Maturity Issues

[Mojoreef]

Hey Eric great posts as always. I have a couple qustions relating to this.
Knowing that nitrification occurs in the areobic zone and Denitrifications occur in the anerobic zone (by facultative anaerobes) what purpose do you feel the huge anoxic zone does for us that keep a reef tank.
Concidering the drawbacks of the biproducts produced by bacteria in this zone, is it even woth trying to keep one???

thanks buddy

Mike

 

[SPC]

Steve:

you are very right, and your comments are also the answer.

The sands around reefs are coarse and well sifted - and they are pretty functionless, too. You can dig your hand up to the armpit in sands in a reef spur and groove area and see nothing but pur white flakes of carbonate and very little life.

Hi Eric,

I agree, and this is the point I'm trying to get at. If the natural reefs have this kind of substrate, then there must be a reason for this, which IMO is greatly related to high energy cleaning this substrate. It would seem to me that the sand around reefs would work more along the lines of a fluidized bed filter (highly aerobic).

If it were constantly highly stirred in tanks, it would be fine to do this but not very functional. As it is, if you moved a chunk of the real reef to a calm organic-laden sand area near a mangrove and then disturbed the sediments, same thing would happen. Probably why you don't have many pathc reef communities in these areas, and why areas that get high organic sedimentation have a limited variety of corals that can thrive there.

But I'm not sure I agree with you that the substrate would have to be strirred in these in shore areas to affect corals. When I think of these areas, the first thing that comes to mind is the sulfur odor that one can smell from miles away. I have also noticed that during tide changes, the water will often cloud up with a dark grey or brown color that to me indicates detritus in suspension. This being the case, I would think that these areas would be extremely high in organics (sulfates, phosphates etc...) and wouldn't think that the substrate would need to be stirred to realize this.

The sand in our tanks aesthetically looks like the sand there, but fucntions like the seagrass/mangrove/ lagoon sands - that's where the action is in the wild in terms of excess production of the reef in the wild, and also where all the nutrient processing is in tanks.

Again I agree that the DSB's in our tanks act like "seagrass/mangrove/ lagoon sands", but is this what I really want in a reef tank? My DSB is white for about the first 1". After this it goes from grey, to some dark (sulfer?) areas that appear in lower flow areas and under rocks.

From the reading that I have done, it seems to me that one of the major contributers to pollution on the reefs comes from these "functioning" sand bed areas closer to shore, is this correct?
Thanks,
Steve

 

[fahz]

Steve:

you are very right, and your comments are also the answer.

The sands around reefs are coarse and well sifted - and they are pretty functionless, too. You can dig your hand up to the armpit in sands in a reef spur and groove area and see nothing but pur white flakes of carbonate and very little life. The sand in our tanks aesthetically looks like the sand there, but fucntions like the seagrass/mangrove/ lagoon sands - that's where the action is in the wild in terms of excess production of the reef in the wild, and also where all the nutrient processing is in tanks. If it were constantly highly stirred in tanks, it would be fine to do this but not very functional. As it is, if you moved a chunk of the real reef to a calm organic-laden sand area near a mangrove and then disturbed the sediments, same thing would happen. Probably why you don't have many pathc reef communities in these areas, and why areas that get high organic sedimentation have a limited variety of corals that can thrive there.

I'm not thinking the sand bed in tanks doesn't need "attention", but that attention probably has special requirements and that having sensitive corals around during that time might kill them.

Eric:

What your saying makes greater sense to anyone who has been diving on coral reefs and seen the barren expances of sand. Pure white areas of sand with little in them or on them. I think this is a harder concert to grasp if you are not a diver. I'm not saying it makes you a better reefer but it does give a person greater insight.

Fahz

 

[EricHugo]

It would make sense to me (and is sort of what I do anyway, though could improve it) to keep coarse aerobic sands in the reef area and have a large find bed remotely (large refugium, separate area, ehatever) that is rarely or difficult to disturb where the anaerobic processes occur.

