How to FEED your reef tank so that your corals will really GROW, instead of ho-hum...

[adirondack]

Hmm...where'd everybody go? Great thread, best information since the famous T5 thread. Still leaves a lot of questions, like how to translate all that to the 85 gals of water I have.

1. I use a 30 gal sump for a 72 gal main tank. The return water is filtered through a sock filter. I don't know why I do this, the sump came with it. Maybe I shouldn't be filtering the return water?

2. It would seem that the sump pump and skimmer should be off for a few hours each night if corals are going to be fed in the evening, so you don't remove the food from the water too quickly, is there a problem with that?

3. I use reef chili 2X week, I try to add it after 10pm when 4 out of 6 lights are off, then at 11pm all lights shut off. Anyone have any experience with reef chili?

4. When I scrape the front glass, especially in the evening, my candy cane coral polyps open up. I suppose it's a combination of diatoms and other larger algae? That tells me that at least some corals can eat anytime when they sense food. Comments?

Thanks for a great thread.

 

[capecoral]

Isn't the most coral food in the tank all the time the best ?

 

[capecoral]

"Zooplankton Feeding By The Caribbean Reef-Building Coral Montastrea Cavernosa. Proceedings of the Second International Coral Reef Symposium, Great Barrier Reef Committee, Oct 1974"

"Montastrea cavernosa is an important reef-builder found from the Atlantic coast of Africa to the Caribbean. In San Blas, it has at least two polymorphic forms: A small polyped form (polyps 0.48cm in diameter), and a large polyped form (polyps 0.92cm in diameter)."

"Montastrea cavernosa was observed under a variety of natural and laboratory conditions. Underwater observations were made with scuba, both day and night at different depths, to determine its feeding behavior and daily activity pattern. Small colonies between four and ten cm in diameter were collected from between one to five meters on Ulacsucun Reef, and without exposure to air, were transferred to a 300 liter glass aquarium for observation. The corals were placed back on the reef after observations, where they could be collected again if necessary. Corals were handled in this way for over a year without visibly deleterious effects."

"Guts were extracted two hours after sunset from the Montastrea cavernosa, on coral reefs in San Blas, Panama. Zooplankton [pods, etc] found in the guts include: copepods, amphipods, nemerteans, turbellarians, polychaetes, nematodes, appendicularians, salps, miscellaneous eggs, and the larvae of decapods, copepods, polychaetes, cirripedes, bryozoans, and corals. Most of the eaten [pods], both by number and by weight, are near-bottom [types] and are either demersal (truly bottom dwelling) or meroplanktonic (settling to the bottom at some time in the life cycle), and are preyed upon heavily by corals when [the pods] come up off the reef at sunset and presumably also as they settle down at dawn."

"Based on the highly variable amount of zooplankton in the guts [of the corals], and the highly variable amount of zooplankton in the water, corals are probably extremely flexible in their utilization of zooplankton as a source of energy. Since most of the zooplankton in the gut comes from the reef itself [and not the open ocean], the results point to tight recycling of nutrients and biomass within the coral reef ecosystem. [i.e., no external input; most food is grown on the reef]"

"Montastrea cavernosa is a voracious carnivore. From the field and tank observations, it seems reasonable that it is one of the most effective zooplankton feeders in the Caribbean. As with many other coral species in the Caribbean, Montastrea cavernosa is most commonly expanded at night [for feeding], and closed during the day."

"These observations were repeated on the reef at night using scuba and 88,000 candlepower flashlights. The lights were trained onto the coral head, and the interaction between the coral and the artificially-attracted-zooplankton observed. The Montastrea cavernosa ate every visible zooplankter that collided with it, and occasionally individual tentacles could be seen to follow after and intercept a moving zooplankter. All zooplankters visible to us were eaten: copepods, mysids, crab zoea, ostracods, isopods, and other crustaceans, chaetognaths, appendicularians, nematodes, nemerteans, polychaetes, small medusae, salps, and even a tiny ctenophore. The coral avoided nothing, missed nothing, an regurgitated nothing during our observation periods. [...] Well over 200 zooplankton captures were observed with lights on the reef at night, and over 120 in the tanks at night."

"It is well known that corals have the greatest proportion of prey capture surface-to-tissue bulk of any other group of animals, and that corals can eat and digest, with ease, a variety of animal prey."

"Vids we like:

Zooplankon on sea floor, filmed from robot:
http://www.nauticvideo.com/Daisy Brittle Star.m1v

Brain coral eating small mysis:
http://www.youtube.com/watch?v=avuzNWddI_g

Brain coral eating large mysis:
http://www.youtube.com/watch?v=TKQfN5cuxkQ "



link:
http://www.reefbase.org/download/download.aspx?type=10&docid=8607

 

[capecoral]

"Corals require many things to grow. Reefers know that most corals need light, and some other corals do not. And reefers should understand by now that all corals need food, in one form or another. No exceptions. Many reefers understand that stoney corals also require calcium, alkalinity, magnesium, and a few other minerals to grow skeletons. But only some experienced and/or more advanced reefers know that there are a few other things needed that are not mentioned much. They are not mentioned because they generally are not lacking in the average tank. But when you really want strong and fast growth, and when you have lots of corals consuming things quickly, these additional things may indeed begin to limit growth. What are they?"

