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

[capecoral]

"It has long been known that algae produces vitamins and amino acids. Algae, after all, is the main primary producer of food in oceans and lakes, and actually is the most efficient primary producer of food, per unit biomass, on the earth:"

" 'Another significant difference between the land and the oceans lies in their standing stocks [of chlorophyll] - while accounting for almost half of total production, oceanic autotrophs only account for about 0.2% of the total biomass.'
http://en.wikipedia.org/wiki/Primary_production "

"This is because algae grows so quickly. The algae cells multiply so fast that they reach their saturation point (of self-shading) within just a few days. This is compared to things like trees which take decades before they "maximize" their growth." Matter of fact, algae growth is measured in "doublings per day", whereas trees, bushes and grass are measured in "inch or cm per year".

"But on reefs, because the water is so shallow compared to the open ocean, most of the primary production of food is done by sea-floor (benthic) algae (see attached graph) instead of phytoplankton. This is a very fortunate situation for aquarists, because it means you have the option of using the same production of food for your corals."

"So the focus of this writing is vitamins. Corals need vitamins just like you do, and in the ocean, the vitamins are produced by algae (phytoplankton in the open ocean; sea-floor algae on the reefs). Vitamins are also contained in the food you feed your fish, so the fish waste (especially if it goes through a powerhead and gets blended up) goes to feeding corals too. But the vitamins in fish waste are in a particulate form (detritus), whereas algae produces vitamins in a dissolved form (DOC). Both forms, of course, are available to corals on natural reefs, so the idea is to be able to make both forms available to the corals in your tank."

"The following study from 1970 helps clarify this. And while aquarists can have a multitude of varieties of algae working at the same time (thus having many different total vitamins), this study breaks down the vitamin production to individual alga species:"

"Production of Vitamin B-12, Thiamin, and Biotin by Phytoplankton. Journal of Phycology, Dec 1970"

"In the sea, [algae] may contribute a major portion of the amount of dissolved vitamins. In a recent study of the coastal plankton of La Jolla, California, concentrations of dissolved Vitamin B12, Thiamine (Vitamin B1), and Biotin were often highest when phytoplankton standing stock was high. The vitamin requirements of most of the phytoplankters were not known, since only a few have been cultured successfully in the laboratory [in 1970]. But if many of the phytoplankters required vitamins [themselves], it would be reasonable to assume that the dissolved vitamin concentrations of the waters would be low when the standing stock [of algae] was high. But the concentrations of vitamins [in the water], instead, indicated that they were being produced at a rate much more rapid then they were being utilized."

"[In the tests], some ecologically important phytoplankton released vitamins [...] during growth. [Two types of phytoplankton that were tested] produced both Thiamine (Vitamin B1) and Biotin when growing [in water that was supplied with] either 12 or 2 nanograms of Vitamin B-12 per liter. [Another phytoplankton] produced Thiamine [when growing in water supplied with] 12 nanograms of Vitamin B-12 per liter, and [another alga] produced Vitamin B12 and Biotin [when growing in water supplied with] 120 nanograms Thiamine per liter, but only Biotin [when supplied with] 10 nanograms Thiamine per liter. The amount of vitamins produced by an alga, and rate at which it was produced, varied with the phytoplankton, the concentration of the required vitamin [in the water], and the [growing] time. Vitamins produced during early and exponential growth were due to excretions [from the algae], and those produced at stationary growth resulted from excretion and release due to cell [breakage]."

"Table 2. Production of Thiamine and Biotin by [Alga #1], in water with 12 and 2 nanograms of Vitamin B12/liter [simplified]:


12 nanograms of Vitamin B12 in water:
----------------------------------
Stage of Growth.........Molecules/u3/day

.............................Thiamine.........Biotin
0-2 Days....................1080.............76
2-6 Days.....................236..............33
6-9 Days.....................106..............21



2 nanograms of Vitamin B12 in water:
----------------------------------
Stage of Growth.........Molecules/u3/day

.............................Thiamine.........Biotin
0-1 Days....................1100............220
1-3 Days.....................140.............110
3-6 Days.....................620..............30



"Table 5. Production of Vitamin B12 and Biotin by [Alga #2] in water with 120 and 10 nanograms of Thiamine/liter [simplified]:


120 nanograms of Thiamine in water:
-----------------------------------
Stage of growth........Molecules/u3/day

............................Vitamin B12...Biotin
0-2 Days.....................510..........3100
2-5 Days.......................52...........470
5-8 Days........................9............160



10 nanograms of Thiamine in water:
-----------------------------------
Stage of growth.........Molecules/u3/day

............................Vitamin B12...Biotin
0-1 Days........................0.........14000
1-3 Days........................0.........27000
3-6 Days........................0.........49000



"The production of dissolved vitamins into the [water] by phytoplankton may be attributed to excretion, and to release upon death and subsequent [opening] of the cells. In the present study, vitamins produced during early and exponential growth were excreted into the [water]. (The cells looked intact and well-pigmented under the microscope, and were apparently healthy)."

