Friday, October 26, 2007

Friday: The Missing Thursday Pics Arrive



Time and the tides wait for no man ... not even FC. I wanted these pics to be in Thursday's post because we had just enjoyed a full moon.

As you know, full and new moons give us our strongest tides of the month. These are the Spring tides. On a spring tide, we have our highest highs and our lowest lows. The name comes from a Nordic word, "springen" which means to jump up. It has nothing to do with the seasons as these are monthly events.

The opposite monthly tides are called Neap (pronounced "nip") tides, but they are weak and uninteresting.

A spring tide is an amazing thing, caused by a straight line arrangement of sun ---earth---moon.

Instead of working against each other, this arrangement allows the sun and moon to accentuate the bulge of water formed by the spinning of the earth.

That's the same arrangement that gives us beautiful full moons and mysteriously absent new moons.

If you're a feeder in the intertidal zone, the tides control when you get to eat. The fiddlers in the top pic don't feed much when the tide is up. They're either nervously wringing their chelipeds in some burrow, hoping a drum or ray doesn't suck them out, or they're hiding in the spartina grass hoping the shore birds eat their neighbor and not them.
It's tough being a small crab ... especially if that Survivor Man guy shows up on your beach.



For the egrets and other shorebirds, low tide is dinner time and a spring tide exposes even more "table" for them to use. The snowy above is chasing killifish in a tide pool left by the retreating tide. Killifish are amazingly well adapted to being left behind. I have stuck a thermometer in a tiny washtub sized tide pool on a summer day and measured the water at 100 degrees F, but the killi's in it are doing just fine. Plus, they have the ability to duck under the mud in a puddle like that and hide from wading birds. Gotta love such toughness.

Low tide concentrates food and allows access to both trapped fish and buried treats like polychaete worms, mollusks, fiddlers, and other subterranean inverts.

Of course the tide doesn't really "go out" or "come in". What's really happening is that your part of this amazing planet is spinning away from the bulge (tide is falling) or into the bulge (tide is coming in).

All tides are a important and wonderful, but spring tides are just more so. Tides flush nutrients in and out of coastal waters, disperse young and eggs to new habitats, and reshape shorelines over time. Imagine a world without them.

For the fiddlers, the changing tides mean changing predators ... fish and larger crabs beneath the high tides, shore birds during low tides.

For nerdy ocean oriented primates like me, spring tides offer challenges to navigation as bottom suddenly appears where there is normally enough water for Summer School to skim along. I have gotten out and pulled the boat behind me like Bogie more than once.


Low spring tides are fun to explore as they open up usually hidden areas to the curious.
That would be me ...
... and you.



The tides shaped that beautiful oyster bar above.

Here's a question for you.

Is the tide rising or falling in that picture?

Remember to support your answer or no credit.

14 comments:

Thunder Dave said...

I'm going to say falling, but I really couldn't tell which direction the flow currents looked like they were moving.

I liked the refernce to the "African Queen", one of my favorite movies! I finally got Lightnin to watch it with me and she loved it (of course I knew she would)!
Very sad news to report, and I'll try to do that this weekend.

Mark said...

If I had to guess, I would guess rising because the oyster bar looks dry. But I'm not an ocean kind of guy, and I know nothing.

By the way, 'nip' must be a Florida pronunciation. I heard it rhyming with 'leap' in school. That's also the way the M-W online dictionary pronounces it. But if it's your tide, I guess you can pronounce it any way you like. We certainly do that with some names around here.

Doug Taron said...

Tides are probably the single thing that I miss the most about no longer living near the ocean. It was a rhythm that I really enjoyed having incorporated into my life.

The tops of the oyster shells look dry to me. So I'll guess that the tide had been down for a while, giving them time to dry off and is now coming back in.

Mrs Mecomber said...

To answer your question: yes.

Kidding!

Um, being no expert on tides (why couldn't you ask about lake effect snow or something?), I'd have to guess that the tide is rising. It's not much of a guess, but you did say that the "tides shaped that beautiful oyster bar," not that the tides were shaping it.

roger said...

i'll go with rising also (altho yes is certainly a correct answer to the question as posed) because the oysters and the pilings look to be dry.

love the tide. soon we'll be checking out low tide in monterey bay. yay. real tide pools with octopi and all the rest.

SophieMae said...

I'm really liking that last picture! Intertesting you should post about this. I was just talking with DS about how high the high tide has been this week. It's at its highest yesterday and today. The lowest lows are supposed to be today, tomorrow and Sunday.

Sharon said...

I say rising, because the oyster bed looks dry on top. I tried to enlarge it and look at the pilings, but I couldn't tell. That's all I got. :)

threecollie said...

Guessing rising because there is no water line that I can see on the pilings, which would seem something you would see to indicate falling...
And to get away from being quizzed, this is the kind of post that keeps me checking Pure Florida first. Great stuff.

Deb said...

I agree with those who say rising, for their reasons.

Of course, this could be a trick question. This could have been taken at the very exact moment the tide was between falling and rising.

Those tidal flats look so interesting!

Word verification: seadnk

Floridacracker said...

Blogger just ate all my carefully crafted comments.

So here's another, but shorter, try:

The tide is rising, the dry oysters are your clue to that fact.
Good job.

I shall now hold my mouth right and click publish.

pablo said...

I would, of course, given the correct answer and provided supporting arguments, but this post of yours didn't show up in my universe until Saturday morning. That happens some times. I feel like I'm late to a party, uncertain if I'm even invited, and all the good snacks are already gone.

Anyway, I can see that you must be an excellent teacher!

Floridacracker said...

Pablo,
Weird about that time warp between here and KC.
Rest assured you have a permanent invite to this party.

Wayne said...

Well, I probably over-analyzed it but came to the conclusion of a rising tide. Note the birds - they're facing the wind, toward the open sea, I suspect, and therefore we're talking onshore breeze and so it should be afternoon. With a full moon, the high tide should be at midnight for a diurnal spring tide location and therefore the tide should be rising toward its peak in the late night.

Of course, it could be morning and then my silly analysis falls completely to compost!

Floridacracker said...

Wayne,
You can never have too much compost and the tide is rising, so it's all good.