Red tide that is blue

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Lately we have been seeing blooms of Noctiluca scintillans lighting up the beaches in southern Tasmania. Not every beach, everywhere, yet there has been a particularly fantastic bloom happening down at South arm beach.

I was out aurora hunting with my buddies Matt and Learna last Friday night when we noticed the neon glow along the waves at Lauderdale in Ralph’s bay. Unfortunately the tide was way out which meant trudging through the sand flats would have been a nightmare in disguise. We cruised past Bellerive but saw nothing there so headed home.

Saturday night we headed out again on the hunt for both bioluminescence and aurora and weren’t having much luck until we drove back through South arm. And there it was, in its full blooming glory. A sight I remember reading about many years ago when I was studying various microalgae at uni. I flashed my lights to Matt, Learna and Leena who were driving ahead and pulled over. I thought they had driven off and left me by the side of he road but they just stopped further ahead luckily.

The photos are amazing, for sure. But I would have to say this sight is even better to see with your own eyeballs. Due to the long exposures you need in such a dark environment it was very hard to capture the true appearance of this bloom. The colour was most intense on the cusp of the wave. Literally like someone and installed a neon tube of light just where it breaks. So intense and bright. When the waves were really really gentle the edges just lit up like out of a sci fi movie, and when the waves were a bit less gently the glow was more uniform. Throw a rock in and there was a wonderful splash of colour where the water was agitated.

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Of course the first night I found them I needed to go home and look at them through the microscope to get and id. And then sit up until 3am reading articles and journals about them and try to identify all the bits. Luckily I have a super rad marine science friend, Lisa Ann Gershwin (yes name drop, go google her and read her book it’s freakin rad and will open your eyes to a whole new world) So I made sure she got out there again with me on Sunday night so I could pick her wonderful brains.  And you’ll be pleased to know I became ever more obsessed with it. As only Lisa can do. Make you even more obsessed with something you already are. So now it’s your turn to become obsessed.

The microscopic organisms that create this wonderful sight are called Noctiluca scintillans. They are a type of microalgae called a Dinoflagellate. Often referred to as a phytoplankton this species technically isn’t as it doesn’t contain chloroplasts. You could call it zooplankton but it technically isn’t an animal either. So you could call it more of just a plankton, yeah just a technicality. Lots of other dinoflagellates do have chloroplasts, which means they can make their own energy from the sun and carbon dioxide. Noctiluca scintillans however doesn’t. It needs to consume other organic matter in order to stay alive. It munches on other small planktons and even fish eggs.

The light they produce is known as bioluminescence. Not to be confused with phosphorescence which is more like the glow in the dark stars you have on your ceiling. Bioluminescence is a light produced inside the organism by a chemical reaction, a luciferin/luciferase reaction. Luciferin being the protein and luciferase being the enzyme which catalyses the protein. Basically the luciferin protein gets broken and the product of breaking the luciferin is light! Pretty rad huh. Yeah I reckon so. Science.

The common name for this kind of bloom is ‘red tide’. During the day the water won’t be glowing neon blue but instead will be a pinkish to red murky colour. Hence the name ‘red tide’. It can be a problem to ecosystems it blooms in and has been known to have had significant impact on fisheries around the east and west coasts of India where it has bloomed a lot.

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It has generally been a species known to more northern, temperate regions, yet it was first spotted in Tasmania in 1994, seemingly carried down by the East Australia Current.  It has since gone even further south and hit the Southern Oceans, quite possibly impacted by climate change.

Blooms like this are caused by the same things that generally cause other algal blooms. Storms or really high rainfall which wash a whole lot of extra nutrient into the waterways (eutrophication). This along with the right conditions causes them to go into a frenzied state of reproduction and the numbers multiply by the billions creating a bloom which is easily seen with the eyes.

This current spate of blooms have been spotted at various beaches and bays around the South Arm region as well as further up in the Derwent around Howrah. Learna and I were down at Verona Sands in the channel a few weeks back and spotted some very very faint colour on the beach there, at first we couldn’t work out if it was bioluminescence or the moon casting light on the water but after studying our photos and running around on the beach looking at all angles we figured it was a faint glow.

So go forth and look at the world. Find cool stuff yeah.

Or hang out online and read cool stuff:

Climate-driven range expansion of the red-tide dinoflagellate Noctiluca scintillans into the Southern Ocean

Luciferin / leciferase reaction

Noctiluca scintillans

For even more amazeballs photos from everyone in the area who had a camera at the time or drove there to see it check out the Facebook Group Bioluminescence Tasmania

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2 comments on “Red tide that is blue”

    • Gumboots Reply

      It is amazing! I spent 17 years in Melbourne and am very glad to be back home again. Even more appreciative of the wonderful outdoors we have!

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