How to FEED your reef tank so that your corals will really GROW, instead of ho-hum...
- Thread starter capecoral
- Start date
dave willmore
New member
In my experience tank size isn't related to microalgae clumping, circulation tends to keep microalgae well suspended. At very high densities phytoplankton can clump, especially diatoms llike Isochrysis galbana, but these densities are well above what we have in our tanks. My comment was not regarding algae it regarded bacteria. Our tanks dominate in bacteria that cling to surfaces because water column organisms (bacteria, ciliates, protozoa, algae) are excluded by pumps and skimmers.
It seems to me that changing our method of water turnover to keep live plankton would be the first line in coral feeding. The second line would be determination of which type of free floating bacteria or algae to dose our tanks with.
Many types of zooplankton can be grown in seperate tanks and then screened out for addition to the main tank. This keeps N and P low, although even microalgae drip to the main tank can be solved by macroalgae harvest from the refugium. It's a question of balance between refugium and tank sizes.
"Continued:
http://www.youtube.com/watch?v=quH4x640Jgs
http://www.youtube.com/watch?v=rdIjMQATQks
Currently we are preparing the texts/studies, which will follow the videos soon. "
http://www.youtube.com/watch?v=quH4x640Jgs
http://www.youtube.com/watch?v=rdIjMQATQks
Currently we are preparing the texts/studies, which will follow the videos soon. "
"œThis primary-production related video really covers DOC well:"
http://www.youtube.com/watch?v=bc_fGWjmNeI "œ
http://www.youtube.com/watch?v=bc_fGWjmNeI "œ
"œHere's the last recommended video to learn about primary production, before we get into the studies in the next posts; this one is a little more complex"¦
http://www.youtube.com/watch?v=pQaE0e0iD3s
And in case you need to review the previous videos again, here is the list of them in the recommend order from simple to more complex:
http://www.youtube.com/watch?v=qfMaBeLwiO4
http://www.youtube.com/watch?v=7d96F0ak4uY
http://www.youtube.com/watch?v=WTBlq3gUv5Y
http://www.youtube.com/watch?v=FwZDIU6sM_4&
http://www.youtube.com/watch?v=SnlCx7mVcZ4
http://www.youtube.com/watch?v=LtZ75KW2t-U
http://www.youtube.com/watch?v=quH4x640Jgs
http://www.youtube.com/watch?v=rdIjMQATQks
http://www.youtube.com/watch?v=bc_fGWjmNeI
http://www.youtube.com/watch?v=pQaE0e0iD3s "œ
http://www.youtube.com/watch?v=pQaE0e0iD3s
And in case you need to review the previous videos again, here is the list of them in the recommend order from simple to more complex:
http://www.youtube.com/watch?v=qfMaBeLwiO4
http://www.youtube.com/watch?v=7d96F0ak4uY
http://www.youtube.com/watch?v=WTBlq3gUv5Y
http://www.youtube.com/watch?v=FwZDIU6sM_4&
http://www.youtube.com/watch?v=SnlCx7mVcZ4
http://www.youtube.com/watch?v=LtZ75KW2t-U
http://www.youtube.com/watch?v=quH4x640Jgs
http://www.youtube.com/watch?v=rdIjMQATQks
http://www.youtube.com/watch?v=bc_fGWjmNeI
http://www.youtube.com/watch?v=pQaE0e0iD3s "œ
"Primary Production:
(see attached graphic)"
"Hopefully the last few videos that we linked to helped make Primary Production more clear. So now let's get into it: What is Primary Production, and why should a reefer care? Well the 'why' is easy: If you put Primary Production to work properly in your reef tank, most of your feeding, and all of your filtering, will be taken care of for you automatically. This means very highly-fed corals, yet very low nutrients in your system. And with very little effort and equipment too. It also happens to be exactly how the oceans and lakes operate."
"What exactly is Primary Production? It is the most important biological process on Earth. It feeds all life on the planet, including you, and of course the oceans and the lakes. It also does all the filtering for the oceans and lakes. It is for this reason that we created the term "Primary Reduction" (introduced several articles ago), because it is through Primary Production that all the nutrients are removed from the water. This nutrient removal process keeps nitrate and phosphate at very low levels in the upper 100 meters of water (which is where the light penetrates), and thus it encompasses all reefs."
"It also might be interesting to know that Primary Production makes all the oxygen you breath, and removes the C02 out of both the air and the water. If Primary Production were to stop, in a short amount of time you would not be able to breathe, and even if you could, shortly thereafter you would starve. In the same manner, if Primary Production were to stop, all life in the oceans and lakes would stop too."
"From Wikipedia: 'Primary production is the production of organic compounds [food] from atmospheric or aquatic carbon dioxide, principally through the process of photosynthesis, with chemosynthesis being much less important. Almost all life on earth is directly or indirectly reliant on primary production. The organisms responsible for primary production are known as primary producers or "autotrophs", and they form the base of the food chain. In terrestrial eco-regions, these are mainly plants, while in aquatic eco-regions, algae are primarily responsible.' "
" 'Primary Production is the production of chemical energy in organic compounds [food] by living organisms. The main source of this energy is sunlight; [...] this energy is used to synthesize complex organic molecules from simpler inorganic compounds such as carbon dioxide (CO2) and water (H2O). The following [equation is a] simplified representation of photosynthesis:
CO2 + H2O + light --> CH2O + O2 ' "
" 'The end point is reduced carbohydrate (CH2O), typically molecules such as glucose or other sugars. These relatively simple molecules may be then used to further synthesize more complicated molecules, including proteins, complex carbohydrates, lipids, and nucleic acids [foods], or be respired to perform work. Consumption of primary producers by heterotrophic [food eating] organisms, such as animals, then transfers these organic molecules (and the energy stored within them) up the food web, fueling all of the Earth's living systems.' "
" 'Unlike terrestrial eco-systems, the majority of primary production in the ocean is performed by free-living microscopic organisms called phytoplankton [algae]. Larger autotrophs, such as the seagrasses and macroalgae (seaweeds) are generally confined to the [coastal and reef] zones and adjacent shallow waters, where they can attach to the underlying substrate but still be within the photic zone [where light can penetrate; thus they are important to reefs].' "
" 'The availability of light (the source of energy for photosynthesis), and mineral nutrients (the building blocks for new growth), play crucial roles in regulating primary production in the ocean." [And sure enough, the "mineral nutrients" in reef tanks are mostly nitrate and phosphate]' "
"And here is the Wikipedia quote that gives the golden reason why algae is so powerful: 'Another significant difference between the land and the oceans lies in their standing stocks [of photosynthetic organisms] -- while accounting for almost half of total production, oceanic autotrophs [algae] only account for about 0.2 percent of the total biomass. '"
"Yes, this is it. Compared to photosynthetic organisms on land -- trees, grass, etc. -- the photosynthetic organisms in water (algae) produce about the same amount of food on Earth. However, it takes 500 times more land biomass to do it. Why? Because of growth rates: On a cell-biomass scale, algae grows 500 times faster than trees, grass, etc. In fact, as compared to trees or grass which have growth rates of inches per year, the growth rate of algae is measured in doublings per day. And the faster the growth of the algae, the faster the nutrients are consumed from the water, and the faster that food is produced for corals."
[size=-2]link[/size]
(see attached graphic)"
"Hopefully the last few videos that we linked to helped make Primary Production more clear. So now let's get into it: What is Primary Production, and why should a reefer care? Well the 'why' is easy: If you put Primary Production to work properly in your reef tank, most of your feeding, and all of your filtering, will be taken care of for you automatically. This means very highly-fed corals, yet very low nutrients in your system. And with very little effort and equipment too. It also happens to be exactly how the oceans and lakes operate."
"What exactly is Primary Production? It is the most important biological process on Earth. It feeds all life on the planet, including you, and of course the oceans and the lakes. It also does all the filtering for the oceans and lakes. It is for this reason that we created the term "Primary Reduction" (introduced several articles ago), because it is through Primary Production that all the nutrients are removed from the water. This nutrient removal process keeps nitrate and phosphate at very low levels in the upper 100 meters of water (which is where the light penetrates), and thus it encompasses all reefs."
"It also might be interesting to know that Primary Production makes all the oxygen you breath, and removes the C02 out of both the air and the water. If Primary Production were to stop, in a short amount of time you would not be able to breathe, and even if you could, shortly thereafter you would starve. In the same manner, if Primary Production were to stop, all life in the oceans and lakes would stop too."
