Listen Now Download as mp3 from the show Glittering seas: the science of ocean bioluminescence
Helen- Well, I nearly chose for one of my top firework makers the bioluminescent dinoflagelates that glow in the sea when you go diving at the right time in the right place and they just flash these fantastic lights when you move.
Sarah- I think those are in the beach, arenít they, in that film when they go swimming in that lagoon and you move your hands through water and it startles them and they produce all these teeny lights.
Helen- Yeah, it is absolutely brilliant. And it does happen like that, it really does. You can basically have a lot of fun pretending to be an underwater wizard because you can throw fireballs, itís fantastic. I have been swimming one time at night and come out and it stuck to my skin. So that if you actually then draw with your finger on your skin it glows again, itís like you are covered in this crazy paint. It is fabulous.
I am not choosing them, so I am cheating, slightly. Those dinoflagelates only flash when they are disturbed. But there is another phenomenon in the ocean that glows constantly and that is a thing called the milky seas effect.
It is a surreal night time phenomenon that mariners have puzzled over for hundreds of years. Itís called milky because it looks white but is actually blue and but is such a low light that your eyes just use your rods which donít distinguish color, so it looks white.
It went unexplained for a long time, and itís still pretty mysterious; but, we think, the latest theories are, that it is caused by a type of bioluminescent bacteria, Vibrio harveyi. And these glowing seas have been spotted from space, this is fantastic.
This is all thanks to a meteorologist called Steve Miller, back in 2003 he was basically pondering the idea ďcould you see glowing seas from spaceĒ, could we do this, is it possible. Everyone said no donít be stupid, itís far too brief, itís not bright enough, there is no way you could do it. But he was determined to see if he could figure this out.
So, like all good scientists he went straight to the internet and hunted around for descriptions of the milky seas effect. He found a report from the ship SS Lima, from Jan 1995 when it was in the Northern Indian Ocean and it went something like this:
ď22:00 local time on a clear, moonless night a whitish glow was observed on the horizon and, after 15 min of steaming, the ship was completely surrounded by a sea of milky-white color with a fairly uniform luminescence. The bioluminescence appeared to cover the entire sea area, from horizon to horizon . . . and it appeared as though the ship was sailing over a ﬁeld of snow or gliding over the clouds..ď
Isnít that wonderful?
So, basically Steve got this report and then he wanted to figure out if that particular milky sea could be spotted from space. So, he teamed up with some other researchers including bioluminescence expert Steve Haddock from the Monterey Bay Aquarium Research Institute.
They sifted through satellite images, and low and behold, there was the milky sea spotted from space in exactly the right place and the right time as SS Limaís description. It turned out to be an enormous patched of glowing sea, it measured over 15,000 square kilometers, the size of the county of Yorkshire if you are a Brit or the state of Connecticut if you are in the US, everyone else will just have to figure out how big that is.
A satellite image showed that it glowed on 3 consecutive nights, between the 25 and the 27th of January. Check this out, weirdly it is the same date, the 27th, although a hundred years earlier that the passengers on board the Nautilus, in Jules Verneís novel 20,000 Leagues Under the Sea, in a very similar part of the ocean sailed through a milky sea. How weird is that?
It only happens in the right conditions, and that is when there is a huge concentration of bacteria. It estimated that this particular milky sea had 40 billion trillion bacteria, and that is quite a lot. In fact, if you had a grain of sand for every one of those bacteria youíd cover the entire planet to a layer of 10cm thick in sand. Itís huge.
Anyway, I had a quick chat with Steve Miller the other day and he said since that 2005 paper came out describing the satellite spotting of the milky sea in the Indian Ocean he has had lots of reports from sailors of milky seas but so far hasnít had satellite images to match it up. Because weíre really talking extremely low light levels here, youíve got to have very sensitive satellite images.
But the good news is, in October just past, NASA launched a new satellite called NPP and its carrying a new, improved low light sensor. So that does increase the chance of it spotting the milky sea from space and it perhaps gives researchers a chance to dash out on a ship and grab some of the sea water in the same place. And Steve told me if that happens he is going to put down his science hat and just frolic around in the glow.
Sarah- But, is that safe? Could you get infections from those kinds of bacteria or is it a safe thing to go swimming in?
Helen: That is a really good question. These are bacteria that are all the way through the oceans, just at very low concentrations compared to milky seas. But no, I think I might have to ask Steve that one, perhaps get him to go first and see what happens.
Find out more:
Milky Seas from Space - website with more info and links to Steve Miller and Steve Haddock's 2005 paper