Hair algae is microalgae?!??

[Jamesurq]

Maybe I'm confused - but if microalgae is defined as a unicellular organism, how does a multicellular strand of hair algae get categorized as microalgae?

 

[sjvl51]

I thought hair algae (bryopsis) was a macro algae not a micro algae. Please see this thread - http://www.reefcentral.com/forums/showthread.php?s=&threadid=167632

Where did you see it posted as a micro algae?

Vickie

 

[mellen]

Some dinoflagellate microalgae/cyannobacteria will form chains of connected cells resembling extremely thin hair strands; generally, these look like smooth rods under the microscope. Some Macro algae species have a habitus ("body shape") which look like thicker strands of hair, but if you look closely, you will see other structures on the strands that look like fronds. The common name of "hair algae" is applied to both or either, depending on your source of info; hence the confusion.:rollface:

 

[Frick-n-Frags]

And just to muddy the waters further, the giant bubble Valonia Ventricaria is a huge single cell and it is usually called a macro because of its size. Just from looking at Bryopsis, my own opinion is that it grows in somewhat differentiated stalks vs the mentioned chains of cells (like cyano and some hair algae) and therefore I consider it a macro.

 

[kmk2307]

"Hair algae" is probably either Cladophora, Derbesia, or Bryopsis. Here's google's help in defining the word macroalgae: http://www.google.com/search?hl=en&lr=&ie=UTF-8&safe=off&oi=defmore&q=define:Macroalgae Cladophora is multicellular while the other two are coenocytes (one big cell). I would refer to all three as periphyton. I would refer to cyano or diatoms and microalgae and Caulerpa or Sargassum as macroalgae. Valonia is a single cell but a common misunderstanding is that it is like most cells in the fact that it has one nucleus in the center. It is more like a flat sheet with many nuclei in the sheet rolled up into a sphere with a hollow space (filled with seawater?) in the middle.

Kevin

 

[Jamesurq]

so what you're saying is that cladophora is multicellular and the other two are single celled - but all three fall into a category of Periphyton? But isn't this category inclusive of both macros and micros?

 

[mellen]

http://www.epa.gov/bioindicators/html/periphyton.html

Yes, it is broad term referring to growth habit, but true micro algaes don't have the kind of holdfast structures implied in the term, per se. Kevin was indicating why hairlike micro algae and hairlike macros look similar (benthic example species of each group). Also a mispell "and" instead of "are" in following sentence in his post. He is a very busy student and must fly all over this site answering marine botany Qs as time permits.