"Vitamins and amino acids. All growing organisms need them; they are usually in abundant supply in aquariums (other things are usually lacking first). But the point we would like to make is not so much that they ARE needed (even if this is the first time you have heard this), but WHERE they come from. Think about it: Corals have adapted to survive on what is available in the ocean. There is no pizza or beer, but there are lots of food particles, dissolved organics (which are just very fine food particles), and vitamins and amino acids. So, corals have adapted to use all of these, and of course the corals expect them to be in your tank."

"But how do the vitamins and amino acids get into the ocean in the first place? We know that food particles are just plankton and detritus, but what produces the vitamins and amino acids? The same thing that makes all the food in the ocean: Algae..."

" 'Secretion Of Vitamins and Amino Acids Into The Environment By Ochromanas Danica'. Journal of Phycology, Sept 1971 [Phycology means the study of algae]"

"Ochromonas danica [a species of algae] grown on a chemically defined medium under controlled conditions in the light [created] the following vitamins: ascorbate, B6, N5-methyltetrahydrofolate, tetrahydrofolate polyglutamates, oxidized folate monoglutamates, nicotinate, pantothenate, riboflavin, vitamin A, beta carotene, and vitamin E but no vitamin B12. The cells also secreted molecules into their growth medium including the vitamins ascorbate, B6, the above folates, nicotinate, pantothenate, riboflavin, vitamin E, and the amino acids alanine, aspartic acid, leucine, and valine. [Thus the algae not only create vitamins and amino acids for themselves (which are then eaten by pods and then by corals), but they also create them to put them directly into the water.] The role of such secretions in nature is discussed."

"An extensive list of biologically active compounds are now known to be secreted by algae into their natural or in-vitro environment (Table 1), and these molecules undoubtedly contribute to the food chain."

"In this paper we report on the cell content and secretion of vitamins and amino acids by [algae], grown under carefully controlled physical and chemical conditions."

"Table 1. Organic molecules secreted into their environment by algae:

Carbohydrates
Amino Acids
Glycolic Acid
Citric Acid
Vitamins
Nucleic Acid derivatives
Polypeptides
Proteins
Enzymes
Lipids "


"Table 2. Quantity of vitamins in cells and cell-free supernatant of 1 week old, light-grown [algae]:

.......................................................Vitamin Content (x 10-9 grams/mg dry cells)

Vitamin.............................................Cell content.....Supernatant content

Ascorbate.........................................830.................2110
Biotin*.............................................1.....................9
B6...................................................23...................29
N5-Methyltetrahydrofolate...................2.....................1
Other tetrahydrofolate polyglutamates...6.....................2
Oxidized folate monoglutamates............1.....................0.4
Nicotinate.........................................89...................73
Pantothenate....................................37....................65
Riboflavin..........................................35...................40
Thiamine*.........................................60...................117
Vitamin A..........................................137..................0
Beta Carotene...................................1640.................0
Vitamin E..........................................2170.................0

* Biotin at 10 x 10-9 and thiamine at 1000 x 10-9 were added to
each ml of medium because they are required by [the algae] for
multiplication. All of the biotin, and 18 percent of the
thiamine, are accounted for in the table. "


"Light-grown [algae] cells synthesized a full complement of water soluble vitamins (except for vitamin B12 and several fat-soluble vitamins or precursors) (Table 2)."

"Several amino acids -- alanine, aspartic acid, leucine, and valinc -- were secreted."

"In the light of the work reported here [in 1971], and in the work of others, it is likely that at least some algae are capable of secreting vitamins into their environment. It also becomes possible that the vitamins found free in natural waters may be derived, at least in part, from algal metabolism. Furthermore, the increasing evidence (Table 1) that algae can secrete a variety of metabolites and macro-molecules into their environment, indicates that they play a far more active role in the exchange of nutrients in their environment that has heretofore been credited to them."

"Nice long video we like:

Scripps Institute: Algae, world's most important plants:
http://www.youtube.com/watch?v=CB2XlpD-Ld4 "






link
http://www3.interscience.wiley.com/journal/119691458/abstract

 

[Aquarist007]

Does np reducing pellets or vodka dosing have a positive affect on coral growth and coloration

 

[capecoral]

np?

 

[GreshamH]

N&P... Nitrate and Phosphate. Plenty of threads on the subject of you search for them in the Chemistry Forum.

 

[Aquarist007]

N&P... Nitrate and Phosphate. Plenty of threads on the subject of you search for them in the Chemistry Forum.

I follow this one
http://www.reefcentral.com/forums/showthread.php?t=1694529

 

[adirondack]

Isn't the most coral food in the tank all the time the best ?

