Inducing broadcast coral spawning ex situ: Closed system

Scrubber_steve

I'm really very likeable
The Horniman Museum has a project where they have spawned two different corals in captivity.

https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.3538

They give a rundown on the Mesocosm design, & they use algae filtration in the mix, which is the part I like. :bounce3::bounce3::wavehand:

"Water then flowed into an algae refugium housing a mix of macro algae (Caulerpa prolifera, C. brachypus,
C. racemosa, and Chaetomorpha spp.) that were lit by four 54 watt T5HO fluorescent bulbs
(Wave Point 54 watt Luminar, x2 Sun Wave & x2 Super Blue) (Figure 1i) on a 12/12 hr cycle.
As algae grew NO3 and PO4 were taken up from the water and exported from the mesocosm via regular algae harvesting."


ece33538-fig-0001-m.jpg


Mesocosm setup: (a) 780 L broodstock aquarium, (b) main drive pump, (c) 40 mm polyvinyl chloride (PVC) stand pipes,
(d) mechanical filtration section of sump, (e) algae refugium, (f) protein skimming section of sump, (g) main drive pump section of sump,
(h) E200 PowerRoll filter, (i) wave point luminar, (j) protein skimmer, (k) baffle, (l) 32 mm PVC inlet, (m) fluidized reactor,
(n) Triton Base elements CORE 7, (o) four channel peristaltic pump, (p) multi chamber container for individual element corrective dosing,
(q) aquarium chiller, (r) Radion XR30w Pro LED light, (s) lunar LED, (t) black mdf panel fitted into an aluminum frame, (u) integrated blackout blind

.
 
I've been supporting Horniman's Project Coral for roughly a year and half now and would strongly encourage everyone to do so. They are doing very important work expanding our understanding of what it takes to maintain corals long term.

The Horniman Museum has a project where they have spawned two different corals in captivity.

https://onlinelibrary.wiley.com/doi/full/10.1002/ece3.3538

They give a rundown on the Mesocosm design, & they use algae filtration in the mix, which is the part I like. . .

Let's just gloss over the fact they DID NOT chose to use an ATS to help control nitrogen and phosphorus. In fact their livestock selections specifically were to control and minimize turf algae growth. :D

For those intersted there's quite a bit of research showing how the Labile DOC released by algae promotes pathogenic bacteria to corals. For starters I would encourage everyone to get Forest Rohwer's "Coral Reefs in the Microbial Seas". Even though it has a couple hundred references listed it is an easy read, sometimes funny, sometimes poignant, and is an excellent introduction to the roles of DOC in influencing teh microbial populations on reefs.

And here's a list of some of the research that's been done over the last couple decades:

FYI: DOC can be roughly seperated into three catagories, Labile, Semirefractory and Refractory. Most of the following papaers are looking mainly at Labile DOC. This will raise the hackles on some reefers but keep in mind Labile DOC and Carbon Dosing are synonamous. Jasper deGeoij's work shows cryptic sponges remove labile DOC about a thousand times faster than bacterioplankton. Included are links to some of the research showing what cryptic sponges are doing as well. Also, researchers tend to use DOM (Dissolved Organic Matter) and DOC (Dissolved Organic Carbon) interchangebly.

long-term stony coral survival in the Coral Reef Exhibit at Reef HQ Aquarium, Townsville, Australia was measured in days, not years. (See figure 3) (Thanks for this link Scrubber Steve. :D)
https://www.burgerszoo.com/media/560502/chapter-9.pdf

Indirect effects of algae on coral: algae‐mediated, microbe‐induced coral mortality
Coral seperated from algae with a .02 µm filter die. Treatment with aampicillan prevents death.
https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1461-0248.2006.00937.x

Influence of coral and algal exudates on microbially mediated reef metabolism.
Coral DOC improves oxygen (autotrophy), algae DOC reduces oxygen (heterotrophy).
https://peerj.com/articles/108/?utm_source=TrendMD&utm_campaign=PeerJ_TrendMD_0&utm_medium=TrendMD