"All the [algae] used in these studies were [sterile] cultures. Therefore, the activities of bacteria in influencing the reported results were eliminated."

"As mentioned previously, it had been observed during the study of coastal plankton that in many cases where the biomass of phytoplankton was high, the concentrations of dissolved vitamins were also high. The results of the present study show that certain [algae], some of which predominate in many blooms, may contribute a significant amount of dissolved vitamins in the waters. The vitamins would be produced by healthy cells, and also released into the water upon death and cell [rupture]. This is also supported by observation of a "red tide" bloom of Newport Beach, California in 1967; [...] the bloom was dissipating, and concentrations of dissolved vitamins were relatively high. It is probably that the activities of phytoplankters (as well as bacteria and other heterotrophic organisms) are important in supplying vitamins to the sea."

"Acknowledgement: This work was supported in part by the Marine Life Research program, Scripps Institution of Oceanography's component of the California Cooperative Oceanic Fisheries Investigation, a project sponsored by the State of California, and in part by the U.S. Atomic Energy Commission."

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[Aquarist007]

Carbon this, carbon that

it is a very important circle of life---the carbon cycle---you might want to do a little reading on this:thumbsup:

 

[gasman059]

carbon this and that for sure---
:beer:

Guys this are controlled environments and in no way shape or form will be remotely similar to the vast ocean.

You can cut and paste all the info you want but in the end its all about husbandry,
Sorry I cou;n't resist!

BTW I do run a carbon source-- BP that is. It just makes me sad when I c soooo many useless posts with copy and paste stuff that means nothing to the average thread reader.

 

[Paul B]

I agree 100% with what Capecoral posted.
It also has been my own findings that algae is important to our captive ecosystems and am fast to point out to someone that says they have an algae problem they want to "cure".
We need algae in our tanks and I have always known and posted that algae supplies vitamins and other needed chemicals to our tanks.
I don't want algae all over my corals but when it is growing in my tank I know all is well and the corals, and fish fare much better. I worry if there is absolutely no algae growing in my system, then something is wrong.
Here where I live in NY the sea is full of algae of various sorts as is much of the northern waters, all the great fisheries of the world are in northern waters. This is because of algae which gets it's nutrients from the upwelling of various muds from the deep northern sea. If you hold up a glass of water from the northern waters it will be full of microscope life. If you hold up a glass of tropical water you will see nothing.
Algae is important in the sea and in our tanks. Also, sterility in a captive reef is a detriment to it's health. Detritus along with algae is what feeds what we call pods but is a combination of many life forms that nourish larger life forms in the sea and in our tanks.
My tank would be considered dirty by most aquarists but it is full of life from microscope diatoms to 1/4" amphipods. If your tank is aged enough and it is not full of this type of life, it is not a very healthy, stable system.
Sorry I don't have any graphs or links to direct to you but I do my own research and have been carefully looking at this stuff for probably too long.
I have spent countless hours peering at these things through a scope.
Maybe even longer than I look at the fish.
Just my opinion of course.

 

[Masterofnonsense]

I agree 100% with what Capecoral posted.
It also has been my own findings that algae is important to our captive ecosystems and am fast to point out to someone that says they have an algae problem they want to "cure".
We need algae in our tanks and I have always known and posted that algae supplies vitamins and other needed chemicals to our tanks.
I don't want algae all over my corals but when it is growing in my tank I know all is well and the corals, and fish fare much better. I worry if there is absolutely no algae growing in my system, then something is wrong.
Here where I live in NY the sea is full of algae of various sorts as is much of the northern waters, all the great fisheries of the world are in northern waters. This is because of algae which gets it's nutrients from the upwelling of various muds from the deep northern sea. If you hold up a glass of water from the northern waters it will be full of microscope life. If you hold up a glass of tropical water you will see nothing.
Algae is important in the sea and in our tanks. Also, sterility in a captive reef is a detriment to it's health. Detritus along with algae is what feeds what we call pods but is a combination of many life forms that nourish larger life forms in the sea and in our tanks.
My tank would be considered dirty by most aquarists but it is full of life from microscope diatoms to 1/4" amphipods. If your tank is aged enough and it is not full of this type of life, it is not a very healthy, stable system.
Sorry I don't have any graphs or links to direct to you but I do my own research and have been carefully looking at this stuff for probably too long.
I have spent countless hours peering at these things through a scope.
Maybe even longer than I look at the fish.
Just my opinion of course.

Most of us though are trying to grow tropical corals in tropical reef tanks, so it would make sense that we try to keep our tanks on the cleaner side. My opinion is that you are best off with really powerful filtration so you can feed a lot, often, but get it out of your tank before it decomposes and ups your undesirable nutrient levels.

 

[capecoral]

"Detritus in coral reef ecosystems: fluxes and fates. Proceedings of the 6th International Coral Reef Symposium, 1988."

