Salinity

| 7 Comments

From Minnesota to Texas to Israel, my absentee ballot has completed better than half of its rather substantial round trip. Now just as soon as I can establish who around here has "authority to administer oaths" I can get this thing back on its way. Of course then I need to figure out how to express the idea of "This should go quickly, and not via the Cargo Ship Express."

But that's the sort of thing department secretaries are good at. And we have those.

In fact, the inventory of things we have on campus is suprisingly long.

red_sea 2.jpg
Map of the Red Sea and surrounding regions, borrowed from this Saudi Geologic Survey page.

This came up over pizza with my advisor and my officemate last night, at which time it was observed that some staff and faculty around here have been known not to leave the campus for days or weeks at a time. After all, we have our own grocery store (and although the two in town are much better, for enough shekelim they will deliver), health club, restaurants, museums, and so forth. Altogether self-contained. A bit like the Red Sea.

Whether or not you get off campus regularly (and I do, since I like the walk and the good baker and the cheaper everything), the Red Sea has been on people's minds of late. The whole point of the Sinai resorts that were attacked last week was to cater to people that like a quiet, undeveloped beach to lie on, or warm, clear water to go diving in. Bounded as it is by largely undeveloped desert, the Red Sea seems to fill this need in a way the crowded, polluted, and built-up coastlines of the Mediterranean don't. And for that matter, neither do the Texas Gulf Coast nor the Minnesota lakes, back in either of the places I call home.

It began as an offhand comment by my officemate that the Mediterranean is warmer than the Red Sea despite being farther north, and that he'd been told that this was related to the Red Sea's depth. My advisor, being who he is, promptly seized upon a distantly-related and seemingly contradictory point: given that geothermal heat causes mineshafts to heat up at great depth, the ocean floor at great depth should also be hot -- in which case, why is the bottom of the ocean so cold?

As it happens, I think he is overestimating the actual amount of heat seeping through the deep sea floor (the abyssal and hadal zones, or the "abyss"). However, a bit of quick research suggests that I was on the right track when I pointed out that cold water sinks. Thanks to the thermohaline cycle, the water in deep basins originated in the polar regions, where it cools, sinks, and spends a few centuries wandering the globe before showing back up in equitorial upwellings. As a result, the water at the bottom of the ocean is pretty consistently close to freezing, and frequently a little below that, remaining liquid only thanks to its salinity.

Which brings us back to the slightly odd temperatures of the Mediterranean and Red Seas. Neither, the astute will quickly point out, is well-connected to an ocean, and as a result, they lack access to the cold deep abyss (a word that I rarely get to use seriously). In fact, it is reported that the bottom temperatures of these bodies are nowhere near freezing, but something like 13 C (55 F) for the Mediterranean, and 21 C (70 F) at the bottom of the Red. But hold on! That means the bottom of the Red Sea is warmer than that of its northern neighbor, despite the top supposedly being cooler.

The key, I think, is salinity. The Red Sea is evidently the saltiest of the non-landlocked seas, thanks to the fact that no rivers flow into it (c.f. the desert thing) and it's pretty sunny and windy around here, driving lots of evaporation. Which is what I meant by calling it "self-contained." As a side effect, this lack of input means that there is very little sediment in the waters there, either; hence the famously clear and blue nature of the "Red" Sea. The same kind of thing happens in the mid-Atlantic, and when the resulting dense, salty water cools off up north, it sinks with enough force to drive a planetary circulation system. I wonder if a similar process is at work on a smaller scale here, causing the surface water to be more effectively mixed with the bottom than in the Mediterranean. This would lead to an unusually small temperature difference from surface to floor, or cooler swimmer-depth water and warmer at submarine-depth.

The Wikipedia, incidentally, blames the "Red" moniker on either the occasional red tide or on the red mountains nearby in Egypt. It, like everything else, asserts that the Red Sea is famously blue and wonderful for diving.

Now I wonder if we have a SCUBA trainer on the campus. I wouldn't be surprised.

Late update -- 9:28 PM

On closer reading of the instructions in consultation with my advisor, we believe that he, as another registered Minnesota voter, is able to witness my absentee ballot. But if anyone with a stronger grasp of Minnesota election law has an opinion on this, feel free to leave a comment.

7 Comments

milligan, you should have got a scuba certification here on campus. it's fairly cheap, though saying that, i must emphasize that there is no connection with dumpster diving!!
of course i am not one to talk...i have yet to use my certification in a body of water warmer than 50 degrees F or one where i could actually see more than a few feet away....
hmmmmm, maybe i should go somewhere warm, too. but wait, i am bound by the chains of capitalism. tear.
c

Reading your latest tired, I noticed how easy it is to mistake the word "salinity" for "sanity." This isn't really some veiled metaphorical essay about sanity as related to something that might rhyme with that? Damn, we should have worked out the safe words before you left. :)

So in all your wandering around the bakeries and such, have you run across any of the infamous antiquities markets? I kind of doubt that Israel is exactly the destination most looters would aim for, but I'm curious about what you've seen.

If there is loot to be had, you can be sure Milligan is on the trail.

Plunder forth!

Well, I would be surprised if said infamous markets do not exist, but I rather doubt that they are to be found in a little hamlet such as Rehovot. Sounds like more of a Jerusalem thing, if I had to guess.

I have a fairly decent grasp of election law and access to those who know more about it than I do, although you may have resolved your question by now. If you're voting absentee in Minnesota, we believe that your ballot can be witnessed by another registered Minnesota voter. If you are voting with an absentee ballot from another state (I'm not sure where you are originally from), then that won't work. If you want to be extra sure that there are no questions about your ballot, the local U.S. consular office should have a notary public on hand for these kinds of things or any bank should be able to help you. And I won’t even ask who you’re voting for!

I live at 10851 Commonwealth in Seattle. Been up here before?

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This page contains a single entry by Milligan published on October 13, 2004 7:18 PM.

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