Underwater lightning?

[JohnHuth]

Here is a navigational oddity that I've been playing with for some time. David Lewis, who is rather famous in Pacific Island navigation circles, reported a phenomenon that is called 'te lapa' or 'underwater lightning'. He reported three Pacific Island navigators who claim to have seen/used this.

According to the reports, on dark, overcast nights, they would see flashes of light leading to islands when they were many nautical miles away from islands that pointed toward islands. There have also been some reports of this by others, although another anthropologist, Rick Feinberg, says he tried, but could not verify it.

There is no real causal mechanism attributed to underwater lightning, but I found the topic difficult to stay away from. The informants went to some lengths to distinguish this underwater lightning from normal bioluminescence kicked up in the wake of a canoe or from waves crashing.

I showed some of these reports to a colleague who specializes in dinoflagellates - single celled organisms that photosynthesize during the day, but give off light at night when hit with a pressure wave. My colleague, Woody Hastings, said he had seen something like this from fish darting. We couldn't really figure out how this might give directional information, but I decided to do a test. I got some dinoflagellate 'starter' from Woody and cultivated 3 liters of the little guys and then poured the concoction into a long trough and pulled a fishing lure through and photographed it to see if it looked like underwater lightning - at least my impression of what it might look like.

Here's a YouTube with it:

[gyork]

There is no real causal mechanism attributed to underwater lightning, but I found the topic difficult to stay away from. The informants went to some lengths to distinguish this underwater lightning from normal bioluminescence kicked up in the wake of a canoe or from waves crashing.

Neat stuff John-THANKS for GIVING us a peek into your laboratory. I think you've demonstrated well a form of "slow" lightning. For those lucky enough to witness the "real" deal, I'm assuming they describe an unbroken, non-expansile, linear flash, extending for several hundred feet or yards?

Now what are the fastest swimmers under water? Dolphins?

gary

[JohnHuth]

Now what are the fastest swimmers under water? Dolphins?

gary

Gary -

That's the next mystery. I know that mahi-mahi (dolphin fish) are powerful swimmers and have very fast side-to-side dart, but would they be directional?

Another candidate is the large spotted snake moray, Uropterygius polyspilus. It lives in the islands where this is reported, is nocturnal, but its habits aren't well known. I suspect that eels tend to move more slowly and wouldn't produce the kind of rapid flashes.

Any suggestions are most welcome.

John

[rick stoehrer]

i used to see something like when i lived/dove around St Thomas. the contrail left by a small fish could be of impressive size but nothing that could ever have been confused with any kind of lightning.

could a temperature change along a thermocline cause anything like that i wonder?

what's biological that could be moving fast enough to agitate all those little critters for the speed/distance to be called lightning?

what about a sonar wave from some passing mammal? would that set the little devils off?

and the starring dinoflagellate thing was pretty funny!

[JohnHuth]

Mahi mahi are pretty amazing in their speed if you're close to the surface of the water in a canoe.

What I'd really like to see is someone film the phenomenon. There are other navigators who give it slightly different names, like "the glory of the sea" in a micronesian dialect - I suspect 'underwater lightning' is grasping for language to describe it. I honestly don't know what it is, but am just trying to chase down some possibilities.

[PeterB]

Mahi mahi are pretty amazing in their speed if you're close to the surface of the water in a canoe.

What I'd really like to see is someone film the phenomenon. There are other navigators who give it slightly different names, like "the glory of the sea" in a micronesian dialect - I suspect 'underwater lightning' is grasping for language to describe it. I honestly don't know what it is, but am just trying to chase down some possibilities.

I have witnessed bioluminescence caused by fish darting . Many years ago I worked for the National Park Service on a research project in the Gulf of Mexico and lived on Horn Island (part of Gulf Islands Natl.Seashore.) , the two rangers there were Parrotheads (Buffett fans) and had a powerboat so they liked to rip around at night, sometimes on business, sometimes not, and at times you could see many dorsal fins cutting the surface of the water as schools of mullett (Mugil cephalus) would follow our boat . It was quite spectacular, as sparks trailed from their dorsal fins where they cut the waters surface, which reminded me of a car driving down the road with a loose muffler dragging on the pavement.

I don't know how fast we were going but it felt pretty fast, so I can personally attest that fish can move fast, and kick up bioluminescence. It would stand to reason that a large enough school of fish, moving at some speed , would create a bioluminescent trail that could be seen from some distance.

[bob budd]

Cool article in Globe mag about underwater photography and photographer, including unwise outer wear in our waters at Thanksgiving. Hope you weren't following a string of photo flashes.