Yes, feeding continuously would be wonderful. But that would require automatic feeding somehow, and stable systems capable of dealing with all the nutrients, which is definitely possible. If you read Eric Borneman's posts at the marine depot forum on his tanks, he feeds a ton of food to his corals and fish, but he has enough nutrient uptake to deal with it. Also on that forum is santamonica's algae scrubber system for nutrient uptake, which looks very interesting. Skimming removes a lot of food that corals eat, so I turn it off several hours each night after feeding.

 

[lolgranny]

Following, this will be good in a few months!

 

[capecoral]

"Swarming of Polychaetes on the Great Barrier Reef. Proceedings of the 6th International Coral Reef Symposium, 1988"

"During the study period from October-January, mass swarming of polychaetes [worms] occurs, with occasional peaks in October, November and December at Lizard Island, northern Great Barrier Reef. Similar swarmings have been seen in late November/December on the southern GBR. Swarming is followed by mass spawning, and the spent worms then disappear from the water column. Several families and species are involved in the mass swarming on any one night. The species vary considerably in the morphological changes which they have undergone. Emergence of swarming polychaetes from the sediment or coral substrate occurs around 6:30pm, and continues for several hours. The species typically swarm in the upper layers, but under certain weather conditions, they may remain close to the substrate."

"Polychaetes are a major component of coral reef ecosystems, occurring in large numbers in both lagoonal and inter-reefal sediments, and within infaunal communities of coral reef substrates. These polychaete communities are diverse, and include representatives of many families and species. Generalized comments have been made as to the role that polychaetes may play in the coral reef ecosystem, which include food sources for a variety of organisms, initial borers of recently dead corals, and recyclers of the abundant mucus produced on the reef."

"Isolated occurrences of swarming polychaetes in the reef plankton, often luminescent, had been reported in the late spring / early summer in the early 1980's on the Great Barrier Reef."

"The sampling area selected was Lizard Island, Great Barrier Reef. Sampling was concentrated around the time expected for mass coral spawning, as polychaetes had been reported in the water column at this time. A variety of sampling techniques were used to sample the polychaetes in the water column:"

"A) Plankton tows were made on the 19th November 1986, at a fixed speed over marked 50 meter [areas] at 5 locations. These locations were: (1) between Bird and South Islands on the reef slope, outside the lagoon; (2) across a fringing reef off Lizard Island in the lagoon; (3) across the lagoon on sand; (4) across patch-reef at the entrance to the lagoon; (5) across the lagoon on sand near Bird Islet. Mesh size of the nets was 100 microns, and the nets were towed for 10-15 minutes at a depth of 1 to 3 meters below the surface. The first set of tows were made between 7:00-8:30pm, and the second set between 10:00-10:45pm."

"B) Flashlight and Dipnet: A spotlight was held into the water from a small anchored boat, and animals were collected using a hand held dipnet. The same procedure was employed to collect samples below the surface with SCUBA. [...] Samples were taken at 30 minute intervals by dipnetting for 5 minutes from 9:30pm until 1 hour after the last polychaetes were seen in the water column."

"To determine the origins of the swarming polychaetes found in the plankton, [sea-floor] plankton traps were laid just before dark on (1) lagoonal sediment and (2) on small patch reefs, and either sampled at intervals during the evening or collected at dawn the following day. On some nights, using SCUBA, visual observations were made to determine if polychaetes were emerging from the sediment or coral substrate."

"Large numbers of swarming polychaetes were seen on several nights during the sampling periods in the water column. The polychaetes consisted of several families, all of these except one being typically cryptic families with species living in sand or coral substrate. The one exception is a member of [an] entirely [water column] species. This represents only a small percentage of the reefal polychaete fauna. It seems likely that the polychaete fauna of the Lizard Island region is in the order of 300-500 species. Over 95 percent of all individuals collected were [ready to spawn]. Species swarm in the water column, although one group of [them] were surface skimmers, often moving in tight circles referred to as nuptial dances. The majority of species were strongly attracted to bright lights [...]. Whilst swimming, some species of [them] flashed, and the species were seen to emit streams of luminescent material, consisting primarily of spawned gametes."

"After they had been swimming in the water column for some time, the polychaetes disappeared and it is presumed that they had spawned. This was confirmed by the collection of some spent polychaetes, indicating that gametes had been released in dipnet samples at 10:00 and 10:30pm. Swimming [spawn-ready] polychaetes are basically 'swimming gamete sacs', and once spawning has occurred, mainly by rupturing of the body wall, the polychaetes die."

"Similar species and numbers of individuals were collected in the plankton tows over coral reef areas as those collected over the sandy areas. It appears from the limited number of plankton tows taken, that fewer species were collected by this method in contrast to dipnetting. [Other researchers] suggest that organisms such as polychaetes avoid plankton nets, but can be readily caught in [sea floor] traps."

"We suggest [...] that the [ready-to-spawn worms] found swarming in the water column emerge from both lagoonal sediments and coral substrates."

"Over 95 percent of all swarming individuals collected by all sampling methods were [ready to spawn], and subsequently spawned."