"The bulk of detritus [waste] in coral reefs is produced [...] mainly from filamentous [hair] and sand-dwelling algae [...]. Mucus secreted from corals and other reef invertebrates constitutes the major source of non-algal detritus on coral reefs. [...] According to [a previous researcher], from 10 to 80 percent of net primary production may be available to reef consumers as detritus. This wide estimate reflects the uncertainty of detritus fluxes [movements] and fates in reef food chains [in 1988], despite the fact that little of this material appears to be exported."

"A seemingly endless variety of pelagic organisms consume dissolved and particulate detritus (benthic algal fragments, algal exudates, fecal pellets, coral mucus, and amorphous aggregates) and associated micro flora on coral reefs. Planktonic activity on reefs appears to be enhanced in response to [release from corals and other organisms on the sea floor]. Most of the [nutrition] in reef waters are conducted through microbial pathways, where detrital nitrogen (released by the benthos) is [eaten by zooplankton]."

"A large body of literature now exists documenting the role of mucus [DOC] in reef waters, especially utilization by bacteria and zooplankton. In the reefs of the Dry Tortugas, [another researcher] observed higher rates of microbial production and elevated biomass in coral surface micro layers (the mucus-rich zone extending a few millimeters above the surface of the coral). And in laboratory experiments, [copepods and mysids] ingested coral mucus detritus."

"Consumption of bacteria by proto-zooplankton and zooplankton has been made difficult to quantify. In the water column of Davies Reef, Great Barrier Reef, [another researcher] found that schools of mysid shrimp had a negligible impact in removing single celled phytoplankton and bacteria from the water column. In reef waters of Kaneohe Bay, Hawaii, [another researcher] observed that [micro zooplankton] did not control bacteria populations. [Bacteria remain the largest biomass in the ocean]."

"Other organisms such as [larger net-caught] zooplankton and fish are capable of playing a significant role in nutrient cycling on coral reefs. For instance, juvenile French and white grunts aggregate over coral colonies in reefs of St. Croix during the day, and feed at night in adjacent seagrass beds. These migrating [fish], by excretion, can double the amount of ammonium available to corals over a 4 hour period, as well as depositing feces [food] on the coral colonies."

"Here is a related video we found on Youtube:

Microbial Food Web:
http://www.youtube.com/watch?v=bc_fGWjmNeI "

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[Tigre9]

Great Info

Great Info

Thanks for all the great information everyone has provided, this thread is awsome & time consuming.

Love It! :thumbsup:

 

[bimmer88]

thanks for the info =)

 

[cloyd A.]

OK,what is sweetwater Zooplankton?

 

[capecoral]

I still say that it sounds like good chowder

 

[capecoral]

"[Some websites really get down to the serious, useable information about corals. This site is one of them:]"

"CoralScience.org:

"Life on earth is always classified into systematic groups by biologists, on the basis of external appearance (e.g. birds and mammals), behavior (diurnal or nocturnal) or the characteristics of living cells (e.g. plant or animal cells). A fourth means of distinction is metabolism, which can be autotrophic or heterotrophic. These terms are commonly used in marine biology, especially when regarding bacteria."

"Autotrophy means that organisms use inorganic molecules (such as CO2 and bicarbonate) to build organic ones, such as carbohydrates [DOC]. Examples are plants, which convert CO2 into carbohydrates by using sun's energy, or sulphur bacteria, which utilize the chemical energy stored in sulphur to convert CO2 to organics. For plants, we call this photoautotrophy (photo: light, auto: self and trophy: feeding) and for bacteria, in this case, we call this chemoautotrophy (chemo: chemical reaction). Another term for photoautotrophy is photosynthesis, another word for chemoautotrophy is chemosynthesis. Autotrophic organisms are also called primary producers ["primary reducers"], as they are the first link in the food chain which leads to biomass production from inorganic molecules. [And thus they reduce these inorganics]"

"Heterotrophy means that organisms make direct use of organic molecules, which are either present in the environment, or have been produced by autotrophic organisms. The consumption of plants by snails or cows is a form of heterotrophic feeding. From CO2, carbohydrates have been formed by using sunlight, which the plants have converted into biomass; this is subsequently consumed and converted into animal biomass."

"The photosynthates which zooxanthellae provide their [coral] hosts with can deliver up to 100% of the daily required energy [but not growth] budget for corals. These are often deficient in nitrogen and phosphorus [which ARE required for growth], and are thought to be used as fuel for respiration and mucus secretion, rather than being assimilated into biomass [growth]. Zooxanthellae transfer glucose, glycerol, fatty acids, triglycerides and even amino acids [all these are DOC] to their [coral] hosts. [...] Unfortunately, photosynthates alone are not sufficient to build animal tissue. These elements [which ARE needed to build tissue] are ingested by corals by catching particulate organic matter (plankton, detritus) from the water, and by absorbing dissolved [DOC] molecules. Heterotrophy [feeding] is essential for all corals and can meet up to 100% of the daily required energy in corals which are bleached or inhabit deep or turbid waters [and thus get NO energy from light]."

