DSB Related Journals, Newspaper Articles, ETC...

[Bomber]

Originally posted by Habib
I have seen many things in Ron's articles regarding DSB which IMO are incorrect.

Hold that thought Hab.

He's trying his best to change as fast as he reads these things. Who knows, by next year he may be right.

[Habib]

He's trying his best to change as fast as he reads these things. Who knows, by next year he may be right.

In general one can't change things which have been written and have been repeated as such. That is are being reconfirmed.

Sure and can change the POV etc but that also changes a LOT.


Who knows, by next year he may be right

Not referring to "he" but in general, then the POV was previously wrong, either completely or partially.


FWIW:

"Over the last several years, so-called "sand beds," essentially layers of sand of various thicknesses and arrangements, have come to be common fixtures in marine reef aquaria. The use of these sand beds has been correlated with significantly increased survivability of many organisms in reef aquaria, particularly when compared to the bare bottom tank arrangements that were in the vogue about a decade ago. Nevertheless, few hobbyists seem to realize why sand beds should contribute to the success of their tanks, and fewer yet seem to understand how those beds work."

Combine that with the recent DSB thread in Ron's forum and shiver.

[PRC]

Does anyone know if anyone has done any real science on this?

Wow, guess that answers my question!
I figured there would have been some research, but this is truly impressive. Hats off to Yellotang, search tool user extraordinaire. Unfortunately, now I feel obliged to actually read all this stuff.
I'm having a reverse epiphany here. Thought I had some minor clue what was going on with this and now I'm realizing how incredibly ignorant I actually am. Just to prove it I'll ask a couple questions...
Jay, do you think you could test your hypothesis (at least a little) by checking PO4 levels near the sand bed and pH in the sand bed to see if there's any correlation? I'm probably oversimplifying again.
Here's an idea sure to be shot foll o holes, but what the heck. How about a remote DSB with a bunch of Mangroves planted in it. Could they possibly absorb enough phosphorous directly out of the sand bed to temper spikes of PO4 release?
Thanks to all for all this great info!
Paul

[SPC]

Originally posted by PRC
Here's an idea sure to be shot foll o holes, but what the heck. How about a remote DSB with a bunch of Mangroves planted in it. Could they possibly absorb enough phosphorous directly out of the sand bed to temper spikes of PO4 release?
Thanks to all for all this great info!
Paul

Hi Paul,

Unfortunately mangroves are very slow growers. Some of the more successful hobbyist with this tree have reported 3 or 4 leaves/ year growth.

Another thing I think of with mangroves is the substrate that they lived in around South Florida. If all those mature mangrove trees down there can't stop the substrate from going rotten, then I don't think they would do much good with my high organic reef tank.
Steve

[Rick Davis]

Originally posted by Habib
The detrivores don't die all of them at the same time and they actually seem to die because that is simply the reason why one needs to "recharge" them.

This (IMO) automatically implies that the capacity of each type of mechanism (e.g. bacteria and detrivores are different mechanisms) in breaking down and binding of nutrients/organics etc will fluctuate in time in an unpredictable way.

If this is correct a DSB is highly instable and there is a chance it might crash. The chance that such a DSB crash would occur will increase in time.

Good post Habib

When a sand bed critter dies 2 bad things happen:

1. It dumps it's nutrient content back into the system.

2. It leaves a "hole" in the detritivore guild because it is no longer assimilating some nutrients into it's body. The hole will remain until another critter fills in the gap.

The impact of course will vary depending on the size of the critter - if a pod dies, no big whoop. But you definitely want to be at home when the cuc kicks the bucket.

Add to this the fact that these critters keep reproducing like crazy which adds to the death toll.

So, yeah, I can see highly unstable alright.

[Bomber]

PRC, Steve's right about the mangroves.

[QUOTE]Originally posted by PRC
Jay, do you think you could test your hypothesis (at least a little) by checking PO4 levels near the sand bed and pH in the sand bed to see if there's any correlation? I'm probably oversimplifying again.[/QUOTE

Testing for the type of phosphorous compounds that would mean anything are way beyond the scope of what a hobbyist can do. It takes a little heat and some acid.

[Bomber]

http://archive.reefcentral.com/forum...36#post1960236

Can anyone get around these three points?

1)We know for a fact that bacterial degradation of sediments rapidly creates anoxic areas and these anoxic areas remobilize dissolved phosphate into the water column.

2)We know for a fact that phosphate is stored in sediments and as these sediments oscillate between reduced and oxidized states, phosphate is released.

3)We know for a fact that pools of oxidized sediments enhance the retention of phosphorous.