"Video of catching zooplankton from a ship:
http://www.youtube.com/watch?v=_UiKfYUAJAI "

[size=-2]link[/size]​

 

[capecoral]

[This is the most complete study we've presented yet, as to how coral-feeding and water-filtering work together; reefers hopefully have learned enough to be able to follow it. We understand that it would be nice if it were simpler, but this is how it actually works and it does get complex. So, this is the first study we've presented that fully integrates the feeding side (primary production of coral food) with the filtering side ("primary reduction" of nutrients)].

The two main things to keep in mind, is that "primary production" means making food from sunlight, and, that this study is done in a 'crystal clear' lagoon which has lots of corals.]

"Part II. Nutrients, Particulate Organic Matter and Planktonic and Benthic Production of the Tikehau Atoll (Tuamotu Archipelago French Polynesia). Atoll Research Bulletin, The Smithsonian Institution, 1994"

"Matter and energy [amounts] for coral reefs, their components, and the world around them can, do, and must balance in a theoretical context. In this paper, we will try to establish nitrogen, phosphorus and silica [usage amounts] between ocean and lagoon waters of the Tikehau atoll, with the purpose to learn more about the functioning of coral reef lagoons. Nutrient concentrations (dissolved components, and particulate organic matter) were measured in the lagoon and in the surrounding oceanic surface waters between 1983 and 1987."

"The average nutrient concentrations ["¦] were not unusual, being of the same order of magnitude as the [amounts] in coral-reef waters as reviewed by [another researcher]."

"Particulate organic phosphorus, carbon and nitrogen (POP, POC and PON) [these are all food items for corals] profiles are shown in Figure 3. Concentrations generally decrease with depth [because primary production is less when there is less light]."

"Table 6 [partial]: Average concentrations (mmol/m3, not ppm) of oceanic and lagoonal waters:

Nutrient...Ocean Waters...Lagoon Waters

NH4...........0.80...........1.90
NO2...........0.04...........0.02
NO3...........0.30...........0.09
DON...........2.30...........4.60 [food particles]
PON...........0.40...........1.40 [food particles]
PO4...........0.38...........0.16
DOP...........0.26...........0.39 [food particles]
POP...........0.02...........0.10 [food particles]
SIO2..........1.00...........0.80 "

[Note that the higher algal content (both planktonic and sea-floor algae) of the lagoon provides lower inorganic nutrients, yet higher quantities of food particles, than the open-ocean reef water does. The primary production of the algae makes more food particles for the food chain (and corals), while the "primary reduction" of the algae keeps the nutrients reduced.]

"During the crossing over the reef-flat, and the [time] in the lagoon, oceanic waters become impoverished in NO2 and NO3, and enriched in NH4 and organic nitrogen." [In other words, water coming in from the ocean has higher NO2 and NO3, which is then reduced by the "primary reduction" of the reef flat.]

"Increase in the nitrogen [NH4] content of water flowing above the reef-flat is attributed to gaseous nitrogen fixation, mostly by cyanobacteria, of which a great variety occur on limestone substrata of coral reefs. At Tikehau, large quantities of cyanobacteria were recorded in the lagoon water column." [Cyanobacteria 'makes' its own NH4 from the nitrogen gas dissolved in the water.]

"Mineral phosphorus (PO4) water content decreases, and organic phosphorus (dissolved organic phosphorus + particulate organic phosphorus) [food for corals] increases during crossing of oceanic waters over the reef edge, and during the residence time in the lagoon."

"The pattern of [food] production emerging from all this discussion is that the high primary production ["primary reduction"] over the reef, and in the lagoon, results from an input of nitrate and phosphate from enriched oceanic waters, and from a great gaseous nitrogen fixation by cyanobacteria [which makes NH4], and lastly, from the mineralization of organic compounds in the lagoon." [In other words, the ocean supplies nitrate and phosphate into the reef; the ocean does not waterchange the nitrate and phosphate out. And once the nitrate and phosphate are in the reef and lagoon, the algae consume it and convert it into organic material].

"Phytoplankton of coral-reef ecosystems have often been considered as a low primary producer, since the overwhelming majority of coral-reef studies are carried out in shallow ecosystems [that are not deep enough to have much phytoplankton]. In atoll lagoons, however, the reef area vs. the total area ratio is low. Lagoonal plankton may thus be a major contributor to total primary productivity of the ecosystem as a whole."

"Phytoplankton production [of food], integrated up to 15 meters of depth, drops during May, June and August. This decrease is correlated with light energy reduction that occurs in winter in the southern hemisphere. Phytoplankton biomass is low, but this is typical of coral reef ecosystems [because of the shallow water]. Biomass is greater in May, June and July, while conversely, production rates are lowest. [However], concentrations in the lagoon are approximately three times greater that those found in surface oceanic waters." [Meaning, the water in the lagoon has three times the concentration of phytoplankton, but since the lagoon is only 24 meters (75 feet) deep, there is still not as much phytoplankton as in the open ocean.]

