YASMIN MEEDA: I have seen bioluminescence only once and it

was honestly the most magical thing that I have ever seen.

ROSIE HOLDSWORTH: It's a bucket list natural phenomenon every

traveller would love to experience. Bioluminescent tides

or sea sparkles are a rare and ethereal looking sight. And

we're heading to the ocean to meet the strange species who use

light to send signals through the dark. I'm Ranger Rosie

Holdsworth. Welcome to Wild Tales, Bioluminescent Baywatch.

You might have seen the pictures on Instagram of lagoons of

electric blues and greens. People on the shore at night

splashing in waves that look lit up as if by magic. This natural

phenomenon is called a bioluminescent tide.

So, what causes the sea to light up in this eerie way? What's it

like to experience it? And why is Bioluminescence itself found

in so many mysterious ocean creatures? To find out, we need

to go down to the ocean where it's... Dark at night or in deep

deep waters where light shows up in the pitch black.

YASMIN MEEDA: I'm Yasmin Meeda, I'm a marine biologist by

training and I'm now working as a postdoctoral researcher at

Cranfield University.

ROSIE HOLDSWORTH: Dr Yasmin Meeda who goes by Yaz is not

your typical marine biologist. You might imagine people in

Yaz's profession out in research boats, studying dolphins,

turtles, fish or other big fauna of the seas. But Yaz is

interested in something different. She specialises in a

branch of marine biology called microbiology.

YASMIN MEEDA: I deal with all the tiny hidden wonders of the

ocean that nobody really thinks about. It's often overlooked.

I'm really interested in understanding how these

microbial life actually sustain all the bigger species in the

ocean that we know and love, like whales and sharks. But we

really need to understand these tiny organisms.

ROSIE HOLDSWORTH: Yaz is usually found in her white coat in her

lab, pouring over the little guys, the weird and wonderful

hidden microscopic organisms that don't get a lot of love,

but they're essential for all ocean life.

Yaz has another great passion, to make sure science is for

everyone.

YASMIN MEEDA: I'm really trying to champion the fact that

science should be accessible to absolutely everyone. Myself, I

actually failed my A-levels when I was at school. And then

suddenly I really had a passion for science. And I believe that

you don't have to have straight A's to actually get through and

become a scientist.

ROSIE HOLDSWORTH: Yaz's drive to open up science to more people

led to her creating her Instagram account.

YASMIN MEEDA: So I post on social media with a handle

@marinebiologywithyaz. And it started just as showcasing to

family and friends what I get up to. I mainly made this page to

showcase the hidden wonders of the ocean.

ROSIE HOLDSWORTH: As a marine biologist, Yaz knows all about

bioluminescence. But she's only ever actually seen it once. And

the experience has stayed with Yaz as one of the most memorable

of her career.

YASMIN MEEDA: I have seen bioluminescence. Only once. And

it was honestly the most magical thing that I have ever seen. I'm

an ambassador for the Marine Stewardship Council in the UK.

We were fishing for sardines using ring net fishing. So this

is a way to reduce bycatch so you're only fishing for what you

want.

I was fortunate enough to go out on a sardine fishing boat in

Newlyn in Cornwall and I've never been on a fishing boat and

as a marine biologist I'm always in the lab. I'm hardly ever out

at sea so this was a really new experience for me. So we set off

at around 8pm in the evening. And I was told it should be

quite calm. It should be OK. But we're going out at night and

we'll be back early hours of the morning.

So there's me, never been even fishing before. And so I'm now

on this fishing vessel that we're going out. We're going out

quite far into the ocean. And I'm like, wow, there's nothing

around me. It's pitch black. I could see the stars. I could see

the milky way.

I've never even seen that so vivid because obviously with

light pollution, you can't see it. And as we were fishing, once

they'd deployed the net, this is when I saw so many birds just

coming down. And there were loads of seabirds, some

seagulls, other species of birds I didn't even know. And it was

so loud.

The noise was just immense. And then as I was looking at these

birds, I could see that they had these specks or these sparkles

of a greeny blue hue. And I was like, this looks interesting.

And then one of the fishermen was like, it's the phosphorus.

It's the phosphorus.

ROSIE HOLDSWORTH: Phosphorus is a chemical element that can

sometimes glow in the dark. But Yaz knows what they're seeing is

something different.

YASMIN MEEDA: And I was like, what are you on about? And they

were like, that's what we call it, the phosphorus. And I was

like, no, I think that's bioluminescence. And they were

like, oh, is that what it's called? And I said, yeah, I've

never seen it in real life. I've only ever seen videos. The

colour was definitely like a bluey-green. You only see

bioluminescence when there's movement in the water.

So as the waves are crashing and the birds are diving into the

water, you then get this kind of different shades of this

bioluminescence coming up and it's brighter in some areas and

it's dimmer in others. And honestly it was just like an

alien world to me because we were the only vessel I could see

for a while. We were in the middle of the ocean I couldn't

even see land and yet all around me were just these birds and

bioluminescence and it was incredible.