I don;t really want to jump back into the sand bed discussion which we covered quite in depth a while back. As for answers on long-term sandbeds and what keeps them acting efficiently, I cannot say with any assuredness except for my own case where I do not see any nutrient buildup. Also, I think the functionality of them far outweighs any downsides. Like I said, I think the way we appraoch them and the way we install them could stand some improvement.

Steve, I'm with you on the inshore areas. There is aplethora of literature to describe all of this...we're both on pretty firm ground here and I think on the same side.

 

[Mojoreef]

It would make sense to me (and is sort of what I do anyway, though could improve it) to keep coarse aerobic sands in the reef area and have a large find bed remotely (large refugium, separate area, ehatever) that is rarely or difficult to disturb where the anaerobic processes occur.

Yea Eric this was my thinking to. For me you loose to much keeping it in the main tank. just with the loss of flow and the ever present danger of digging to deep did it for me. I went with a coarse substraight in the main (about an inch) and the created a lagoonal refuge in a remote location. I found with strong flow most of the detritus was removed via the skimmer and the demand on the 3 inches of sand in the refuge was really easy to deal with.
I agree with the areobic and anerobic zone mimicing, thier use as a denitrifier and a place to house planktonic critters is a big plus, but I just dont understand the need to go beyond it with the large anocix zone???

Mike

 

[EricHugo]

Because that's where the majority of denitrification and remineralization is occurring. Reductive areas.

 

[ReefDiver]

Eric:

Would it make any sense to use a "course gravel" (bottom layer), "soil" (middle layer), and "fine gravel" (top layer) in a separate "refuge"? The "layers" could be varied in order to see which type of stratification would work best at reducing NO3, PO4, etc... the object being to produce the most variety of benthic & other organisms that would be beneficial in "stabilizing" the water environment in the "main tank".

Question is would this also take care of the organic matter produced in the main tank, or, would you still need to run a protein skimmer as well?

I guess that the size of the refuge would be dependent on the set up in the main tank, i.e., majority of SPS species, vs. LPS, vs. combo of the two, vs. fish stocked in either, and varied combinations, if you know what I am getting at?

I think that this is the idea with a "Mangrove" type of setup. But how do these systems function overall. There is really no real research being done in this area. OR, is there and I am missing it?

 

[Mojoreef]

Because that's where the majority of denitrification and remineralization is occurring. Reductive areas

Dentrificating bacteria being facultative are dominate first in that line arent they. since the are facultative they would reside in the anerobic zone above the anoxic reducers such as sulfate/methagene and carbon reducers which highly dominate the anoxic zone.
Do you really think we get much in the way of remineralization in the DSB?? I have no idea if that is viable or not.

Thanks fo the conversation.

Mike

 

[Bomber]

Psst Mike,
It's aerobic (respiration in the presence of free O2) on the top.
Anoxic (O2 level between .05-2.0 mg/l) in the middle.
Anaerobic (absence of free O2) on the bottom.

and reminerialization happens too s-l-o-w-l-y to do you any good in these closed systems.

Everything you want to happen is going on in the anoxic areas. In the middle.

Hey Eric :wave:

 

[Mojoreef]

You know that is the 3rd time this month I have written them down backwards...duh

 

[saltshop]

You know that is the 3rd time this month I have written them down backwards...duh

At least you are consistent

 

[Mark]

Eric
Awesome write up! I'm bookmarking this one.

In terms of DSB's and the subject at hand, here's my take on it:

The current in our tanks is usually pretty dismal relative to the flow on an actual reef. In fact, the flow required to mimic a real reef crest would blow a fine particle size DSB out of the water. It's also accepted in this thread that our DSB's mimic the dynamics and meiofauna of a seagrass/mangrove habitat. So, along with the low flow, aren't we basically trying to keep corals in a microcosm that overall more closely mimics a mangrove habitat? Furthermore, isn't there a reason that many types of corals we like to keep do not occur in those habitats? And lastly, is it really so surprising that our tanks with DSB's and low flow begin to look like a mangrove habitat(without the mangroves) after 4-5 years? The various algae communities have a greater competitive advantage over corals in these muddy areas due to a greater presence of nutrients which are usually limited in a reef community.