"[It was] previously shown that a great part of lagoon phytoplankton is made up of cells smaller than 5 microns, with cyanobacteria dominating. Cyanobacteria can contribute up to 75 percent of the carbon production ["primary reduction" of NO2, NO3 and PO4] of plankton primary producers."

"Phytoplankton production is significantly correlated with light energy."

"Figure 9 shows phytoplankton and [sea-floor algae] in a 5 meter depth interval. Total primary production is slightly the same whatever the depth interval is. The [sea-floor] production, however, is greater than phytoplankton production within the first 10 meters, being 25 times higher in the 0 to 5 meter depth interval. From 20 meters downward, phytoplankton is the major contributor to the total primary productivity of the whole ecosystem." [In other words, near the surface, most nutrient reduction is being done by the algae that is attached to the rocks, instead of by the phytoplankton in the water column, simply because there is not much water.]

Continued...

 

[capecoral]

Continued...

"The fate of the abundant particulate organic matter [coral food] in the Tikehau Lagoon, and the level of efficiency of utilization of it by consumers, are two aspects which are of primary importance in an understanding of the functioning of the lagoon [water column] food web. Once sunk to the bottom, are the [particulates] consumed mostly by pelagic animals in the water column, or by [sea floor] ones?"

"Zooplankton Biomass:

"[Size] 3 to 35 microns: An average number of 71 hetero-flagellates, and 7 ciliates, were found per ml in samples taken in April 1986 in the lagoon."

"[Size] 35 to 200 microns: Consists of 43 percent of organisms smaller than 100 microns, of which 73 percent are protozoans [...]. The second most abundant [animal] smaller than 100 microns consists of naupliar copepods (18 percent), and the third, of meroplankton bivalve larvae (8 percent). Out of organisms larger than 100 microns, protozoans account for 33 percent of total numbers, of which 23 percent are tintinnids. Metazoans are noticeably dominant, accounting for 67 percent of the total. Copepod nauplii are the most abundant organisms (41 percent). Bivalve larvae do not exceed 7 percent of total numbers."

"[Size] 200 to 2000 microns: Zooplankton at Tikehau are characterized by periodic blooms of copepods, larvae, pteropods and salpe. As shown ["¦], the annual mean value [of zooplankton in the lagoon] is six times greater than the oceanic plankton concentrations measured in the vicinity of the pass."

"Detritus [waste] dry-weight represents 70 percent of 5 to 200 micron particles; between 1 and 21 percent of 200 to 2000 micron particles; and 0 percent of particles larger than 2000 microns."

"The estimated bacterial biomass was 2 times higher than the phytoplanktonic [biomass] in the Tikehau lagoon. Dominance of bacterial biomass was also observed in the [low nutrient] waters of the Sargasso Sea [...]; the interpretation [is] that bacteria consume significant amounts of carbon, probably released from phytoplankton directly, or via herbivores."

"Detritus, smaller than 35 microns, represent the most important particulate organic carbon pool in the lagoon. They originate from lagoonal primary production [from algae], and their sedimentation onto the bottom exceeds [sea floor] primary production. Plankton bacteria biomass is of same order of magnitude as [sea floor algae] biomass, and is equal to twice the phytoplankton biomass. [Water column] bacteria dominance can be interpreted by a microbial loop returning energy released as dissolved organic matter by phytoplankton and zooplankton, but also energy released as mucus from lagoon coral communities."

"Considering the total living biomass, the primary producers [algae] largely dominate with about 60 percent of the total organic matter."

"The detritus pool (84 percent of all Particulate Organic Carbon) originates in lagoonal primary production."

"On the average, 50 percent of the Particulate Organic Matter is made up of suspended particles smaller than 5 microns, but this percentage can vary considerably."

"Phytoplankton account for 35 percent of the living carbon with a strong dominance of cyanobacteria, while heteroflagellates [zooplankton] and ciliates account for 6 percent of the living carbon (fig.5)"

[size=-2]link[/size]​

 

[CLINTOS]

Phytoplankton it's self will grow if the inorganic level's are too high.

so it is important to add just the right amount and increase as the filter feeder's increase

There is a sweet spot where you can actually use the phytoplankton to reduce inorganics if you add just a little more then what the filter feeder's eat while keeping a low inorganic level

the phyto will grow for a few hours consuming the light/inorganics all the while being consumed from filter feeder's until the next time you add a perfect level of phyto

jmo

 

[capecoral]

Ok I'm starting to understand... kind of a circle of life

 

[capecoral]

"Shelf-scale nitrogen and phosphorus budgets for the central Great Barrier Reef. Proceedings of the Eighth international Coral Reef Symposium, 1997."

"The nutrient fluxes [movements of nitrate and phosphate] which support the productivity of coral reef ecosystems and their constituent communities, remain a continuing source of interest in studies of reef ecology and bio-geochemistry. Historically, much of the focus was directed toward the apparent contradiction between the high productivity of coral reef ecosystems, and the apparent paucity of nutrients in the waters in which these reefs are immersed. This contradiction has diminished, as it has become apparent that coral reefs can exist in wide range of nutrient environments, and [also because of the fact that] coral reef communities have considerable capacity to extract dissolved [DOC] and particulate [waste] nutrients from the vast volumes of water which circulate around and through reef structures."

