Reef Chemistry Question of the Day #185 Macroalgae and Nutrient Uptake

[beaslbob]

7" 5 fingered hand tangs. LOL
(isn't it 4 fingered and thumbed?)
I think gha responds good to cleaner crews. so Hopefully it will clear up.

Sure sound like as a last resort you can cut the lights back then make adjustments until the gha goes away and corals thrive.

my .02

 

[go_bucky]

7" 5 fingered hand tangs. LOL
(isn't it 4 fingered and thumbed?)
I think gha responds good to cleaner crews. so Hopefully it will clear up.

Sure sound like as a last resort you can cut the lights back then make adjustments until the gha goes away and corals thrive.

my .02

Not exactly a last resort. I ran the display with limited lighting for a two month period while I had fish (and before I started putting in corals). I turned up the lights when I started adding coral early last month, and that's when the gha popped up (and I can't reduce the lighting now, at least not enough to kill the algae). So I improved the lighting on the fuge and have added several trochus, astrea, cerith, and small nassarius snails along with a couple of asian fighting conches, and couple of tongan tiger conches to the display. I also added some scarlet hermit crabs to the display. Nothing wanted to touch the thick gha patches. I don't want to add some of the other crabs that may eat it (like porcelain crabs) since they may be problematic after the gha is gone. Finally, I added a blue tuxedo urchin, and he mows down the gha wherever he's been, but that will take a while. I still need the hand tangs for at least a while.

Anyway, I didn't mean to hijack this thread. I'm hoping that Randy will chime in here to answer his quiz, and perhaps to provide an explanation of how the redfield ratio might be different (likely higher) for caulerpa. Also if he's aware of any value for turtle grass.

Regards.

 

[beaslbob]

Randy is probably setting back laughing and head shaking at this amateur.

 

[go_bucky]

Randy is probably setting back laughing and head shaking at this amateur.

Hey... a little cyano and gha isn't that out of line for a new tank! Its all good.

 

[JonasRoman]

Reef Chemistry Question of the Day [HASHTAG]#185[/HASHTAG]

Many people grow macroalgae in reef tanks in an effort to reduce nutrients (especially nitrate and phosphate), and it can be a successful method. I use it, along with other methods.

The exact ratio of nitrogen to phosphorus in macroalgae reflects what it took up from the water. This ratio depends not only on the species involved, but, in some cases, on the concentrations of nutrients available to it since they can take up somewhat more N (nitrogen) or P (phosphorus) when more is available.

The species effect alone can alter the relative amounts of N and P by more than a factor of two, but the values are typically clustered reasonably close together because most of the biochemical molecules of life that contain N and P are similar in different species, such as proteins, DNA, RNA, phospholipids, etc.

In typical macroalgae grown in the ocean, which ratio below is closest to the average weight ratio of nitrogen to phosphorus atoms (N) found in the macroalgae?

A. 1:20
B. 1:1
C. 20:1
D. 200:1

Good luck!

































.

I think that none of the alternative are correct...;-)...i have recently red an article where the scientists tested several macroalgue (from a natural reef) and the range differed a lot, but around 50:1 seems to be a value among some macro and event more index concerning caulerpa .....i can post the article later se below. Thus i do not think the redfield (16:1) or 20:1 is the correct answer......

 

[JonasRoman]

here Randy is the figures

 

[Randy Holmes-Farley]

here Randy is the figures

That's the article I am drawing the question from. Whatever answer you give, make sure you are using the same units I am. That table gives two different types of units. One is weight, the other is an atom ratio.

 

[JonasRoman]

That's the article I am drawing the question from. Whatever answer you give, make sure you are using the same units I am. That table gives two different types of units. One is weight, the other is an atom ratio.

oki, sorry, you ment weight ratio if i understand you? I will read the article again, you made me unsure, i was assuming the ration to the right in the table was weight ration of atomic weight of N and P. Is it not?..i will read, and i guess you are right. have to check again

 

[JonasRoman]

Randy, thanks for that explanation, i have looked at the table again and realize that the frist to lines is in weight%, and the last one is in number of atoms. Then i also say 20/1.

 

[Randy Holmes-Farley]

oki, sorry, you ment weight ratio if i understand you? I will read the article again, you made me unsure, i was assuming the ration to the right in the table was weight ration of atomic weight of N and P. Is it not?..i will read, and i guess you are right. have to check again

TN:TP in that table on the far right appears to be the atom ratio. It is not just the weight ratio, which comes out lower.

For example, for the two extreme cases...
2nd line N weight/P weight = 12.7/0.14 = 91/1
4th line N weight/P weight = 0.78/0.06 = 13/1

 

[Randy Holmes-Farley]

Randy, thanks for that explanation, i have looked at the table again and realize that the frist to lines is in weight%, and the last one is in number of atoms. Then i also say 20/1.

Well, its a little early for me to give the answer, but that seems a good choice.

 

[JonasRoman]

BUT: I still have a comment: Caulerpa, which is our most common macro, still have a much more higher ration than your alternative, then range between the ratios are around 13/1, to 90/1...then i still think this question have no simple correct answer actually, and the most interesting for us, is the caulerpa ratio (i guess?) and that ratio is if i recalculate to weight index, between 70/1, to 90/1 for caulerpa...or?..

 

[go_bucky]

Jonas, the table you show is from the same article that I posted a link to earlier. I had the same confusion. Thanks for making the question more clear to Randy as I wasn't getting a response. As you, I have been focusing on the common macro algae species (caulerpa), and those don't fit into the four options that we're offered.

 

[Randy Holmes-Farley]

BUT: I still have a comment: Caulerpa, which is our most common macro, still have a much more higher ration than your alternative, then range between the ratios are around 13/1, to 90/1...then i still think this question have no simple correct answer actually, and the most interesting for us, is the caulerpa ratio (i guess?) and that ratio is if i recalculate to weight index, between 70/1, to 90/1 for caulerpa...or?..

True. That is why I wrote in the question "The species effect alone can alter the relative amounts of N and P by more than a factor of two, " and I will go into it more in the answer.

 

[Randy Holmes-Farley]

And the answer is...C. 20:1

As mentioned in the question and shown in the data above, there is substantial variability from species to species (from 13:1 to 90:1), but this answer fits best the range shown.

Here is the whole article for anyone interested in reading it. It also has some interesting discussion of whether the macroalgae is being limited by nitrogen or phosphate, and shows that in the same water, different species may be limited by different nutrients.

https://web.archive.org/web/20040720161739/http:/www.botany.hawaii.edu/Bot482/Kaneohe Bay algae N-P Larned Mar Biol.pdf

 

[masterbuilder]

Thanks Randy...... standing by for the next quiz . I really need to raise my grade.

 

[beaslbob]

dern

if was the redfield ration afterall

 

[beaslbob]

dern

if was the redfield ration afterall

or
it was the redfield ratio after all