Jaubert Plenum Sysetm

[MR Teee]

Stumbled across this and thought it may be of some use to people.

The Jaubert System Revisited
by Mike Paletta - SeaScope Volume 14, Winter 1997
It has now been four years since what has come to be known as the Jaubert system of reefkeeping was introduced. I have used modified versions of this system in two of my own tanks as well as in six other tanks, all of which have been set up for at least one year. Two others have been set up for almost three years. After working with this system in several different forms, I recognize both its strengths and inadequacies.

When this concept was first explained it seemed simple enough: use a plate to produce a space for water (a plenum) under a bed of live sand to allow for anoxic conditions to develop. When the oxygen levels in the plenum fall low enough, processes will occur that convert nitrate into nitrogen gas. In addition to lowering nitrate levels, there is also a gradual dissolution of the carbonate live sand bed, which produces a constant introduction of calcium, strontium, and trace elements into the tank.

I set up tanks according to this simple system, but it seems I did not read all the fine print. The patent by Dr. Jaubert as well as videotapes and lectures by him and his staff reveal that this system is not quite as simple as it appears to be. As a result it has been my experience that success using this system depends on a number of variables. Some of these variables and the effects of small design alterations follow.

As would be expected, the quality of the live sand bed is critical to the success of this system. The type of sand chosen is of course important. Its inhabitants have a major effect on the processes that occur in and under the bed. I refer now to the amphipods, copepods, burrowing molluscs, and particularly the worms. Jaubert describes a mini-ecosystem within the live sand bed that is critical for the success of this system.

Unfortunately it has been my experience that very few of us are able to obtain live sand with the quality of inhabitants that Jaubert describes. In particular, worms and burrowing molluscs are almost always missing from the live sand that is available. This seems to be a distinct disadvantage, because these animals act in a manner similar to their terrestrial counterparts: they aerate the sand and remove any small bits of organic matter that lodge there.

The lack of worms and molluscs is probably a result of live sand collection from areas devoid of these creatures, or from crushing during shipping. In either case, lack of these critical components of the live sand bed starts us off at a disadvantage. Without them the sand is not adequately aerated, resulting in dead spots. Organic matter accumulates in the substrate and results in an increased likelihood of algal blooms.

Another crucial component of the system is sand-sifting organisms. Jaubert uses brittlestars, sea cucumbers, hermit crabs, and sand-stirring fish to further aerate the sand. In many instances the quality and quantity of these animals in our tanks is also low. Many of us also start off with only a small amount of actual live sand, with the rest of the substrate being dead aragonite sand or crushed coral sand. We hope that we can inoculate this dead sand with animals from the live sand. This may occur over time, but most of us are not patient enough.

As a result we stock the tank and feed the inhabitants long before this sand is fully mature. Once again this results in the accummulation of waste and decaying material that acts as a nutrient sink.

One other aspect of Professor Jaubert's system that has gone almost completely unnoticed is that, for the most part, the substrate does not have much live rock or corals resting on it. Jaubert attaches most of his corals and live rock to the side walls of the tank.

Thus the substrate is not compacted and does not have rock-algae interfaces that act as detritus traps. In most of jaubert's systems less than 30% of the substrate has anything resting on it. This helps to limit the amount of waste and detritus that accumulates. Unfortunately, this large amount of open surface is the exception rather than the rule in many of our tanks.

There has been debate about whether these tanks are actually closed systems. They are all at least partly open and many get as much as a 10% water change with ocean water each week. This further reduces any buildup of nutrients.

Based on the design details already mentioned, I no longer recommend this system for the typical hobbyist. My own two tanks experienced algal blooms within two years, forcing me to remove the Jaubert plates and most of the substrate. I did not make this decision lightly, because they were a 90 gallon tank and a 400 gallon tank. The 400 gallon tank contained 24 square feet of substrate three inches deep.

Once I removed the plates and the substrate it took three months for the algae to die.
In the remaining six tanks that I helped set up using this system only two are free of algae and none have nitrate levels lower than 5 parts per million (ppm). The two successful tanks both contain high-quality live sand and have less than 40% of the substrate covered by live rock.

I believe that several other factors influence how successful an aquarium set up on Professor jaubert's system will be. Use of a protein skimmer may affect the dynamics of this system by removing organic material that might otherwise act as a nutrient source for the anaerobic bacteria.

