Is bacteria diversity important in the long term health of reef aquariums?
Few would contest the importance of healthy bacteria populations in our reefs. After being involved in a skimmerless thread, I was introduced to a Article from Advanced Aquaria.
http://www.advancedaquarist.com/2011/3/aafeature
Feature Article: Bacterial Counts in Reef Aquarium Water: Baseline Values and Modulation by Carbon Dosing, Protein Skimming, and Granular Activated Carbon Filtration
By Ken S. Feldman, Allison A. Place, Sanjay Joshi, Gary White
What are the bacteria populations in the water column of reef tanks, a
Counts in Reef Aquarium Water: Baseline Values and Modulation by Carbon Dosing, Protein Skimming, and Granular Activated Carbon Filtration
Feature Article: Bacterial Counts in Reef Aquarium Water: Baseline Values and Modulation by Carbon Dosing, Protein Skimming, and Granular Activated Carbon Filtration
By Ken S. Feldman, Allison A. Place, Sanjay Joshi, Gary White
What are the bacteria populations in the water column of reef tanks, and how does that value compare with bacterial counts in authentic reef water? Does carbon dosing indeed increase water column bacteria populations (i.e., is growth carbon limited)? Does mechanical filtration (protein skimming and/or GAC filtration) actually remove bacteria from the water column, and if so, how much? Ken, Allison, Sanjay, and Gary's in-depth article puts these questions to the test.
CONTENTS
1. Introduction
1.1 The goal of our study - testing the validity of the Carbon Dosing hypothesis
1.2 Bacteria: A general introduction
Bacterial Physiology
Bacterial Surface Charge and Protein Skimming
1.3 Bacterial life processes
Bacterial Metabolism
Bacterial Growth
Bacterial Nutrients
Manipulating Bacterial Growth
The Coral Holobiont
"Probiotic" Application of Bacteria
1.4 Counting bacteria in the water column
2. Experimental Approach
2.1 General experimental
2.2 Control experiments and bacterial contamination
2.3 Data workup
3. Results and Discussion
3.1 Baseline bacteria counts
3.2 Carbon dosing (planned and inadvertent) - How does it affect water column bacteria levels?
3.3 Bacteria removal via mechanical filtration - how effective?
4. Conclusions
5. Acknowledgments
6. References
Departments of Chemistry (Ken S. Feldman, Allison A. Place) and Industrial and Manufacturing Engineering (Sanjay Joshi), The Pennsylvania State University, University Park, Pennsylvania 16802, and Route 66 Marine, Gardena, California (Gary White)
1. Introduction
Bacteria are ubiquitous in the marine environment and they play absolutely decisive roles in every conceivable ecological niche. Numerous studies have documented the impact of bacterial action on life processes and energy transduction in natural reefs, as detailed below. However, a corresponding influx of information about bacteria biology in our captive marine aquaria has been lacking. For example, the inextricable connection between Total Organic Carbon (TOC) in the natural marine environment and one it its major consumers, bacterioplankton, constitutes the most fundamental level of the marine food web (Johannes, 1967; Ducklow, 1979; Eppley, 1980; Ducklow, 1983; Gottfried, 1983; Moriarity, 1985). Thus, bacterial grazing on this carbon-rich food source is an absolutely obligatory first step in the incorporation of this central nutrient into the food chain. In addition to a carbon source, bacteria require nitrogen and phosphorus compounds in significant quantities along with trace amounts of many other elements, perhaps the most critical of which is iron. Deficiencies of any of these macro- or micronutrients can, in principle, serve as a limiter of growth (details below).
On the other hand, much less is known about bacterial nutrient needs in the captive environment of a reef aquarium, and in fact there have not been any studies that document bacterial growth responses to any specific nutrient in a reef tank. Nevertheless, one of the more recent aquarium nutrient export methodologies is based upon the hypothesis that bacteria growth in reef aquaria is carbon limited. This methodology has been dubbed "Carbon Dosing" (Walton, 2008; Michael, 2008), and it has three basic premises:
4. Conclusions
The preliminary studies described herein document, for the first time, the modulation of water column bacteria population in reef tank water as a consequence of either (a) carbon source addition or (b) mechanical filtration (GAC, skimming). This information bears on the Carbon Dosing hypothesis for nutrient removal in marine aquaria.