Effects of Coral Reef Benthic Primary Producers on Dissolved Organic Carbon and Microbial Activity
Algae releases significantly more DOC into the water than coral.
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0027973

Pathologies and mortality rates caused by organic carbon and nutrient stressors in three Caribbean coral species.
Starch and sugars (doc) caused coral death but not high nitrates, phosphates or ammonium.
http://www.int-res.com/articles/meps2005/294/m294p173.pdf

Visualization of oxygen distribution patterns caused by coral and algae
https://peerj.com/articles/106/

Biological oxygen demand optode analysis of coral reef-associated microbial communities exposed to algal exudates
Exposure to exudates derived from turf algae stimulated higher oxygen drawdown by the coral-associated bacteria.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3719127/

Microbial ecology: Algae feed a shift on coral reefs
https://www.nature.com/articles/nmicrobiol201661

Coral and macroalgal exudates vary in neutral sugar composition and differentially enrich reef bacterioplankton lineages.
https://www.ncbi.nlm.nih.gov/pubmed/23303369

Sugar enrichment provides evidence for a role of nitrogen fixation in coral bleaching
https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.13695

Elevated ammonium delays the impairment of the coral-dinoflagellate symbiosis during labile carbon pollution
(here's an argument for maintaining heavy fish loads if you're carbon dosing)
https://www.sciencedirect.com/science/article/pii/S0166445X19307192

Excess labile carbon promotes the expression of virulence factors in coral reef bacterioplankton
https://www.nature.com/articles/ismej2017142

Unseen players shape benthic competition on coral reefs.
https://www.ncbi.nlm.nih.gov/pubmed/22944243

Allelochemicals Produced by Brown Macroalgae of the Lobophora Genus Are Active against Coral Larvae and Associated Bacteria, Supporting Pathogenic Shifts to Vibrio Dominance.
https://www.ncbi.nlm.nih.gov/pubmed/27795310

Macroalgae decrease growth and alter microbial community structure of the reef-building coral, Porites astreoides.
https://www.ncbi.nlm.nih.gov/pubmed/22957055

Macroalgal extracts induce bacterial assemblage shifts and sublethal tissue stress in Caribbean corals.
https://www.ncbi.nlm.nih.gov/pubmed/23028648

Biophysical and physiological processes causing oxygen loss from coral reefs.
https://elifesciences.org/articles/49114.pdf

Global microbialization of coral reefs
DDDAM Proven
https://www.nature.com/articles/nmicrobiol201642

Because sponges are essential players in the carbon, nitrogen and phosphorus cycle(s) on reefs here's some links to research done with them.

Element cycling on tropical coral reefs.
This is Jasper de Geoij's ground breaking research on reef sponges. (The introduction is in Dutch but the content is in English.)
https://www.rug.nl/research/portal/files/14555035/13completethesis.pdf

Sponge symbionts and the marine P cycle
https://www.pnas.org/content/112/14/4191

Phosphorus sequestration in the form of polyphosphate by microbial symbionts in marine sponges
(Chris Kenndall had a problem with low PO4 and had problems raising it with Neophos. Samples sent off showed phosphorus crystals developing in some of the sponges in his system accounting for at least some of his systems consumption.)
https://www.pnas.org/content/112/14/4381

Differential recycling of coral and algal dissolved organic matter via the sponge loop.
Sponges treat DOC from algae differently than DOC from corals
https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/1365-2435.12758

Surviving in a Marine Desert The Sponge Loop Retains Resources Within Coral Reefs
Dissolved organic carbon and nitrogen are quickly processed by sponges and released back into the reef food web in hours as carbon and nitrogen rich detritus.
https://www.researchgate.net/publication/279061640_2013_deGoeij_Science_Sponge_loop

Natural Diet of Coral-Excavating Sponges Consists Mainly of Dissolved Organic Carbon (DOC)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3934968/