"Dissolved organic matter (DOM) [DOC] forms an important food source for many corals and related animals such as Zoanthus [zoo's]. Already in 1960, scientists found that stony corals from the genus Fungia were able to take up radioactively labeled glucose from the water. This was demonstrated by subsequent tissue analysis."

"In science, DOM is often split into various elements such as DON (dissolved organic nitrogen) and DOC (dissolved organic carbon). Important examples are carbohydrates(DOC), amino acids (DON, often referred to as DFAA or dissolved free amino acids) and urea; as less poisonous variant of ammonia which is produced by many animals. [...] This indicates the importance of aquarium supplements for nutrient-poor aquaria, which contain many coral colonies and few fish [because fish-waste is food]. These are mostly aquaria from the aquaculture industry, as most hobbyists tanks are densely stocked with fish."

"It is intriguing that many corals also take up urea [pee] from the water, and they can do this in even greater quantities compared to nitrate (at least in nature). This indicates these animals may have adapted to the presence of higher animals on the reef, such as fish, which collectively produce large amounts of this nitrogen-rich compound [pee] on a daily basis."

"Particulate Organic Matter (POC): This group of particles usually describes detritus [waste]; the small remnants of feces and decayed organisms. In the aquarium, food which is not consumed and removed also becomes detritus. Detritus eventually precipitates [falls] on the ocean floor or aquarium bottom as sediment. This layer of organic material is partially degraded [eaten] by bacteria, and converted into inorganic molecules such as nitrate and phosphate. This process is called mineralization."

"The [POC] sediment which is present on coral reefs contains bacteria, protozoa and their excrements, microscopic invertebrates, microalgae and organics. These sedimentary sources can all serve as coral nutrients, especially for colonies which grow in turbid waters. Experiments during which sedimentary carbon was radioactively labeled showed that corals such as Fungia horrida and Acropora millepora readily took up sediment [as food]. The more sediment present, the more uptake [feeding] is measured; 50-80% of this material is converted into biomass [growth] by several species. This has also been found for the Caribbean species Montastrea franksi, Diploria strigosa and Madracis mirabilis; detritus is taken up by the polyps, and the available nitrogen is converted into biomass [growth]."

"Plankton: This group is sometimes regarded as the living component of POM. The term plankton is a common name for an astoundingly large group of organisms which can be categorized in different ways. Figure 7 shows a commonly accepted division into pico-, nano-, micro- and mesoplankton. These groups consist of (cyano)bacteria and protozoa (picoplankton), algae and protozoa (nanoplankton), microscopic crustaceans such as rotifers and large protozoa (microplankton) and countless other species of crustaceans (mesoplankton). Fish and invertebrate larvae can further be categorized into micro- and mesoplankton, depending on the species."

"Plankton was not considered as an important coral food source for many years; it was believed concentrations on the reef were too low to have any significant effect. In the meantime, more accurate estimations have been made, based on improved measuring techniques. These values are particularly high during summers, which is probably due to the abundance of phytoplankton. This leads to increased concentrations of zooplankton, as they feed on the extra available phytoplankton."

"Other branched SPS corals are however capable of catching more zooplankton per unit of weight compared to species with larger polyps [LPS]. It seems that polyp size is not a solid predictor of capture efficiency, but rather determines maximum prey size."

"The species Pocillopora damicornis and Pavona gigantea which inhabit the Gulf of Panama were found to mainly feed on isopods, amphipods and crab zoea [all plankton]."

"Individual polyps of the Atlantic species Madracis mirabilis and Montastrea cavernosa are able to capture and ingest 0.5 to 2.0 prey per hour. On a colony level, these numbers get big pretty quickly. A small Seriatopora colony of 14 ml in volume is able to capture 10,000 Artemia in 15 minutes! This however requires very high aquarium zooplankton concentrations of 10,000 to 20,000 Artemia per liter."

"Other results show that an aquarium concentration of 2000 nauplii/liter (about 5000 nauplii /gallon) is ideal for stony corals such as Pocillopora damicornis. To reach this concentration, it will take a daily amount of one million nauplii for the average 500 liter (130 USG) aquarium."

"Next to fish, protein skimmers also are voracious particle predators. All forms of mechanical filtration will decrease available nutrients, unfortunately. Without this filtration however, water quality declines quickly. Water changes, phosphate reactors, refugia with Chaetomorpha macro algae [and other solid-algae solutions that we will point out] and denitrification reactors all work well to allow plankton populations to persist, however these are often quite labor intensive. Keeping many organisms in a small aquarium, be it corals or fish, simply degrades water quality quickly. In nature, the ratio between biomass to water volume is much lower. [And in the ocean, algae is 90% of all biomass except bacteria]. Next to this, many waste products are quickly converted into new biomass such as plankton and sponges. This also occurs in the aquarium, to some extent, however this does not outweigh the amount of nutrients which is introduced on a daily basis."

