Scientific paper on the role of NO3 and PO4 in a reef environment

[chimbo84]

Study Reveals How Corals Gain N and P in Darwin’s Paradox | Reef Builders | The Reef and Saltwater Aquarium Blog

An article published in the Journal Nature has found that photosynthetic corals not only host their symbiotic algae, they feed directly on it too, and importantly, it is how they uptake Nitrogen and…

reefbuilders.com

Paper discusses the role of nitrogen and phosphorous and its impact on the reef environment. Based on their study, N and P are consumed indirectly by coral through the zooxanthellae. Turns out, coral will actually consume their algae symbionts to obtain the N and P necessary for growth. Nutrient limited systems are experimentally weaker and less robust compared to systems with readily available nitrogen and phosphorous.

Here's the article itself: https://www.nature.com/articles/s41586-023-06442-5.pdf?pdf=button sticky

 

[JohnNYC8]

This is interesting. I read the summary and article but I couldn't find any numbers that easily translate to the measurements I typically see in the hobby. Are we talking Phosphates of .05-.09 or are we talking values of 0.1+?

With a colony of messy sea birds I would think very high but then again the ocean is a big place...

 

[chimbo84]

This is interesting. I read the summary and article but I couldn't find any numbers that easily translate to the measurements I typically see in the hobby. Are we talking Phosphates of .05-.09 or are we talking values of 0.1+?

With a colony of messy sea birds I would think very high but then again the ocean is a big place...

They didn't establish a set concentration of nutrients but instead provided a steady supply through constant small additions of both N and P. From the third page of the paper:

Three coral species (Euphylliaparadivisa, A. polystoma and S. pistillata) were exposed to daily 2-h pulses of controlled amounts of 15N-enriched NO3 and PO4 for 5 days perweek over a period of more than 8 months in separate compartmentsof the otherwise nutrient-limited experimental system

 

[JHSteepat]

The supplemental data on the Nature website mentions 25-150 mg N/ cubic meter (DIN) at the birds site.

 

[chimbo84]

The supplemental data on the Nature website mentions 25-150 mg N/ cubic meter (DIN) at the birds site.

Nice catch. With a molecular weight of 62g/mol for NO3, that equates to a range of 9.8 to 59ppm of Nitrate.

 

[Dan_P]

Nice catch. With a molecular weight of 62g/mol for NO3, that equates to a range of 9.8 to 59ppm of Nitrate.

A cubic meter is 1000 liters. 25-150 mg N per cubic meter would be 25-150 ppb N or roughly 100-600 ppb NO3.

 

[biom]

Study Reveals How Corals Gain N and P in Darwin’s Paradox | Reef Builders | The Reef and Saltwater Aquarium Blog

An article published in the Journal Nature has found that photosynthetic corals not only host their symbiotic algae, they feed directly on it too, and importantly, it is how they uptake Nitrogen and…

reefbuilders.com

Paper discusses the role of nitrogen and phosphorous and its impact on the reef environment. Based on their study, N and P are consumed indirectly by coral through the zooxanthellae. Turns out, coral will actually consume their algae symbionts to obtain the N and P necessary for growth. Nutrient limited systems are experimentally weaker and less robust compared to systems with readily available nitrogen and phosphorous.

Here's the article itself: https://www.nature.com/articles/s41586-023-06442-5.pdf?pdf=button sticky

Unfortunately this paper (in Nature magazine) says nothing new.
It is know from almost 100 years that corals digest their symbionts controlling their density and obtaining nutrients that way. Very good reading on this from 1996 here

https://www.int-res.com/articles/meps/139/m139p167.pdf

This field experiment that finds symbiotic corals grow faster in a natural environment enriched with dissolved inorganic nutrients from seabirds guano than in the nutrient poor waters is just...how to say it politely well not something new or unexpected.

The experiment of keeping corals in filtered water and flushing with nutrients is the only interesting thing but definitely doesn't solve any scientific puzzles.
Finally they say:
"In sum, our study provides a missing piece of the puzzle required to explain the success of coral reefs in seemingly barren ocean waters that has intrigued scientists since Darwin’s pioneering work to explain why coral reefs grow where they do."
– No, their study does not provide anything that was not known so far and using Darwin’s name is cheap way to bring sensation. Poor Nature Magazine... And Reef builders title citing "...Darwin's Paradox..." is no good too.