Proper PAR for Chaeto

[Ron Reefman]

Well thanks to that video I now want a H380

Sorry, but I'm not spending $300 for a grow light in my refugium!

 

[Subsea]

Sensors can be influenced by many factors. @Dana Riddle recomended my first PAR meter almost 30 years ago. In those days, that equipment came from greenhouse industry with a waterproof sensor to get specific in tank readings. When one is reaching into a tank, the angle of the plane (geometry) need be perpendicular to the light point source to get full PAR. Measurements fluctuated dramatically with tiny movement. It is not intuitive to me, bu5 8 a: told that PAR values with led drop faster in air as opposed to water. If this is so, can someone explain why that is so?

Here in Austin, Texas during noon day sunlight in the middle of tthe summer, PAR values exceeded my meters ability to register. I guess that value would be about 2000 PAR with a Kelvin color spectrum of 5000K.

A value of 700PAR would sunburn a lot of coral. You would sunburn under that value. I have scalded/sunburned Chaetomorphy moving it outside under unfiltered sunlight.

 

[User]

Sensors can be influenced by many factors. @Dana Riddle recomended my first PAR meter almost 30 years ago. In those days, that equipment came from greenhouse industry with a waterproof sensor to get specific in tank readings. When one is reaching into a tank, the angle of the plane (geometry) need be perpendicular to the light point source to get full PAR. Measurements fluctuated dramatically with tiny movement.

Here in Austin, Texas during noon day sunlight in the middle of tthe summer, PAR values exceeded my meters ability to register. I guess that value would be about 2000 PAR with a Kelvin color spectrum of 5000K.

A value of 700PAR would sunburn a lot of coral. You would sunburn under that value. I have scalded/sunburned Chaetomorphy moving it outside under unfiltered sunlight.

To be fair- you’d only sunburn if that light had uv-b wavelengths. You can blast 2000 par of straight up royal blue light and you wouldn’t notice it, since the wavelength is too long to cause damage

Your chaeto burned because unfiltered sunlight has a lot of uv-b.

 

[User]

Sorry, but I'm not spending $300 for a grow light in my refugium!

Especially when a $50 eBay it $20 Home Depot bulb work just fine

 

[Subsea]

To be fair- you’d only sunburn if that light had uv-b wavelengths. You can blast 2000 par of straight up royal blue light and you wouldn’t notice it, since the wavelength is too long to cause damage

Your chaeto burned because unfiltered sunlight has a lot of uv-b.

No worries. It grew back with a vengeance. So, when it grew back did uv-b assist with photosynthesis?

In the case of corals on the reef, photo blocking pigments color brown.

 

[mch1984]

Sorry, but I'm not spending $300 for a grow light in my refugium!

I agree, I have no problem spending money on equipment. When I was doing my build I could not bring myself to drop that much cash on a fuge light. I figure even if the UFO light only last a year, I’ll be ok buying a few of them and still save money.

 

[User]

Uv-b is typically detrimental but may be utilized if exposure is heavily regulated or the ratio with uva and overall par is facourable. UVB has a wavelength between 290 and 320nm.

 

[Dana Riddle]

No worries. It grew back with a vengeance. So, when it grew back did uv-b assist with photosynthesis?

In the case of corals on the reef, photo blocking pigments color brown.

In a day when we sometimes look for sound bites to answer our questions, there is no easy answers to the role of UV-B in photosynthesis. Photopigments (chlorophylls) can absorb UV-A and -B and use it in photosynthesis. However, ooxanthellae (and other plants, algae) have the ability to produce mycosporine-like amino acids (MAAs) that absorb and essentially render harmless UV-B and some UV-A wavelengths. Production of these nitrogen compounds is in response to external stimuli (UV, PPFD) and sudden increased exposure could result in cellular damage. As for the coral animal, it could obtain MAAs through consumption of algae or zooplankton that have consumed algae. Clear as mud, right?

 

[Subsea]

In a day when we sometimes look for sound bites to answer our questions, there is no easy answers to the role of UV-B in photosynthesis. Photopigments (chlorophylls) can absorb UV-A and -B and use it in photosynthesis. However, ooxanthellae (and other plants, algae) have the ability to produce mycosporine-like amino acids (MAAs) that absorb and essentially render harmless UV-B and some UV-A wavelengths. Production of these nitrogen compounds is in response to external stimuli (UV, PPFD) and sudden increased exposure could result in cellular damage. As for the coral animal, it could obtain MAAs through consumption of algae or zooplankton that have consumed algae. Clear as mud, right?