"[Bacteria and protozoa] play an important role in the marine food chain. In terms of biomass and photosynthesis, these organisms form the most important part of pelagic plankton. On the reef, bacterial concentrations sometimes lie around one million per milliliter! For cyanobacteria, the number fluctuates around 10,000-100,000 per ml, and for flagellates around 10,000 per ml. As these microbes grow fast, they are highly important for the nitrogen and carbon cycles in the ocean. For the model species Stylophora pistillata, if has been found that [eating] microbes yields almost three times as much nitrogen as ammonia, nitrate and amino acids together."

"Montipora capitata colonies have been found to increase their plankton feeding rates after bleaching, which completely satisfies their daily metabolic requirements."

"Although it may seem that feeding and photosynthesis are two separate processes, they are in fact intricately linked. Nutrient exchange between corals and symbiotic algae is diverse, and this is increased by extra light and feeding. More feeding stimulates zooxanthellae growth and buildup of pigments such as chlorophyll. This makes the coral a more effective 'solar cell', which is able to convert more light into chemical energy. This benefits both the coral and the algae. It has become clear from CORALZOO-experiments that corals grow less than expected under high intensity lighting. This is most likely due to [lack of food]. French scientists found that this limitation can be reduced by providing extra nutrition in the form of zooplankton. This in fact occurs in nature as well, mostly during summers, when ample light and zooplankton particles are available. This situation can be simulated in the aquarium as well, by providing extra plankton in combination with T5 or metal halide lighting."

"After eight weeks of zooplankton feeding (such as Artemia nauplii), calcification [growth] rates of Stylophora pistillata doubled. As tissues grew faster compared to the skeleton, this led to fleshier corals. When these corals received less light, a decline in growth rate could be prevented by providing additional plankton. This fact is interesting for aquarists who do not want to make use of heavy lighting above the aquarium, for obvious reasons."

"Coral feeding quickly leads to increased tissue production and protein concentration. This increase was about 2-8x for Stylophora pistillata after three weeks of zooplankton feeding! Next to proteins, lipid content also increased. Both saturated and unsaturated fatty acids increased in Galaxea fascicularis tissue after feeding with Artemia nauplii. More light actually decreased tissue fat contents [this is bad]. Although this seems contradictory, these corals probably invested more fatty acids into growth and zooxanthellae production to enhance usage of extra light."

"[Here is] an overview of the studies discussed in this article, which shows the diverse effects of feeding on coral physiology. Fed corals display (1) twofold greater protein concentrations and photosynthetic rates per unit skeletal surface area; (2) twofold higher dark and light calcification rates; (3) twofold greater organic matrix synthesis in the dark and a 60% increase during daytime."

"For Stylophora pistillata, zooxanthellae tissue concentrations doubled within several weeks of zooplankton feeding, both at low and high light levels."

"Stony corals such as Leptoseris and Montipora spp. also occur in the mesophotic zone, even though light levels be may as low as 1% of the sunlight irradiance experienced at the surface! This shows that even zooxanthellate corals can adapt to very low light intensity levels, as long as this is compensated by heterotrophy such as plankton feeding."

"It must be noted that major differences exist between the fastest growing coral, and the most attractive one. Most aquarists favor bright colors, which arise by coral host pigmentation. Brown zooxanthellate pigments such as chlorophyll are considered to be unattractive. These last pigments do provide the energy for increased growth, in contrast to brightly colored pigments which act as sunscreens. Producing them also goes at the expense of coral growth. [Thus, increase feeding when you want growth, and decrease feeding when you want colors.]"

 

[capecoral]

...

 

[allsps40]

Where I live most LFS get this stuff called "Reef Stew" it is grown locally. Consists of several different types of live zooplankton, phytoplankton, brine shrimp, mysis shrimp and even some shrimp larvae from time to time. This stuff is great for feeding sps and all filter feeders. It really cool when you get it and look through the bag, you see all the little critters swimming around. Regularly feeding this in the past has created a large population of live mysis in my fuge. A tank move killed them all off though I am just now trying to get the population back.

 

[capecoral]

Sounds like an ant farm

 

[capecoral]

"[The next few studies will be about DOC in the ocean. DOC is dissolved organic carbon, not to be confused with GAC which is the granular activated carbon that some people use as a filter to remove DOC. The following studies are part of a focus we want to give DOC because of the misunderstandings that many reefers have about it. The first study (below), actually is not a research study per se, but an academic paper. These types of papers are great at explaining difficult things on a level that, while very simple for biologists, is much easier to understand for hobbyists. The main thing to remember while reading studies about DOC is that DOC is the largest portion of carbon in the ocean, and that it feeds almost everything, especially corals. When you are looking at "crystal clear" reefs, you are actually looking directly through the DOC that is keeping the corals alive. Everything in the ocean has adapted to grow best in this DOC.]"