Ozone and carbon levels may also have some impact. My tanks are smaller and contain a much higher ratio of animals to water than jaubert's tanks. This probably has a negative impact on the system. I also make water changes less frequently.

Despite all of this I will probably continue to experiment with the jaubert system, but I will make one major change. Thejaubert plate and substrate will be in an external chamber separate from my tank. If problems do arise the system can be simply taken off line without the effort now required to remove the plate and substrate.

[moorish]

quite a few people use these systems with a different degree of success.i know people who have used the plenum method with great success others have experienced a lot of problems. there is not enough life in the sand we buy to keep it going as most live sand has no worms etc in it to keep the sand clean and aerated.derek

[Chris, Reef Ranch]

Mr Sprung did a very interesting article on this in Coral Magazine February/March 2005 Vol. 2, No. 1. It was a very balanced article and contained information of mostly the correct nature with regard to the reality of in-tank substrates. It “talks” of sulphide production from the bed that kills fish at night if you don’t put air through the aquarium. It also mentions a rise in nitrate over time that Sprung attributes to an imbalance of nitrification to de-nitrification, but in reality a build up of organics will cause this

http://adsabs.harvard.edu/abs/1996GBioC..10..661M

It mentions that Mr Jaubert had many failed attempts to make his system run correctly prior to perfecting it. The methods to stop fish death included installation of pumps and skimming heavily.

Mr Sprung suggests ways of using the plenum in separate modules remote from the bottom of the aquarium. One of the most correct and honest articles I have read for a long time. A truly balanced account of the risks and benefits. I suggest you read this prior to installation of any type of substrate in aquariums.

Best wishes

Chris
X

[Chris, Reef Ranch]

I am waiting for some elaborate inflammatory post with numerous quotes. It might be taking Mr Teee a while to compose? Either way there is still time to play.

I heard that Mr Teee is now high up in some Church in America. This would make him some sort of vicar?

Can you imagine having an afternoon’s religious meeting with him? Imagine being part of this meeting and someone broke wind. Over here someone would no doubt say-

"More tea vicar"

But over there you could say-

"Pass-the-tea……. Pasteur….Teee"

HeHe...............

[Tetley]

I am waiting for some elaborate inflammatory post with numerous quotes. It might be taking Mr Teee a while to compose? Either way there is still time to play.

I heard that Mr Teee is now high up in some Church in America. This would make him some sort of vicar?

Can you imagine having an afternoon’s religious meeting with him? Imagine being part of this meeting and someone broke wind. Over here someone would no doubt say-

"More tea vicar"

But over there you could say-

"Pass-the-tea……. Pasteur….Teee"

HeHe...............



"Everything comes to he who waits" :D

[MR Teee]

Can't be arsed, I'm not here to argue with everything I don't agree with.

[Chris, Reef Ranch]

Can't be arsed, I'm not here to argue with everything I don't agree with.

I entirely agree. I am not surprised really. However, if you are genuinely interested in getting the definitive answers to this and other queries then we can set-up a little research team.

The reason why we are constantly arguing back a forth is because of the sources of literature. We might as well don a pair of Mickey Mouse ears and go and get our information down the Pub.

If we use primary scientific literature- i.e. papers published in scientific journals there is no disputing the evidence. Then if we tackle it in the right way we should know as much as there is to know about a certain discipline and YES; over and above what the NAMES are writing in the magazines for us. We might even put this forum firmly on the global map for excellence in literary research and finding out the right answers to hobbyist’s problems.

It will take as long time to get to the bottom of most queries, possibly months. It would also be better if we have a small team of possibly 5 people that could all work together to a common goal. Another problem is that science is a language and one that takes time to learn. I don't for a minute think I am the only one out there that can decipher science at this level, so we need to appeal to someone in University studying their BSc (Hons) or above. This could also allow us to access full text documents on the web.

Anyone interested and capable?

Chris
X

[Kev]

Nah. Unless it involves copious amounts of ale! :D

[Tangman]

Nah. Unless it involves copious amounts of ale! :D
Trust you Kev:D would you understand it better then.:D Eric

[TerraC]

I think you'd need a pint or two after reading scientific literature.. :D or maybe coffee to keep you awake..!

[Chris, Reef Ranch]

I can put it in plain English for you. I know you have seen my plain English before, but it is much more understandable when I have deciphered it.

Chris
X

[Chris, Reef Ranch]

Is there anyone out there who cares?

