I'm certainly no expert on these subjects; however, it's helpful, to me, to summarize my perceptions and the reasons for them. I'm sharing this here, for anyone else who may be interested and if anyone actually reads though it LOL, to possible gain new perspectives into the topics. This is just some of my thoughts, you can probably skip to the conclusion too if you are familiar with these topics. I'm just interested in seeing where people think carbon dosing will lead us, specifically with regard to nutrient transport and competition in our systems.
Thanks for looking!
The boom in popularity of carbon dosing has certainly led to a lot of thought and insight into the subject of carbon dosing. The countless threads on the topic show this and hint that fundamental paradigm shift is happening in the hobby as a result. In addition to many of these threads, contributions to, two recent threads really got me thinking about how carbon dosing fits into the current reefkeeping schema and where the schema should go from here.
These contributions were from some fellow RCers such as wmdick_2007, mesocosm, Tom, Nate and Randy in the thread
http://www.reefcentral.com/forums/showthread.php?t=1981622&page=3
As well as others from thread started by HighlandReefer
http://www.reefcentral.com/forums/showthread.php?t=1986614
In my mind, the fundamental question is still how does carbon dosing help our systems? I think reefers all too often get caught up in the paradigm, low nutrients = good, high nutrients = bad. Lowering the nutrients may be good, but in the real biological world, everything is a competition for resources. So, I think in reality, it's fairly safe to say that the ultimate goal of any husbandry practice, including carbon dosing, should be to shift the competitive advantage away from undesirable organisms and towards desirable organisms. So, what other tools and considerations do we need to do this in this new era of carbon dosing?
Below are some notable thoughts and questions that I got from reading through these threads. If you already read the threads, or just don't want to read all this, you can probably skip to the conclusion.
1) Gary(mesocosm) pointed out that carbon dosing can be useful for detnitrification if we can manage the unknowns. However, exactly what are the unknowns?
2) Tom(tmz) advised, that due to the risks, carbon dosing should only be used if there are excess nutrients. However, as I mentioned above, IMO the ultimate goal of carbon dosing should be to shift the competitive advantage away from undesirable organisms and towards desirable organisms. For me, the goal of reefkeeping is to produce a diverse healthy marine environment. To do so, it seems that carbon dosing, along with other methods, could be utilized to expand the biodiversity and improve the growth of desirable organisms. I think that, under the right conditions, carbon dosing is potentially useful even in relatively low nutrient systems.
2) wmdick_2007 provided the article http://www.oscarfish.com/article-home/water/72-heterotrophic-bacteria.html Although the article deals with freshwater, it has some interesting and relevant points. One such is Competition for surface area for bacterial colonization. How do we ensure that desirable bacteria will dominate the available surfaces of our systems and that that this bacteria is not overrun by less useful, or even possibly harmful bacteria?
4) Tom(tmz) suggested that the form of the carbon source could influence how many processes in the anaerobic chain are required to reduce it and that additional bacteria will likely be required to do so. So, to what extent can this be used to influence the bacterial populations growing in our systems?
5) RHF pointed out that carbon dosing has been tried and tested for years. There does not appear to be any great trick to it, however, in his experience, it does work best in combination with other methods.
6) It was pointed out that carbon dosing may not be useful against cyanobacteria. RHF pointed out that cyanobacteria can fix N2 and reducing PO4 may be a better strategy.
Also, m2434 pointed out that cyano bacteria can utilize carbon sources directly. so, it's possible, to some extent this could also fuel the growth of cyanobacteria..
7) Tom(tmz) brought up mutualistic relationships between cyanobacterium and some bacteria. I think that this could be useful for maintaining the population of bacteria, even when certain nutrients become limited. However, could this, and if so, how could this, be used to help improve the overall health of desirable organisms in our systems.
8) m2434 pointed out that another nuisance "algae" (term used loosely) diatoms are useful food source for desirable organisms. Tom(tmz) pointed out that carbon dosing may also add to the foodweb. Nate(Genetics) pointed out the correlation between organic molecules and biodiversity. Tom(tmz), Nate(Genetics) and RHF pointed out some of the range of organisms which may consume dissolved organic carbon.
9) From the article presented by Cliff(HilandReefer) http://www.advancedaquarist.com/2011/3/aafeature
Protein skimming may lead to approximately 1/10th the bacterial population of a reef. Some bacteria may be removed by a skimmer, but others may not be. GAC is not able to effectively remove surface bound bacteria
10) RHF points out that we should not necessarily focus on water column bacteria.
And points out that surface bound bacteria can grow on the GAC and is removed when the GAC is changed out.
11) RHF points out that zooxanthellae may be able to utilize carbon sources. I wonder if therefore other dinoflagellates can utilize these carbon sources and upon further investigation, find that there are a number of threads out there that suggest this to be true.
