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This is off topic but I can't think of a better-informed group to ask:

At sea in bad weather, at night, I have often noticed that the surface
of the water seems surprisingly bright. I have put that down to streaks
of foam catching the light from my ship's masthead lights and reflecting
it back.

However, on 28 September, we had a visit from Hurricane Juan. About 2145
AST, all power went out, so there was little or no artificial light for
miles around. New Moon had been on the 25th, with moon set on the 28th
being about 1910, according to the almanac. If any moonlight was
catching the tops of the clouds, very little of it can have been
reflected down to sea level. (It was raining hard and blowing -- 40 to
50 knots at a guess.) In short, there should have been more than a
minimal amount of incident light reaching the surface of the Harbour.

Around 2230 AST, I went out to take a look at the weather and looked
from the road down to the nearest water of Musquodoboit Harbour, maybe
150 metres away and 10 metres down. The water was glowing -- not with a
steady light but with more of a thread-like pattern which, as best as I
could see (through the rain and without my glasses, which would have
been more hindrance than help), was flowing downwind along the shore in
front of me.

I then walked the half-mile of so to a point where the road dips to sea
level and the harbour shore turns into a small cove, which comes all the
way to the road. The wind was gusting through the trees on the shore of
the cove, with the miniature gust fronts sweeping across the water. Each
gust front was very clearly glowing, with the combination of them making
the surface of the cove quite bright. (To avoid blundering off the road
and into the ditch, I was carrying a dim kerosene lantern. However, my
eyes must have been well adapted to the dark.)

I realize that Musquodoboit Harbour may have had a bloom of some
phosphorescent plankton, which glowed when disturbed by the wind.
However, it seems a little odd for anything to be blooming that
prolifically so late in the year. Hence (at last) my questions:

Does seawater itself glow, however faintly, when violently disturbed (as
by extreme wind action)? Does muddy seawater glow in that way (perhaps
if the mud is composed of particular types of clay particles)? Does
seawater with dissolved terrestrial material glow like that?

[The upper basin of Musquodoboit Harbour is salty enough for seaweeds to
grow but it has considerable input of river water. It is shallow near
the shore and the bottom muds will certainly have been stirred up by the
weather. The river also brings down a fair amount of tannins and the
like, making the harbour water quite dark at the best of times.

I guess what I am really wondering is whether the surface of the open
sea, whipped to a fury by the wind, really does glow, rather than just
reflect incident light.


Anybody willing to venture an answer?


Trevor Kenchington



--
Trevor J. Kenchington PhD                         Gadus@iStar.ca
Gadus Associates,                                 Office(902) 889-9250
R.R.#1, Musquodoboit Harbour,                     Fax   (902) 889-9251
Nova Scotia  B0J 2L0, CANADA                      Home  (902) 889-3555

                     Science Serving the Fisheries
                      http://home.istar.ca/~gadus

   

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