"From Wikipedia: 'Primary production is the production of organic compounds [food] from atmospheric or aquatic carbon dioxide, principally through the process of photosynthesis, with chemosynthesis being much less important. Almost all life on earth is directly or indirectly reliant on primary production. The organisms responsible for primary production are known as primary producers or "autotrophs", and they form the base of the food chain. In terrestrial eco-regions, these are mainly plants, while in aquatic eco-regions, algae are primarily responsible.' "
" 'Primary Production is the production of chemical energy in organic compounds [food] by living organisms. The main source of this energy is sunlight; [...] this energy is used to synthesize complex organic molecules from simpler inorganic compounds such as carbon dioxide (CO2) and water (H2O). The following [equation is a] simplified representation of photosynthesis:
CO2 + H2O + light --> CH2O + O2 ' "
" 'The end point is reduced carbohydrate (CH2O), typically molecules such as glucose or other sugars. These relatively simple molecules may be then used to further synthesize more complicated molecules, including proteins, complex carbohydrates, lipids, and nucleic acids [foods], or be respired to perform work. Consumption of primary producers by heterotrophic [food eating] organisms, such as animals, then transfers these organic molecules (and the energy stored within them) up the food web, fueling all of the Earth's living systems.' "
" 'Unlike terrestrial eco-systems, the majority of primary production in the ocean is performed by free-living microscopic organisms called phytoplankton [algae]. Larger autotrophs, such as the seagrasses and macroalgae (seaweeds) are generally confined to the [coastal and reef] zones and adjacent shallow waters, where they can attach to the underlying substrate but still be within the photic zone [where light can penetrate; thus they are important to reefs].' "
" 'The availability of light (the source of energy for photosynthesis), and mineral nutrients (the building blocks for new growth), play crucial roles in regulating primary production in the ocean." [And sure enough, the "mineral nutrients" in reef tanks are mostly nitrate and phosphate]' "
"And here is the Wikipedia quote that gives the golden reason why algae is so powerful: 'Another significant difference between the land and the oceans lies in their standing stocks [of photosynthetic organisms] -- while accounting for almost half of total production, oceanic autotrophs [algae] only account for about 0.2 percent of the total biomass. '"
"Yes, this is it. Compared to photosynthetic organisms on land -- trees, grass, etc. -- the photosynthetic organisms in water (algae) produce about the same amount of food on Earth. However, it takes 500 times more land biomass to do it. Why? Because of growth rates: On a cell-biomass scale, algae grows 500 times faster than trees, grass, etc. In fact, as compared to trees or grass which have growth rates of inches per year, the growth rate of algae is measured in doublings per day. And the faster the growth of the algae, the faster the nutrients are consumed from the water, and the faster that food is produced for corals."
[size=-2]link[/size]
Attachments
"Now on to the studies: First we'd like to paint a picture of what is doing the most Primary Production on coral reefs: Solid algae. This is as opposed to phytoplankton, which does all the Primary Production in the open oceans and deep lakes. The following study describes the solid [non-phytoplankton] algae that occupies a coral reef: How much there is, how is distributed around the corals, and what different types there are:"
"The Benthic Algal Composition, Standing Crop, and Productivity of a Caribbean Algal Ridge. Atoll Research Bulletin, 1977."
"The distribution and standing crop of benthic [sea-floor] algal species on a Caribbean algal ridge (St. Croix, Virgin Islands) and its associated carbonate pavements [coralline] is discussed and contrasted with that of other eastern Caribbean algal ridges, and a Pacific algal ridge. [Average] standing crops of 3 kg [6.6 pounds] per square meter (wet weight), and a species richness of about 40 species (for ten 0.25 square meter samples) were encountered on St. Croix. Non-calcified or fleshy algae are greatly reduced in standing crop with depth away from the high-wave energy ridge crests. This is correlated with the greater grazing abilities of fish and invertebrates under less turbulent conditions."
"Our study of fleshy benthic algae distribution was conducted on several of the algal ridges along the eastern shore of St. Croix. The collections were especially concentrated on the Boiler Bay algal ridge in the northeast."
"In our studies of the Boiler Bay algal ridge, and that of Doty at Waikiki, average wet standing crops up to 3.5 kg per square meter were found, with individual [sections] ranging up to 5 kg [11 pounds]. On several considerably larger algal ridges, and on pavements that we are now studying in Martinique, algal standing crops are nearly twice as high [10 kg wet algae weight [22 pounds] per square meter]. [...] While perhaps temperate standing crops of larger algae tend to be higher than those in the tropics, algal ridge and beachrock standing crops (those in turbulent zones) can be similar, and generally in the seas around the older parts of the higher volcanic eastern Caribbean islands, algal standing crops of reef structures are quite equivalent to or perhaps larger than the average for northern shores."
"On reefs of typical lower eastern Caribbean islands, only where the force of water movement across intertidal algal ridges prevents intense grazing by fish and echinoids, are general high levels of algal standing crop and [primary] productivity developed. However, in the more [high-nutrient] waters of the higher islands, and where wave action is greater, dense standing crops of larger fleshy algae can also extend [below low tide] to depths of at least 10 meters."
"The windward reef margins of large numbers of Pacific atolls, and some high islands, are rimmed by an algal ridge, a partly intertidal and supratidal calcareous reef framework built primarily by crustose coralline red algae. Less well known are the scattered but locally abundant occurrences of algal ridges in the Caribbean and tropical Atlantic. [...] In this paper, we describe the fleshy algal flora of the St. Croix algal ridges, and its richness and ecology in terms of standing crop."
"Few studies have been done on the standing crops of benthic [sea-floor] marine algae on algal ridges or coralline-rich reef areas (coralline pavements). [A previous researcher] describes the difficulty of collecting on the Bikini ridge (Marshall Islands). He gives an account of removing algae from a particularly thick zone (a few millimeters to a centimeter in thickness) on the ridge. [Another researcher] describes an algal turf association on the fringing reef flat of American Samoa. His algal associations of low standing crop and high diversity, decrease in coverage across the reef flat, to the seaward side where first crustose algae, and then further seaward, living corals, predominate. [Another researcher] indicates that standing crop and algal diversity are greatest in the reef flat surf zone, where water movement is greatest (250 grams per square meter dry weight), and decrease in all directions from there."
"[Another researcher's] studies on the standing crop on an algal ridge and associated coralline pavements off Waikiki Beach, Hawaii, are among the few [in 1977] detailed quantitative studies treating the attached flora of a coralline reef. Using [that researcher's] data for November 1967 as being about average for the entire period covered, the mean standing crop reaches a maximum of about 3.4 kg [7.5 pounds] per square meter wet-weight on the algal ridge, and a minimum of about 1.3 kg in the deeper zone immediately behind the ridge (approximately 1 meter deep)."
"The Boiler Bay algal ridge, in an intermediate stage of development, consists of a series of 30 to 35, more or less horseshoe-shaped coralline frameworks ranging in diameter from about 50 meters to as little as 2 to 3 meters. For convenience of reference, the larger of these "boilers", "micro-atolls" or algal ridge "lobes" are named as reefs. The Boiler Bay algal ridge, essentially in its present plan, was actively growing from about 2000 to 500 years before present."
"Distinctive zones of crustose coralline algae, coral and coralline-coral pavement are visible on and around the ridges, and were delineated by color patterns on aerial photographs. Color patterns on the ridges and the surrounding pavements are often due to the fleshy algae populations peculiar to each zone, which in turn are largely dependent on depth, wave action, and the grazing of animals. Eight distinct algal zones were determined and are described below. Zones 1 to 4 lie on the coralline-constructed algal ridge; the remaining zones lie on the associated carbonate pavements, or other rock as described. The zone locations in Boiler Bay are indicated in figures 3 [attached]."
"Zone 1 is the horizontal strip of algal ridge which lies above mean-low-water spring tide levels. Between wave crests, it is potentially exposed to [drying] and intense sunlight, though the wave wash is rather constant, and severe drying did not occur during our two year stay in St. Croix. Zone 1 is characterized by a turf of Rhodophyta species up to 10 cm thick, dominated by Hypnea spp., Laurencia spp., Jania spp., Amphiroa spp. and Gracilaria mammillaris. Smaller amounts of other reds, as well as scattered clumps of Sargassum spp., Colpomenia sinuosa and other Phaeophyta with occasional small Chlorophyta species are also present."
"Zone 2 is chiefly populated by Halimeda opuntia, Laurencia papillosa and Gelidiella acerosa, though Pterocladia americana and Jania spp. are also important."
"Zone 3: Below zone 2, the algal ridge continues to slope shoreward, tending to form open-backed basins behind each boiler or lobe, with depths of about 30 to 60 cm. These basins are designated as zone 3. Here, Porites astreoides occupies about 15 percent of the surface area, and there are also scattered sand pockets in the coralline substrate. The flora here is similar to the second zone, but Laurencia papillosa and Halimeda opuntia are reduced, and the total biomass of fleshy algae is one third less than in Zone 2."
"Zone 4: The vertical seaward faces of the algal ridge at about 1 to 1.5 meters depth were designated Zone 4. This is a relatively smooth coralline surface with a light cover of fleshy algae of many small species, the most obvious being Dictyopteris delicatula."