Aquaria subjected to active filtration via skimming present water column bacteria populations that are approximately 1/10 of those observed on natural reefs. The consequences of this disparity on the long-term health of the tank's livestock are not known. How do reef tank organisms adapt to such a bacteria-deficient environment? Is the whole food web in an aquarium perturbed, or are there compensatory mechanisms that maintain an appropriate energy transduction through all of the trophic levels? Is "old tank syndrome" related to possible nutritional deficiencies stemming from this bacteria "gap"? Alternatively, could "old tank syndrome" be symptomatic of a gradual decrease of bacterial diversity as a consequence of selective skimmer-based removal of only bubble-susceptible bacteria? At present, it is not possible to go beyond speculation on these points - further research is needed.
On the other hand, our studies have shown that bacterial growth appears to be carbon limited in reef aquarium water. However, there is a demonstrable difference between reef tank water in an active reef tank, and reef tank water removed from the tank. In the latter case, bacteria consumers are largely absent, and so fueling bacteria growth via carbon addition translates to rapid and large increases in bacteria population. In an active reef tank, however, this population increase is not manifest, presumably because active predation keeps the overall level in check. Thus, the highly dynamic nature of bacteria populations in the water column of reef aquaria is highlighted by these studies. From a different perspective, the bacteria population in a reef tank seems to act as a buffer to help dissipate the otherwise potentially serious negative consequences of (inadvertent?) tank pollution via rapid carbon addition, at least perhaps up to a saturation point.
Finally, mechanical filtration in the form of skimming but not GAC does provide an effective means of bacteria export, at least up to a point. It appears likely that some types of bacteria are indeed "skimmable", but others are not. Thus, skimming inadvertently provides severe (?) evolutionary pressure to skew the tank's resident water column bacteria population to favor the "non-skimmable" cohort.
The bottom line with respect to the carbon dosing hypothesis is clear; the basic tenets of this theory appear to hold up to experimental scrutiny; carbon dosing does increase water column bacteria populations, and skimming does remove some bacteria with their attendant nutrient loads. Thus, the underlying science behind this approach to nutrient export appears valid.
Few would contest the importance of healthy bacteria populations in our reefs. After being involved in a skimmerless thread, I was introduced to a Article from Advanced Aquaria.
http://www.advancedaquarist.com/2011/3/aafeature
Feature Article: Bacterial Counts in Reef Aquarium Water: Baseline Values and Modulation by Carbon Dosing, Protein Skimming, and Granular Activated Carbon Filtration
By Ken S. Feldman, Allison A. Place, Sanjay Joshi, Gary White
What are the bacteria populations in the water column of reef tanks, a
Counts in Reef Aquarium Water: Baseline Values and Modulation by Carbon Dosing, Protein Skimming, and Granular Activated Carbon Filtration
Feature Article: Bacterial Counts in Reef Aquarium Water: Baseline Values and Modulation by Carbon Dosing, Protein Skimming, and Granular Activated Carbon Filtration
By Ken S. Feldman, Allison A. Place, Sanjay Joshi, Gary White
What are the bacteria populations in the water column of reef tanks, and how does that value compare with bacterial counts in authentic reef water? Does carbon dosing indeed increase water column bacteria populations (i.e., is growth carbon limited)? Does mechanical filtration (protein skimming and/or GAC filtration) actually remove bacteria from the water column, and if so, how much? Ken, Allison, Sanjay, and Gary's in-depth article puts these questions to the test.