"We have developed a [nitrate and phosphate estimate] for a shelf-scale section of the Great Barrier Reef. The goal of the [estimate] is to quantify and compare the major internal and external nutrient [movements] likely to affect water quality at the regional scale."

"The 200 kilometers of shelf between Cape Tribulation and Dunk Island is characterized by an open matrix of platform reefs. [...] Shelf-width increases from 42 kilometers at Cape Tribulation, to 81 kilometers at Dunk Island. [...] The total shelf region of interest has an area of 13,800 square kilometers, and an estimated seawater volume of 510 cubic kilometers. Coral reefs within this section have a aggregate area of 1455 square kilometers. Estimates of the nutrient [nitrate, phosphate] pool sizes are based upon water sampling in the period between 1988 and 1995."

"Most (greater than 75 percent) of the water column nitrogen is in the form of dissolved organic nitrogen [DON and DOC, which corals can eat]. Particulate nitrogen [detritis, which corals can also eat] is the second largest nitrogen pool, averaging 18 percent of total water column nitrogen. Dissolved inorganic nitrogen [ammonia/ammonium, nitrite, nitrate] comprises less than 5 percent of the total water column pool. Water column stocks of phosphorus are more equally balance between dissolved inorganic (PO4), dissolved organic [DOP and DOC], and particulate forms. [The organic and particulate forms are eaten by corals]"

"First-order estimates of water column demand for nitrogen and phosphorus can be calculated from measurements of phytoplankton primary production, and stoichiometric ratios of phytoplankton composition (C:N = 106:16:1)."

"Most of the nitrogen and phosphorus used by [phytoplankton in the water column] to support this primary production is derived from [decomposed] organic matter."

"[Bacterial decomposition] of organic nitrogen in the water column the largest source of [nitrite, nitrate]."

"All of the above [movements of nutrients] takes place against a very large background of re-suspension and deposition of particulate matter and associated nitrogen and phosphorus. A significant proportion of the total particulate nitrogen and particulate phosphorus measured in shelf water is detrital [waste], and much of this detritus is derived from or at least recycled through the [reef floor]."

"In the [estimation] presented, we have attempted to quantify [in numbers, which we omitted] the identifiable input, loss, and recycling [movements] on the central Great Barrier Reef shelf. This comparison clearly shows the relative magnitude of nutrient [nitrate, phosphate] sources which support the productivity of the Great Barrier Reef ecosystem."

"Primary production-based demand for nitrogen by phytoplankton in shelf waters is twice calculated by recycling inputs of nitrogen from the water column and [reef floor]. The estimated demand is weighted toward summer primary production rates. [Organic material decomposed by bacteria] is the largest source of nitrogen to support this demand. [...] In the absence of external inputs, algal uptake of nitrogen will be constrained to [the amount of decomposed nitrogen]."

"Phytoplankton demand for nitrogen and phosphorus must largely be met by recycling [of the water already there, instead of replacement of the water with new water]."

[size=-2]link[/size]​

 

[capecoral]

"A lot of the previous information presented here has been zooplankton-based, because the goal here is to be able to operate our reef tanks more like the ocean. The ocean has [or had, before climate change] the largest coral growth rates of any reef tank. And although we only touched on the topic before (with a picture of the pool of phytoplankton), we will now start incorporating more information about how the ocean uses algae to filter all its water, and feed all its corals. Eventually, we would like to see reefers have all the information they need to have tanks which function exactly like the ocean. It all boils down to the understanding of primary production."

"As a reminder, algae is 90 percent of all life in the ocean (except bacteria). Most of the remaining 10 percent is zooplankton. The last little remaining bit is everything else: fish, corals, inverts, etc. Most of the biological activity in the ocean is a cycle between algae, zooplankton, and bacteria: Algae use the sun to grow; the algae are then eaten by zooplankton (pods), which die and cause more algae to grow. Repeat. This is the process throughout all the oceans, and the lakes too. There is no body of water that does not have this process going. Algae feeds pods, which die and feed algae."

"The other things, like fish and corals, are just small objects living in this giant ocean cycle of algae and pods. Matter of fact, if you removed all the fish and corals and inverts, the oceans would continue to operate exactly the same. You could even remove humans and animals from the land, and the algae/pods process would still continue normally in the ocean. The point to remember is that the ocean is totally controlled by the presence of algae and pods, and anything else that wants to live in the ocean (this would include corals) needs to be finely tuned to the environment that algae and pods provide. Any organism that was not good at living in this algae/pod environment is long since gone."

"Algae (using chlorophyll) produce most of the oxygen on the earth, including the oxygen you breath. Algae are the primary producers, because they are the things which produce ocean-food from the sun. Nothing else in the ocean does. Algae take light, amazingly, and combines it with carbon, which is taken mostly from CO2 that is dissolved in the water, and create living creatures (more algae cells). Nothing else can do this, and that's why algae are the "primary" producers of food on earth. The chlorophyll in trees produce food too, but there is more water on the earth than there is land, and the water is much deeper that a forest. And algae grow much quicker too; you measure tree growth in inches/cm per year, but you measure algae growth 'doublings per day'. That's a lot of new food produced each day."