[G-money]

Bomber, I hope you aren't mad at me ....

Originally posted by Bomber
1)We know for a fact that bacterial degradation of sediments rapidly creates anoxic areas and these anoxic areas remobilize dissolved phosphate into the water column.

I am assuming these anoxic areas are somewhat removed from the normal oxic areas where the sand-moving fauna dwell? I guess where I'm confused is that aside from possible diffusion, how are these phosphates significantly "remobilized" into the water column unless that sediment is distrurbed and contact is made with the water column? If there is no flow though a fine substrate, how does remobilization occur in an anoxic zone? H2S seems to stay put fairly well (albeit increasingly) as evident by the pretty black streaks prevalent in all long-term DSBs. I know H2S isn't party to the same mechanisms as phosphate...

Are they really liberated to any great degree by microorganisms? Perhaps problems occur once the phosphate processing/absorbing capacity of the bed is reached, but until then...??? Does that explain why DSBs seem just fine in the short term? Just thinking out loud...

2)We know for a fact that phosphate is stored in sediments and as these sediments oscillate between reduced and oxidized states, phosphate is released.

Do we know at what rate the phosphate is released? I have to admit, I haven't read all 5 pages . Wouldn't reduction be required in areas of low or no oxygen? With that, aren't these areas largely left alone by the infauna? If there is no oxygen, these areas must also be removed from contact with the water column...perhaps the best thing to do is remove these sediments occassionally?

3)We know for a fact that pools of oxidized sediments enhance the retention of phosphorous.

So the problem is keeping them oxidized. Would ozone be of any use?

[ldrhawke]

One of the research articles posted to this thread earlier stated that one way the phosphates go back into solution is a through a reduction and change in salinity.

[Megalodon]

So does this mean you folks will NOT be taking Dr. Ron's on-line DSB course for $175?

[G-money]

Originally posted by Megalodon
So does this mean you folks will NOT be taking Dr. Ron's on-line DSB course for $175?

[IMG]http://**********************/contrib/blackeye/lol.gif[/IMG]

There is enough info out here that if I can't figure it out from what's already been said, I'll wait for his students to start talking...if all else fails, I'll just pitch the Dirty Sand Bed altogether...

Anyhoo, it seems there are others equally as qualified to discuss such matters...and they don't wear blinders.

[photobarry]

Originally posted by Graham
if all else fails, I'll just pitch the Dirty Sand Bed altogether

ROTFLMAO That's the spirit!

[Megalodon]

[IMG]http://**********************/contrib/blackeye/lol.gif[/IMG]

I guess I shouldn't laugh too hard. I have a 8-week-old DSB and I don't know what to do with it now!

[ldrhawke]

I guess I shouldn't laugh too hard. I have a 8-week-old DSB and I don't know what to do with it now

Wait another few weeks until it really gets loaded with phosphate and nitrate, take it out and put it in a pot and grow tomatoes in it or if you live North of the border pot....

[G-money]

Nah, I'm sure you have $175 for the cause...

I had trouble with my latest DSB after about 12 weeks (cyano).
Now I'm at the 15 week point and all's clear. Found out I was low in Mg and my Alk wasn't quite where I wanted it to be. Once Alk was up to 12 dKh, things improved over about 4 days....I also did a bit of siphoning (and ditched that silly CS Bioassay, that's why the Mg was low...back to IO ).

I am going to try the replacement of small portions of substrate about every year (maybe 1/4 of the bed) as preventative maintenance. If I get that far with it, that is. My last one was working like a charm for almost 3 years - then I moved and had to take it down. Never did any real maintenance on that one....go figure. There were quite a few areas of H2S in it, but no clumping. Lots of animals...

Seems like dumb luck plays a role, as always

The main thing is they seem to be pretty high maintenance - more than you'd think. I'm sure you've read it all, so I don't need to offer any more opinions on the basics. I do think the exportation and replacement of a portion of it (with minimal other disturbance) may be what is lacking in the current philosophy. It seems like the only way to get the phosphate out.

[SlavicSavage]

What search tool are you using to find all these journal articles? I wonder if any of this is in Gallileo, i cant remember if they have biological journals in their databases

[Habib]

Rick:

Thanks.

[Habib]

The following clipping from a recent publication shows basically what happens in some reef sediments.

When reading this take into consideration that the DSB will have MUCH more input of food and other waste products then a reef sediment because of the input of a lot of dead food in the aquarium.

Bolding is mine, refernce is given at the end.