The Role of Marine Sponges in Carbon and Nitrogen Cycles of COral Reefs and Nearshore Environments.
https://search.proquest.com/openvie...9d1e5/1?pq-origsite=gscholar&cbl=18750&diss=y

And since we're discussing favorable and not so favorable bacteria here's a paper looking at how different corals and polyps are influencing the bacteria in the water column.
Aura-biomes are present in the water layer above coral reef benthic macro-organisms
https://www.ncbi.nlm.nih.gov/pubmed/28828261

And if you want to get your system tested aquabiomics.com can test it.
(I haven't gotten around to testing nay of my tanks in case anyone is wondering.)
 
Let's just gloss over the fact they DID NOT chose to use an ATS to help control nitrogen and phosphorus. In fact their livestock selections specifically were to control and minimize turf algae growth.

I note tim your misguided attack on ATS is an indirect attack on me. That's fine.

Firstly tim, I'll point out that I don't consider you anywhere in the realm of an elite reef aquarium hobbyist (a portrayal of yourself that you attempt to project everywhere) no matter how many links to scientific papers you provide, & no matter how many boring rants you produce.

On the matter of attacking "turf algae", I don't grow turf algae on my scrubber screen, & I don't know of anyone doing so, at least on a modern 'Algae Scrubber'.

In any case, lets discuss "turf algae"!

What is "turf algae" ?

Turf algae are multispecies assemblages of diminutive, mostly filamentous algae that attain a vertical height of only 1 mm to 2 cm (Figure 1). Turf algae often exist as assemblages (algal turfs), are ubiquitous in reef systems and are composed of the small, juvenile stages of macroalgae (e.g., Gelidium spp., Gelidiella spp., Digenia simplex) along with faster-growing filamentous species (usually red algae such as Polysiphonia spp., Herposiphonia spp., and Ceramium spp.; blue-green algae (cyanobacteria); diatoms; brown algae; green algae; and coralline algae) and detritus and sediments.
https://repository.si.edu/bitstream/handle/10088/21635/SCMS39_Lang_17.pdf

Just how bad is "turf algae" & it's effects on coral reefs ?

Introduction to Turf Algae
Algal Turfs: Ecological Importance
"¢ Algal turfs are integral to the healthy function of one of the richest habitats on earth
"“ e.g., Knowlton 2001
"¢ Rapid turnover of this organic matter forms the base of coral reef trophic structure
"“ e.g., Wanders 1976, Adey & Steneck 1985, Carpenter 1985, 1986, Klumpp et al. 1987, Klumpp & McKinnon 1989
"¢ Algal conglomerates accumulate detritus and sediments that provide raw materials for nutrient recycling "“ e.g., nitrogen fixation by filamentous cyanobacteria
"¢ Heterogeneous microhabitats for other unicellular algae (such as diatoms), protozoans and micro invertebrates
"¢ In intertidal regions, turf communities can temper environmental stressors by retaining water and providing shade among densely packed filaments "“ Hunt & Denny. 2008.
"¢ Benefit of shading has been shown to be advantageous to some corals which resist bleaching when inhabited by endolithic algae "“ Shashar et al. 1997
"¢ Some corals recover from bleaching episodes (loss of zooxanthellae) better when green‐algal derived photo-assimilates are incorporated into coral tissue6 "“ Fine & Loya 2002
https://www.stri.si.edu/sites/taxonomy_training/Docs/phycology_docs/4_1_Introduction_Turf_Algae.pdf

&

Competitive interactions between corals and turf algae depend on coral colony form
Abstract
Turf algae are becoming more abundant on coral reefs worldwide, but their effects on other benthic organisms remain poorly described. To describe the general characteristics of competitive interactions between corals and turf algae, we determined the occurrence and outcomes of coral"“turf algal interactions among different coral growth forms (branching, upright, massive, encrusting, plating, and solitary) on a shallow reef in Vietnam.

