Forum: Author Hangout

Need some technical details for a story.

The scene revolves around a deep water upwelling of water, often helped by underwater currents in deep-sea trenches, but more often accounted for by temperature variants (similar to air currents allowing birds to hover in place). Assuming there is a substantial temperature difference, what would be the effect at the surface, seeing as how the oceans are warmer at the surface and extremely cold deep underwater. Would the water at the surface be freezing, or warmer than usual (assuming there are no volcanic vents involved).

I'm assuming the temperatures are different deep underwater, but the effect is negated as the water rises. In which case, the water continues rising because it's being pushed by the uprising water beneath it.

Any oceanographers among us?

Any oceanographers among us?

Not me. I recall there being thermoclines in the ocean that submarines can use to prevent detection, so the the water temperature is not a uniformly increasing gradient from ocean floor to surface.

It seems as though that effect at the surface would depend on several variables.

If the upwelling is deep enough the rising water might disperse or cool and settle without ever reaching the surface.

Alternatively, if the upwelling extends upward over time or is strong enough, it seems as if an observer might see sediment and debris rising a one point and flowing outward before it sinks or disperses. Surface winds could affect the visibility of this surface disturbance.

The scene I'm envisioning is a location where whales, dolphins and seals (all known to dive to incredible distances underwater), breach the surface where most surface debris is swept aside by the uprising currents (the particulate matter often dissipates (drifts off) on the way up). However, I need to know whether the water at the surface would be warmer or colder than normal.

The assumption is, the animals all 'ride the currents' to ease their journeys.

Drat. According to your link, most of the 'uprising water' from the deep sea flows, only rise where the Atlantic meets the Pacific and Indian oceans (I need it to occur mid-Atlantic, between NY and England).

I seem to recall (from somewhere) that there are a couple isolated 'upwelling points' around Iceland/Greenland where the deeper cold water rises to the surface, warming as it rises. However, I'm now questioning those assumptions (as I probably heard it as a child).

Having been near a blow hole, and also a current uplift, the water in both comes from deeper down and is actually colder than the surrounding water when it's still in the up-swelling and just after it reaches the surface. It then spreads and reaches the same temperature as the water around it, but the up-swelling continues to be cold due to the constant flow of cold water from much deeper down.

The two cases of water up-swelling I know of were due to a strong current flowing in to meet some under water rocks near the coast, the rocks deflected a part of the current upward while the rest flowed on by. The deflected water flowed upward with the pressure of the current, and maintained it's cold deeper water temperature until it hit the surface in a sort of dome, and spread out from it into the surrounding water. The rocks that deflected it upwards showed evidence of being worn down by the constant flow of the water, too.

BTW Thermoclines are usually depicted as the interface where two very different water temperatures meet, and thus the sharp temperature gradient creates a reflective barrier.

To expand upon what Ernest said, imagine the typical mushroom cloud, only with cold water at the base. It's going to be very cold at the bottom, warming slightly as it rises, and then roiling together to create the 'cloud' zone, where the warmer surface water is mixing with the colder water coming from below.

In a confined space - a rock quarry, for example - you're going to find sharp thermoclines, typically two or three, depending upon how deep you go. In open and flowing water, you'll hit the first thermocline, and then it may take a while to hit the second, just due to currents.

From what it sounds like you're describing, you COULD get away with a simple volcanic vent. Those happen all the time, and it could be warming the water enough around it to cause an uptick in the plankton growth, enough for the plankton feeders to congregate. Those are called hydrothermal vents.

http://animals.mom.me/list-animals-live-near-thermal-vents-2973.html

Thanks, D.S. the links are appreciated.

The asteroid impact is probably not necessary there are known natural vents along the mid-Atlantic ridge.

Spoiler Warning: I went the asteroid impact route because it fits the story, not because I thought it was necessary to include thermal venting in the story. In fact, it would fold perfectly into the story. (Now, does anyone not know what story I'm talking about?) :)

Stoopid question - shouldn't that be Oceanic Upwellings? Oceanaut makes me think of Astronaut and Cosmonaut.

AJ