Let’s not give the wrong impression. It might appear to a new comer that forums are more about A BIG TRUMPET, AN OAR AND A WOODEN SPOON rather than wanting the right answers.

It strikes me that some people put a real effort into their posts, but let us focus that energy in the right way.

Chris
X

[TerraC]

I care. I just dont have the time or the patience to decipher it. :(

[Tetley]

[QUOTE=Chris, Reef Ranch;25729]Is there anyone out there who cares?

Yes of course we care. :)

[Chris, Reef Ranch]

I care. I just dont have the time or the patience to decipher it. :(

I will do that for you, hopefully with some one else’s help. Plus if you try reading this type of literature it gets easier and easier in time.

Chris
X

[TerraC]

I'd be willing to give it a go. I'm interested in why things work. as per most people though if it's presented in plain english by someone you are more likely to take an interest in what they say. Maybe why a lot of people believe heresay?

btw where do we start on finding these published papers?

[Chris, Reef Ranch]

I'd be willing to give it a go. I'm interested in why things work. as per most people though if it's presented in plain english by someone you are more likely to take an interest in what they say. Maybe why a lot of people believe heresay?

btw where do we start on finding these published papers?

Glad to have you on board. Google Scholar is a great start. I would rather get an entire team together first and formulate some hypotheses prior to embarking on a journey of discovery. We need around 5 people.

The literature must be from a primary source- i.e. published in a scientific journal by authors that are in positions of respect in a University or research institution. Until someone else is on board who has access to full text articles we will have to work of abstracts. Abstracts are a précis of the entire paper.

An example

http://adsabs.harvard.edu/abs/1996GBioC..10..661M

The most important part is this

"Rates of benthic denitrification are most sensitive to the flux of labile organic carbon arriving at the sediment-water interface and bottom water concentrations of nitrate and oxygen. Denitrification always increases when bottom water nitrate increases but may increase or decrease if oxygen in the bottom water increases. Nitrification is by far the most important source of nitrate for denitrification, except for organic-rich sediments underlying oxygen-poor and nitrate-rich water".

The first sentence

Interpretation-
The rate of denitirfication in marine sediments is greatly influenced by how much sediment (detritus) there is overlying the substrate and the concentrations of nitrate and oxygen deep within the substrate.

Try this, understandable of not?

Chris
X

[TerraC]

thats a lot better yes. plain english that I can understand. :D

[Chris, Reef Ranch]

Let us see then if anyone else wants to be involved.

Chris
X

[TerraC]

yep hopefully we'll get some takers. c'mon guys get onboard. We have a chance here to take on some knowledge from respected scientific institutions in a readable format. I for one wouldnt mind learning something from a respected source instead of weighing up the heresay and best guessing.

[MR Teee]

mmmmmmmm interesting.

[Chris, Reef Ranch]

mmmmmmmm interesting.

Com'on Mr Teee we need you. Instead of looking at scantly dressed women draped over a Massey Fergussons whilst you are on the loo, you could be doing this.

Chris
X

[MR Teee]

Trouble is Chris as soon as I disagree with something the whole thing is gonna stop.

You can find scientific articles about anything, I could find one that says something else. Who do you believe?, who do you trust? , who is the most credible?

Are we out to set up sucessfull reeftanks or are we out to disprove that everything in this hobby is wrong and there is one true unified method.



What I want to do is set some kind of knowledge base up in language that is understanble.

So you could have

How deep should a DSB be?
What I would want is a article that gives the reader credible scientific evidence for the ideal depth but also practical evidence of what we see in sucessfull tanks.

Think of it as a reefkeepers wikepedia.

[MR Teee]

How about we continue this in General Discussions in its own dedicated thread?

Would you like to start a new thread Chris in there.

[Kev]

Trust you Kev:D would you understand it better then.:D Eric

What do you think Eric?;)

[TerraC]

You can find scientific articles about anything, I could find one that says something else. Who do you believe?, who do you trust? , who is the most credible?

Are we out to set up sucessfull reeftanks or are we out to disprove that everything in this hobby is wrong and there is one true unified method.

The way I see it I dont think it's about having a row about it. If there are two conflicting opinions i'd like to know about both of them. Thing is they'd be from a decent textbook source not "someone on that forum said so"..

