Nitrates in an SPS Tank

[prattreef]

Sorry, still not quite getting it.

 

[ShaunW]

Additionally the growth rates of zooxanthellae are dependent on the external environment.

In HIGH nutient environments - zooxanthellae grow slower.
In LOW nutrient environments (like a coral reef) - zooxanthellae grow faster.

Re-reading what I wrote I probably should rephase/add to it: the ability to have stimulated growth by nutrient addition, i.e. population density of zoox plays an important role on how they grow.

 

[kimoyo]

From the article:

Growth rate is probably density-dependent, as growth rates of zoox in situ appear to be greatest in conditions of low population density. This has been observed both in natural hosts with different population densities and in experimental infections of algae-free hosts. While one interpretation is that more "space" is available, we propose that host catabolism provides a greater relative supply of nutrients for symbionts at low population densities. Moveover, the achieveable algal biomass of the symbiosis will depend on the supply of "new" nutrients to the symbiosis.

Still not following the individual growth vs. cell division (population increase) and I'm realizing now that some the information is contradicting. At one point in the course lecture she says "no nutrients + photosynthesis = cell division" but the papers say high nitrates lead to cell division. Then again, maybe its not contradicting and photosynthesis and nitrates can both lead to cell division separately. Can you help me here Solbby?

There were some other parts that I didn't fully follow and that why I was so interested in the nitrate uptake model. They are also being general in saying "nutrients". In the ammonium model the host provides the symbiont a carbon source it uses thru a form of catabolism (I guess you would call it that). This thru photosynthesis enables the host to eventually make amino acids for itself. In this model it would seem that the host is controlling the flow of nutrients to the symbiont And I am curious if the coral would be able to use its own CO2 as a carbon source for calcification.

But in the nitrate studies it would seem that high nitrates level lead to increased population density of zoox and lack of skeletal growth of the coral. Implying that the coral does not contral the nitrate transport system. But if ammonium levels are raised at the same time coral growth was possible. Kinda seems like there are two different systems here and when CO2 production slows the zoox are able to use the carbonate/bicarbonate from the water when in high nitrate levels.

Here's the model that was proposed in that article found by Deanos and Solbby, but I'm not exactly sure how it would fit. The interesting thing is that there is two ways Carbon enters the coral/zoox. I wonder how it might be linked to nitrate levels (nitrogen intake).


(I know this might seem kinda pointless to some people but controlling the zoox population in corals is a key growth and color.)

 

[ShaunW]

Sorry, still not quite getting it.

I guess my point to summarize, is that zoox represent a significant biomass above nuisance plankton blooms in an oligotrophic environment and can be considered to be an "enormous, localized potential demand for nutrients".

Additionally, the optimal growth of zoox require an optimal state of nutrients to be available, where too much nutrients present are bad (lack of growth) and too little is also bad (starvation). This is directly related to the host by actual space limitations in the host for zoox to grow, and host availability to nutrients. Therefore a good homostasis is required between the environment, the host, and the zoox.

 

[ShaunW]

Still not following the individual growth vs. cell division (population increase) and I'm realizing now that some the information is contradicting. At one point in the course lecture she says "no nutrients + photosynthesis = cell division" but the papers say high nitrates lead to cell division. Then again, maybe its not contradicting and photosynthesis and nitrates can both lead to cell division separately. Can you help me here Solbby?

The contradiction is corrected by understanding the utilization of different metabolic pathways for biogenesis. Also the term 'nutrients' represent's more than just a N source like nitrate.

 

[ShaunW]

But in the nitrate studies it would seem that high nitrates level lead to increased population density of zoox and lack of skeletal growth of the coral. Implying that the coral does not contral the nitrate transport system. But if ammonium levels are raised at the same time coral growth was possible. Kinda seems like there are two different systems here and when CO2 production slows the zoox are able to use the carbonate/bicarbonate from the water when in high nitrate levels.

From my reading, it is hypothesized that the coral/host does indeed control the nitrate transport system. Paul, where did you see the contrary proposed?

 

[kimoyo]

I guess my point to summarize, is that zoox represent a significant biomass above nuisance plankton blooms in an oligotrophic environment and can be considered to be an "enormous, localized potential demand for nutrients".

Additionally, the optimal growth of zoox require an optimal state of nutrients to be available, where too much nutrients present are bad (lack of growth) and too little is also bad (starvation). This is directly related to the host by actual space limitations in the host for zoox to grow, and host availability to nutrients. Therefore a good homostasis is required between the environment, the host, and the zoox.

Doesn't this contradict the article when it says that high nitrates lead to large growth of zoox in corals that were previously keep in low nutrient waters.

And doesn't that quote say the don't believe its the space limitations?

 

[kimoyo]

From my reading, it is hypothesized that the coral/host does indeed control the nitrate transport system. Paul, where did you see the contrary proposed?

I would ask you the same thing, where you saw it hypothesized that it does control nitrate transport not just facilitate it .