"It's this incredibly fast growth which allows algae to feed and filter all the oceans and lakes of the world. Remember that primary production of food is really the same thing as "primary reduction" of nutrients, which is the term we created to help explain how the ocean gets rid of all the ammonia, nitrite, nitrate and phosphate that is produced from dying pods (see attached graphics). Rocks and sand do not do that much filtering in ocean; the nutrients (except for reef/coastal areas) don't make it down to the rocks and sand; the top 300 feet (100 meters) of ocean water has the nutrients removed ("reduced") by the phytoplankton algae long before the nutrients can make it down to the rocks and sand."

"As most reefers know, the ocean is very low in nutrients. But what most reefers don't know is that it's just the top 300 feet (100 meters) that is low in nutrients; not the whole thing. When you go below this (which is where algae can't get enough light to grow), the nutrients jump up to high levels. And most reefers also don't know that it is indeed the algae that is keeping these nutrients low. Algae that grow on rocks near coastal areas do a lot of the filtering too, especially when you are looking at just a local reef system which cycles it's nutrients within the local reef area."

"It's actually this "solid" algae, which grows on surfaces instead of floating as particles, that we are going to focus on more. Chlorophyll is chlorophyll, whether it's contained in phytoplankton particles, trees, or hair algae. What controls how much filtering and feeding the chlorophyll can do, is how much of it is exposed to light and nutrients. The ocean has the advantage of being deep like a pool, so light can reach all the algae particles. But reef tanks are not deep, so the algae needs to be a more concentrated "solid" variety to do the same amount of filtering and feeding in a small space. As far as being exposed to nutrients in reef tanks, this is just a matter of flow; the more flow, the more nutrients are delivered to the algae, and thus the more "reduction" they get."

"That is why reef tanks (actually, all tanks) grow algae super quickly if you don't remove nutrients some other way. The algae are adapted to always being the only filter in bodies of water; if there are nutrients available, algae WILL grow and reduce these nutrients, and at the same time, the algae WILL start feeding pods. The algae growth will continue until the nutrients are reduced to a low level, and this will be the limit to how many pods can be produced. So we will start focusing more on how the feeding of corals, and the filtering of the reef tank water, can all be done by the same algae."

 

[Aquarist007]

N&P... Nitrate and Phosphate. Plenty of threads on the subject of you search for them in the Chemistry Forum.

Here is a link to a new blog I created on Probiotics

http://www.reefcentral.com/forums/showpost.php?p=17690651&postcount=321

 

[capecoral]

Carbon this, carbon that

 

[capecoral]

"Effects of prey escape behavior, and water flow, on prey capture by the scleractinian coral Meandrina Meandrites. Proceedings of the 8th International Coral Reef Symposium, 1997."

"Corals feed on zooplankton [pods], mostly at night. Capture of zooplankton depends on delivery of prey [the pods] to the tentacles, and the ability of the corals to retain the prey, although mechanisms of prey capture are still not well understood. We designed a recirculating laboratory flow tank that yielded oscillatory flow comparable to [natural] reef conditions. This flow tank, in conjunction with high magnification video recordings with infrared illumination, allowed us to analyze small scale interactions using the coral Meandrina meandrites, and zooplankton prey collected at a reef near Discovery Bay, Jamaica during 1994 and 1995. Prey behaviors (average swimming speed, avoidance and escape abilities) altered susceptibility to predation for five [types of pods]. Flow conditions (still vs. oscillatory) and flow speed had significant effects on prey contact with the predator, with flow affecting both encounter and escape frequencies of the prey."

"Zooplankton provide much of the [nutrition] of corals, and are crucial for replenishment of nitrogen, phosphorus, and other nutrients that cannot be supplied completely by the symbiotic zooxanthellae [from light]."

"Copepods and other suspension-feeding zooplankton form crucial links in the coral reef food web, so factors that affect coral feeding rates are important to quantify. Understanding prey [pod] behavior, associated with predator prey interactions, is critical if we are to correctly assess the contribution of zooplankton to coral nutrition, energetics, and growth."

"During video analysis, all zooplankton that were in focus were categorized by type, and copepods were further identified to genus. After identification, each zooplankton-coral interaction event was characterized as one of the following: No Reaction - Zooplankter and tentacle were within 3 mm, but there was no change in swimming speed or angle; Avoidance - Zooplankter changed swimming speed and/or direction while approaching a tentacle (no contact); Escape - Zooplankter made contact with tentacle, but was not captured; Capture - Zooplankter made contact with tentacle and was captured. When a zooplankter remained in clear focus throughout the encounter, the swimming path was traced, frame-by-frame, from a high resolution 19" monitor. Two-dimensional swimming speeds [were calculated]."