Ray

[Tangman]

What do you think Eric?;)
Hi Kev if your anything like me it will go right over your head m8.:confused: Eric

[MR Teee]

Exactly Ray, but what is a credible source.

A scientific paper that says DSB should be 1"

Or a reefer with a tank stuffed full of flourishing corals using a 6" DSB.

You can use all the science you want, and tell people about it. But at the end of the day all I want out of it is a nice tank and an understanding of why its gonna stay nice in the future.

[Chris, Reef Ranch]

Trouble is Chris as soon as I disagree with something the whole thing is gonna stop.

You can find scientific articles about anything, I could find one that says something else. Who do you believe?, who do you trust? , who is the most credible?

Are we out to set up sucessfull reeftanks or are we out to disprove that everything in this hobby is wrong and there is one true unified method.



What I want to do is set some kind of knowledge base up in language that is understanble.

So you could have

How deep should a DSB be?
What I would want is a article that gives the reader credible scientific evidence for the ideal depth but also practical evidence of what we see in sucessfull tanks.

Think of it as a reefkeepers wikepedia.

The point is that evidence contrary to this type of evidence very rarely exists. If you find something that does contradict most of the research papers and is more up to date, none of use could argue about it we would just have to accept it. This is because it will be fact rather than hearsay. Might I also inform you though that the stuff isn’t published in the first place if there is any doubt. Only hypotheses are proved or disproved the facts don’t change. It is the real deal, the real McCoy etc, etc. The thing you must bare in mind though is that if this information indicates something that you don't personally believe then you will also have to accept it as gospel.

Do you want to know the truth, can you handle the truth?

PS Wikepedia is not primary scientific literature, we will be going over the heads of wikepedia fans.

Enter my voyage of discovery HA...HA...HA HeHe

With all due respect to reports about hobbyist’s set-ups and aquariums, there are many that spout about how wonderful something is but never mention anything bad that has happened. Don't you think it is a little strange that none of the reports mention that a fish may have died or that they once had a nitrate problem etc, etc. You can bet you life that not everything has been absolutely perfect from word go. We have been or are still hobbyists and this doesn’t even seem like reality. A photograph or a visit is also just a snap shot in time.

Chris
X

[Chris, Reef Ranch]

Exactly Ray, but what is a credible source.

A scientific paper that says DSB should be 1"

Or a reefer with a tank stuffed full of flourishing corals using a 6" DSB.

You can use all the science you want, and tell people about it. But at the end of the day all I want out of it is a nice tank and an understanding of why its gonna stay nice in the future.

We probably won’t find a paper that that tells us how deep to have a sand bed, but I have already found evidence that should tell us at what depth denitrification tails off and at what depth the production of ammonia and nitrate increases. The problem is that we can't access the full text of the article. However, if there is one there will be more.

http://aem.asm.org/cgi/content/abstract/35/2/301

To be thorough we will need to come up with at least 5 papers to back up our hypotheses. Be aware that the hypotheses will be along the line of

Beyond a certain depth, the efficiency of denitrification is reduced and the bacterial populations are biased toward the production of ammonia and nitrate.

Prove or disprove.

Proving or disproving this will take a while and will also only be only a small part of the whole picture. We will keep chipping away at the surface until the whole story is revealed.

We won't be arguing we will be working towards a common goal. OR, Mr Teee do you just prefer to argue? Just pulling you leg m8.

I also want you on board for the sake of objectivity, you are natural born sceptic and this will be very healthy form a scientific point of view.

Chris
X

[MR Teee]

God your so bloody hard to argue with!:D

But OK then I'll go along with you and Ray.

As you say peer reviewed scientific literature cannot really be argued with, as long as it is relevant to the subject at hand, or somebody cleverer than me can make the links for me.

Maybe in a few yrs time, i'll put all the theories into practice and create a stunning tank!.

PS I know wikepedia is written for dummies, but it contains alot of useful links to the sources of the informaation.

[TerraC]

I think most of us have setup tanks based on the "it works for others" principal without really knowing why or how to any great extent. Now there's nothing really wrong with that and I believe there are many ways to run a successful tank depending on how much technology you have, maintenance you want to do or money you have to throw at it.

However, personally if something interests me I want to know exactly how it works and why, questions i've found myself wanting from most other sources on the internet and LFS. I see this as an opportunity to have some of the scientific babble translated into a laymans language and maybe learn something along the way.

