From Eurekalert
Sponges recycle carbon to give life to coral reefs
Coral reefs support some of the most diverse ecosystems on the planet, yet they thrive in a marine desert. So how do reefs sustain their thriving populations?
Marine biologist Fleur Van Duyl from the Royal Netherlands Institute for Sea Research is fascinated by the energy budgets that support coral reefs in this impoverished environment.
According to van Duyl’s former student, Jasper De Goeij, Halisarca caerulea sponges grow in the deep dark cavities beneath reefs, and 90% of their diet is composed of dissolved organic carbon, which is inedible for most other reef residents. But when De Goeij measured the amount of carbon that the brightly coloured sponges consumed he found that they consume half of their own weight each day, yet they never grew. What were the sponges doing with the carbon? Were the sponges really consuming that much carbon, or was there a problem with De Goeij’s measurements? He had to find out where the carbon was going to back up his measurements and publishes his discovery that sponges have one of the fastest cell division rates ever measured, and instead of growing they discard the cells. Essentially, the sponges recycle carbon that would otherwise be lost to the reef. De Goeij publishes his discovery on November 13 2009 in The Journal of Experimental Biology at http://jeb.biologists.org.
Travelling to the Dutch Antilles with his student, Anna De Kluijver, De Goeij started SCUBA diving with the sponges to find out how much carbon they consume. ‘It is quite dark and technically difficult to work in the cavities,’ explains De Goeij, but the duo collected sponges, placed them in small chambers and exposed the sponges to 5- bromo-2′-deoxyuridine (BrdU). ‘The BrdU is only incorporated into the DNA of dividing cells,’ explains De Goeij, so cells that carry the BrdU label must be dividing, or have divided, since the molecule was added to the sponge’s water, and cells can only divide if they are taking up carbon. But when De Goeij returned to the Netherlands with his samples, he had problems finding the elusive label.
Discussing the BrdU detection problem with his father, biochemist Anton De Goeij, De Goeij Senior offered to introduce his son to Bert Schutte in Maastricht, who had developed a BrdU detection system for use in cancer therapy. Maybe he could help De Goeij Junior find evidence of cell division in his sponges.
Taking his samples to Jack Cleutjens’s Maastricht Pathology laboratory, De Goeij was finally able to detect the BrdU label in his sponge cells. Amazingly, half of the sponge’s choanocyte (filtration) cells had divided and the choanocyte’s cell division cycle was a phenomenally short 5.4 hours. ‘That is quicker than most bacteria divide,’ exclaims De Goeij.
The sponge was able to take up the colossal amounts of organic carbon that De Goeij had measured, but where was the carbon going: the sponges weren’t growing. De Goeij tested to see if the cells were dying and being lost, but he couldn’t find any evidence of cell death.
Presenting his results to the Maastricht Pathology Department, someone said ‘Lets look at this like a human intestine, then you should see shedding where old cells detach from the epithelia’. De Goeij knew that he had seen some loose cells, and thought that they were artefacts from cutting the samples, but when he and his Pathology Department colleagues went back and looked at the samples, De Goeij realised that choanocytes were shedding all over the place. And then De Goeij remembered the tiny piles of brown material he found next to the sponges in the aquarium every morning.
The sponges were shedding the newly divided cells, which other reef residents could now consume. ‘Halisarca caerulea is the great recycler of energy for the reef by turning over energy that nobody else can use [dissolved organic carbon] into energy that everyone can use [discarded choanocytes],’ explains De Goeij.
REFERENCE: De Goeij, J. M., De Kluijver, A., Van Duyl, F. C., Vacelet, J., Wijffels, R. H., De Goeij, A. F. P. M., Cleutjens, J. P. M. and Schutte, B. (2009). Cell kinetics of the marine sponge Halisarca caerulea reveal rapid cell turnover and shedding. J. Exp. Biol. 212, 3892-3900.
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Two phrases you will find indicate real science is underway —
Hmmm — that is odd?
