If you’ve been in the reef hobby for any length of time, you’ve probably at least
heard of dinoflagellates.
Maybe you’ve battled them in your reef tank, where they covered coral and killed snails
with their toxins.
They’re responsible for at least a few reefers quitting the hobby - but they also live in
most coral, where they provide a large percentage of the coral’s energy needs.
Some species cause red tides, sickening countless swimmers around the world every year.
But what exactly is a dinoflagellate?
Hi guys and girls, I’m ReefMan, and today we’re talking about that scourge of many
reef tanks - the phylum of dinoflagellates!
This phylum has over 2,000 species in it, so dinos are very much not a one-size fits
all type of organism.
They live in freshwater as well as saltwater, and I’m absolutely certain that your reef
tank already has them in it.
We can learn some about dinoflagellates just from the name - dino - like a t-rex, and flagellate
- which just means it has a little tiny tail that allows it to swim around a bit.
Dinoflagellates can swim around in the water, and some species do this nightly in order
to disperse into new places to spread and grow.
Ok, so maybe dino doesn’t really refer to dinosaurs, but it’s fun to imagine tiny
little t-rex’s wreaking havoc in our reef tanks.
In reality, from the latin dinos - it just means “whirling”.
So, imagine that little tail whirling around - and bingo - you have the meaning of their
name.
So, are they plants?
Maybe they’re bacteria?
Something else?
Fungus?
It really depends on who you ask, and how that person defines what a plant vs all those
other things really is.
Plants, algae, chaetomorpha, trees - it’s normally defined by having a tough cell wall,
a central thing called a vacuole that holds water, and a bunch of chloroplasts - that’s
the green part.
They also have a single nucleus that holds their genetic information - they’re called
eukaryotes.
Dinoflagellates do have chloroplasts, and they have cell nuclei, but that’s really
where the similarity ends.
Some species - and there are thousands - even hunt other single celled organisms and consume
them - they’re predators.
That doesn’t sound very plant-like to me.
There are also dinoflagellates that live in the tissue of our coral, and still other types
that live parasitic lives - getting all their energy from some unfortunate host.
The dinoflagellates that live in our coral are called endosymbionts - they live inside
the cells of our coral, and both the coral and the dinoflagellate benefit from the situation.
These sort of dinoflagellates are from the genus Symbiodinium, and they’re expelled
from a coral when it bleaches.
The loss of these dinos is, to a large extent, the reason why tissue becomes transparent,
revealing the coral’s white skeleton below.
Of course, in our tanks, this is much more rare than on coral reefs.
In the wild, under great conditions, a bleached coral can recover.
Usually in our tanks what we commonly call bleaching is caused by an infection, it’s
actually rapid or slow tissue necrosis.
It’s rare for, say, a reef tank to experience temperature related bleaching.
Dinoflagellates generally reproduce simply by mitosis - a cell splits into two, and now
you have twice as many dinos.
They can also reproduce sexually where two cells join into one before budding off new
cells through mitosis, and this ability to do pretty much whatever the environmental
conditions call for is one reason they’re so hard to get rid of in reef tanks.
The only somewhat effective way to rid a tank of free swimming dinos - the kind that usually
grow during the day into mats covering everything from sand to coral, and then spread throughout
the entire tank at night - is a UV sterilizer.
I’ll probably be adding one to my tank as I slowly recover from my crash.
We’ll see how it works.
Dinos are crazy adaptable though, so pretty much any other mechanism is unlikely to truly
work.
Often, they just disappear one day as quickly as they arrived.
Many species of dinoflagellate can form cysts to survive long periods of bad environmental
conditions.
These cysts grow an extra cell wall, which you can even see in these photos.
These cysts can survive bad conditions for years before reactivating and growing anew
- so I think if you’re at your wits end the only thing you can do to really rid your
tank of these is letting it fully dry out - which of course will reset your tank back
to square one overall as well.
It really is best to try to live with dinos.
In fact, you probably already are, they’re in just about every reef tank.
Try a UV sterilizer if you have a species that disperses at night.
But don’t nuke your tank from orbit just to be sure that you’ve rid yourself of dinos.
They’ll go away with time and good maintenance and they’re very interesting creatures in
their own right.
That’s all for this video, I hope you enjoyed it!
If you have any questions, leave a comment.
If you liked the video and would like to see more like it, subscribe to the channel.
Have a fantastic day!
Bye!