Biological question

[bradleym]

(ok the hydroponic analogy is a little weak because plants versus animals - but it directionally illustrates the point)

Well now I'm confused. I thought zooxanthellae were a type of algae. Am I wrong? Because if they are algae then this makes perfect sense to me, at least as far as the algae goes anyway. Sounds like the anemone is, for lack of better terminology, a living hydroponics garden. It regulates the light, water, and nutrient transport in and out, and if the crop grows too large it will throw out the excess to keep it in check. In return, it lives off the "fruit" of the "garden" it grows.

 

[Saadatski]

It isn't exactly the same, but I like to think of hydroponics and plants. Plants cannot live in distilled water. They need nutrients that cannot be provided by photosynthesis alone. Therefore hydroponics require nutrient solutions that include calcium, magnesium, and potassium (typically in cation form) and nitrogen, sulfur and phosphorous (typically in anion form). Combined with photosynthesis, these nutrients provide a complete "diet" for plants.

Hold on, anemones need calcium supplements like corals? i thought the salt in the water would be enough for them not to go into a isotopic (if i recall, i think thats what its called from biology class) state.

 

[BonsaiNut]

That's why I was saying the analogy to freshwater hydroponics was weak Don't take anything that I said about freshwater hydroponics literally and apply it to saltwater animals It was to illustrate a point that photosynthesis cannot apply all the nutritional needs of a creature.

In the case of anemones - not only do zooxanthellae require nutrients not provided by photosynthesis, but the anemone itself does as well. I think the original question (the 1970 comment) was whether you needed to "feed" your anemone in order to provide those nutrients, or whether an anemone could passively obtain those nutrients in your reef tank (one way or another) without requiring you to directly feed it. If you don't need to feed it, people might mistakenly assume that the anemone is getting 100% of its needs met by photosynthesis, when in fact there are a lot of other mechanisms in play that are not immediately obvious.

 

[bradleym]

In the case of anemones - not only do zooxanthellae require nutrients not provided by photosynthesis, but the anemone itself does as well. I think the original question (the 1970 comment) was whether you needed to "feed" your anemone in order to provide those nutrients, or whether an anemone could passively obtain those nutrients in your reef tank (one way or another) without requiring you to directly feed it. If you don't need to feed it, people might mistakenly assume that the anemone is getting 100% of its needs met by photosynthesis, when in fact there are a lot of other mechanisms in play that are not immediately obvious.

Well every good farm needs the chickens and the cows.

 

[m2434]

BonsaiNut, I think I mostly agree, although, I would point out that, as far as I know, it has not been shown that all, (if any) can obtain dissolved nutrients directly from the water column. I suspect it does occur though, but that is a guess really. Also, I think it depends on the nem, which types of particulate matter can be consumed. Marine organisms can be surprisingly picky about their diets. A reason being it takes specific enzymes to break down specific food sources. However it takes energy to produce enzymes, so organisms tend to produce enzymes only for food sources which are common for the environment that they have "adapted" too so, even if say a nem in the wild lives off clownfish poop, that doesn't mean it will be able to utilize clownfish poop in an aquarium, from a different species of clownfish, eating a different diet. It can take some trial and error to see which food sources are best, although certainly, at least in some cases, those that are readily available in our systems may be sufficient.


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[BonsaiNut]

BonsaiNut, I think I mostly agree, although, I would point out that, as far as I know, it has not been shown that all, (if any) can obtain dissolved nutrients directly from the water column.

Well I don't mean to be a total anemone geek, but I have actually read up on this Section 2.2.8 of Schick's "Functional Biology of Sea Anemones" is actually titled "Uptake of Dissolved Organic Matter". The section starts with this sentence:

In view of their small ingested rations and the relatively great abundance of dissolved organic matter (DOM) in seawater, sea anemones might derive much of their energy and nutrients by direct absorption of DOM. This was originally suggested by Putter (1911), who calculated that Actinia equina meets 30-40% of its energy needs in this manner. This topic has been reviewed in cnidarians by Schlichter (1980) and Schlichter et al. (1987).

The section is rather technical and goes into a lot detail around uptake systems for amino acids. But there HAVE been studies including absorption studies using various anemone membranes.

Additionally I want to point out that NONE of these studies suggest that 100% of the nutritional needs of anemones are being met WHOLLY by absorption - they all point to a supplementary role, particularly in the absence of solid food or with young anemones. At the same time, I have never found anything specific for any of the clown anemone species - or any attempt to create a nutritional equation (if you will) for the relative importance of various nutritional channels for clown anemones (which is really what we are talking about).

I agree with everything else you say. The entire subject is almost infinitely complex to me - particularly when you add zooxanthellae (and their nutritional needs and outputs) into the equation. Conditions change by anemone species, environmental factors, zooxanthellae clade, etc - and just as you pointed out what is good one day may not be good the next and what you fed one anemone may not exactly work for another. Perhaps it is best to consider them garbage disposals - feed them small amounts of a broad array of things, and let them selectively digest what they will

 

[m2434]

Cool, i'll have to add that to my reading list! IIRC there may be some studies on nutrient uptake from the water. Most have looked at aptaisia and A. Vitoria though I think. Aptaisia has been shown to take up dissolved ammonium for example, but I believe, at least from what i know of corals, special enzymes are required to take up nitrogen, for example, which limits the range of species which can do so. I would think the same would apply to anemones. In our systems though nitrate is a more prevalent source of N, whereas in the ocean there isn't much N. I'm not sure what difference that would make or how it would effect the clownfish anemone relationship. Perhaps aquaculture of clownfish and anemones will lead to changes in the relationship for these cultured specimens... I'm not as familiar with uptake of over nutrients, although presumably they could also be quite species specific, or even specific to organisms from specific reefs.


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[Saadatski]

last question, im guessing this zoo stuff is the photosynthetic algea that grows in the anemone?

 

[bradleym]

Yep. It's also what makes an anemone look like it's filled with mud water FYI. When it looks like it's full of crystal clear water you may be in trouble.

 

[jeff@zina.com]

Do you think in a couple 1000 years, Clowns will eventually develop an understanding of this and become a parasitic relationship?

Good question. Let me jump in the Tardis and find out...

...

...

Nope. In 5464, clownfish are still stupid. But hot pants are back!

Jeff

 

[Saadatski]

lol i just opened this thread again and found your post jeff.

Great, i already got my pair on right now!