There are a number of items we could look into that some of us could benefit from. They too could probably learn a bit from the hobbyist if one day they took the broomstick out of their backsides for 5 minutes but obviously that's probably never gonna happen. We just have to be smart, learn from the scientific community where we can, combine it with the word of mouth we know and love, compare and come up with a reasoned opinion.

hows that sound? :D

[MR Teee]

Sounds like what goes on in every Reefkeeping forum around the world at the moment.

[Chris, Reef Ranch]

I think most of us have setup tanks based on the "it works for others" principal without really knowing why or how to any great extent. Now there's nothing really wrong with that and I believe there are many ways to run a successful tank depending on how much technology you have, maintenance you want to do or money you have to throw at it.

However, personally if something interests me I want to know exactly how it works and why, questions i've found myself wanting from most other sources on the internet and LFS. I see this as an opportunity to have some of the scientific babble translated into a laymans language and maybe learn something along the way.

There are a number of items we could look into that some of us could benefit from. They too could probably learn a bit from the hobbyist if one day they took the broomstick out of their backsides for 5 minutes but obviously that's probably never gonna happen. We just have to be smart, learn from the scientific community where we can, combine it with the word of mouth we know and love, compare and come up with a reasoned opinion.

hows that sound? :D

You are entirely correct. The more you know the better you will be at designing your own systems. This information also allows you to design systems whilst considering all the variables. This makes everything safer and much more stable for your animals. The advantages go on and on......

Anyone else for the taking?

Chris
X

[TerraC]

Sounds like what goes on in every Reefkeeping forum around the world at the moment.

From where i'm standing it looks like a few select people like Randy Holmes Farley are doing the scientific translation work and everone else is banding it around like chinese whispers. How about some of us trying to lookup this information ourselves and adding to the knowledge pool first hand?

[MR Teee]

Thing is, only a select few have access to the articles. I am still on a university computer system but there is no way I have access to articles from all over the world.

Looking up the information is no big deal. Applying it to a tank setup is!

[Chris, Reef Ranch]

Thing is, only a select few have access to the articles. I am still on a university computer system but there is no way I have access to articles from all over the world.

Looking up the information is no big deal. Applying it to a tank setup is!

All we need is things like ingenta or Athens log in capabilities which come as standard from most University Degrees. We could just work off abstracts. It is more difficult, but not impossible.

Go onto Google Scholar

Don’t' mean to patronise but <click on MORE>; go down the list to Google Scholar and click on it. Try Typing "denitrification in marine substrates" in and searching. There will be thousands of abstracts all indicating a little piece of the jigsaw.

Chris
X

[MR Teee]

Athens log in capabilities

Got that, gimme an article to search for!

[MR Teee]