"Online photochemical oxidation and flow injection conductivity determination of Dissolved Organic Carbon [DOC] in estuarine and coastal waters. The University of the South Pacific Library, 1999."

"Carbon is the link between the inorganic environment, and the living organisms. The carbon cycle basically illustrates the interchange of carbon between the atmosphere, hydrosphere, biosphere and the lithosphere. The focus of this [paper] is the dissolved organic carbon (DOC) in natural waters, specifically marine and estuarine waters. In natural waters, the total organic carbon (TOC) is composed of particulate organic carbon (POC) and DOC. In most of these waters, the concentration of DOC is greater than the concentration of POC. For example, in the sea, the concentration of DOC surpasses POC by a factor of 50 to 100 percent. [Meaning, there is more DOC than there are food "particles", even though the DOC is invisible.]"

"DOC in natural waters is usually made up of fatty acids, carbohydrates, amino acids, hydrocarbons, hydrophilic acids, fulvic acids, humic acids, viruses and clay-humic-metal complexes. [And this is what corals have adapted to grow best in]."

"In oceanic waters, DOC levels vary around 0.5 mg/L, but can also be as high as 20 mg/L in coastal waters, and at the continental shelf."

"The total DOC in seawater is [estimated at] 0.7 mg C/L, and is a major reservoir of organic carbon. In coastal waters, because of increased phytoplankton activity and the input from land, DOC values can be as high as 20 mg/L."

"The [in-ocean] production of DOC is led by the phytoplankton, via exudation ["giving off"] and cell lysis [breakage]. The role of phytoplankton in DOC production is also important in other natural water bodies like lakes, where such release is of ecological significance because the DOC released provides a source of energy to heterotrophic [without light] consumers and decomposers. The release of DOC by phytoplankton is also considered to be a functional response of individual cells to changes in environmental conditions. In addition to phytoplankton, planktonic grazers like copepods and protist grazers also contribute to DOC production via excretion [waste]. Other marine organisms also excrete DOC via their wastes, and the decomposition of their dead bodies by microorganisms like bacteria and fungi."

"Carbohydrates account for 5 to 10 percent of the DOC in seawater. All forms of planktonic cells (phytoplankton and zooplankton) consist of 10 to 70 percent carbohydrate, and the DOC they release into the water column has a 30 percent component as carbohydrate. The contribution by carbohydrates to DOC has not been considered significant in the past, because of the insensitive analytical techniques used for their measurement. The carbohydrates identified were predominantly polysaccharides. Carbohydrates are highly reactive [substances], and they support heterotrophic metabolism [consumption by animals, like corals]."

"Apart from fulvic and humic acids, there is another subclass of humic substances known as hydrophilic acids. [...] In seawater, hydrophilic acids constitute 50 percent of the DOC. However, since the hydrophilic acids have been isolated only recently [in 1999], very little is known about their structures and chemistry."

"The metabolic activities of marine organisms also results in the production of a range of biomolecules that form part of DOC in the ocean. These compounds (biomolecules) include hydrocarbons, lipids, carboxylic acids and amino acids. These compounds usually constitute 10 to 20 percent of the total DOC in most natural water bodies. [...] Apart from these, there are other trace compounds like aldehydes, sterols, organic bases, organic sulfur compounds, alcohols, ketones, ethers, chlorophyll and other pigments, and organic contaminants that are present as DOC in estuarine and marine coastal waters."

"DOC plays an important role in the bio-geochemistry of any aquatic system, because it is a component of the total carbon which is cycled through organisms, the water body, sediments and plants. Therefore the bulk analysis of water for DOC is essential for the overall understanding of the production-decomposition cycle, and the [time and place] variability of DOC in an aquatic system."

"The tissue of all plants and animals in the marine and estuarine waters have significant amounts of carbon. The carbon is taken primarily in the dissolved state [DOC] by the organisms. In other words, DOC in aquatic ecosystems provides energy and carbon for the metabolism of heterotrophic bacteria, plus some species of phytoplankton which can subsist heterotrophically on dissolved organic [substances] [instead of just light]. Marine organisms also release DOC compounds to control some aspects of their environment. The released compounds can function as toxins to repel predators and competitors, neutralize toxins and to function as attractants for mating. [And these compounds are consumed by bacteria and corals as well]."

"DOC in the form of humic substances have phenolic, hydroxyl and carboxylic groups that can chelate with toxic metal ions like mercury, aluminum and lead. When toxic metals bind to DOC, their toxicity is reduced. This is because dissolved metal ions (free metal ions) are more toxic compared to their complexed form. In aquatic systems, the complexation processes of metal ions by DOC also results in the transport of the metal ions through the uptake of the complexed DOC by organisms, and the aggregation of DOC onto participate matter which eventually sink to the ocean bed [and gets buried in the sediment]."