In total, the amount of turf algal interaction, i.e., the proportion of the coral boundary directly bordering turf algae, was quantified for 1,276 coral colonies belonging to 27 genera and the putative outcome of each interaction was noted. The amount of turf algal interaction and the outcome of these interactions differed predictably among the six growth forms.

Encrusting corals interacted most often with turf algae, but also competed most successfully against turf algae.
The opposite was observed for branching corals, which rarely interacted with turf algae and rarely won these competitive interactions.

Including all other growth forms, a positive relationship was found between the amount of competitive interactions with neighbouring turf algae and the percentage of such interaction won by the coral. This growth form dependent ability to outcompete turf algae was not only observed among coral species, but also among different growth forms in morphologically plastic coral genera (Acropora, Favia, Favites, Montastrea, Montipora, Porites) illustrating the general nature of this relationship.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4867736/


Now, what does Dana Riddle, a true Elite hobbyist, tim, say about Algae Turf Scrubbers, & algae filtration in general, in discussions I've had with him ? Unlike you tim, Dana ran commercial coral farms, and -

Dana Riddle, quote -
"œI ran a commercial coral farm back in the '90's using ATS technology."
"œMultiple frag grow-out systems (literally thousands of SPS.) 20 coral genera (hundreds of frags, perhaps a 100 species)."
"œThis 1,500 gallon system was filtered by 3 algal turf scrubbers (totaling about 3 m2 surface area) plus protein skimming."
"œNo nuisance algae were growing."
"œThe algae we grew were true turf algae and the pads were covered with various red, green, and brown types."


Did Dana have any concerns at all with the turf algae he was growing? Yes.

Quote "This red alga would attack some of the corals (Acropora mostly) and bore into the skeletons. It made some sort of toxin that dissolved coral tissues."

Only one species of red turf algae did Dana have any problem with.
A what is Dana's opinion on algae scrubbers, tim ?

quote "I'm a proponent of algae scrubbers if they use the right algae and are maintained correctly."

Now that I've covered "turf algae", lets consider algae on a coral reef in general.

This is a quote from a Ron Shimek article you may find interesting, tim?

"Upon examination of the material of a coral reef it becomes apparent that corals are only one component of the life on such a reef, and although they appear large and evident, their contribution to the actual amount of living material on the reef is relatively small.

In their pioneering study of the reef at Enewetak atoll, the Odums in 1955 showed that the majority of non-bacterial biomass on a "coral" reef was actually in the form of algae. They found that various types of algae were everywhere. There were algae growing in the coral tissues, of course, as zooxanthellae, but additionally there were algae growing freely and widely across the coral reef. The algae on the surface of the reef were diverse in form, and belonged to many groups, from large green algae such as Codium, to coralline red algae, to coralline green algae, to diatoms and dinoflagellates.

In point of fact, they found enough algae on the reef to consider it far more reasonable to call such reefs algal reefs instead of coral reefs. I wonder how many aquarists would be hobbyists today if these biogenic structures were named after their most abundant life forms and called "algal reefs" rather than coral reefs.

In addition to the algae growing visibly on the surface of the rocks, the Odums were surprised to find that algae were growing INSIDE of all the substrates on a reef. Algae, primarily filamentous green algae, lived inside of coral heads, inside of dead coral skeleton, and inside of all coral rock and rubble. In fact, on an old coral atoll such as Enewetak where all evidence of the volcano that gave the reef its start has vanished with subsidence (the volcanic basis for the reef at Enewetak is found under some 5,000 feet (1515 m) of coral reef deposited over several million of years coral growth), virtually all of the rocks are riddled with algae and contain a lot of algal growth and biomass.

The Odums found that in the average coral head, in the region of the polyps, the density of the algal component was about 0.004 grams/cm3 and the animal component was about 0.021 g/cm3, while among the bases of the polyps the filamentous algae had a density of about 0.022 g/cm3. Below the polyp zone of the coral head the algae had a density of 0.037 g/cm3.