Not that muddy, but we are talking biochemistry which is quite complex. I quote you often from articles at Advanced Aquaria on coral nutrition: “Photosynthesis connects the organic & the inorganic world”.

From an operations point of view, what does the macro algae slough off into the water that is in response to differrent light spectrum that require protective pigments. In the case of macro algae, this cellular leakage is different than normal DOC given off due to photosynthesis.

What is MAA in coral?

 

[Dana Riddle]

It has been a while since I've looked at MMAs but found there have been some of them described that I was unable of. It is likely that not all of these are found in corals/zooxanthellae. If I recall correctly, shinorine was isolated from a stony coral and one of the 'paly' MAAs was found in a Palythoa specimen.

MAA Max. Abs.
Mycosporine-methylamine-taurine 309
Mycosporine-glycine 310
Palythine 320
Palythine-serine 320
Palythine-serine-sulfate 320
Mycosporine-methylamine-serine 327
Mycosporine-methylamine-threonine 327
Asterina-330 330
Mycosporine-glutamic acid-glycine 330
Palythinol 332
Mycosporine-2-glycine 334
Porphyra 334
Shinorine 334
Mycosporine-glycine-valine 335
Palythenic acid 337
Usujirene 357
Euhalothece-362 362

I'm not sure I understand your question about microalgal sloughing. Can you clarify?
Here's the absorption of chlorophyll a, which is found in plants. algae, and zooxanthellae.

 

[Subsea]

Exudates are DOC compounds that are the natural byproducts of coral & algae photosynthesis: Normally this would be carbohydrates, proteins & lipids, that comprise differrent DOC.

In the case of macro algae, when photosynthesis exceeds demands of growth requirement the excess bio chemistry during photosynthesis must go somewhere; sloughing off may not be scientific.

 

[jda]

The question is how well will they outcompete algae in the display?

The stuff in the fuge outcompetes the stuff in the display only if you have consumers... the fuge algae goes unchecked and the display algae has fish, snails, urchins, etc. that keep it knocked down. If you let both run wild, then they will both run wild.

 

[Subsea]

It has been a while since I've looked at MMAs but found there have been some of them described that I was unable of. It is likely that not all of these are found in corals/zooxanthellae. If I recall correctly, shinorine was isolated from a stony coral and one of the 'paly' MAAs was found in a Palythoa specimen.

MAA Max. Abs.
Mycosporine-methylamine-taurine 309
Mycosporine-glycine 310
Palythine 320
Palythine-serine 320
Palythine-serine-sulfate 320
Mycosporine-methylamine-serine 327
Mycosporine-methylamine-threonine 327
Asterina-330 330
Mycosporine-glutamic acid-glycine 330
Palythinol 332
Mycosporine-2-glycine 334
Porphyra 334
Shinorine 334
Mycosporine-glycine-valine 335
Palythenic acid 337
Usujirene 357
Euhalothece-362 362

I'm not sure I understand your question about microalgal sloughing. Can you clarify?
Here's the absorption of chlorophyll a, which is found in plants. algae, and zooxanthellae.

What are the many compounds listed? Are they byproducts of photosynthesis that dissolve into the water to become dissolved organic carbon?

 

[Dana Riddle]

What are the many compounds listed? Are they byproducts of photosynthesis that dissolve into the water to become dissolved organic carbon?

They're mycosporine-like amino acids produced by some bacteria, plants, algae, and zooxanthellae. These MAAs act as sunscreens - the numbers in the list are their maximum absorption wavelengths (UV-B and UV-B.) These are produced by the Shikimate Pathway. As for your question of plants'/algae compounds migrating to the water column... Water becomes colored (yellow to brown) when plants decay. Tannins and any water soluble compound (called gilvin or gelbstoff) are the cause. But I think your question involves the release of yellowing substances when the plant/algae is alive. It likely happens but is a little beyond my field of study. Perhaps someone else can chime in?