"The chelation of essential ions like magnesium, calcium and iron is another important role of humic substances with respect to living systems in aquatic bodies like the sea. In the chelated form, the essential ions can be taken in by living organisms, and furthermore, chelation prevents the essential ions from precipitating [onto the sea floor]."

"DOC, primarily in the form of humic and fulvic acids, binds organic pollutants such as phthalates and pesticides as in the case of heavy metals. Humic acids have a greater affinity for hydrophobic compounds than fulvic acids. In addition, unlike fulvic acids, humic acid's binding ability is not affected by large changes in pH. This is because fulvic acids are soluble throughout the entire pH range; therefore they are available for binding with suitable metal centers and organic pollutants."

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[jefathome]

That's excellent news. Here I always thought it was a protective response and that they were all really mad at me.

I wonder what this forum would think about using blood as a coral food? Red blood cells are appx 8 microns in size. And while they are not the best source of protein they do have some proteins that I'm sure biological organisms would eat. Blood is plentiful, and can be relatively easy to get. The saline in our tanks nearly mimincs the human osmolality so they would stay intact for quite some time, at least enough to find their way to a coral or other filter feeder.

About the only thing I can think they would be missing is the calcium in the exoskeletons of the plankton.

.....discuss.....

Aaron

Atack of the Vampire Corals!!

I'm thinking a cross between Seymore (Little shop of horrors) and TrueBlood.

 

[capecoral]

Blood food! Just make a donation to you tank each week

 

[GreshamH]

Blood food! Just make a donation to you tank each week

Blood has been used in feeding aquariums for a long long time. It's more a public aquarium deal, but it's still be used for a rather long time

 

[capecoral]

"[The following study is meant to address the thought which some reefers have, that DOC "build ups" in a closed systems. DOC is actually consumed by bacteria, whether the system be closed or open.]"

"Bacterioplankton carbon growth yield and DOC turnover in some coral reef lagoons. Proceedings of the 8th International Coral Reef Symposium, 1997.

"DOC [dissolved organic carbon, not to be confused with GAC which is granular activated carbon] is widely recognized as one of the largest carbon standing stocks [amounts] on the earth; but still, little is known about DOC utilization by bacterioplankton [bacteria in the water column, not on sand or rocks] and its subsequent transfer in pelagic [water column] foodwebs. The estimation of Carbon Growth Yield (C.G.Y.) is key to the evaluation of the contribution of bacterioplankton in pelagic [water column] networks. We examined DOC standing stocks [amounts], consumption, and turn-over in some Tuamotu atoll lagoons (French Polynesia) [these are basically "closed systems"], and in the Great Astrolabe Reef lagoon (Fiji) [these are semi-closed systems]. [...] Results of these experiments show that average DOC values range between 105 and 121 uM in the lagoons visited, and were significantly higher compared to surrounding surface oceanic waters (87-102 uM). [...] Bacterial CGY [Carbon Growth Yield] is very low, and ranges between 4 and 7 percent. DOC turnover is estimated to be 11 to 32 days in the lagoons visited. These data suggest that bacteria are resource-limited in these lagoons. This is in agreement with the slow growth rates of bacterioplankton in these coral reef lagoons. [This means that the bacteria in the water column (not on the sand or rocks) consume the DOC faster than the DOC is produced, thus keeping the DOC at low levels, and that the bacteria would grow faster if more DOC were available.]"

"Growth of planktonic bacteria [which corals eat] is highly dependent upon the supply of inorganic nutrients [Nitrate, Phosphate] and dissolved organic carbon (DOC), either directly or through POM [particulate organic matter] solubilization by exoenzymes [enzymes which break down the particles]. This is an important function of heterotrophic [not using light] bacteria, as this carbon pool would be otherwise lost for the trophic [food] networks. While DOC is admitted to be one of the largest carbon standing stocks [amounts] on the Earth, at present time [1997] few studies have focused on utilization of natural DOC by bacterioplankton, the first step by which DOC reaches the upper levels of food webs [DOC -> bacteria -> microbes -> zooplankton -> corals]. The efficiency of transformation of DOC into bacterial biomass [bacteria consume the DOC], here referred as bacterial carbon growth yield (CGY), is a crucial parameter in attempts to evaluate the fate of primary production and [outside] inputs in aquatic systems."

"Very few studies [as of 1997] have dealt with DOC in coral reef environments. And to our knowledge, in atoll or island lagoons, bacterioplankton CGY and DOC turnover have not been yet investigated. The goal of this study was to examine DOC standing stock, turnover, and [DOC's ability to change] in some coral reef lagoons."