In other words, in a coral head with living coral tissue on it, the animal component accounted for about one-fourth of the total, 0.021 g/cm3, while the various algal components amounted for 0.063 g/cm3.

Interestingly, as well, the filamentous algal component of a coral head had a much greater biomass (about 16 times greater) than did the zooxanthellae in the coral.

The algae in the coral heads do not die when the coral animal does, and the amount of the coral algae in various rock components of the reef is shown in Figure 1. This figure, modified from the Odums' 1955 paper, shows the relative biomass of several rocky areas on the reef. I have colored the algal biomass amounts green, and the biomass inside rock that could be collected as live rock in yellow. The amount of algae living inside the various components of coral rubble and rock is quite significant, and those algae are quite important to our discussion of live rock porosity. If corals are grown in environments free of the algae that colonize their skeletons, those skeletons are typically quite porous. However, the algae growing within the rock add to the porosity by dissolving fine holes for their filaments."


.http://reefkeeping.com/issues/2004-0...ture/index.php

:lolspin: :lolspin: :lolspin:
 
And here's a list of some of the research that's been done over the last couple decades:

long-term stony coral survival in the Coral Reef Exhibit at Reef HQ Aquarium, Townsville, Australia was measured in days, not years. (See figure 3) (Thanks for this link Scrubber Steve. :D)

Adding this particular link, tim, just proves to me that you are an ideologue, because you refused to accept the facts the link, & the other link(s) I provided to another paper by the same authors. The papers destroyed your argument in relation to Reef HQ Aquarium, in Townsville, which I have had a personal guided tour through.

Let me refresh your memory, Tim.
Your argument was that the removal of the algae turf farm (ATF) (which didn't grow turf algae by the way) from the coral reef system exhibit at Reef HQ directly resulted in a turnaround in coral mortality from around 75% to only around 25%. But the marine biologists who wrote the paper(s) clearly stated the real reasons for the mortality rate turnaround, & the removal of the algae turf farm was not one of them.

They in fact state that the removal of the ATF made no difference.
And this was because the ATF's total algae biomass accounted for only 0.5% of the systems total algae biomass, the remainder 99.5% being algae growing within the systems display.

The marine biologists clearly state that the great improvement in coral mortality was due to "“

1. The switch from using priori ultra-clean oceanic water, collected offshore by barge, to using "˜less pure' estuarine water collected on the incoming tide from the Ross Creek to increase nutrients and provide an external source of plankton for coral food.

2. The removal of internal mechanical filtration (three large sand filters). This improve overall tank health by avoiding "˜over stripping' the water column of particulates and encouraging plankton production, greater coral food availability, and larval settlement, especially during spawning periods

3. Internal circulation was greatly increased, to deliver food to corals more effectively (and through Dana's Riddles work we now know that this increased flow would also have increased the rate of coral photosynthesis).

4. The use of calcium chloride to raise average calcium levels from 250 ppm, to 420 ppm.


The fact is, the Algae Turf Farm was removed from the system, within a total system change of protocol, for no other reason than it being labour intensive, tim!

:love1: :lolspin:
 
I note tim your misguided attack on ATS is an indirect attack on me. That's fine.

Firstly tim, I'll point out that I don't consider you anywhere in the realm of an elite reef aquarium hobbyist (a portrayal of yourself that you attempt to project everywhere) no matter how many links to scientific papers you provide, & no matter how many boring rants you produce.

On the matter of attacking "turf algae", I don't grow turf algae on my scrubber screen, & I don't know of anyone doing so, at least on a modern 'Algae Scrubber'.

I'm curious how you've determined no one has any turf algae species in their ATS? Irregardless. If you had read the links I posted the research done by scientists I posted links includes "foliacious" alga as well. The research clearly identifies the labile DOC or Dissolved Combined Neutral Sugars (DCNS) released by alga as promoting pathogenic

In any case, lets discuss "turf algae"!