"Zone 5 occurs on the nearly flat and irregular seaward margin of the fore-ridge carbonate pavement at depths of 3.5 to 4.5 meters. The substrate in this zone is a largely a coralline-algal pavement of dead corals cemented together by crustose corallines, foraminifera, and probably submarine cementation of sediment. A few live corals, Porites astreoides, Porites porites, and Siderastrea spp., are also present. The dominant algae are Halimeda opuntia, Dictyota divaricata, Amphiroa tribulus, and Halimeda tuna."
"Zone 6 is also predominantly a cor-algal pavement, but about 11 percent of the surface is covered by the same living corals that characterize zone 5, Porites astreoides being especially important. This zone occurs around the sides and shoreward margins of the ridge lobes at depths of 0.5 to 1.5 meters. The most abundant algae here are Halimeda opuntia, Dictyopteris delicatula, Dictyota divaricata, Dictyota dentata, Sargassum vulgare, and Jania spp., but numerous other species also occur in small amounts."
"Zone 7 lies in the shallow water (0.5 to 1.0 meters) near shore landward of the algal ridge, where a band of carbonate and terrigenous cobbles and pebbles occurs along much of the shore of Boiler Bay. Some corallines and corals also occur here, but in rather small amounts. In this band, the dominant algal species are Jania adherens, Padina sanctae-crucis, Sargassum vulgare, Halimeda opuntia and Cladophoropsis membranacea."
"Zone 8 occurs on the beachrock which runs parallel to the shore in the western and eastern sections of Boiler Bay. This zone is frequently well above mean-low-water, and since it is partly protected from wave action by the algal ridge, it is somewhat more subject to [drying] and temperature and salinity extremes. However, our [sections] were taken below mean-low-water springs at depths of about 0 to 0.5 meters. Much of zone 8 is characterized by a turf of Hypnea musciformis, Laurencia papillosa and other Rhodophyta. However, at the east end of Boiler Bay, the Chlorophyta dominate this zone, particularly Halimeda incrassata, Halimeda opuntia and Dictyosphaeria cavernosa. At the west end of the bay, the beachrock is covered predominantly with Sargassum vulgare, with considerable amounts of Sargassum platycarpum, Dictyotadentata and Chaetomorpha linum."
"In each of the above zones, [sections] were subjectively chosen from several algal ridge lobes, and their associated pavements, as being typical in algal cover for that particular zone. Macroscopic benthic algae were removed, as well as chunks of substrate from within a 0.25 square meter area. The substrate was carefully examined for the smaller species, and all algae collected was sorted, identified, and weighed for wet biomass."
"The importance of [fish] grazing in the shallow tropical marine environment has attracted considerable interest in recent years [1975]. [A previous researcher] contrasted the luxuriant intertidal algal crop in Hawaii with the low stubble of the upper [low tide] and attributed it to fish grazing (Acanthuridae, Scaridae and Pomacentridae). [...] It is difficult to escape the logic of this conclusion - an algal ridge or shallow pavement is a special, turbulent water environment which is usually inaccessible to grazing fish and [urchins]. A few invertebrates (mostly crabs, snails, limpets and chitons) do graze in this zone, although their effectiveness is apparently limited. [Urchins] are often abundant on algal ridges and beachrock, however the wave energy is apparently generally sufficient to largely confine these echinoids to their holes, and to feeding on drift."
"Our research group has spent a considerable amount of time in the daytime snorkeling around the algal ridges in Boiler Bay. Our collective casual observations on the intensity of fish grazing are as follows: Zones 1 and 2 on the ridge, and zone 8 on the beachrock, and perhaps to a lesser extent zone 7 near shore, are rarely grazed by larger fish. These zones are either exposed in wave troughs, or are continuously washed by waves. Zone 3, the algal ridge bowl, is periodically grazed, sometimes heavily depending on sea conditions. Zones 4 and 6 on the other hand, are heavily and consistently grazed. Not only are these zones easily reached by grazing fish, but [hiding places] for the fish are abundant in the form of holes in the pavements and coral structures, especially Acropora palmata. Zone 5, the deep pavement, is the zone over which we have greatest disagreement concerning fish grazing pressure. Generally, we do agree that it is less than the pavement zone 6 because of lack of cover [hiding] for the fish. Periodically, however, it is probably massively grazed, especially by schools of tangs and parrot fish. [...] Generally there is indicated a strong inverse relationship between the ability of fish to graze effectively, and the standing crop of fleshy and filamentous algae."
"The intertidal wave-washed crustose coralline algal ridges of St. Croix, Virgin Islands develop a dense standing crop of fleshy algae and have a gross [primary] productivity which is high for the tropical reef environment. In caged areas, and areas with considerably greater wave action (especially in the presumably [high nutrient] waters around the higher volcanic islands such as Martinique), the standing crop is often denser and also extends to greater depths. In St. Croix, where wave energy is moderate, the heavy coverage of fleshy algae is greatly reduced with depth away from the ridge crests. Thus, lack of intense grazing pressure (under turbulent water situations) is probably responsible for the rich algal area on the ridges."
"The Benthic Algal Composition, Standing Crop, and Productivity of a Caribbean Algal Ridge. Atoll Research Bulletin, 1977."
"The distribution and standing crop of benthic [sea-floor] algal species on a Caribbean algal ridge (St. Croix, Virgin Islands) and its associated carbonate pavements [coralline] is discussed and contrasted with that of other eastern Caribbean algal ridges, and a Pacific algal ridge. [Average] standing crops of 3 kg [6.6 pounds] per square meter (wet weight), and a species richness of about 40 species (for ten 0.25 square meter samples) were encountered on St. Croix. Non-calcified or fleshy algae are greatly reduced in standing crop with depth away from the high-wave energy ridge crests. This is correlated with the greater grazing abilities of fish and invertebrates under less turbulent conditions."
"Our study of fleshy benthic algae distribution was conducted on several of the algal ridges along the eastern shore of St. Croix. The collections were especially concentrated on the Boiler Bay algal ridge in the northeast."
"In our studies of the Boiler Bay algal ridge, and that of Doty at Waikiki, average wet standing crops up to 3.5 kg per square meter were found, with individual [sections] ranging up to 5 kg [11 pounds]. On several considerably larger algal ridges, and on pavements that we are now studying in Martinique, algal standing crops are nearly twice as high [10 kg wet algae weight [22 pounds] per square meter]. [...] While perhaps temperate standing crops of larger algae tend to be higher than those in the tropics, algal ridge and beachrock standing crops (those in turbulent zones) can be similar, and generally in the seas around the older parts of the higher volcanic eastern Caribbean islands, algal standing crops of reef structures are quite equivalent to or perhaps larger than the average for northern shores."
"On reefs of typical lower eastern Caribbean islands, only where the force of water movement across intertidal algal ridges prevents intense grazing by fish and echinoids, are general high levels of algal standing crop and [primary] productivity developed. However, in the more [high-nutrient] waters of the higher islands, and where wave action is greater, dense standing crops of larger fleshy algae can also extend [below low tide] to depths of at least 10 meters."
"The windward reef margins of large numbers of Pacific atolls, and some high islands, are rimmed by an algal ridge, a partly intertidal and supratidal calcareous reef framework built primarily by crustose coralline red algae. Less well known are the scattered but locally abundant occurrences of algal ridges in the Caribbean and tropical Atlantic. [...] In this paper, we describe the fleshy algal flora of the St. Croix algal ridges, and its richness and ecology in terms of standing crop."
"Few studies have been done on the standing crops of benthic [sea-floor] marine algae on algal ridges or coralline-rich reef areas (coralline pavements). [A previous researcher] describes the difficulty of collecting on the Bikini ridge (Marshall Islands). He gives an account of removing algae from a particularly thick zone (a few millimeters to a centimeter in thickness) on the ridge. [Another researcher] describes an algal turf association on the fringing reef flat of American Samoa. His algal associations of low standing crop and high diversity, decrease in coverage across the reef flat, to the seaward side where first crustose algae, and then further seaward, living corals, predominate. [Another researcher] indicates that standing crop and algal diversity are greatest in the reef flat surf zone, where water movement is greatest (250 grams per square meter dry weight), and decrease in all directions from there."
"[Another researcher's] studies on the standing crop on an algal ridge and associated coralline pavements off Waikiki Beach, Hawaii, are among the few [in 1977] detailed quantitative studies treating the attached flora of a coralline reef. Using [that researcher's] data for November 1967 as being about average for the entire period covered, the mean standing crop reaches a maximum of about 3.4 kg [7.5 pounds] per square meter wet-weight on the algal ridge, and a minimum of about 1.3 kg in the deeper zone immediately behind the ridge (approximately 1 meter deep)."
