NPS corals, heterotrophs or mixotroph

[sixty_reefer]

Does anyone know if NPS corals are full heterotrophic or do they have the capability to become.
I have in mind a few common NPS like the often called sun coral that has a calcium carbonate skeleton, would we consider a sun coral to be heterotrophic?

 

[firechild]

Yes, they are full heterotroph and do not have the ability to become autotrophic.

 

[sixty_reefer]

Yes, they are full heterotroph and do not have the ability to become autotrophic.

Would a sun coral be getting all their nutrients from particulate food including the minerals necessary to build they’re calcium carbonate skeleton? Heterotrophic organisms normally have a digestive system I can’t think of many that don’t have it. Maybe I got my terminology wrong again and I’m looking for a different term.

 

[death-by-reef]

sorry, I'm new to the hobby, what exactly is an NPS coral?

 

[sixty_reefer]

sorry, I'm new to the hobby, what exactly is an NPS coral?

Non photosynthetic corals, corals that don’t need light to live.

 

[taricha]

Yeah, nps corals (like sun coral) lack all symbiotic zooxanthellae. It's not just that they have less - they have none. So they get zero energy from light.
They get Ca for skeleton building from the water like other corals, not really from ingested organisms though.

 

[sixty_reefer]

Yeah, nps corals (like sun coral) lack all symbiotic zooxanthellae. It's not just that they have less - they have none. So they get zero energy from light.
They get Ca for skeleton building from the water like other corals, not really from ingested organisms though.

I think that’s what I’d like to discuss not all autotrophic organisms need light to obtain energy, sun coral for example could be getting Calcium and alkalinity and trace from the water column could they also be getting phosphates and nitrates from the water column making them mixotrophs? Or that is only possible if zooxanthellae is present in the coral?

 

[taricha]

Fair question, I don't know. I'd have to do some Google scholar to get a sense of whether the uptake of N and P from water to coral happens in NPS coral or if it's only significant in coral with algal symbionts. Regarding energy/carbon there just isn't enough readily digestible energetic compounds dissolved in the water to meet a corals energy budget needs that way.
When I had sun corals, each head could eat like 1/2 a mysis every day or two. Obviously that intake would massively dwarf anything the coral could uptake from the water.

 

[firechild]

I think that’s what I’d like to discuss not all autotrophic organisms need light to obtain energy, sun coral for example could be getting Calcium and alkalinity and trace from the water column could they also be getting phosphates and nitrates from the water column making them mixotrophs? Or that is only possible if zooxanthellae is present in the coral?

There is no need for NPS to take up nitrates or phosphates as these are only taken up by autotrophic corals to provide them for the zooxanthellae, corals, whether autotrophic or heterotrophic have no need for either nitrates or phosphates directly.

 

[sixty_reefer]

Fair question, I don't know. I'd have to do some Google scholar to get a sense of whether the uptake of N and P from water to coral happens in NPS coral or if it's only significant in coral with algal symbionts. Regarding energy/carbon there just isn't enough readily digestible energetic compounds dissolved in the water to meet a corals energy budget needs that way.
When I had sun corals, each head could eat like 1/2 a mysis every day or two. Obviously that intake would massively dwarf anything the coral could uptake from the water.

Fair question, I don't know. I'd have to do some Google scholar to get a sense of whether the uptake of N and P from water to coral happens in NPS coral or if it's only significant in coral with algal symbionts. Regarding energy/carbon there just isn't enough readily digestible energetic compounds dissolved in the water to meet a corals energy budget needs that way.
When I had sun corals, each head could eat like 1/2 a mysis every day or two. Obviously that intake would massively dwarf anything the coral could uptake from the water.

I’ve been looking for some articles myself without any luck so far, though putting the question here could help.
I was thinking in the tissue and muscle building if they were using nitrogen, phosphates sources from the water column.

 

[sixty_reefer]

There is no need for NPS to take up nitrates or phosphates as these are only taken up by autotrophic corals to provide them for the zooxanthellae, corals, whether autotrophic or heterotrophic have no need for either nitrates or phosphates directly.

That’s the thing are photosynthetic corals not heterotrophic themselves and relying on the symbiotic relationship with autotrophic zooxanthellae to feed them? Could nps have a similar method to assimilate nutrients from the water column without the need of zooxanthellae?

 

[death-by-reef]

Non photosynthetic corals, corals that don’t need light to live.

ok thanks

 

[taricha]

NPS corals certainly need C N P and all the rest to build tissue, proteins, DNA etc.
One would reason from their adaptations and their ravenous dietary habits, that they aren't coming close to meeting those needs from the water. But I do not know if that means they get no N and P from the water or just much much less than from ingested prey.