"This work was carried out as part of several programs intending to describe the water column biological productivity of coral reef lagoons. The work on Great Astrolabe Reef lagoon was performed in May 1994. Bacterioplankton variables and DOC concentrations were determined at 10 sites from samples collected at 10 meters depth (stations are 20 to 40 meters deep). Samples were collected at an oceanic station up to a depth of 100 meters. In Takapoto lagoon, samples were collected daily at 0.5 meters depth from 16 to 25 January 1994 at two stations. Samples were collected from 8 other stations in late January 1994. In Tikehau lagoon, samples were collected daily from 16 May to 3 June 1993 at 0.5 meters depth at the lagoon reference station (total depth 20 meters) which is representative of the main part of Tikehau lagoon (average depth 25 meters). Oceanic water (0.5 meters) samples were collected on the southern part of the atoll."


"Table 1 [simplified]

Site...........................................DOC (uM)

Tikehau lagoon............................105
Takapoto lagoon..........................121
Great Astrolabe lagoon..................114
Ocean near Tikehau (surface).........87
Ocean near Tikehau (0-40 deep).....102 "


"[In-ocean] DOC turn-over, due to bacterioplankton consumption, may be estimated from bacterial production (BP) and bacterioplankton carbon growth yield (CGY) which was determined in [the laboratory]. Bacterial carbon consumption (BCC) would thus equal BP/CGY. In the Great Astrolabe Reef lagoon, with an average BP of 4.32 ugC per liter per day, and a CGY of 6.6 percent, BCC = 4.32/0.066 = 65 ugC per liter per day [thus bacteria are consuming 65 micrograms of DOC per liter per day]. DOC turnover rate would thus equal 65/1372 = 0.048 per day, and DOC turnover time would be 1/0.048 = 21 days [thus the entire amount of DOC in the lagoon would be depleted by bacteria in 21 days]."

"A calculation for Tikehau and Takapoto lagoons would give turnover times of 13 and 35 days, respectively [for all the DOC to be depleted by bacteria]."

"DOC values in the 3 lagoons visited are close to the values determined in comparable environments (Table 3). In the oceanic sites, values ranging from 87 to 110 uM are in the range reported for Pacific surface waters."


"Table 3: DOC concentrations in Pacific surface waters and in some coral reef lagoons [simplified]:

Site............................................................DOC

Pacific near Eniwetok.....................................86
Pacific near Houtman Abrolhos atoll lag. (Aust)...13-33
West Pacific.................................................101
Equatorial Pacific (1989).................................125-225
Station Aloha Hawaii......................................90-115
Equatorial Pacific (1992).................................63-67
Pacific near Miyako Island...............................93
Pacific surface near Tikehau............................87
Pacific (0-40 meters deep) near G. Astro. Rf......110
Mauro Atoll lagoon.........................................145
Ponape Island lagoon.....................................223
Eniwetok atoll lagoon.....................................100
Houtman Abrolhos atoll lagoon (Australia)..........130-305
Kaneohe Bay, Hawaii......................................148
Bora Bay, Miyako Island..................................84
Wreck Reef..................................................64
Tikehau lagoon.............................................105
Takapoto lagoon...........................................121
Great Astrolabe Reef lagoon............................114 "


"At the oceanic station near the Great Astrolabe Reef, dissolved organic carbon decreases from the surface to 100 meters depth (Figure 4), while bacterioplankton characteristics show a classical vertical [increase] pattern with a maximum abundance in surface water, and a maximum activity in deeper layers, in relation to phytoplankton maximum production [which is a little bit below the surface; thus the most bacteria activity is where there is the most algae]."

"Total DOC turnover in the lagoons visited ranges from 2 to 5 weeks. This is consistent with the long turnover time of bacteria in the three lagoons visited (4 to 8 days), regarding the average temperatures around 30 degrees C."

"The comparison between total DOC decrease and bacterial biomass increase [in the laboratory] allowed the estimation of bacterial Carbon Growth Yield consistent in three different coral lagoon waters. [...] The low CGY values confirm the importance of bacterioplankton in the mineralization processes [the conversion of organics to inorganics] occurring in coral reef waters. Such low CGY values are an index of bottom-up limitation of bacterioplankton growth in the coral reef lagoons, and are in agreement with the low bacterial growth rates (turnover times of 4 to 8 days), considering an average temperature of 30 degrees C. This [slow bacterial growth] could be due to a poor availability of either organic carbon, or inorganic nutrients. [Thus, the bacteria are ready and able to grow more, and consume more DOC, but they are limited by either not enough DOC or inorganics]."

[size=-2]link[/size]​

 

[acropora1981]

if you ever get a chance to use a microscope to watch coral polyps (especially SPS) use their chemicals to zap and eat pods, you'll understand. A polyp senses a pod (some polyps actually chase pods), and then it stings the pod with chemicals; it then wraps around it with a sticky net and pulls the pod into the "stomach" of the coral where the pod gets digested over the next couple of hours.

uhh...no. Nope. They don't sting with chemicals. They use nematocysts. Its a physical process. You can see a video on youtube.

http://www.youtube.com/watch?v=6zJiBc_N1Zk