going to be the vector by which carbon dioxide is removed from our atmosphere, it is possible that we'll need to count on our friends in the satellite photo to do the dirty work.

A stirring thought

So, after that last post, I thought I should give something a little lighter.

I can't remember where exactly I found this image (somewhere on the NASA site, I think), but it is absolutely phenomenal.
There are a lot of neat things to point out:

First off, what are all those colours in the ocean?
That's an estimate of how much chlorophyll (and kind of how much phytoplankton) are present. Based on the colour of the ocean viewed from space, some smart people have come up with ways to estimate the ocean's chlorophyll content.

See that yellowish oval south of the Bay of Fundy and east of Cape Cod?
That's Georges Bank. Due to some very neat physics that I won't get into, the waters there get well mixed and trapped over the bank. This results in a productive hot spot seen in this image.

See those grey swirls just off the Labrador coast?
I'm not positive on that one but I think that's ice! Ice being stirred and sheared. If you zoom in, it looks amazingly similar to those colours in the ocean. (I remember once I got an exam question that said nothing more than "Ice is a metamorphic rock. Explain." I wish I had this picture.)

See that donut-looking lake in the middle of Quebec?
If I remember correctly, that's from a meteor impact. The middle rebounded but edges were depressed enough to make that lake.

See the clouds making a ring just east of Newfoundland?
That's a low pressure system. You can tell because the "spinning" is in a counter-clockwise direction which, in the northern hemisphere, means a low pressure system.

Okay, I could keep going here, and maybe I will later on, but that's it for now. I just think this image is very cool.