If the coral is providing the zoox with nitrate and the nitrate is allowing the zoox to grow very fast. I was making the assumption (maybe wrongly) that coral would recognize that the zoox is outcompeting it for a carbon source and halting its growth (possibly killing it). And if the coral had the ability to control the nitrate transport to the zoox it would slow it in order to grow.

 

[ShaunW]

Doesn't this contradict the article when it says that high nitrates lead to large growth of zoox in corals that were previously keep in low nutrient waters.

I was specifically thinking of the HIGH nitrates in the "Nitrate increases zoox population density and reduces skeletogenesis in corals" paper.

See it is the definition of "high" that is the problem. We need to subdivide the amount of nitrate into a few different amounts.

And doesn't that quote say the don't believe its the space limitations?

I don't interpret it that way. I think that both are correct, i.e. space limitations affecting growth and host catabolism.

 

[spykes]

I have not read the article yet, but this is what i interpreted while reading shaun's abstract.

this is like in any living animal, tho we dont have any symbiosis, in my interpretation i feel, like a person intaking way to much nutrients, they store most of the triglycerides, stored in the greater omentum in a human( you belly) doesnt mean you will grow stronger and better. You will have a excessive stored energy for growth which is not utilized, eventually get into a unheathy state, where zoox is at a greater mass then normal to produce glucose as well as aspartic acid for the coral. Where in a low nutriented condition and a optimal condition of both nitrate and po4, your coral should perform at it's best. Potential energy stored in the coral is not properly utilized just build up in my opinion.

i know in humans, when your fatter, your slower and usually very tired and unproductive.

 

[ShaunW]

I would ask you the same thing, where you saw it hypothesized that it does control nitrate transport not just facilitate it .

OK let me look for the exact quotes.

 

[ShaunW]

I have not read the article yet

Dave, WHAT ARE YOU WAITING FOR!!! :lol: This is right up your alley!! We need your input, get busy man!!

 

[spykes]

im doing a lab report on salivary amylase, lipase, and pepsinogen, under diffrent denaturalizating and optimal condition, i would love to read the article :p, im gonna take my time while you guys have fun breaking it down =D

 

[kimoyo]

Still not following the individual growth vs. cell division (population increase) and I'm realizing now that some the information is contradicting. At one point in the course lecture she says "no nutrients + photosynthesis = cell division" but the papers say high nitrates lead to cell division. Then again, maybe its not contradicting and photosynthesis and nitrates can both lead to cell division separately. Can you help me here Solbby?

Okay I got this wrong.

What Dr. Szmant was saying in her lecture was that when there when the zoox have photosynthesis but no nutrients, they will give the coral the excess C (used for growth).

She also said that at high light intensities corals sometimes corals can't take up enough CO2 from the water to keep up with the demands of photosynthesis. This might be when the zoox starts using the carbonate.

And if the population density of the zoox increases this will be even worse.

So in the situation with high alk and high nitrates, this still shouldn't be a problem because there is a maxium density the zoox can achieve (as Solbby just pointed out).

But in the cause of high nitrate and high ammonium level, the coral would be able to process the more CO2 helping to meet depend.

Am I on the right track?

 

[ShaunW]

Potential energy stored in the coral is not properly utilized just build up in my opinion.

Nicely put! ..........and also inhibits the availability of inorganic carbon for calcification.

 

[kimoyo]

The contradiction is corrected by understanding the utilization of different metabolic pathways for biogenesis. Also the term 'nutrients' represent's more than just a N source like nitrate.

Right, I see where I made the mistake. Photosynthesis and nutrients are both needed for zoox growth.

 

[ShaunW]

Am I on the right track?

I would say that we are getting on the same wavelength.

I say we next enter the host and look specifically at the interaction between host and zoox in nutrient uptake, exchange, and growth.

 

[kimoyo]

this is like in any living animal, tho we dont have any symbiosis, in my interpretation i feel, like a person intaking way to much nutrients, they store most of the triglycerides, stored in the greater omentum in a human( you belly) doesnt mean you will grow stronger and better. You will have a excessive stored energy for growth which is not utilized, eventually get into a unheathy state, where zoox is at a greater mass then normal to produce glucose as well as aspartic acid for the coral. Where in a low nutriented condition and a optimal condition of both nitrate and po4, your coral should perform at it's best. Potential energy stored in the coral is not properly utilized just build up in my opinion.

What do you mean by store potential energy? Are you speaking about photosynthesis or nitrates? I was under the impression that corals don't store energy.

 

[kimoyo]

I would say that we are getting on the same wavelength.

I say we next enter the host and look specifically at the interaction between host and zoox in nutrient uptake, exchange, and growth.

Eventually it would be pretty good to also understand how pigment population density works in the zoox (for color).

 

[ShaunW]

What do you mean by store potential energy?

He probably means energy stored for a rainy day, like we mammels do when we over eat and convert energy to fat reserves (potential energy). He is generalizing not being specific to the questions at hand.

And your right Paul, corals don't store energy, they just grow and Grow and GROW!!.