"The Boiler Bay algal ridge, in an intermediate stage of development, consists of a series of 30 to 35, more or less horseshoe-shaped coralline frameworks ranging in diameter from about 50 meters to as little as 2 to 3 meters. For convenience of reference, the larger of these "boilers", "micro-atolls" or algal ridge "lobes" are named as reefs. The Boiler Bay algal ridge, essentially in its present plan, was actively growing from about 2000 to 500 years before present."
"Distinctive zones of crustose coralline algae, coral and coralline-coral pavement are visible on and around the ridges, and were delineated by color patterns on aerial photographs. Color patterns on the ridges and the surrounding pavements are often due to the fleshy algae populations peculiar to each zone, which in turn are largely dependent on depth, wave action, and the grazing of animals. Eight distinct algal zones were determined and are described below. Zones 1 to 4 lie on the coralline-constructed algal ridge; the remaining zones lie on the associated carbonate pavements, or other rock as described. The zone locations in Boiler Bay are indicated in figures 3 [attached]."
"Zone 1 is the horizontal strip of algal ridge which lies above mean-low-water spring tide levels. Between wave crests, it is potentially exposed to [drying] and intense sunlight, though the wave wash is rather constant, and severe drying did not occur during our two year stay in St. Croix. Zone 1 is characterized by a turf of Rhodophyta species up to 10 cm thick, dominated by Hypnea spp., Laurencia spp., Jania spp., Amphiroa spp. and Gracilaria mammillaris. Smaller amounts of other reds, as well as scattered clumps of Sargassum spp., Colpomenia sinuosa and other Phaeophyta with occasional small Chlorophyta species are also present."
"Zone 2 is chiefly populated by Halimeda opuntia, Laurencia papillosa and Gelidiella acerosa, though Pterocladia americana and Jania spp. are also important."
"Zone 3: Below zone 2, the algal ridge continues to slope shoreward, tending to form open-backed basins behind each boiler or lobe, with depths of about 30 to 60 cm. These basins are designated as zone 3. Here, Porites astreoides occupies about 15 percent of the surface area, and there are also scattered sand pockets in the coralline substrate. The flora here is similar to the second zone, but Laurencia papillosa and Halimeda opuntia are reduced, and the total biomass of fleshy algae is one third less than in Zone 2."
"Zone 4: The vertical seaward faces of the algal ridge at about 1 to 1.5 meters depth were designated Zone 4. This is a relatively smooth coralline surface with a light cover of fleshy algae of many small species, the most obvious being Dictyopteris delicatula."
"Zone 5 occurs on the nearly flat and irregular seaward margin of the fore-ridge carbonate pavement at depths of 3.5 to 4.5 meters. The substrate in this zone is a largely a coralline-algal pavement of dead corals cemented together by crustose corallines, foraminifera, and probably submarine cementation of sediment. A few live corals, Porites astreoides, Porites porites, and Siderastrea spp., are also present. The dominant algae are Halimeda opuntia, Dictyota divaricata, Amphiroa tribulus, and Halimeda tuna."
"Zone 6 is also predominantly a cor-algal pavement, but about 11 percent of the surface is covered by the same living corals that characterize zone 5, Porites astreoides being especially important. This zone occurs around the sides and shoreward margins of the ridge lobes at depths of 0.5 to 1.5 meters. The most abundant algae here are Halimeda opuntia, Dictyopteris delicatula, Dictyota divaricata, Dictyota dentata, Sargassum vulgare, and Jania spp., but numerous other species also occur in small amounts."
"Zone 7 lies in the shallow water (0.5 to 1.0 meters) near shore landward of the algal ridge, where a band of carbonate and terrigenous cobbles and pebbles occurs along much of the shore of Boiler Bay. Some corallines and corals also occur here, but in rather small amounts. In this band, the dominant algal species are Jania adherens, Padina sanctae-crucis, Sargassum vulgare, Halimeda opuntia and Cladophoropsis membranacea."
"Zone 8 occurs on the beachrock which runs parallel to the shore in the western and eastern sections of Boiler Bay. This zone is frequently well above mean-low-water, and since it is partly protected from wave action by the algal ridge, it is somewhat more subject to [drying] and temperature and salinity extremes. However, our [sections] were taken below mean-low-water springs at depths of about 0 to 0.5 meters. Much of zone 8 is characterized by a turf of Hypnea musciformis, Laurencia papillosa and other Rhodophyta. However, at the east end of Boiler Bay, the Chlorophyta dominate this zone, particularly Halimeda incrassata, Halimeda opuntia and Dictyosphaeria cavernosa. At the west end of the bay, the beachrock is covered predominantly with Sargassum vulgare, with considerable amounts of Sargassum platycarpum, Dictyotadentata and Chaetomorpha linum."
"In each of the above zones, [sections] were subjectively chosen from several algal ridge lobes, and their associated pavements, as being typical in algal cover for that particular zone. Macroscopic benthic algae were removed, as well as chunks of substrate from within a 0.25 square meter area. The substrate was carefully examined for the smaller species, and all algae collected was sorted, identified, and weighed for wet biomass."
"The importance of [fish] grazing in the shallow tropical marine environment has attracted considerable interest in recent years [1975]. [A previous researcher] contrasted the luxuriant intertidal algal crop in Hawaii with the low stubble of the upper [low tide] and attributed it to fish grazing (Acanthuridae, Scaridae and Pomacentridae). [...] It is difficult to escape the logic of this conclusion - an algal ridge or shallow pavement is a special, turbulent water environment which is usually inaccessible to grazing fish and [urchins]. A few invertebrates (mostly crabs, snails, limpets and chitons) do graze in this zone, although their effectiveness is apparently limited. [Urchins] are often abundant on algal ridges and beachrock, however the wave energy is apparently generally sufficient to largely confine these echinoids to their holes, and to feeding on drift."
"Our research group has spent a considerable amount of time in the daytime snorkeling around the algal ridges in Boiler Bay. Our collective casual observations on the intensity of fish grazing are as follows: Zones 1 and 2 on the ridge, and zone 8 on the beachrock, and perhaps to a lesser extent zone 7 near shore, are rarely grazed by larger fish. These zones are either exposed in wave troughs, or are continuously washed by waves. Zone 3, the algal ridge bowl, is periodically grazed, sometimes heavily depending on sea conditions. Zones 4 and 6 on the other hand, are heavily and consistently grazed. Not only are these zones easily reached by grazing fish, but [hiding places] for the fish are abundant in the form of holes in the pavements and coral structures, especially Acropora palmata. Zone 5, the deep pavement, is the zone over which we have greatest disagreement concerning fish grazing pressure. Generally, we do agree that it is less than the pavement zone 6 because of lack of cover [hiding] for the fish. Periodically, however, it is probably massively grazed, especially by schools of tangs and parrot fish. [...] Generally there is indicated a strong inverse relationship between the ability of fish to graze effectively, and the standing crop of fleshy and filamentous algae."
"The intertidal wave-washed crustose coralline algal ridges of St. Croix, Virgin Islands develop a dense standing crop of fleshy algae and have a gross [primary] productivity which is high for the tropical reef environment. In caged areas, and areas with considerably greater wave action (especially in the presumably [high nutrient] waters around the higher volcanic islands such as Martinique), the standing crop is often denser and also extends to greater depths. In St. Croix, where wave energy is moderate, the heavy coverage of fleshy algae is greatly reduced with depth away from the ridge crests. Thus, lack of intense grazing pressure (under turbulent water situations) is probably responsible for the rich algal area on the ridges."
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"When studying the feeding of corals, you need to know how much food you are dealing with. In the field of aquatic biology, food (and sealife in general) is quantified by how much Carbon is in it. This might be a new idea to reefers who have only heard about GAC (Granular Activated Carbon), but in aquatic biology the term "Carbon" always refers to food or life. Some reefers, however, may be familiar with Carbon Dosing, as in vodka or pellets; this is indeed much closer to the concept that we need to understand."
"Researchers who study aquatic Primary Production basically try to figure out how much energy from the sun is converted to food, and who/what (in the oceans and lakes) consumes it. Researchers do this by figuring out how much Carbon is 'fixed' by the photosynthetic process: How much CO2 is taken out of the atmosphere and put into the water, how much 'O2' is removed by chlorophyll, how much 'H20' is added, and how much 'CH2O' is made in the end."
"What is CH20? Food! Yes, by just releasing the oxygen from the CO2, and then adding water, you make food. In particular, you make a monosaccharide, which is a simple sugar. Amazing: CO2 plus water makes sugar! Well, using photosynthesis it does."
"So how do researchers measure this food-making? They measure the amount of Carbon that goes into it. If there is enough Carbon, it will eventually add up to be one gram. So researchers measure how many grams of Carbon are converted from CO2 to sugar in the photosynthetic process. Generally they do this over a given area (such as a square meter), and over a given time (such as a day or year). So a typical study might end up finding that a particular reef or lake produces 365 grams of Carbon per year, per square meter. This of course would be 1 gram of Carbon per day."
