Sexual Halimeda plant???

[ronj]

i am not sure, but does halimeda go sexual?? i know caulerpa does..at night, my halimeda is always white, and during the day it is green...well today i found it like this during the day..it has what looks like hundreds of tiny green polyps all over it and the plant itself is still white..here are some pics

 

[jesshimom]

Oh wow that is really weird. I did read halimeda goes white at night and the color returns when the lights are on. I got a huge bunch of halimeda from a club member but it was always white so I trimmed it all back and now it's growing well but I've never seen that before. Can't wait to hear what that is.

DO you have a lot of it growing?

 

[Curtswearing]

Ron and Colleen,

It happens each and every night. Algaes can't run and hide so they've developed defenses. Some develop toxins, some retreat.

However, I think that your Halimeda is going asexual so water changes and Carbon changes are in order.

Caulerpa fanciers are usually familiar with those algae's method of sexual reproduction. A colony will expel its gametes along with all of its cytoplasm, leaving a snow white or transparent (and very dead) clump of algae and a pea soup green aquarium in its wake. Halimeda's sexual reproduction is similar, but with the added benefit of a known warning indicator. Hours before releasing gametes, the algae will turn pale white with dots of very dark green or almost black along the edges of the thalli. The dots are called gametangia and contain all of the contents of the living plant, concentrated in tiny capsules.

 

[ronj]

that certainly sound like it...i may remove it because i have some expensive frags in that tank!!!! thanks Curt

 

[bobt2]

never heard any of this. i have it growing on aquacultured rock from the keys.it's always green, even at night. when a "leaf" turns white it falls off, i understand its all calcium and helps build the sand bed.

 

[ronj]

every halimeda plant i have ever owned turned white during the nighttime..are you sure yours is halimeda??? this is the first one that has ever looked like this..i just removed it..i may try to keep it, but i might just throw it out

 

[bobt2]

heres a picture taken at 3am. the lower left and right sides have halimeda

 

[ronj]

yep, sure is..that's strange..mine has always turned white during the nighttime

 

[bobt2]

maybe where it comes from ? this is atlantic, from the keys.

 

[Dr. Dee]

Ron and Colleen,

It happens each and every night. Algaes can't run and hide so they've developed defenses. Some develop toxins, some retreat.

However, I think that your Halimeda is going asexual so water changes and Carbon changes are in order.

I agree with this that happened in my tank before.

 

[ronj]

did it affect your livestock at all????

 

[Dr. Dee]

did it affect your livestock at all????

No,Because i ran some new carbon for a week and no problem.It just made my water milky,yeah just sexual man :|

 

[bobt2]

ronj, paying closer attention, i do now realize first thing in the morning the halimeda is a very light shade of green, so it looses some color overnight

 

[Ashlar]

I'm holding some livestock for a club member who had almost all of her halimeda die at once, polluting the tank. Not sure if it went sexual, but it had gotten very thick, and it's roots were everywhere.

 

[Curtswearing]

My original answer wasn't clear at all. Halimeda turns white every night.

Some of the few predators that threaten Halimeda are the chloroplast-thieving sacoglossan slugs. Lettuce slugs steal chloroplasts from algae, killing or damaging the algae and rendering themselves photosynthetic. Halimeda are vulnerable to this robbery, but have developed, perhaps inadvertently, a defense against even this type of grazing. The chloroplasts of the green tissue, which are normally clustered near the surface of the thallus, migrate more deeply into the tissue at night, leaving little for a marauding slug to pilfer (Drew 1990).

http://www.reefkeeping.com/issues/2004-04/nftt/index.php

However, yours was going asexual and that is different from turning white every night.

Halimeda's sexual reproduction is similar, but with the added benefit of a known warning indicator. Hours before releasing gametes, the algae will turn pale white with dots of very dark green or almost black along the edges of the thalli. The dots are called gametangia and contain all of the contents of the living plant, concentrated in tiny capsules. This creation of the gametangia is called sporulation. Shortly thereafter, the gametes are released in a fashion similar to Caulerpa's. Plants that reproduce in this fashion, with the entire plant becoming reproductive, are said to be holocarpic. These sexual events have been blamed for sudden deaths of tank inhabitants, and the secondary metabolites of the algae are often fingered as the cause. While this is certainly possible, it seems more likely that fish and invertebrates succumb to oxygen deprivation during these gamete-releasing events. The entire content of large masses of algae is concentrated in millions of short-lived gametes, putting an incredible oxygen demand on the system.

I'm holding some livestock for a club member who had almost all of her halimeda die at once, polluting the tank. Not sure if it went sexual, but it had gotten very thick, and it's roots were everywhere.

They most likely didn't die. That's the problem with having a lot of Halimeda in your tank. If one plant goes asexual, they ALL go asexual.

Recent observations have shown that sexual reproduction in Halimeda plants is to some extent synchronised (Clifton 1997, Hay 1997). Many individuals in a population may become fertile within a period of only a few days, and sometimes on the same day. Synchrony can be so exact that fertility events
have been observed to occur simultaneously in the field and in a laboratory aquarium (Drew and Abel, 1988).

http://www.aims.gov.au/pages/reflib/bigbank/pages/bb-08d.html

BTW....someone I know lost most everything in their frag tank from Halimeda going asexual. This is his 180g frag tank AFTER a 90% waterchange.

 

[ronj]

whoooo!!! i am glad a removed it..it started out as like a 2" piece..this plant was about the size of a soccerball..it was huge..i still have it..i put it in a huge tupperware bowl..i can't decide what to do with it...it still has the dark polyp looking things on it

 

[Curtswearing]

Throw it out in the back yard like Tom did.

Just kidding!!! He was a little upset as you can imagine.

Here's the thing. Most macro's have reproductive events when their needs aren't being met. I.e. not enough nutrients, etc. Halimeda is different. Halimeda holocarpy is often triggered by 'critical mass'. THINK SOCCER BALL. Unlike other algae where holocarpy is only an extreme reproductive recourse, what you experienced is an expected consequence of the alga colonizing and dominating an environment --with no need for minor environmental disasters as triggers.

Regular harvesting or even interspersal with competing macroalgae seems to prevent it. Harvesting of Halimeda is NOT about trimming the tops, but is simpler --you pull up a sprig in the middle of the mass and sever any rhizoidal filaments/root-runner connecting it to other sprigs.

 

[KRG]

I'm subscribing to this thread! I've got a ton of Halimeda and there's some good info here!