Due to
the porous structure of the coral sand, its permeability
is relatively high and the porosity of the reef sediment
can reach 50%. Pore water analyses in these cal-
careous sediments revealed elevated nutrient concentrations
relative to the overlying bottom water (Holm
1978, Smith et al. 1981, Arenas & de la Lanza 1983,
Entsch et al. 1983, Nixon & Pilson 1983, Williams 1984,
Williams et al. 1985, Furnas et al. 1993, Szmant &
Forrester 1996).
Beneath the living surface of the coral reefs, coral
skeletal remains and other calcareous biogenic materials
form a highly permeable framework, where the
volume of coral reef cavities may reach up to half the
bulk volume (Ginsburg 1983). These framework
cavities are inhabited by a wide variety of organisms
(Kobluk & van Soest 1989). Organic matter trapped
within the framework or imported by the reef fauna is
consumed by the organisms that colonize the cavities
and that return ammonia and phosphate to the framework
water (Ferrer & Szmant 1988). Nutrient concentrations
in reef cavities, therefore, exceed those of
waters surrounding the reef (Risk & Müller 1983,
Ayukai 1993, Richter et al. 2001).
Because of their large specific surface areas, coral
sands and reef framework may have an important
biocatalytic function and may act as nutrient buffers in
reef ecosystems exposed to seasonal nutrient changes.

PS: Compare the seasonal nutrient changes to reduced feeding, water changes, improved skimming etc.



Above (exept the PS) is from:

MARINE ECOLOGY PROGRESS SERIES
Mar Ecol Prog Ser
Vol. 239: 277–285, 2002 Published August 23
Effect of reef framework and bottom sediment on
nutrient enrichment in a coral reef of the
Gulf of Aqaba, Red Sea
Mohammed Rasheed1, 2,*, Mohammad I. Badran2, Claudio Richter3, Markus Huettel1

[Habib]

After you have read the above read this (edited by taking some sentences and names out and bolding is mine):

Originally posted by rshimek
Hi ....,

.......................

How do I now I am right? Well, these sand beds, when maintained (as by your own admission you were too disinterested to do) work. They are good analogues of natural systems, and are supported by a vast of scientific literature (and a list of some of those you could read, for starters) is given on my web site and linked to from this forum and other sites.

Read....

So whatt is properly maintained?

From Ron's article in RK:

"By simply setting up a deep sand bed, and then maintaining that bed with the proper diversity and mix of animals, reef aquarists can facilitate the utilization of the necessary excess nutrient resulting from normal feeding. "


AND

"If aquaria are artificial ecosystems, however, the component that is least artificial is the sand bed. This part of a reef aquarium, with little input from the aquarist, functions much as do the sandy areas near a real reef. That functionality is due to a rather complex interaction of physical and biological factors, but most of those interactions are unseen, and, I think, unappreciated by the average aquarist. Without those interactions our reef aquaria would simply fail. The fact that they don't fail is a tribute to the ease of constructing this one major functional analogue to an extremely critical coral reef community."



Rather complex interactions means to me as not understood interactions.

And if it is complex some changes might result in drastic changes.

But they don't seem to fail because "ease of constructing this one major functional analogue to an extremely critical coral reef community."

[Bomber]

Originally posted by Graham
I have to admit, I haven't read all 5 pages .

Take a minute and read this thread and the articles in it. I have purposely tried to stay away from answering direct questions because I don't want anyone to just take my word for it.

I don't think Ron should have dared us to "do some reading".

For what it's worth. We are having another "black water" event in Florida Bay right now. It's another phosphate burp.

[Bomber]

Originally posted by Habib
Rather complex interactions means to me as not understood interactions.

And if it is complex some changes might result in drastic changes.

But they don't seem to fail because "ease of constructing this one major functional analogue to an extremely critical coral reef community."

Hab you're exactly right again.

Rather complex interactions means to me as not understood interactions.

Just depends on who you ask.

[Habib]

Black water

Normal:




A few months later; Black water:

http://earthobservatory.nasa.gov/New...ifs_fl_blk.jpg

[Bomber]

Just another one of those "cycles" you go through with a full DSB.

Hab, can you see me in that picture?

[Habib]

Originally posted by Bomber

Hab, can you see me in that picture?

Yes, if I blow up the picture in photoshop.

It was taken on the day that you went skinny dipping.

[Bomber]

Eek!



Here's my prediction. You know how these DSB gurus have always pushed DSB's as being "natural" filtration? a little slice of nature in your living room. Which BTW they are just as natural as under gravel filters and bio-balls, it's all bacterial filtration just like nature.

Watch and see if they don't try to come up with some sort of "well these are actually better than nature" game plan to try and save it.