Wait — that can’t be right?
Larry
I am confused–what does this have to do with CO2? CO2 is not a nutrient. It’s not a source of energy. These sponges recycle organic carbon–sugars, fats, glycerols and so on.
Here is the actual paper:
http://jeb.biologists.org/cgi/content/abstract/212/23/3892
CodeTech-
You realize that dissolved organic carbon (DOC) is not the same as dissolved carbon dioxide, H2CO3?
I don’t see anything here (explicitly) that has big implications for ocean pH. Sponges eat carbon in one form and shed it in another. Cool research, but a bit off-topic as a buffer against excess H2CO3. You need the calcium-pooping fish for that.
…he found that they consume half of their own weight each day, yet they never grew. What were the sponges doing with the carbon? Were the sponges really consuming that much carbon, or was there a problem with De Goeij’s measurements? He had to find out where the carbon was going to back up his measurements
Well, that is obviously where he’s going wrong. What he should do if he want further funding is declare that the sponges were going to be decimated by increased levels of carbon, and thus the entire reef would die, by, let’s say 2050 at random.
Now THAT would get proper funding!
Just a note, so that I can stop grinding my teeth: Predominate is a verb, Predominant is an adjective.
OT sort of. Mr A. Revkin promises a carrot to posters who a are polite and topical (whatever that means to a journalist). Details here: http://dotearth.blogs.nytimes.com/
The sponges were shedding the newly divided cells, which other reef residents could now consume. ‘Halisarca caerulea is the great recycler of energy for the reef by turning over energy that nobody else can use [dissolved organic carbon] into energy that everyone can use [discarded choanocytes],’ explains De Goeij.
Wow…Food and Poo.
Does the American government know these sponges are eating their poison?
“I am confused–what does this have to do with CO2? CO2 is not a nutrient. It’s not a source of energy. These sponges recycle organic carbon–sugars, fats, glycerols and so on.”
Indeed, but they make it available to other reef creatures that may fix CO2 in their shells and crusts. Plus, they can clean up their environment when it might become too rich on these soluble nutrients and promote for e.g., extensive growth of some bacteria leading to imbalance of the system.
BCC (14:29:22) :
“You realize that dissolved organic carbon (DOC) is not the same as dissolved carbon dioxide, H2CO3?”
And, yet, I can’t shake this feeling that they have something in common…
BCC (14:29:22) :
CodeTech-
You realize that dissolved organic carbon (DOC) is not the same as dissolved carbon dioxide, H2CO3?
I don’t see anything here (explicitly) that has big implications for ocean pH. Sponges eat carbon in one form and shed it in another. Cool research, but a bit off-topic as a buffer against excess H2CO3. You need the calcium-pooping fish for that.
You mean like this:
http://chiefio.wordpress.com/2009/02/25/the-trouble-with-c12-c13-ratios/#FishRocks
@ur momisugly EM Smith
I agree with your comments on your own blog about the effects of overfishing and actually emailed Rod Wilson (author of the Ca-pooping fish study) if he’d care to predict the effects of halving or doubling fish biomass on ocean pH and carbon cycle. He declined to avoid scooping his next publication.
There’s also some interesting articles on this site;
http://www.fisherycrisis.com/
including;
http://www.fisherycrisis.com/CO2/strangelove2.htm
Cheers
Darryl
They’re talking about Organic Carbon. CO2 is NOT included in Organic Carbon. So what’s the relevance to climate change?
[quote]They’re talking about Organic Carbon. CO2 is NOT included in Organic Carbon. So what’s the relevance to climate change?[/quote]
There is (effectively) none. The study is important in understanding food web dynamics on coral reefs and adjacent ecosystems. It has no meaningful impact on climatology, ocean acidification, etc. These are wholly different topics (e.g., different somewhat like the price of Barbie dolls and apple pie recipes are wholly different, despite the fact that both Barbie dolls and apple pies contain C).