<table style="border-collapse: collapse;" border="0" cellpadding="2" cellspacing="0" width="100%"><tbody><tr><td class="LableBold" style="padding-right: 15px;" valign="top" width="100"> Resource: </td> <td valign="top"> <!-- contents --> ISI Web of Science (http://javascript%3Cb%3E%3C/b%3E:open_window_resource_name%28) </td> </tr> <tr> <td class="LableBold" style="padding-right: 15px;" valign="top" width="100"> <!-- tag --> Title: </td> <td valign="top"> <!-- contents --> Production of N-2 through anaerobic ammonium oxidation coupled to nitrate reduction in marine sediments (http://litsearch.shu.ac.uk/V/AFFS9JC1HPLAG7PDYEXDS3FT6DHKH6RH5I23Y643FDUBB4AN6R-39602?func=lateral-link&doc_number=002186844&line_number=0004) </td> </tr> <tr> <td class="LableBold" style="padding-right: 15px;" valign="top" width="100"> <!-- tag --> Author: </td> <td valign="top"> <!-- contents --> Thamdrup, B (http://litsearch.shu.ac.uk/V/AFFS9JC1HPLAG7PDYEXDS3FT6DHKH6RH5I23Y643FDUBB4AN6R-39603?func=lateral-link&doc_number=002186844&line_number=0003) </td> </tr> <tr> <td class="LableBold" style="padding-right: 15px;" valign="top" width="100"> <!-- tag --> Add.Author / Editor: </td> <td valign="top"> <!-- contents --> Dalsgaard, T (http://litsearch.shu.ac.uk/V/AFFS9JC1HPLAG7PDYEXDS3FT6DHKH6RH5I23Y643FDUBB4AN6R-39604?func=lateral-link&doc_number=002186844&line_number=0019) </td> </tr> <tr> <td class="LableBold" style="padding-right: 15px;" valign="top" width="100"> <!-- tag --> Citation: </td> <td valign="top"> <!-- contents --> APPLIED AND ENVIRONMENTAL MICROBIOLOGY 68 (3): 1312-1318 MAR 2002 </td> </tr> <tr> <td class="LableBold" style="padding-right: 15px;" valign="top" width="100"> <!-- tag --> Year: </td> <td valign="top"> <!-- contents --> 2002 </td> </tr> <tr> <td class="LableBold" style="padding-right: 15px;" valign="top" width="100"> <!-- tag --> Abstract: </td> <td valign="top"> <!-- contents --> In the global nitrogen cycle, bacterial denitrification is recognized as the only quantitatively important process that converts fixed nitrogen to atmospheric nitrogen gas, N-2, thereby influencing many aspects of ecosystem function and global biogeochemistry. However, we have found that a process novel to the marine nitrogen cycle, anaerobic oxidation of ammonium coupled to nitrate reduction, contributes substantially to N-2 production in marine sediments. Incubations with N-15-labeled nitrate or ammonium demonstrated that during this process, N-2 is formed through one-to-one pairing of nitrogen from nitrate and ammonium, which clearly separates the process from denitrification. Nitrite, which accumulated transiently, was likely the oxidant for ammonium, and the process is thus similar to the anammox process known from wastewater bioreactors. Anaerobic ammonium oxidation accounted for 24 and 67% of the total N-2 production at two typical continental shelf sites, whereas it was detectable but insignificant relative to denitrification in a eutrophic coastal bay. However, rates of anaerobic ammonium oxidation were higher in the coastal sediment than at the deepest site and the variability in the relative contribution to N-2 production between sites was related to large differences in rates of denitrification. </td> </tr> <tr> <td class="LableBold" style="padding-right: 15px;" valign="top" width="100"> <!-- tag --> </td> <td valign="top"> <!-- contents --> Thus, the relative importance of anaerobic ammonium oxidation and denitrification in N-2 production appears to be regulated by the availability of their reduced substrates. By shunting nitrogen directly from ammonium to N-2, anaerobic ammonium oxidation promotes the removal of fixed nitrogen in the oceans. The process can explain ammonium deficiencies in anoxic waters and sediments, and it may contribute significantly to oceanic nitrogen budgets.
</td></tr></tbody></table>
That was a search on denitrification in marine sediments.

Only thing I am stuck with now is which databases to search!

P.S just looked and I can get full text articles from the database where that one is stored. Not sure about others though.

[Blue]

Sorry I missed this guys, can I join? I may not have a great deal to imput, but I really do love to learn :) . Nobody knows everything and those that say they do are liars. I like good solid evidence and this is a good place to start.

Regarding the deep sand bed, surely the size of the sump in relation to the main tank is what needs to be determined, Yes or No?
This is assuming that we are talking about sumps.

I will try my best to find info, but as you know I am always busy, but I suppose there is no rush, we have all our lives to find out :D I know the same will be for you lot too.

[Chris, Reef Ranch]