What is "turf algae" ?

Turf algae are multispecies assemblages of diminutive, mostly filamentous algae that attain a vertical height of only 1 mm to 2 cm (Figure 1). Turf algae often exist as assemblages (algal turfs), are ubiquitous in reef systems and are composed of the small, juvenile stages of macroalgae (e.g., Gelidium spp., Gelidiella spp., Digenia simplex) along with faster-growing filamentous species (usually red algae such as Polysiphonia spp., Herposiphonia spp., and Ceramium spp.; blue-green algae (cyanobacteria); diatoms; brown algae; green algae; and coralline algae) and detritus and sediments.
https://repository.si.edu/bitstream/handle/10088/21635/SCMS39_Lang_17.pdf

Just how bad is "turf algae" & it's effects on coral reefs ?

Introduction to Turf Algae
Algal Turfs: Ecological Importance
"¢ Algal turfs are integral to the healthy function of one of the richest habitats on earth
"“ e.g., Knowlton 2001
"¢ Rapid turnover of this organic matter forms the base of coral reef trophic structure
"“ e.g., Wanders 1976, Adey & Steneck 1985, Carpenter 1985, 1986, Klumpp et al. 1987, Klumpp & McKinnon 1989
"¢ Algal conglomerates accumulate detritus and sediments that provide raw materials for nutrient recycling "“ e.g., nitrogen fixation by filamentous cyanobacteria
"¢ Heterogeneous microhabitats for other unicellular algae (such as diatoms), protozoans and micro invertebrates
"¢ In intertidal regions, turf communities can temper environmental stressors by retaining water and providing shade among densely packed filaments "“ Hunt & Denny. 2008.
"¢ Benefit of shading has been shown to be advantageous to some corals which resist bleaching when inhabited by endolithic algae "“ Shashar et al. 1997
"¢ Some corals recover from bleaching episodes (loss of zooxanthellae) better when green‐algal derived photo-assimilates are incorporated into coral tissue6 "“ Fine & Loya 2002
https://www.stri.si.edu/sites/taxonomy_training/Docs/phycology_docs/4_1_Introduction_Turf_Algae.pdf

Your link doesn't go to any specific page that states what you supposedly quoted. Can you please include the correct link?

&

Competitive interactions between corals and turf algae depend on coral colony form
Abstract
Turf algae are becoming more abundant on coral reefs worldwide, but their effects on other benthic organisms remain poorly described. To describe the general characteristics of competitive interactions between corals and turf algae, we determined the occurrence and outcomes of coral"“turf algal interactions among different coral growth forms (branching, upright, massive, encrusting, plating, and solitary) on a shallow reef in Vietnam.

In total, the amount of turf algal interaction, i.e., the proportion of the coral boundary directly bordering turf algae, was quantified for 1,276 coral colonies belonging to 27 genera and the putative outcome of each interaction was noted. The amount of turf algal interaction and the outcome of these interactions differed predictably among the six growth forms.

Encrusting corals interacted most often with turf algae, but also competed most successfully against turf algae.
The opposite was observed for branching corals, which rarely interacted with turf algae and rarely won these competitive interactions.

Including all other growth forms, a positive relationship was found between the amount of competitive interactions with neighbouring turf algae and the percentage of such interaction won by the coral. This growth form dependent ability to outcompete turf algae was not only observed among coral species, but also among different growth forms in morphologically plastic coral genera (Acropora, Favia, Favites, Montastrea, Montipora, Porites) illustrating the general nature of this relationship.

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4867736/
The researchers in this paper also recognize the role alga play in promoting bacterial infections in corals. From the first paragraph in the introduction: "Feedback processes exacerbate the decline of coral populations as algae provide refuges for coral pathogens and algal exudates fuel bacterial sources of coral mortality" I'm curious why you left that out?