ROSIE HOLDSWORTH: ROSIE HOLDSWORTH: Bioluminescent

tides occur all around the world and some of the best known spots

include beaches in Australia, Thailand, Puerto Rico and

California. These sea sparkles also appear here in the UK.

Wales has some of the most famous bioluminescent tides and

it's found in other places too, like Yaz's experience in

Cornwall.

What you see in photos and videos can look a little

different to with the naked eye, though no less magical to

witness.

YASMIN MEEDA: But I think what people see on photos or on

documentaries can be slightly over-exaggerated. This is a

little bit similar to my experience with the northern

lights. I think your camera can really overexpose the green hue.

You could definitely see it. And it was more like a, almost a

neon green.

ROSIE HOLDSWORTH: We know bioluminescent tides look

magical, but what exactly is happening? Bioluminescence, when

an organism lights up from inside its body through a

chemical reaction, is found in nature in certain species. In

the case of tides like those Yaz saw, these are caused by a type

of algae called dinoflagellates.

In these dinoflagellates, bioluminescent light is created

when two chemicals, luciferin and luciferase, interact with

oxygen. This chemical reaction is triggered when water

containing the dinoflagellates is disturbed, like when waves

crash on the shore or when birds dive into the sea to catch fish.

YASMIN MEEDA: Bioluminescence happens in loads of different

organisms but in the ocean it is typically from dinoflagellates

which are a group of phytoplankton and they are

microscopic so you can't see them with the naked eye you'd

need a microscope to see them normally. But when they create

this bioluminescence you can see it as light and that's because

there are thousands of them so collectively you'll be able to

see this light.

ROSIE HOLDSWORTH: ROSIE HOLDSWORTH: Bioluminescent

light isn't just found in these tiny dinoflagellates. It's found

in lots of species, occasionally on land but by far most

widespread in the ocean.

YASMIN MEEDA: Fireflies are a really good example of

bioluminescence and so they cause bioluminescence within

themselves but I've never actually seen fireflies myself.

The anglerfish that are found in the deep sea, I want to say ugly

but maybe that's unfair. They're the ones that if you've seen

Finding Nemo, it's got the big light on the end of its head.

And the bacteria that are within these anglerfish are responsible

for the Bioluminescence that you see. So that's how they can see

in the dark when they're in the really deep sea.

For different species, there could be different reasons as to

why they have bioluminescence. Sometimes it could be because of

mating. So it could attract a mate. Or for the case of

dinoflagellates in the ocean, it could be to deter a predator.

And then that will deter the predator because they'll think,

oh, there's something there and it will scare them off, which I

think is pretty cool.

ROSIE HOLDSWORTH: And perhaps the most mysterious is the

centuries-old story of milky seas. Sailors talked of an eerie

phenomenon of looking out to the ocean at night and seeing it

transformed, as if blowing ghostly white all the way to the

horizon.

In the 1990s, scientists looking at satellite images finally

confirmed these milky seas were a type of Bioluminescence, this

time caused by bacteria, and that the light could be seen all

the way from space.

Bioluminescent tides like in Yaz's story are relatively rare

but they occur often enough for you to have a chance of

witnessing them. So what are the top tips for seeing them for

yourself?

YASMIN MEEDA: My top tips if you want to see bioluminescence

would definitely be to look out on the coast. There are certain

areas within the UK that you could see it such as in Wales

I'd definitely say Cornwall is a really good spot.

My experience was not from the shore so I don't know how

prominent it will be if you're just watching from a beach and

want to go and hunt for it. But if you can get on a boat and go

and explore I think definitely looking at either Facebook

groups or looking online at different travel blogs or

Instagram or TikTok I think you could definitely find it and

spot it from there.

ROSIE HOLDSWORTH: I've seen bioluminescence myself just one

time, on land. In glowworms' shining green bums in Leeds. It

was really, really magical. But I've never seen bioluminescent

tides in the ocean. They're really high on my bucket list.

The fact this phenomenon even exists reminds us that our world

is still so full of mystery and wonder.

YASMIN MEEDA: I think the fact that bioluminescence is really

unique is something that I think is quite alien to the world. And

for me, I think that's one of the most amazing things about

evolution and just the natural world, is that these things have

just sprung up in nature based on either it could attract a

mate, it could deter predators.

And so I just think it's absolutely incredible that

different organisms have such different traits that help them

survive in our planet.

ROSIE HOLDSWORTH: If you'd like to look for bioluminescence for

yourself, do search for groups dedicated to spotting it along

the Welsh coast and other parts of the UK. Just please don't do

anything daft and follow safety advice when you're mixing with

water, tides and the dark.

Summer is a great time to see the UK's glowworms. You can find

out more about them in our episode show notes. Until next

time, follow Wild Tales on your podcast app. Find us on

Instagram @wildtalesnt. And share your stories with us with

#wildtaleswednesday. See you next time.