"Well for you, a reefer interested in feeding corals, you are only interested in information that helps your corals grow. So what is needed is a way to convert "grams of Carbon" into "grams of food". We thought that the most common form of food that would be familiar to reefers would be frozen food cubes, and in particular, the frozen zooplankton cubes, since they are good food for corals. These cubes are obviously 'wet' since they are frozen, and so we'll use their wet-weight as a reference: Most cubes weigh 3 grams each."
"Now, most studies of primary production give their results in terms of how much algae is produced (since algae produces the food for the rest of the aquatic world). However few reefers feed algae, so what we really need to know is how many 'grams of Carbon' of algae equals how many 'cubes of frozen zooplankton'. In other words, if primary production has produced a certain amount of algae, then how many cubes of frozen zooplankton would be equivalent to it, in terms of grams of Carbon. This is done by using conversion factors from previous studies:"
" 'Seasonal and Inshore-Offshore Variations in the Standing Stocks of Micro Necton and Macro Zooplankton of Oregon', table 4 on PDF page 8, says that grams of Carbon = .065 X zooplankton wet weight.
http://fishbull.noaa.gov/74-1/pearcy.pdf "
" 'Simulated and Observed Response of the Southwest Vancouver Island Pelagic Ecosystem to Oceanic Conditions in the 1990s', first paragraph on PDF page 3, says that grams of Carbon = .067 X zooplankton wet weight.
http://www.nrcresearchpress.com/doi/pdf/10.1139/f99-170 "
" 'Energy Contents and Conversion Factors for Sea Lion's Prey', table 11 on PDF page 3, says that grams of Carbon = .12 X zooplankton wet weight.
http://www2.fisheries.com/publications/reports/fcrr_13(1)/Chap7energycontent.pdf "
"And lastly, 'World Ocean Atlas 2001, Vol 5: Plankton', table 2 on PDF page 12, says that grams of Carbon = .12 X zooplankton wet weight.
ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/PUBLICATIONS/woa01v5d.pdf "
"We'll use .10 as an average of the above four numbers, and just say that about 10 percent of the wet weight of zooplankton is Carbon. So in the studies that are to follow, if 1 gram of Carbon is produced, this would be equivalent to 10 grams of wet zooplankton, which would be a little over 3 frozen cubes."
"Researchers who study aquatic Primary Production basically try to figure out how much energy from the sun is converted to food, and who/what (in the oceans and lakes) consumes it. Researchers do this by figuring out how much Carbon is 'fixed' by the photosynthetic process: How much CO2 is taken out of the atmosphere and put into the water, how much 'O2' is removed by chlorophyll, how much 'H20' is added, and how much 'CH2O' is made in the end."
"What is CH20? Food! Yes, by just releasing the oxygen from the CO2, and then adding water, you make food. In particular, you make a monosaccharide, which is a simple sugar. Amazing: CO2 plus water makes sugar! Well, using photosynthesis it does."
"So how do researchers measure this food-making? They measure the amount of Carbon that goes into it. If there is enough Carbon, it will eventually add up to be one gram. So researchers measure how many grams of Carbon are converted from CO2 to sugar in the photosynthetic process. Generally they do this over a given area (such as a square meter), and over a given time (such as a day or year). So a typical study might end up finding that a particular reef or lake produces 365 grams of Carbon per year, per square meter. This of course would be 1 gram of Carbon per day."
"Well for you, a reefer interested in feeding corals, you are only interested in information that helps your corals grow. So what is needed is a way to convert "grams of Carbon" into "grams of food". We thought that the most common form of food that would be familiar to reefers would be frozen food cubes, and in particular, the frozen zooplankton cubes, since they are good food for corals. These cubes are obviously 'wet' since they are frozen, and so we'll use their wet-weight as a reference: Most cubes weigh 3 grams each."
"Now, most studies of primary production give their results in terms of how much algae is produced (since algae produces the food for the rest of the aquatic world). However few reefers feed algae, so what we really need to know is how many 'grams of Carbon' of algae equals how many 'cubes of frozen zooplankton'. In other words, if primary production has produced a certain amount of algae, then how many cubes of frozen zooplankton would be equivalent to it, in terms of grams of Carbon. This is done by using conversion factors from previous studies:"
" 'Seasonal and Inshore-Offshore Variations in the Standing Stocks of Micro Necton and Macro Zooplankton of Oregon', table 4 on PDF page 8, says that grams of Carbon = .065 X zooplankton wet weight.
http://fishbull.noaa.gov/74-1/pearcy.pdf "
" 'Simulated and Observed Response of the Southwest Vancouver Island Pelagic Ecosystem to Oceanic Conditions in the 1990s', first paragraph on PDF page 3, says that grams of Carbon = .067 X zooplankton wet weight.
http://www.nrcresearchpress.com/doi/pdf/10.1139/f99-170 "
" 'Energy Contents and Conversion Factors for Sea Lion's Prey', table 11 on PDF page 3, says that grams of Carbon = .12 X zooplankton wet weight.
http://www2.fisheries.com/publications/reports/fcrr_13(1)/Chap7energycontent.pdf "
"And lastly, 'World Ocean Atlas 2001, Vol 5: Plankton', table 2 on PDF page 12, says that grams of Carbon = .12 X zooplankton wet weight.
ftp://ftp.nodc.noaa.gov/pub/data.nodc/woa/PUBLICATIONS/woa01v5d.pdf "
"We'll use .10 as an average of the above four numbers, and just say that about 10 percent of the wet weight of zooplankton is Carbon. So in the studies that are to follow, if 1 gram of Carbon is produced, this would be equivalent to 10 grams of wet zooplankton, which would be a little over 3 frozen cubes."
"Notes for this study:
Epilithic = Algae that is attached to rocks; also known at 'benthic'.
Productivity = Primary Production of food = Primary 'Reduction' of nutrients.
Carbon = Biomass that is alive; is not GAC.
Turnover = How fast algae is eaten by grazers, which is followed by new algal growth.
The reef zones used in this study are different from the zones in the previous study. "
"Community structure, biomass and productivity of epilithic algal communities on the Great Barrier Reef: Dynamics at Different Spatial Scales. Marine Ecology Progress Series, Sept 1992."
"This study provides the first quantification of variation in the structure, biomass and productivity of the Epilithic Algal Community on a number of reefs over a wide area of the Great Barrier Reef. In addition, it describes within-reef and seasonal variability of these parameters."
"The Epilithic Algal Community (EAC) of coral reefs is a diverse assemblage of crustose coralline and [fleshy] turf algae growing upon coral rock. In this case, the term 'turf' refers to the multi-specific and inconspicuous association of unicellular, and short (usually less than 1 cm high), simple filamentous algae [...]."
"The main goal of this study was to examine the natural (in situ) variations in community structure, biomass, photosynthesis-irradiance relationship, and primary productivity of the Epilithic Algal Communities on the Great Barrier Reef (GBR). Comparisons are made between seasons, successive years, and different habitats and reefs situated across and along the continental shelf. This is an extension of a study which focused on the differences between habitats and seasons within a single reef (Davies Reef, central GBR). Data on primary production of the EAC are compared with the [roughness] and nature of the reef substratum to estimate the contribution made by the EAC to whole reef productivity."
"This study was carried out along 2 major [areas] designed to give a wide geographical coverage of the Great Barrier Reef. The first of these was a central GBR cross-shelf [area] comprising a reef on the inner- (Pandora), mid- (Davies) and outer-shelf (Myrmidon). General environmental and structural features of these reefs are described elsewhere. The second [area] comprised a pair of reefs on the mid- and outer-shelf at 3 latitudes; McGillivray and Yonge, Davies and Myrmidon, and Heron and One Tree Islands."
"Epilithic Algal Communities covered a high proportion of the reef flats (50 to 80 percent) and reef slopes (30 to 70 percent) on the coral reefs of the north, central and southern regions of the Great Barrier Reef (GBR). Crustose coralline algae and turf algae (fine and damselfish territory types) dominated the Epilithic Algal Communities in reef flat habitats, except in the near-shore region where turf algae predominated. Turfs also dominated the EAC on reef slopes. Patches of crustose coralline algae had a higher biomass [because of the calcium], but a lower photosynthetic rate per unit biomass [thus less nutrient reduction] than the equivalent area of fine turf algae. The net result was that these two main forms of epilithic algae had comparable rates of [per unit area] productivity. The [primary] productivity of turf-dominated communities was inversely correlated with algal biomass. [A previous researcher] also noted this effect in his examination of epilithic algae on a Caribbean reef, and suggested that it is probably related to self-shading."