 

[Subsea]

They're mycosporine-like amino acids produced by some bacteria, plants, algae, and zooxanthellae. These MAAs act as sunscreens - the numbers in the list are their maximum absorption wavelengths (UV-B and UV-B.) These are produced by the Shikimate Pathway. As for your question of plants'/algae compounds migrating to the water column... Water becomes colored (yellow to brown) when plants decay. Tannins and any water soluble compound (called gilvin or gelbstoff) are the cause. But I think your question involves the release of yellowing substances when the plant/algae is alive. It likely happens but is a little beyond my field of study. Perhaps someone else can chime in?

Thank you for explaining complexities in photosynthesis and responses of coral zooanthelia to various spectrum.

Yellowing substances are the most obvious DOC but there are many other differrent DOC which are beyond my expertise, but I know that they/are there. For what purpose is much more complex. In my 25 year old system, I have removed GAC which was the only chemical filtration. The 30G EcoSystem mud/macro refugium was converted to cryptic sponge refugium which now houses several differrent NPS which was a long range goal. Changes were made one year ago. Avording to Steve Tyree research on Cryptic sponges, they absorb DOC and produce DIC & Marine Snow, both of which feed coral. Because measuring differrent DOC is above my “pay grade”, I rely on long range results as bioindicator: Sea Apples, flame scallops, Chilli Coral and several deep water gorgonions. I will introduce this topic on chemical forum with Randy.

 

[Dana Riddle]

Thank you for explaining complexities in photosynthesis and responses of coral zooanthelia to various spectrum.

Yellowing substances are the most obvious DOC but there are many other differrent DOC which are beyond my expertise, but I know that they/are there. For what purpose is much more complex. In my 25 year old system, I have removed GAC which was the only chemical filtration. The 30G EcoSystem mud/macro refugium was converted to cryptic sponge refugium which now houses several differrent NPS which was a long range goal. Changes were made one year ago. Avording to Steve Tyree research on Cryptic sponges, they absorb DOC and produce DIC & Marine Snow, both of which feed coral. Because measuring differrent DOC is above my “pay grade”, I rely on long range results as bioindicator: Sea Apples, flame scallops, Chilli Coral and several deep water gorgonions. I will introduce this topic on chemical forum with Randy.

Interesting. I grew some unidentified blue sponges when in Hawaii, and they were apparent only after I introduced a lot of water motion. As for measuring DOC, there is a proxy test that is easy to perform bt requires the ability to test for dissolved oxygen. This test is the Five-day Biochemical Oxygen Demand test, or BOD5. It is sometimes and incorrectly called the Biological Oxygen Demand test. I have performed this test on water samples from tanks using the Berlin Method as well as those using algae scrubbers. In all cases, the drop has been around 0.2 mg/l (or ppm, if you prefer.) This drop does not meet the required drop of 2 mg/L for the test to be considered valid, and is in fact often that seen in the control. I should mention there are at least two 'oxygen demands' in play here - the first is that of the carbonaceous demand (bacteria 'eating' available carbon in the Carbon Cycle) and the second is the nitrogenous demand (oxygen used in the conversion of ammonia to nitrate.) The higher the degree of pollution, the higher the BOD. Wastewater plants are usually allowed to discharge an effluent of 30 mg/L or less, so this puts the 0.2 mg/L drop I've seen in aquaria into perspective.

 

[Subsea]

Interesting. I grew some unidentified blue sponges when in Hawaii, and they were apparent only after I introduced a lot of water motion. As for measuring DOC, there is a proxy test that is easy to perform bt requires the ability to test for dissolved oxygen. This test is the Five-day Biochemical Oxygen Demand test, or BOD5. It is sometimes and incorrectly called the Biological Oxygen Demand test. I have performed this test on water samples from tanks using the Berlin Method as well as those using algae scrubbers. In all cases, the drop has been around 0.2 mg/l (or ppm, if you prefer.) This drop does not meet the required drop of 2 mg/L for the test to be considered valid, and is in fact often that seen in the control. I should mention there are at least two 'oxygen demands' in play here - the first is that of the carbonaceous demand (bacteria 'eating' available carbon in the Carbon Cycle) and the second is the nitrogenous demand (oxygen used in the conversion of ammonia to nitrate.) The higher the degree of pollution, the higher the BOD. Wastewater plants are usually allowed to discharge an effluent of 30 mg/L or less, so this puts the 0.2 mg/L drop I've seen in aquaria into perspective.

Thank you for those details. I was schooled in waste water treatment and can identify with some of those similarities. Activated sludge says it all. @Paul B had it right 40 years ago: bacteria are the microbial overlords in our reef tanks.