The coral holobiont is a mix off all possible organisms living on and in the coral.
Recent research of many sources show how the coral holobiont does function. How the nutrient availability is managed within the holobiont, depending of the environment. Many articles are written in the past about the effects of nitrogen and phosphorus on calcification and the symbiodinium, many discussions on this and other forums have spread the believe that increased nitrogen and phosphorus availability measured in the water column must be avoided. Increasing nitrogen and phosphorus levels are battled without asking the question why? Most reefers are shooting at the messenger. In most cases the messengers are linked to a visual problem, the first advice given to lower the level of basic nutrients is dosing organic carbon. We collected a lot of approved papers concerning research about the coral holobiont and the effect of nutrient availability in the surrounding waters.
We now do know increased availability of phosphorus does NOT lower the calcification rates, confirmed by not one but many sources from all over the world.
High nitrate -nitrogen consumption does limit calcification rates by +- 8% which is a lot less as expected because most organisms slow down there metabolism x4 even x8 when using nitrate as a nitrogen source.
High nitrogen availability is reported to be responsible for bleaching, but only in combination with periods of increased growth ( warmer water?) interrupted by an insufficient supply of phosphorus and or other essential building materials.
Anyway, the nitrate and phosphate level has never been a live treating parameter in a reef aquarium needing immediate action.
For the health of corals often the addition of supplemental organic carbon is advised in an attempt to control the nutrient availability. But what does dosing of supplemental organic carbon mean for the coral holobiont in a closed system?
It seems that corals are able to control the nutrient supply by controlling the composition of the coral holobiont, by influencing fast growing organismn, consuming more ore less nutrients. They are able to do that by controlling the organic carbon availability within the holobiont by excreting mucus, also rich in anorganic phosphorus. This makes corals less dependent of the nutrient availability in the environment. This way they are able to manage the nutrient supply to what is needed. When the supply of some essentials is limited corals may stop providing organic carbon for fast growing heterotrophs. In nature corals use mainly organic nutrients and building materials provided by the holobiont, carbon is provided by the symbiodinium.
Not looking at all other caveats wich may be or and can be linked to carbon dosing, what may or will be the effect of dosing organic carbon on the nutrient management within the coral holobiont? Will the cure become a lot worse as the desease, ?
Recent research of many sources show how the coral holobiont does function. How the nutrient availability is managed within the holobiont, depending of the environment. Many articles are written in the past about the effects of nitrogen and phosphorus on calcification and the symbiodinium, many discussions on this and other forums have spread the believe that increased nitrogen and phosphorus availability measured in the water column must be avoided. Increasing nitrogen and phosphorus levels are battled without asking the question why? Most reefers are shooting at the messenger. In most cases the messengers are linked to a visual problem, the first advice given to lower the level of basic nutrients is dosing organic carbon. We collected a lot of approved papers concerning research about the coral holobiont and the effect of nutrient availability in the surrounding waters.
We now do know increased availability of phosphorus does NOT lower the calcification rates, confirmed by not one but many sources from all over the world.
High nitrate -nitrogen consumption does limit calcification rates by +- 8% which is a lot less as expected because most organisms slow down there metabolism x4 even x8 when using nitrate as a nitrogen source.
High nitrogen availability is reported to be responsible for bleaching, but only in combination with periods of increased growth ( warmer water?) interrupted by an insufficient supply of phosphorus and or other essential building materials.
Anyway, the nitrate and phosphate level has never been a live treating parameter in a reef aquarium needing immediate action.
For the health of corals often the addition of supplemental organic carbon is advised in an attempt to control the nutrient availability. But what does dosing of supplemental organic carbon mean for the coral holobiont in a closed system?
It seems that corals are able to control the nutrient supply by controlling the composition of the coral holobiont, by influencing fast growing organismn, consuming more ore less nutrients. They are able to do that by controlling the organic carbon availability within the holobiont by excreting mucus, also rich in anorganic phosphorus. This makes corals less dependent of the nutrient availability in the environment. This way they are able to manage the nutrient supply to what is needed. When the supply of some essentials is limited corals may stop providing organic carbon for fast growing heterotrophs. In nature corals use mainly organic nutrients and building materials provided by the holobiont, carbon is provided by the symbiodinium.
Not looking at all other caveats wich may be or and can be linked to carbon dosing, what may or will be the effect of dosing organic carbon on the nutrient management within the coral holobiont? Will the cure become a lot worse as the desease, ?