 

[firechild]

That’s the thing are photosynthetic corals not heterotrophic themselves and relying on the symbiotic relationship with autotrophic zooxanthellae to feed them? Could nps have a similar method to assimilate nutrients from the water column without the need of zooxanthellae?

Arguably yes to the first question. However, with the second part, autotrophic corals are taking up nutrients from the water column that they do not use themselves but rather pass to the zooxanthellae. The nutrients they use are produced by the zooxanthellae within their tissue. Neither autotrophic nor heterotrophic corals have the ability to assimilate nitrates and phosphates directly so without zooxanthellae or some other method of converting them to proteins and amino acids.

 

[Hans-Werner]

Could nps have a similar method to assimilate nutrients from the water column without the need of zooxanthellae?

Clearly no.

Like fish, which are also heterotrophs, NPS can most likely take up phosphate from the water. I think nearly every organism can make use of dissolved inorganic phosphate from water or food.

The difference between autotrophs and heterotrophs ist that the first ones can make use of inorganic carbon while the last ones need organic carbon compounds (like carbonhydrates, oils or amino acids from proteins) for energy supply.

Most heterotrophs also need certain amino acids which are essential to them but some heterotrophs like heterotrophic bacteria can make all amino acids from ammonium if other organic carbon compounds are available.

Many heterotrophs also need certain vitamins and essential fatty acids which autotrophs do not need.

Most marine organisms are able to take up for example dissolved amino acids directly from the water, but heterotrophs need organic compounds. Ammonium or nitrate and bicarbonate allone are not sufficient.

 

[sixty_reefer]

Clearly no.

Like fish, which are also heterotrophs, NPS can most likely take up phosphate from the water. I think nearly every organism can make use of dissolved inorganic phosphate from water or food.

The difference between autotrophs and heterotrophs ist that the first ones can make use of inorganic carbon while the last ones need organic carbon compounds (like carbonhydrates, oils or amino acids from proteins) for energy supply.

Most heterotrophs also need certain amino acids which are essential to them but some heterotrophs like heterotrophic bacteria can make all amino acids from ammonium if other organic carbon compounds are available.

Many heterotrophs also need certain vitamins and essential fatty acids which autotrophs do not need.

Most marine organisms are able to take up for example dissolved amino acids directly from the water, but heterotrophs need organic compounds. Ammonium or nitrate and bicarbonate allone are not sufficient.

Yes that makes sense, this would mean that heterotrophic organisms wouldn’t be able to assimilate nitrogen and amino acids from the water column to make protein?

 

[sixty_reefer]

NPS corals certainly need C N P and all the rest to build tissue, proteins, DNA etc.
One would reason from their adaptations and their ravenous dietary habits, that they aren't coming close to meeting those needs from the water. But I do not know if that means they get no N and P from the water or just much much less than from ingested prey.

There was a chap online somewhere that mentioned that all corals need to eat heterotrophic and autotrophic to get all they need, wondering if the same could be happening to NPS as they are definitely fairly tricky to cater for in home aquaria.

 

[sixty_reefer]

Arguably yes to the first question. However, with the second part, autotrophic corals are taking up nutrients from the water column that they do not use themselves but rather pass to the zooxanthellae. The nutrients they use are produced by the zooxanthellae within their tissue. Neither autotrophic nor heterotrophic corals have the ability to assimilate nitrates and phosphates directly so without zooxanthellae or some other method of converting them to proteins and amino acids.

In your opinion the only way for NPS to get the nutrients they need would be by ingesting other organisms is that correct?

 

[oceanleaf]

NPS can utilize organic nutrients from water column to a certain extent (e.g. Balanophyllia Elegans), but they cannot directly consume inorganic nutrients (see here and here).

 

[firechild]

There was a chap online somewhere that mentioned that all corals need to eat heterotrophic and autotrophic to get all they need, wondering if the same could be happening to NPS as they are definitely fairly tricky to cater for in home aquaria.

This article shows that both autotrophic and heterotrophic corals have the ability to synthesise amino acids that are considered essential (i.e. must form part of the diet) in most animals. I would suspect that the problem for most NPS is that there is insufficient organics in the water to sustain them and if enough organics are added to the water, then it would foul and cause bacterial blooms or other problems. For autotrophic corals, those organics are produced from within the corals and passed directly to the coral.
There are some xeniids that do not feed at all so while it is true that all corals need to eat (at least as far as I know), the same is not true for all soft corals.