CONTENTS
1. Introduction
1.1 The goal of our study - testing the validity of the Carbon Dosing hypothesis
1.2 Bacteria: A general introduction
Bacterial Physiology
Bacterial Surface Charge and Protein Skimming
1.3 Bacterial life processes
Bacterial Metabolism
Bacterial Growth
Bacterial Nutrients
Manipulating Bacterial Growth
The Coral Holobiont
"Probiotic" Application of Bacteria
1.4 Counting bacteria in the water column
2. Experimental Approach
2.1 General experimental
2.2 Control experiments and bacterial contamination
2.3 Data workup
3. Results and Discussion
3.1 Baseline bacteria counts
3.2 Carbon dosing (planned and inadvertent) - How does it affect water column bacteria levels?
3.3 Bacteria removal via mechanical filtration - how effective?
4. Conclusions
5. Acknowledgments
6. References
Departments of Chemistry (Ken S. Feldman, Allison A. Place) and Industrial and Manufacturing Engineering (Sanjay Joshi), The Pennsylvania State University, University Park, Pennsylvania 16802, and Route 66 Marine, Gardena, California (Gary White)
1. Introduction
Bacteria are ubiquitous in the marine environment and they play absolutely decisive roles in every conceivable ecological niche. Numerous studies have documented the impact of bacterial action on life processes and energy transduction in natural reefs, as detailed below. However, a corresponding influx of information about bacteria biology in our captive marine aquaria has been lacking. For example, the inextricable connection between Total Organic Carbon (TOC) in the natural marine environment and one it its major consumers, bacterioplankton, constitutes the most fundamental level of the marine food web (Johannes, 1967; Ducklow, 1979; Eppley, 1980; Ducklow, 1983; Gottfried, 1983; Moriarity, 1985). Thus, bacterial grazing on this carbon-rich food source is an absolutely obligatory first step in the incorporation of this central nutrient into the food chain. In addition to a carbon source, bacteria require nitrogen and phosphorus compounds in significant quantities along with trace amounts of many other elements, perhaps the most critical of which is iron. Deficiencies of any of these macro- or micronutrients can, in principle, serve as a limiter of growth (details below).
On the other hand, much less is known about bacterial nutrient needs in the captive environment of a reef aquarium, and in fact there have not been any studies that document bacterial growth responses to any specific nutrient in a reef tank. Nevertheless, one of the more recent aquarium nutrient export methodologies is based upon the hypothesis that bacteria growth in reef aquaria is carbon limited. This methodology has been dubbed "Carbon Dosing" (Walton, 2008; Michael, 2008), and it has three basic premises:
4. Conclusions
The preliminary studies described herein document, for the first time, the modulation of water column bacteria population in reef tank water as a consequence of either (a) carbon source addition or (b) mechanical filtration (GAC, skimming). This information bears on the Carbon Dosing hypothesis for nutrient removal in marine aquaria.
Aquaria subjected to active filtration via skimming present water column bacteria populations that are approximately 1/10 of those observed on natural reefs. The consequences of this disparity on the long-term health of the tank's livestock are not known. How do reef tank organisms adapt to such a bacteria-deficient environment? Is the whole food web in an aquarium perturbed, or are there compensatory mechanisms that maintain an appropriate energy transduction through all of the trophic levels? Is "old tank syndrome" related to possible nutritional deficiencies stemming from this bacteria "gap"? Alternatively, could "old tank syndrome" be symptomatic of a gradual decrease of bacterial diversity as a consequence of selective skimmer-based removal of only bubble-susceptible bacteria? At present, it is not possible to go beyond speculation on these points - further research is needed.
On the other hand, our studies have shown that bacterial growth appears to be carbon limited in reef aquarium water. However, there is a demonstrable difference between reef tank water in an active reef tank, and reef tank water removed from the tank. In the latter case, bacteria consumers are largely absent, and so fueling bacteria growth via carbon addition translates to rapid and large increases in bacteria population. In an active reef tank, however, this population increase is not manifest, presumably because active predation keeps the overall level in check. Thus, the highly dynamic nature of bacteria populations in the water column of reef aquaria is highlighted by these studies. From a different perspective, the bacteria population in a reef tank seems to act as a buffer to help dissipate the otherwise potentially serious negative consequences of (inadvertent?) tank pollution via rapid carbon addition, at least perhaps up to a saturation point.
Finally, mechanical filtration in the form of skimming but not GAC does provide an effective means of bacteria export, at least up to a point. It appears likely that some types of bacteria are indeed "skimmable", but others are not. Thus, skimming inadvertently provides severe (?) evolutionary pressure to skew the tank's resident water column bacteria population to favor the "non-skimmable" cohort.
The bottom line with respect to the carbon dosing hypothesis is clear; the basic tenets of this theory appear to hold up to experimental scrutiny; carbon dosing does increase water column bacteria populations, and skimming does remove some bacteria with their attendant nutrient loads. Thus, the underlying science behind this approach to nutrient export appears valid.