Now, what does Dana Riddle, a true Elite hobbyist, tim, say about Algae Turf Scrubbers, & algae filtration in general, in discussions I've had with him ? Unlike you tim, Dana ran commercial coral farms, and -

Dana Riddle, quote -
"œI ran a commercial coral farm back in the '90's using ATS technology."
"œMultiple frag grow-out systems (literally thousands of SPS.) 20 coral genera (hundreds of frags, perhaps a 100 species)."
"œThis 1,500 gallon system was filtered by 3 algal turf scrubbers (totaling about 3 m2 surface area) plus protein skimming."
"œNo nuisance algae were growing."
"œThe algae we grew were true turf algae and the pads were covered with various red, green, and brown types."


Did Dana have any concerns at all with the turf algae he was growing? Yes.

Quote "This red alga would attack some of the corals (Acropora mostly) and bore into the skeletons. It made some sort of toxin that dissolved coral tissues."

Only one species of red turf algae did Dana have any problem with.
A what is Dana's opinion on algae scrubbers, tim ? How long ago was this written? Has Dana Riddle read the current research showing how alga promote pathogenic processes in the coral holobiont?

quote "I'm a proponent of algae scrubbers if they use the right algae and are maintained correctly."

Now that I've covered "turf algae", lets consider algae on a coral reef in general.

This is a quote from a Ron Shimek article you may find interesting, tim?

"Upon examination of the material of a coral reef it becomes apparent that corals are only one component of the life on such a reef, and although they appear large and evident, their contribution to the actual amount of living material on the reef is relatively small.

In their pioneering study of the reef at Enewetak atoll, the Odums in 1955 showed that the majority of non-bacterial biomass on a "coral" reef was actually in the form of algae. They found that various types of algae were everywhere. There were algae growing in the coral tissues, of course, as zooxanthellae, but additionally there were algae growing freely and widely across the coral reef. The algae on the surface of the reef were diverse in form, and belonged to many groups, from large green algae such as Codium, to coralline red algae, to coralline green algae, to diatoms and dinoflagellates.

In point of fact, they found enough algae on the reef to consider it far more reasonable to call such reefs algal reefs instead of coral reefs. I wonder how many aquarists would be hobbyists today if these biogenic structures were named after their most abundant life forms and called "algal reefs" rather than coral reefs.

In addition to the algae growing visibly on the surface of the rocks, the Odums were surprised to find that algae were growing INSIDE of all the substrates on a reef. Algae, primarily filamentous green algae, lived inside of coral heads, inside of dead coral skeleton, and inside of all coral rock and rubble. In fact, on an old coral atoll such as Enewetak where all evidence of the volcano that gave the reef its start has vanished with subsidence (the volcanic basis for the reef at Enewetak is found under some 5,000 feet (1515 m) of coral reef deposited over several million of years coral growth), virtually all of the rocks are riddled with algae and contain a lot of algal growth and biomass.

The Odums found that in the average coral head, in the region of the polyps, the density of the algal component was about 0.004 grams/cm3 and the animal component was about 0.021 g/cm3, while among the bases of the polyps the filamentous algae had a density of about 0.022 g/cm3. Below the polyp zone of the coral head the algae had a density of 0.037 g/cm3.

In other words, in a coral head with living coral tissue on it, the animal component accounted for about one-fourth of the total, 0.021 g/cm3, while the various algal components amounted for 0.063 g/cm3.

Interestingly, as well, the filamentous algal component of a coral head had a much greater biomass (about 16 times greater) than did the zooxanthellae in the coral.

The algae in the coral heads do not die when the coral animal does, and the amount of the coral algae in various rock components of the reef is shown in Figure 1. This figure, modified from the Odums' 1955 paper, shows the relative biomass of several rocky areas on the reef. I have colored the algal biomass amounts green, and the biomass inside rock that could be collected as live rock in yellow. The amount of algae living inside the various components of coral rubble and rock is quite significant, and those algae are quite important to our discussion of live rock porosity. If corals are grown in environments free of the algae that colonize their skeletons, those skeletons are typically quite porous. However, the algae growing within the rock add to the porosity by dissolving fine holes for their filaments."