Chris (22:03:35)
You can’t convince me that posting this with a title like “Sea sponges soak up carbon …like a sponge” is not intended to imply they are a carbon sink.
Umm, yeah, I know…
The research relates to trophic dynamics on coral reefs and has nothing to do with climatology and/or providing a sink for CO2. The title of this post implies that the sponges are acting as a sink for CO2, as you suggest, which in fact has nothing whatsoever to do with what the research demonstrates.
This sponge takes up large amounts of DOM. It has very rapid turnover of choanocytes and sheds them into the environment. The result of these activities is to fuel material/energy from the DOM pool into the POM pool, which is more readily accessible to most reef organisms. None of that has a thing to do with climatology.
Agreed, the title was poorly and misleadingly worded.
errr, should read “funnel material/enegy” not “fuel material/energy”
ginckgo (18:54:57) :
“They’re talking about Organic Carbon. CO2 is NOT included in Organic Carbon. So what’s the relevance to climate change?”
Inorganic carbon enters the biosphere via photosynthesis where it is incorporated into organic carbon. Thence, it proceeds to the ocean via rivers. It is part and parcel of the overall carbon cycle.
Only a small portion of the DOC in the ocean derived from terrestrial sources. Most of it comes from planktonic organisms. Regardless of the source, however, the research this article describes is about DOM/POM cycling on coral reefs. It has nothing whatsoever to do with sinking C (there are no sinks in the system in question, that’s the point!).
“Most of it comes from planktonic organisms.”
Where do they get it?
FTA: ‘‘Halisarca caerulea is the great recycler of energy for the reef by turning over energy that nobody else can use [dissolved organic carbon] into energy that everyone can use [discarded choanocytes],’ explains De Goeij’
After you answered that question, I was going to ask, what happens to the carbon when those creatures ingest “discarded choanocytes”?
Food.
The same thing that happens to all organic C: it is remineralized to DIC/CO2 (with a tiny, tiny portion slowly making its way into the geologic reservoir).
The first answer is evasive. The second, I know of reputable papers from the early 2000’s which hypothesize otherwise, but as they may be out of date, I’m not going to hang my hat on them.
Regardless, if the cycle leads to CO2 in the ocean, isn’t that relevant to the climate debate?
All in all, I would have preferred it if you had stated, “while this could be an important link in the carbon cycle, it does not appear to provide a significant path for either long term storage (CO2 sink) or production (CO2 source). As such, it is not likely a significant finding as relates to the climate debate.”
Likely, nobody would have argued with you, people would have come away a little wiser, and you would have stood a better chance of attracting people to your side.
How do you figure??? Most DOC in the ocean comes form planktonic organisms. They derive the C from food. So, when you ask where plankton get C from, the answer is food. The answer is simple, not evasive.
Huh? You know of papers from the early 2000’s that suggest the reminieralization/respiration of organic material in the ocean does not result in the production of DIC? Please explain how that works.
No, not really, because the effect is far to small to have global implications. The DOC concentration varies little in the most of the ocean. The few exceptions are places where you get a lot of DOC production, like around coral reefs. However, that excess production is coupled somewhere along the line with remineralization/utilization as we can tell by almost all of the ocean having a relatively invariant DOC concentration.
On coral reefs this sponge acts to funnel energy/material in DOC into POC, which is generally more accessible to most organisms. Whether the DOC goes through this pathway or is remineralized at some other stage, however, is completely immaterial to climatology. When trying to understand coral reef ecology/energetics, this is an important observation because it maters how and where material/energy moves. When creating a material budget for climatology it really doesn’t matter much if the DOC gets chewed up by sponges on a reef, or microbes far off in the water column. It gets chewed up and returned to DIC just the same.
There’s no reason to think it is an important link in the global C cycle. It is an important link in coral reef ecology. If you didn’t like the way I phrased my comment, ummm, ok? What can I do about that? I gave as simple, straightforward an answer as I could.