"For a number of reasons, the Epilithic Algal Community is thought to play an extremely important role in the [feeding] dynamics of coral reefs. Firstly, a large proportion of the net primary production within specific habitats of coral reefs is provided by the EAC. This is most clearly evident in the shallow habitats, where it has been relatively easy to measure the metabolic rates of benthic [sea floor] reef communities. However, relatively little is known about the productivity of benthic plant communities on reef slopes and in deep lagoons. Epilithic [attached to rocks] algae are intensively grazed [by fish], and in the process are maintained in a state of low biomass, but rapid turnover. In the few cases where whole reef systems have been examined, the biomass of the Epilithic Algal Community is found to be considerable due to its extensive coverage of reef surfaces (up to 80 percent in some habitats), and the high [roughness] of the reef substratum. Hence, the EAC almost certainly makes a substantial contribution to the [per unit area] productivity of most reefs. Moreover, a high proportion of the carbon [food] produced by the coral reef EAC is thought to be directly available to the reef food web via herbivorous grazers. Indeed, recent studies [in 1992] of reef flats have demonstrated that grazers consume around half of the annual net production of the EAC, with the balance presumably channeled into detrital pathways in the form of [DOC] exudates and particulate matter [which are food for corals]."
"Epilithic Algal Communities from various reef habitats at the same depth had equal [per unit area] and biomass-specific productivity, regardless of their location on [areas] extending both across and also along the Great Barrier Reef. EAC productivity changed in a predictable manner with season (maximum in summer, minimum in winter) and depth (decreasing with depth). [...] The EAC at 10 meters on reef slopes had approximately half the [per unit area] productivity of the community on the adjacent reef flat, but the EAC from these habitats had a similar biomass-specific productivity. Productivity of the EAC per unit area of reef, which takes into account the [roughness] and coverage of reefs by the EAC in particular habitats, varied between reefs, and ranged from 150 grams carbon (per square meter, per year) on the reef flat of the near-shore reef and on all reef slopes, to 500 grams carbon (per square meter, per year) on some mid- and outer-shelf reef flats. There was no apparent latitudinal pattern of change in EAC productivity per unit area of reef. Thus, availability of the EAC, the major food resource of grazers on coral reefs, appears to correlate well with known large-scale variations in grazing activity."
"Experimental plates (8 X 8 X 2 cm) cut from the coral Porites spp. were bolted directly to the reef substratum in a haphazard manner within different reef zones. [...] Plates were left in the field for 6 to 12 months to establish a 'natural' Epilithic Algal Community."
"The type and irregularity of the reef surface, at the sites where algal production was measured, were surveyed at Pandora, Myrmidon, Heron and One Tree Reefs in October 1989, and at MacGillivray and Yonge Reefs in December 1989. Reef surface type, expressed as proportional coverage by sand, and 7 functional groups of biota: fine turf, damselfish-territory turf, crustose coralline algae, encrusting brown algae, macroalgae (e.g. Halimeda spp.), hard corals and other fauna (e.g. soft corals, sponges), was quantified using line transects."
"The percent cover of coral plates by the 4 major functional components of the Epilithic Algal Community (fine turfs, damselfish territory turf, crustose coralline algae, and encrusting brown algae), averaged over all seasons, was similar for the 2 reef-flat zones on Davies and Myrmidon Reefs. Both turfs and coralline algae were important in these habitats, but coralline algae were more abundant on reef crests. Fine turf dominated (57 to 67 percent cover) and coralline algae were much less abundant (20 percent cover) in the reef-slope algal community. The reef flat on Pandora on the inner-shelf differed markedly from similar habitats on the mid- and outer-shelf reefs, in that coralline algae were rare, and 87 percent of algae was damselfish territory turf. Epilithic Algal Community structure did not vary significantly with season."
"The maximum net photosynthetic rate [maximum reduction of nutrients] of the Epilithic Algal Communities, in both [per unit area] and biomass-specific terms, varied seasonally, with the maxima in summer and the minima in winter [less light] in all zones, on all reefs."
"[Primary] production of the EAC based both on area and biomass varied strongly with season for all zones and reefs of the cross-shelf and latitudinal [areas]. Productivity was highest in summer and lowest in winter."
"Thus, annual production of the EAC (without taking EAC coverage, or irregularity of the reef surface, into account) is 400 grams carbon (per square meter, per year) on reef flats [equivalent to 3.7 cubes of frozen zooplankton per square meter, per day], and 220 on reef slopes."
"The EAC (turfs plus coralline algae) covered a high proportion of the surface on all mid- and outer-shelf reefs examined. [...] In general, hard corals were the other major occupant of space on these reefs (11 to 44 percent on flats; 14 to 35 percent on slopes). Although there were some significant differences between reefs in terms of the cover of particular types of EAC, these did not suggest any latitudinal trends, nor any consistent differences between mid- and outer-shelf reefs. The one inner-shelf reef examined in this study (Pandora Reef) was distinctive in being dominated by zooanthids (61 percent), along with its comparatively low EAC coverage. Moreover, damselfish-territory turf dominated the EAC (75 percent) on the natural surfaces of Pandora Reef, as was observed with [the experimental] coral plates from this reef, whereas in comparable habitats on mid- and outer-shelf reefs, fine turfs and coralline algae were equally important components of the EAC. Reef flats had consistently higher cover of EAC (range: 51 to 81 percent) than the adjacent reef slopes (range: 33 to 73 percent), which had extensive areas of sand. In addition, coralline algae were important on reef flats, and filamentous algae dominated the reef slopes."
"The EAC covers a high proportion of reef flats (up to 80 percent) and reef slopes (up to 50 percent) throughout the GBR. However, the extent of this cover, as well as the community structure of the EAC, varies with location, such that cover of substrata by algae is greatest on reef flats in the mid- and outer-shelf region, where the community is usually dominated by a mixture of well grazed turfs and crustose coralline algae."
"Large fleshy algae (e.g. Sargassum spp.), which are usually relatively rare in all habitats on the mid- and outer-shelf reefs, dominate in some seasons and habitats on inner-shelf reefs. Although large fleshy algae were not common in the study site at Pandora Reef, the adjacent windward edge of this reef has an extensive Sargassum community. The transition from an algal community, comprising mainly coralline and low turfs on reefs of the mid- and outer-shelf, to one characterized by lush turfs and large fleshy algae, correlates with a significant decrease in grazing intensity."
"[Maximum per unit area] productivity occurs in summer in shallow habitats [i.e., the same habitat as a reef tank], and minimum productivity occurs in winter on the reef slope."
"Patches of crustose coralline algae have a higher biomass [because of the calcium], but a lower photosynthetic rate [and nutrient reduction] per unit biomass, than the equivalent area of fine [fleshy] turf algae. The net result is that these two algal forms have comparable rates of [per unit area] productivity. Thus, variation in the relative proportions of coralline and turf algae comprising the EAC is predicted to have an effect upon the biomass and the biomass-specific productivity of the EAC. However, this is complicated by the relative abundance of damselfish territory turf, the third major algal group of the EAC, which is the most productive form of epilithic algae on reefs. Indeed, a comparison of the mid-reef flat with the reef-crest habitat of Davies and Myrmidon Reefs, between which there are considerable differences in the relative proportions of crustose coralline algae and fine turf algae, shows a predicted, though not always significant, difference in biomass and biomass-specific productivity. The biomass of turfs is shown to be another important determinant of productivity of the EAC, since where fine [fleshy] turf dominates the substratum, its productivity is inversely correlated with biomass. [Meaning that as the algae gets thicker/taller, it starts shading the lower parts of itself.]"
"In shallow reef areas, EAC biomass is lowest in summer, and peaks around winter, whereas at 10 meters on the reef slope, biomass is lower than on the reef flat, and it is seasonally stable. The seasonal variation in biomass of EAC on the reef flat can be explained by the seasonal changes in grazing intensity relative to productivity. While variations in productivity and grazing intensity are positively correlated, the magnitude of seasonal change in rate of grazing on algae exceeds that produced, thus resulting in the observed seasonal fluctuations in biomass. On the reef slope, presumably EAC productivity and losses, such as those due to grazing, are in balance over the year. Similarly, [previous researchers] observed that epilithic algal biomass decreased towards summer on the reef flat at One Tree Island, and that this corresponded with an increase in grazing activity. The lower biomass of the EAC on the reef slope compared with the reef flat is in part due to the difference in [algal] community structure; reef slopes are dominated by turfs (80 percent cover), which have a lower biomass per unit area than coralline algae [due to the calcium]."