Conclusion
It seems to me that the main goal of nutrient reduction is not just to eliminating nuisance algae and to make our tanks look "prettier". It's also to shift the competitive advantage, for scare nutrients, away from these undesirable organisms and towards the more desirable ones. As pointed out in these threads, dissolved organic carbon is a fundamental food source for our inhabitants. The food web is complex and contains mutualistic relationships in addition to competition for food and space. While nutrient reduction seems to generally be a fairly reasonable use for and goal of, carbon dosing, in heavily stocked systems. It also seems likely that it could potentially be useful to enhance nutrient transport pathways, in order to ensure these nutrients benefit desirable livestock, in lower nutrient systems as well.
In order to do so however, what other environmental parameters should be considered?
I think for long-term success, these variables need to be considered for high, as well as, low nutrient systems regardless of carbon dosing. However, in addition, carbon dosing may benefit all systems regardless of nutrient levels.
As mentioned, the particular carbon source may be important to determine which organisms are enhanced. Using a variety of carbon sources may shift ratios of organisms, which prosper, from the supplemented organic carbon sources. This may be necessary to maximize space utilization and prevent undesirable consequences. In addition however, to maintain populations of some desirable organisms, when certain nutrients become limited certain mutualistic relationships with less desirable organisms may be beneficial. For example, phosphate and nitrate may be growth inhibitive to scleractinia. However, scleractinia need to feed on organisms which require P and N. Therefore nutrient recycling between cyanobacteria and benitic bacteria, in addition to carbon dosing may be beneficial as it could allow an increased food source to flourish, while inhibitive nutrients, in the water column are kept low through other means such as GFO.
In addition, as pointed out in Genetics and Stony_Coral's article
http://reefkeeping.com/issues/2008-08/nftt/index.php sometimes, thick sludge develops in older tanks. Also, others have noted that other visible bacteria can be found on the rocks and substrate of some tanks when carbon dosing is used. Also, as pointed out in Allison et al. 2011, some bacteria may not be removed and homogeneity of bacteria may start to occur. If this is the case, what can be done about this? Can we promote the growth of other consumers to compete with this bacteria and or consume it and return the reduced by products to the system, which are more easily removed, or used for growth of more beneficial organisms? In this regard, I wonder if it is beneficial to dose other nutrients such sodium silicate in addition to carbon sources. I think this may be reasonable as this would add diversity to the food web and help to prevent heterogeneity in the system. Hopefully this could help cycle nutrients and facilitate removal of excess nutrients.
Anyway, I think it is clear that our perception of nutrient transport and competition is changing. This was a quick summary of my perceptions, I am curious to see what others think of the subject
Thanks for looking!
The boom in popularity of carbon dosing has certainly led to a lot of thought and insight into the subject of carbon dosing. The countless threads on the topic show this and hint that fundamental paradigm shift is happening in the hobby as a result. In addition to many of these threads, contributions to, two recent threads really got me thinking about how carbon dosing fits into the current reefkeeping schema and where the schema should go from here.
These contributions were from some fellow RCers such as wmdick_2007, mesocosm, Tom, Nate and Randy in the thread
http://www.reefcentral.com/forums/showthread.php?t=1981622&page=3
As well as others from thread started by HighlandReefer
http://www.reefcentral.com/forums/showthread.php?t=1986614
In my mind, the fundamental question is still how does carbon dosing help our systems? I think reefers all too often get caught up in the paradigm, low nutrients = good, high nutrients = bad. Lowering the nutrients may be good, but in the real biological world, everything is a competition for resources. So, I think in reality, it's fairly safe to say that the ultimate goal of any husbandry practice, including carbon dosing, should be to shift the competitive advantage away from undesirable organisms and towards desirable organisms. So, what other tools and considerations do we need to do this in this new era of carbon dosing?
Below are some notable thoughts and questions that I got from reading through these threads. If you already read the threads, or just don't want to read all this, you can probably skip to the conclusion.
1) Gary(mesocosm) pointed out that carbon dosing can be useful for detnitrification if we can manage the unknowns. However, exactly what are the unknowns?
2) Tom(tmz) advised, that due to the risks, carbon dosing should only be used if there are excess nutrients. However, as I mentioned above, IMO the ultimate goal of carbon dosing should be to shift the competitive advantage away from undesirable organisms and towards desirable organisms. For me, the goal of reefkeeping is to produce a diverse healthy marine environment. To do so, it seems that carbon dosing, along with other methods, could be utilized to expand the biodiversity and improve the growth of desirable organisms. I think that, under the right conditions, carbon dosing is potentially useful even in relatively low nutrient systems.
2) wmdick_2007 provided the article http://www.oscarfish.com/article-home/water/72-heterotrophic-bacteria.html Although the article deals with freshwater, it has some interesting and relevant points. One such is Competition for surface area for bacterial colonization. How do we ensure that desirable bacteria will dominate the available surfaces of our systems and that that this bacteria is not overrun by less useful, or even possibly harmful bacteria?