.http://reefkeeping.com/issues/2004-0...ture/index.php

Yup. Science has moved on though and you haven't posted anything that shows the labile DOC from alga does not promote pathogenic processes on corals .

:lolspin: :lolspin: :lolspin:
 
Adding this particular link, tim, just proves to me that you are an ideologue, because you refused to accept the facts the link, & the other link(s) I provided to another paper by the same authors. The papers destroyed your argument in relation to Reef HQ Aquarium, in Townsville, which I have had a personal guided tour through.

Let me refresh your memory, Tim.
Your argument was that the removal of the algae turf farm (ATF) (which didn't grow turf algae by the way) from the coral reef system exhibit at Reef HQ directly resulted in a turnaround in coral mortality from around 75% to only around 25%. But the marine biologists who wrote the paper(s) clearly stated the real reasons for the mortality rate turnaround, & the removal of the algae turf farm was not one of them.

They in fact state that the removal of the ATF made no difference.
And this was because the ATF's total algae biomass accounted for only 0.5% of the systems total algae biomass, the remainder 99.5% being algae growing within the systems display.

With the surface area of their ATS about 24% the size of their aquariums foot print you're descriping a display tank that's been over run by alga. Not surprised removing the ATS didn't help The research I posted in my first post provides expalins why they had such a poor survival rate.

The marine biologists clearly state that the great improvement in coral mortality was due to "“

1. The switch from using priori ultra-clean oceanic water, collected offshore by barge, to using "˜less pure' estuarine water collected on the incoming tide from the Ross Creek to increase nutrients and provide an external source of plankton for coral food.

(The low PO4 certainly didn't help, I have posted this research in other threads but I'll do so again here, PO4 is critical for corals and a deficiency leads to bleaching:

Nutrient enrichment can increase the susceptibility of reef corals to bleaching:
http://www.indiaenvironmentportal.org.in/files/file/Nutrient enrichment.pdf

Ultrastructural Biomarkers in Symbiotic Algae Reflect the Availability of Dissolved Inorganic Nutrients and Particulate Food to the Reef Coral Holobiont:
https://www.frontiersin.org/articles/10.3389/fmars.2015.00103/full

Phosphate deficiency promotes coral bleaching and is reflected by the ultrastructure of symbiotic dinoflagellates
https://www.sciencedirect.com/science/article/pii/S0025326X17301601?via=ihub

Effects of phosphate on growth and skeletal density in the scleractinian coral Acropora muricata: A controlled experimental approach
https://www.sciencedirect.com/science/article/pii/S0022098111004588

High phosphate uptake requirements of the scleractinian coral Stylophora pistillata
http://jeb.biologists.org/content/214/16/2749.full )


2. The removal of internal mechanical filtration (three large sand filters). This improve overall tank health by avoiding "˜over stripping' the water column of particulates and encouraging plankton production, greater coral food availability, and larval settlement, especially during spawning periods

3. Internal circulation was greatly increased, to deliver food to corals more effectively (and through Dana's Riddles work we now know that this increased flow would also have increased the rate of coral photosynthesis).

4. The use of calcium chloride to raise average calcium levels from 250 ppm, to 420 ppm.


The fact is, the Algae Turf Farm was removed from the system, within a total system change of protocol, for no other reason than it being labour intensive, tim!


:love1: :lolspin:

You left out that with the removal of the ATS they also went from a completely closed system to roughly 30% biweekly water changes.


From CH 26 https://www.burgerszoo.com/media/560570/chapter-26.pdf

"2. Coral mortality is mostly due to White Syndrome in Acroporids, but the cause for the White Syndrome in the CRE is not known to date."

Since CRE published their results scientists have shown the Labile DOC from alga is able to cause the infections and deaths they were seeing.
 
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