"It is now well established [in 1992] that the EAC represents an extremely important trophic [food] resource on coral reefs through the interaction with grazers. In turn, grazers exercise a strong influence on the biomass and community structure of reef algal communities. Grazing activity, within certain limits, is also thought to stimulate productivity of epilithic algae by selecting for fast growing forms of algae [and thus the most "primary reduction" of nutrients], the removal of [dying] material, and an enhanced availability of [food]. Over an entire reef flat, it has been estimated that grazers account for [consuming] 40 to 70 percent of EAC net production, but there is considerable spatial variability in grazing intensity. For example, grazing rates are highest on the outer shallow reef crests and slopes, and lowest in leeward edges of reef flats and in lagoons. On a larger scale, the abundance of herbivorous fishes (the major grazers on the GBR), and the rate of removal of the EAC by grazers (determined by grazer exclusion experiments) is much higher on mid- and outer-shelf reefs than on reefs near-shore. These differences in grazing pressure within reefs, and between reefs located across the GBR, do not influence the rate of turnover of the epilithic algae (i.e. that established on our [experimental] coral plates) being grazed. For example, algal communities from different habitats at the same depth on Davies Reef are equally productive. Furthermore, the EAC on Pandora Reef was as productive per unit area and per unit biomass as the communities on Myrmidon and Davies Reefs."
"The rate of EAC [primary] production per unit area of reef surface, or actual algal food availability (i.e. the [per unit area] production of EAC on [our experimental] coral plates, corrected for the irregularity and algal coverage of reef surfaces), does however correlate with the rate at which algae are removed by grazers, as was demonstrated in the comparison between reef-flat habitats on Davies Reef. Similarly, in considering the cross-shelf gradient, the availability of algal food resources on Davies and Myrmidon Reefs (400 to 500 grams carbon per square meter, per year) is 3 times that of Pandora Reef (160 grams). This compares with a 3- to 5-fold differential in abundance of grazers on these 2 groups of reefs. These differences in algal food availability between sites are due to differences in algal coverage of reef surfaces. [Previous researchers] estimated grazing rate at 0.1 grams carbon (per square meter, per day) on Pandora Reef, and 0.6 on the mid- and outer-shelf reefs. Hence, grazing accounts for 23 percent of the EAC net production on Pandora Reef and approximately 50 percent of the production on the reefs offshore. This is in close agreement with independent estimates of the average annual grazing impact on the EAC at Davies Reef (57 percent) and on One Tree Island (50 percent). It remains unknown, as pointed out by [a previous researcher], whether grazer abundance controls algal food availability, or vice versa."
Epilithic = Algae that is attached to rocks; also known at 'benthic'.
Productivity = Primary Production of food = Primary 'Reduction' of nutrients.
Carbon = Biomass that is alive; is not GAC.
Turnover = How fast algae is eaten by grazers, which is followed by new algal growth.
The reef zones used in this study are different from the zones in the previous study. "
"Community structure, biomass and productivity of epilithic algal communities on the Great Barrier Reef: Dynamics at Different Spatial Scales. Marine Ecology Progress Series, Sept 1992."
"This study provides the first quantification of variation in the structure, biomass and productivity of the Epilithic Algal Community on a number of reefs over a wide area of the Great Barrier Reef. In addition, it describes within-reef and seasonal variability of these parameters."
"The Epilithic Algal Community (EAC) of coral reefs is a diverse assemblage of crustose coralline and [fleshy] turf algae growing upon coral rock. In this case, the term 'turf' refers to the multi-specific and inconspicuous association of unicellular, and short (usually less than 1 cm high), simple filamentous algae [...]."
"The main goal of this study was to examine the natural (in situ) variations in community structure, biomass, photosynthesis-irradiance relationship, and primary productivity of the Epilithic Algal Communities on the Great Barrier Reef (GBR). Comparisons are made between seasons, successive years, and different habitats and reefs situated across and along the continental shelf. This is an extension of a study which focused on the differences between habitats and seasons within a single reef (Davies Reef, central GBR). Data on primary production of the EAC are compared with the [roughness] and nature of the reef substratum to estimate the contribution made by the EAC to whole reef productivity."
"This study was carried out along 2 major [areas] designed to give a wide geographical coverage of the Great Barrier Reef. The first of these was a central GBR cross-shelf [area] comprising a reef on the inner- (Pandora), mid- (Davies) and outer-shelf (Myrmidon). General environmental and structural features of these reefs are described elsewhere. The second [area] comprised a pair of reefs on the mid- and outer-shelf at 3 latitudes; McGillivray and Yonge, Davies and Myrmidon, and Heron and One Tree Islands."
"Epilithic Algal Communities covered a high proportion of the reef flats (50 to 80 percent) and reef slopes (30 to 70 percent) on the coral reefs of the north, central and southern regions of the Great Barrier Reef (GBR). Crustose coralline algae and turf algae (fine and damselfish territory types) dominated the Epilithic Algal Communities in reef flat habitats, except in the near-shore region where turf algae predominated. Turfs also dominated the EAC on reef slopes. Patches of crustose coralline algae had a higher biomass [because of the calcium], but a lower photosynthetic rate per unit biomass [thus less nutrient reduction] than the equivalent area of fine turf algae. The net result was that these two main forms of epilithic algae had comparable rates of [per unit area] productivity. The [primary] productivity of turf-dominated communities was inversely correlated with algal biomass. [A previous researcher] also noted this effect in his examination of epilithic algae on a Caribbean reef, and suggested that it is probably related to self-shading."
"For a number of reasons, the Epilithic Algal Community is thought to play an extremely important role in the [feeding] dynamics of coral reefs. Firstly, a large proportion of the net primary production within specific habitats of coral reefs is provided by the EAC. This is most clearly evident in the shallow habitats, where it has been relatively easy to measure the metabolic rates of benthic [sea floor] reef communities. However, relatively little is known about the productivity of benthic plant communities on reef slopes and in deep lagoons. Epilithic [attached to rocks] algae are intensively grazed [by fish], and in the process are maintained in a state of low biomass, but rapid turnover. In the few cases where whole reef systems have been examined, the biomass of the Epilithic Algal Community is found to be considerable due to its extensive coverage of reef surfaces (up to 80 percent in some habitats), and the high [roughness] of the reef substratum. Hence, the EAC almost certainly makes a substantial contribution to the [per unit area] productivity of most reefs. Moreover, a high proportion of the carbon [food] produced by the coral reef EAC is thought to be directly available to the reef food web via herbivorous grazers. Indeed, recent studies [in 1992] of reef flats have demonstrated that grazers consume around half of the annual net production of the EAC, with the balance presumably channeled into detrital pathways in the form of [DOC] exudates and particulate matter [which are food for corals]."
"Epilithic Algal Communities from various reef habitats at the same depth had equal [per unit area] and biomass-specific productivity, regardless of their location on [areas] extending both across and also along the Great Barrier Reef. EAC productivity changed in a predictable manner with season (maximum in summer, minimum in winter) and depth (decreasing with depth). [...] The EAC at 10 meters on reef slopes had approximately half the [per unit area] productivity of the community on the adjacent reef flat, but the EAC from these habitats had a similar biomass-specific productivity. Productivity of the EAC per unit area of reef, which takes into account the [roughness] and coverage of reefs by the EAC in particular habitats, varied between reefs, and ranged from 150 grams carbon (per square meter, per year) on the reef flat of the near-shore reef and on all reef slopes, to 500 grams carbon (per square meter, per year) on some mid- and outer-shelf reef flats. There was no apparent latitudinal pattern of change in EAC productivity per unit area of reef. Thus, availability of the EAC, the major food resource of grazers on coral reefs, appears to correlate well with known large-scale variations in grazing activity."
"Experimental plates (8 X 8 X 2 cm) cut from the coral Porites spp. were bolted directly to the reef substratum in a haphazard manner within different reef zones. [...] Plates were left in the field for 6 to 12 months to establish a 'natural' Epilithic Algal Community."
"The type and irregularity of the reef surface, at the sites where algal production was measured, were surveyed at Pandora, Myrmidon, Heron and One Tree Reefs in October 1989, and at MacGillivray and Yonge Reefs in December 1989. Reef surface type, expressed as proportional coverage by sand, and 7 functional groups of biota: fine turf, damselfish-territory turf, crustose coralline algae, encrusting brown algae, macroalgae (e.g. Halimeda spp.), hard corals and other fauna (e.g. soft corals, sponges), was quantified using line transects."
"The percent cover of coral plates by the 4 major functional components of the Epilithic Algal Community (fine turfs, damselfish territory turf, crustose coralline algae, and encrusting brown algae), averaged over all seasons, was similar for the 2 reef-flat zones on Davies and Myrmidon Reefs. Both turfs and coralline algae were important in these habitats, but coralline algae were more abundant on reef crests. Fine turf dominated (57 to 67 percent cover) and coralline algae were much less abundant (20 percent cover) in the reef-slope algal community. The reef flat on Pandora on the inner-shelf differed markedly from similar habitats on the mid- and outer-shelf reefs, in that coralline algae were rare, and 87 percent of algae was damselfish territory turf. Epilithic Algal Community structure did not vary significantly with season."
"The maximum net photosynthetic rate [maximum reduction of nutrients] of the Epilithic Algal Communities, in both [per unit area] and biomass-specific terms, varied seasonally, with the maxima in summer and the minima in winter [less light] in all zones, on all reefs."