Eric, you make a great point about corals being efficient predators as well. I never thought about that. We worry so much about the effect on microcrustacean communities after adding a mandarin, yet don't think twice when adding a euphyllia. I will keep that in mind with my new tank.

I remember talking with Adey about the presence of predators in an aquarium. We both agreed that if the goal is to have a long term diverse tank, predators are a tricky equation. At the density that we keep corals and other predators, refugiums do nothing more than act as a food source. Refugiums don't seem to serve as source for critters to repopulate the main display, when the main display is full of predators. So, even in the presence of a fuge, we lose the significant roles these critters serve in a ecosystem. After all, they do more than just act as a food source.

On a side note, a few years ago I helped my brother set up a reef system. He loved watching mine so much, he wanted one of his own. We set it up with only a tang. After just a year, his tank was extraordinary to look at. The tang obviously prevented the opopportunityor some types of algae to prevail, but the diversity of critters, sponges, and other algae was impressive.

 

[Mark]

SPC,

Thanks for the link to Wilkens tank. It great to see a successful reef tank that old. It's also nice to read that he simply accepts and lives with the fact that his tank over time does not support certain corals, and embraces the fact that others are succeeding. While it's difficult to prove, I'm willing to bet that his yearly 50% substrate change acts a positive disturbance effect on the diversity and nutrient processing dynamics. Probably why he has avoided the OTS.

 

[Bomber]

http://www.rsmas.miami.edu/info/press-releases/ancient-coral.html

And here's my take on it. You guys are nuts! LOL LOL

The next time someone tells you "it's just like nature" "It's natural" etc, point them to any articles/papers on Florida Bay - the worlds largest DSB/refugia/algae filter. Because it hasn't been cleaned out, it's crashed. So tell them it really is just like nature.

:lol:

 

[Mark]

The next time someone tells you "it's just like nature" "It's natural" etc, point them to any articles/papers on Florida Bay - the worlds largest DSB/refugia/algae filter. Because it hasn't been cleaned out, it's crashed. So tell them it really is just like nature.

Today's word is Eutrophication! Everyone say it with me! :lol:

 

[Bomber]

Hypereutrophic

 

[Scuba_Dave]

Great thread, thanks Eric & to everyone else. I think I've followed Eric's layout, except at a faster pace, due to spending all day here. It's the only nice thing about Tech support call center, no calls, I get to surf!
I'm moving in about 2 weeks, then I finally get to setup the 125g that has been sitting in my mom's basement. We will be adding an addition in the spring, so next summer I will be adding a 180g to the system.
So 1.5 years after starting in SW the tank I wanted (actually want a 340g) will start to cycle.
Talk about hurry up & wait!! Thanx

 

[skylsdale]

Thanks for the read thus far guys.

 

[skylsdale]

I've decided that I'm going to try some of this longer period waiting setup in my new system. I'm setting up a 30 gal later today in my office. The rock has pretty much been sitting over the last couple months, and it's grown more foraminaforms, etc. than I've ever had on my rock (I've always kept nanos, so things get predated pretty easily).

Anyway, due to extremely low budget constraints for this tank, I have no other option than to wait painfully long periods of time before major equipment and livestock additions...so this will be quite a drawn out project compared to many of the systems I've seen put together. Eric, this is based off the leeward rubble type environment I asked about a couple months ago. I plan on stocking some Pocilloporids first, then maybe a Porites specimen for the "focal point." Fish will probably be some chromis and maybe a dascyllus. Anyway, it will be interesting to see how this develops over time. My hope is to just let the corals run rampant, and actually do the occasional "storm by hand" to create some friction in the tank.

I'll keep you guys updated if anything noteworthy seems to happen.

 

[commandertekki]

Im a newbie... just wanted to tag this discussion thread so that I can keep up with the readings.

Before this, jumping out of a plane was my idea of enlightment, and I never really thought I'd find myself interested again in marine biology.... But I do love to learn and I wanted to say that I enjoyed reading your discussion and comments on reef ecology.

Phillip