4) Tom(tmz) suggested that the form of the carbon source could influence how many processes in the anaerobic chain are required to reduce it and that additional bacteria will likely be required to do so. So, to what extent can this be used to influence the bacterial populations growing in our systems?
5) RHF pointed out that carbon dosing has been tried and tested for years. There does not appear to be any great trick to it, however, in his experience, it does work best in combination with other methods.
6) It was pointed out that carbon dosing may not be useful against cyanobacteria. RHF pointed out that cyanobacteria can fix N2 and reducing PO4 may be a better strategy.
Also, m2434 pointed out that cyano bacteria can utilize carbon sources directly. so, it's possible, to some extent this could also fuel the growth of cyanobacteria..
7) Tom(tmz) brought up mutualistic relationships between cyanobacterium and some bacteria. I think that this could be useful for maintaining the population of bacteria, even when certain nutrients become limited. However, could this, and if so, how could this, be used to help improve the overall health of desirable organisms in our systems.
8) m2434 pointed out that another nuisance "algae" (term used loosely) diatoms are useful food source for desirable organisms. Tom(tmz) pointed out that carbon dosing may also add to the foodweb. Nate(Genetics) pointed out the correlation between organic molecules and biodiversity. Tom(tmz), Nate(Genetics) and RHF pointed out some of the range of organisms which may consume dissolved organic carbon.
9) From the article presented by Cliff(HilandReefer) http://www.advancedaquarist.com/2011/3/aafeature
Protein skimming may lead to approximately 1/10th the bacterial population of a reef. Some bacteria may be removed by a skimmer, but others may not be. GAC is not able to effectively remove surface bound bacteria
10) RHF points out that we should not necessarily focus on water column bacteria.
And points out that surface bound bacteria can grow on the GAC and is removed when the GAC is changed out.
11) RHF points out that zooxanthellae may be able to utilize carbon sources. I wonder if therefore other dinoflagellates can utilize these carbon sources and upon further investigation, find that there are a number of threads out there that suggest this to be true.
Conclusion
It seems to me that the main goal of nutrient reduction is not just to eliminating nuisance algae and to make our tanks look "prettier". It's also to shift the competitive advantage, for scare nutrients, away from these undesirable organisms and towards the more desirable ones. As pointed out in these threads, dissolved organic carbon is a fundamental food source for our inhabitants. The food web is complex and contains mutualistic relationships in addition to competition for food and space. While nutrient reduction seems to generally be a fairly reasonable use for and goal of, carbon dosing, in heavily stocked systems. It also seems likely that it could potentially be useful to enhance nutrient transport pathways, in order to ensure these nutrients benefit desirable livestock, in lower nutrient systems as well.
In order to do so however, what other environmental parameters should be considered?
I think for long-term success, these variables need to be considered for high, as well as, low nutrient systems regardless of carbon dosing. However, in addition, carbon dosing may benefit all systems regardless of nutrient levels.
As mentioned, the particular carbon source may be important to determine which organisms are enhanced. Using a variety of carbon sources may shift ratios of organisms, which prosper, from the supplemented organic carbon sources. This may be necessary to maximize space utilization and prevent undesirable consequences. In addition however, to maintain populations of some desirable organisms, when certain nutrients become limited certain mutualistic relationships with less desirable organisms may be beneficial. For example, phosphate and nitrate may be growth inhibitive to scleractinia. However, scleractinia need to feed on organisms which require P and N. Therefore nutrient recycling between cyanobacteria and benitic bacteria, in addition to carbon dosing may be beneficial as it could allow an increased food source to flourish, while inhibitive nutrients, in the water column are kept low through other means such as GFO.
In addition, as pointed out in Genetics and Stony_Coral's article
http://reefkeeping.com/issues/2008-08/nftt/index.php sometimes, thick sludge develops in older tanks. Also, others have noted that other visible bacteria can be found on the rocks and substrate of some tanks when carbon dosing is used. Also, as pointed out in Allison et al. 2011, some bacteria may not be removed and homogeneity of bacteria may start to occur. If this is the case, what can be done about this? Can we promote the growth of other consumers to compete with this bacteria and or consume it and return the reduced by products to the system, which are more easily removed, or used for growth of more beneficial organisms? In this regard, I wonder if it is beneficial to dose other nutrients such sodium silicate in addition to carbon sources. I think this may be reasonable as this would add diversity to the food web and help to prevent heterogeneity in the system. Hopefully this could help cycle nutrients and facilitate removal of excess nutrients.
Anyway, I think it is clear that our perception of nutrient transport and competition is changing. This was a quick summary of my perceptions, I am curious to see what others think of the subject