"The two flow treatments had average speeds of 2.0 and 4.9 cm per second, measured along the top of the tentacle tips, and averaged over the entire flow cycle. The oscillatory flow was further divided into three phases: 1. Change in flow direction (characterized by low flow), 2. Increasing or decreasing flow, and 3. Maximum flow. Flow speeds were measured at the coral tentacle tips and within the tentacle zone for each phase of the flow cycle where zooplankton behaviors were observed. During all phases, flow was significantly slower within the tentacle zone. Flow several centimeters above the coral would be much higher and comparable to [natural reef] speeds above the tentacle tips."


"Table 1: Sizes and swimming speeds of abundant prey types measured in still water [simplified]:



........................Body Length......Average Speed(cm/s)....Escape Speed(cm/s)

Copepods

[species 1]........0.69.................0.70...........................6.61
[species 2]........1.29.................2.62...........................8.32
[species 3]........0.96.................0.83...........................7.92

Copepod Naplii.....0.21................0.16...........................0.01

Chaetognaths.....7.22.................0.48..........................10.96 "




"The cyclopoid "Oithona" and the calanoid "Calanopia" were the numerically dominant zooplankton throughout the study, but the calanoid "Temora" also was common in the still water feeding experiments."

"Copepods that interacted with the [corals] had a relatively constant swimming speed and direction preceding an interaction. As a coral tentacle was approached, the copepod either performed an avoidance reaction or made contact, resulting in an escape response or a capture. Avoidance and escape responses were characterized by a distinct change in swimming speed and trajectory. The percent occurrence of contacts was highest in still water, as evidenced by the high proportions of escapes and captures and relatively low avoidance responses. The addition of flow significantly decreased contacts with coral tentacles; 57 percent of copepods observed within 3 mm of a tentacle contacted the [coral] in still water treatments, while only 15 percent made contact in flow treatments."

"Almost all active interactions [of pods with the corals] occurred during Phase 1, which had the lowest flow speeds and fully extended tentacles."

"We found that both [pod] behavior and water flow help explain selective feeding by the coral Meandrina meandrites. Zooplankton on coral reefs have complex behavioral adaptations that promote their survival within the reef ecosystem. Most studies that have quantified [stomach] contents from [corals] show a strong negative selection for copepods. Additionally, selection differences have been observed among copepod genera; Calanopia was captured much more frequently than Oithona, even though the latter was more abundant in ambient water samples adjacent to three coral species."

"Meandrina meandrites uses mucus strands for feeding on particulate material, but this does not appear to be an effective mechanism for zooplankton feeding."

"Corals are passive suspension feeders, relying on water flow patterns to bring potential prey items into proximity with feeding structures. Water flow has profound effects on benthic suspension feeders. Differences in flow will affect suspension feeding by altering plankton contact rates, behaviors, and feeding structure effectiveness. We found a highly significant effect of flow on zooplankton behavior. Our data suggest that not only is flow speed important for determining particle encounter rates, but that the phase of the oscillatory flow is also important for predation by corals. [A previous researcher] characterized scleractinian corals as rigid organisms, regarding flow effects. However, for a coral with large polyps and long tentacles, such as Meandrina meandrites, this is not the best classification. Zooplankton-tentacle interactions occur on a scale smaller than the average height of the flexible tentacles of Meandrina meandrites. Water flow can deform the long tentacles of this coral at flow speeds well below 10 cm/sec. During deformation, the tentacles collapse together, and water (carrying the prey items) passes over the tentacles, following the streamlines."

"Mechanical deformation of the tentacles on top of the colony occurred during Phase 3 of the faster flow speed in this experiment. During this time, there is less surface area available for prey capture. However, tentacles become fully extended during Phase 1. During this phase the zone below the tentacle tips has a lower flow than [surrounding water], and prey are mixed or fall down into the zone below the tips. [Another researcher] also found that particle capture rates of Meandrina meandrites were higher at flow speeds below 5 cm/sec. Phase 1 of the oscillatory flow cycle always had the highest amount of prey contact. Flow regimes that have shorter periods would have less time during which tentacle deformation occurs, and possibly greater turbulence, both of which could increase plankton contact rates."

"As [corals which eat food], an important aspect of the success of corals is their ability to retain and ingest prey items after contact with feeding structures. The design of this study was to quantify specific prey behaviors that enhanced or prevented capture by predators. Our results suggest that in low flow, differences in prey avoidance and escape abilities explain the selective feeding. Oscillatory flow always has a phase where flow speeds are low, and differences in avoidance and escape behaviors of zooplankton would be important. We found that copepods and chaetognaths had excellent behavioral adaptations that prevented capture by corals. During periods of higher flow, tentacle deformation and prey size are more important."


"Yet Another Zooplankton Net:
http://www.youtube.com/watch?v=_UiKfYUAJAI

Zooplankton Under a Microscope:
http://www.youtube.com/watch?v=Y3QVBFFTNaA

Freshwater Zooplankton Tutorial:
http://www.youtube.com/watch?v=WzpO9hDUTek "

[size=-2]link[/size]​