<table style="border-collapse: collapse;" border="0" cellpadding="2" cellspacing="0" width="100%"><tbody><tr><td class="LableBold" style="padding-right: 15px;" valign="top" width="100"> Resource: </td> <td valign="top"> <!-- contents --> ISI Web of Science (http://javascript%3Cb%3E%3C/b%3E:open_window_resource_name%28) </td> </tr> <tr> <td class="LableBold" style="padding-right: 15px;" valign="top" width="100"> <!-- tag --> Title: </td> <td valign="top"> <!-- contents --> Production of N-2 through anaerobic ammonium oxidation coupled to nitrate reduction in marine sediments (http://litsearch.shu.ac.uk/V/AFFS9JC1HPLAG7PDYEXDS3FT6DHKH6RH5I23Y643FDUBB4AN6R-39602?func=lateral-link&doc_number=002186844&line_number=0004) </td> </tr> <tr> <td class="LableBold" style="padding-right: 15px;" valign="top" width="100"> <!-- tag --> Author: </td> <td valign="top"> <!-- contents --> Thamdrup, B (http://litsearch.shu.ac.uk/V/AFFS9JC1HPLAG7PDYEXDS3FT6DHKH6RH5I23Y643FDUBB4AN6R-39603?func=lateral-link&doc_number=002186844&line_number=0003) </td> </tr> <tr> <td class="LableBold" style="padding-right: 15px;" valign="top" width="100"> <!-- tag --> Add.Author / Editor: </td> <td valign="top"> <!-- contents --> Dalsgaard, T (http://litsearch.shu.ac.uk/V/AFFS9JC1HPLAG7PDYEXDS3FT6DHKH6RH5I23Y643FDUBB4AN6R-39604?func=lateral-link&doc_number=002186844&line_number=0019) </td> </tr> <tr> <td class="LableBold" style="padding-right: 15px;" valign="top" width="100"> <!-- tag --> Citation: </td> <td valign="top"> <!-- contents --> APPLIED AND ENVIRONMENTAL MICROBIOLOGY 68 (3): 1312-1318 MAR 2002 </td> </tr> <tr> <td class="LableBold" style="padding-right: 15px;" valign="top" width="100"> <!-- tag --> Year: </td> <td valign="top"> <!-- contents --> 2002 </td> </tr> <tr> <td class="LableBold" style="padding-right: 15px;" valign="top" width="100"> <!-- tag --> Abstract: </td> <td valign="top"> <!-- contents --> In the global nitrogen cycle, bacterial denitrification is recognized as the only quantitatively important process that converts fixed nitrogen to atmospheric nitrogen gas, N-2, thereby influencing many aspects of ecosystem function and global biogeochemistry. However, we have found that a process novel to the marine nitrogen cycle, anaerobic oxidation of ammonium coupled to nitrate reduction, contributes substantially to N-2 production in marine sediments. Incubations with N-15-labeled nitrate or ammonium demonstrated that during this process, N-2 is formed through one-to-one pairing of nitrogen from nitrate and ammonium, which clearly separates the process from denitrification. Nitrite, which accumulated transiently, was likely the oxidant for ammonium, and the process is thus similar to the anammox process known from wastewater bioreactors. Anaerobic ammonium oxidation accounted for 24 and 67% of the total N-2 production at two typical continental shelf sites, whereas it was detectable but insignificant relative to denitrification in a eutrophic coastal bay. However, rates of anaerobic ammonium oxidation were higher in the coastal sediment than at the deepest site and the variability in the relative contribution to N-2 production between sites was related to large differences in rates of denitrification. </td> </tr> <tr> <td class="LableBold" style="padding-right: 15px;" valign="top" width="100"> <!-- tag --> </td> <td valign="top"> <!-- contents --> Thus, the relative importance of anaerobic ammonium oxidation and denitrification in N-2 production appears to be regulated by the availability of their reduced substrates. By shunting nitrogen directly from ammonium to N-2, anaerobic ammonium oxidation promotes the removal of fixed nitrogen in the oceans. The process can explain ammonium deficiencies in anoxic waters and sediments, and it may contribute significantly to oceanic nitrogen budgets.
</td></tr></tbody></table>
That was a search on denitrification in marine sediments.

Only thing I am stuck with now is which databases to search!

P.S just looked and I can get full text articles from the database where that one is stored. Not sure about others though.

A very important article. I didn't mention it yesterday, but I am very happy that you have decided to give this a go. Glad to have you on board. The article above does back up what we have seen up to now in these articles. It appears that deeper within substrates, nitrate is only partially reduced to ammonium rather than nitrogen gas and the process above mentioned ANAMOX (anaerobic ammonia oxidation) then coverts this ammonium back to nitrate. It also indicates once again that complete denitrification is slowed down the deeper you go in substrates.

Chris
X

You could try and go to the journal in question. They will have their own web site. You can then do an advanced search or better still, if you put the first authors name in and their first initial you will bring up all the things that have been published by that author. Remember these people only tackle this small area of science but know everything there is to know about it.

Good Work!

I am going to try and get us a separate section on the site for this reasearch. I will pm James today and see what comes of it.

[Chris, Reef Ranch]

I have read this again and I am in two minds now what it is saying. Can you post the link up by copying the URL directly from the explorer text window? I can't use the title to hyperlink to the abstract on the web.

This does contradict some of what I believed to be true. It is relevant to what we are going to investigate!

Many thanks for finding this.

Chris

[MR Teee]

Chris PM me your email adress and I will send you the full thing in PDF form.