"[Primary] production of the EAC based both on area and biomass varied strongly with season for all zones and reefs of the cross-shelf and latitudinal [areas]. Productivity was highest in summer and lowest in winter."
"Thus, annual production of the EAC (without taking EAC coverage, or irregularity of the reef surface, into account) is 400 grams carbon (per square meter, per year) on reef flats [equivalent to 3.7 cubes of frozen zooplankton per square meter, per day], and 220 on reef slopes."
"The EAC (turfs plus coralline algae) covered a high proportion of the surface on all mid- and outer-shelf reefs examined. [...] In general, hard corals were the other major occupant of space on these reefs (11 to 44 percent on flats; 14 to 35 percent on slopes). Although there were some significant differences between reefs in terms of the cover of particular types of EAC, these did not suggest any latitudinal trends, nor any consistent differences between mid- and outer-shelf reefs. The one inner-shelf reef examined in this study (Pandora Reef) was distinctive in being dominated by zooanthids (61 percent), along with its comparatively low EAC coverage. Moreover, damselfish-territory turf dominated the EAC (75 percent) on the natural surfaces of Pandora Reef, as was observed with [the experimental] coral plates from this reef, whereas in comparable habitats on mid- and outer-shelf reefs, fine turfs and coralline algae were equally important components of the EAC. Reef flats had consistently higher cover of EAC (range: 51 to 81 percent) than the adjacent reef slopes (range: 33 to 73 percent), which had extensive areas of sand. In addition, coralline algae were important on reef flats, and filamentous algae dominated the reef slopes."
"The EAC covers a high proportion of reef flats (up to 80 percent) and reef slopes (up to 50 percent) throughout the GBR. However, the extent of this cover, as well as the community structure of the EAC, varies with location, such that cover of substrata by algae is greatest on reef flats in the mid- and outer-shelf region, where the community is usually dominated by a mixture of well grazed turfs and crustose coralline algae."
"Large fleshy algae (e.g. Sargassum spp.), which are usually relatively rare in all habitats on the mid- and outer-shelf reefs, dominate in some seasons and habitats on inner-shelf reefs. Although large fleshy algae were not common in the study site at Pandora Reef, the adjacent windward edge of this reef has an extensive Sargassum community. The transition from an algal community, comprising mainly coralline and low turfs on reefs of the mid- and outer-shelf, to one characterized by lush turfs and large fleshy algae, correlates with a significant decrease in grazing intensity."
"[Maximum per unit area] productivity occurs in summer in shallow habitats [i.e., the same habitat as a reef tank], and minimum productivity occurs in winter on the reef slope."
"Patches of crustose coralline algae have a higher biomass [because of the calcium], but a lower photosynthetic rate [and nutrient reduction] per unit biomass, than the equivalent area of fine [fleshy] turf algae. The net result is that these two algal forms have comparable rates of [per unit area] productivity. Thus, variation in the relative proportions of coralline and turf algae comprising the EAC is predicted to have an effect upon the biomass and the biomass-specific productivity of the EAC. However, this is complicated by the relative abundance of damselfish territory turf, the third major algal group of the EAC, which is the most productive form of epilithic algae on reefs. Indeed, a comparison of the mid-reef flat with the reef-crest habitat of Davies and Myrmidon Reefs, between which there are considerable differences in the relative proportions of crustose coralline algae and fine turf algae, shows a predicted, though not always significant, difference in biomass and biomass-specific productivity. The biomass of turfs is shown to be another important determinant of productivity of the EAC, since where fine [fleshy] turf dominates the substratum, its productivity is inversely correlated with biomass. [Meaning that as the algae gets thicker/taller, it starts shading the lower parts of itself.]"
"In shallow reef areas, EAC biomass is lowest in summer, and peaks around winter, whereas at 10 meters on the reef slope, biomass is lower than on the reef flat, and it is seasonally stable. The seasonal variation in biomass of EAC on the reef flat can be explained by the seasonal changes in grazing intensity relative to productivity. While variations in productivity and grazing intensity are positively correlated, the magnitude of seasonal change in rate of grazing on algae exceeds that produced, thus resulting in the observed seasonal fluctuations in biomass. On the reef slope, presumably EAC productivity and losses, such as those due to grazing, are in balance over the year. Similarly, [previous researchers] observed that epilithic algal biomass decreased towards summer on the reef flat at One Tree Island, and that this corresponded with an increase in grazing activity. The lower biomass of the EAC on the reef slope compared with the reef flat is in part due to the difference in [algal] community structure; reef slopes are dominated by turfs (80 percent cover), which have a lower biomass per unit area than coralline algae [due to the calcium]."
"It is now well established [in 1992] that the EAC represents an extremely important trophic [food] resource on coral reefs through the interaction with grazers. In turn, grazers exercise a strong influence on the biomass and community structure of reef algal communities. Grazing activity, within certain limits, is also thought to stimulate productivity of epilithic algae by selecting for fast growing forms of algae [and thus the most "primary reduction" of nutrients], the removal of [dying] material, and an enhanced availability of [food]. Over an entire reef flat, it has been estimated that grazers account for [consuming] 40 to 70 percent of EAC net production, but there is considerable spatial variability in grazing intensity. For example, grazing rates are highest on the outer shallow reef crests and slopes, and lowest in leeward edges of reef flats and in lagoons. On a larger scale, the abundance of herbivorous fishes (the major grazers on the GBR), and the rate of removal of the EAC by grazers (determined by grazer exclusion experiments) is much higher on mid- and outer-shelf reefs than on reefs near-shore. These differences in grazing pressure within reefs, and between reefs located across the GBR, do not influence the rate of turnover of the epilithic algae (i.e. that established on our [experimental] coral plates) being grazed. For example, algal communities from different habitats at the same depth on Davies Reef are equally productive. Furthermore, the EAC on Pandora Reef was as productive per unit area and per unit biomass as the communities on Myrmidon and Davies Reefs."
"The rate of EAC [primary] production per unit area of reef surface, or actual algal food availability (i.e. the [per unit area] production of EAC on [our experimental] coral plates, corrected for the irregularity and algal coverage of reef surfaces), does however correlate with the rate at which algae are removed by grazers, as was demonstrated in the comparison between reef-flat habitats on Davies Reef. Similarly, in considering the cross-shelf gradient, the availability of algal food resources on Davies and Myrmidon Reefs (400 to 500 grams carbon per square meter, per year) is 3 times that of Pandora Reef (160 grams). This compares with a 3- to 5-fold differential in abundance of grazers on these 2 groups of reefs. These differences in algal food availability between sites are due to differences in algal coverage of reef surfaces. [Previous researchers] estimated grazing rate at 0.1 grams carbon (per square meter, per day) on Pandora Reef, and 0.6 on the mid- and outer-shelf reefs. Hence, grazing accounts for 23 percent of the EAC net production on Pandora Reef and approximately 50 percent of the production on the reefs offshore. This is in close agreement with independent estimates of the average annual grazing impact on the EAC at Davies Reef (57 percent) and on One Tree Island (50 percent). It remains unknown, as pointed out by [a previous researcher], whether grazer abundance controls algal food availability, or vice versa."
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schabiazabi
New member
To dave willmore
To dave willmore
Dave, you are a genius. The system you described can help me breed cleaner shrimp. Now I can have live food 24/7 with clear water. How come I never thought of that?
To dave willmore
Dave, you are a genius. The system you described can help me breed cleaner shrimp. Now I can have live food 24/7 with clear water. How come I never thought of that?
Aquarist007
New member
Adding np pellets via a reactor will increase the bacteria on the biofilm that builds up on the very large surface area provided by the pellets. They provide the carbon for the bacteria but at the same time allow the bacteria to thrive on a very large surface medium. The aquarists brings the nitrates and phosphates to the pellet reactor via flow. Very litttle bacteria enters the tank this way.
What the external carbon source allows you to do is increase the nutrient levels in your tank so that the corals are surrounded by a much more nutrient environment. The excess nitrates and phosphates that might be produced are removed by the skimmer---a must for this setup.
There are very few corals that eat bacteria---I've only seen acorpora sites as an example.
That stated then one of the reasons the corals do so well with carbon dosing could be the more nutrient rich environment that we are able to create for them.
Stirring up the substrate IMO is detrimental to the system as it breaks the biofilm and reduces the effeciency of it and makes more work for the systems filtration methods.
Try running carbon from a reactor, feeding the heck out of your system and not stirring up the biofilm and see if you don't notice a difference in the growth and coloration of the corals
markaren
New member
I watched a youtube video of a RSM 250 owner who feeds Anemones, Scolymia, Polyps and other corals with a Turkey baster locally...like feeding a baby one by one. sure enough they close right down on the food as if they are eating it.
Here:http://www.youtube.com/watch?v=l4TAgulVm6E
Here:http://www.youtube.com/watch?v=l4TAgulVm6E
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