FishProfiles.com Message Forums

I've been doing some thinking of late (cue groans from Garyroland ). And, on this occasion, the thought that occurred to me centred upon bogwood.

Bogwood is one of those aquarium furnishings that I simply can't live without. As a fully paid-up fan of the 'natural' look, in particular the kind of look that resembles a rainforest stream, an aquarium without either live plants or bogwood (and where possible, I like both, and in quantity!) seems to me unfurnished. Of course, there are circumstances where live plants are unadvisable - alongside plant-eaters such as Silver Dollars or large Barbs, or in an aquarium housing certain large open-water Cichlids that will destroy any plants on the basis that they provide a potential hiding place for egg and fry thieves. But in these aquaria, bogwood is, for me, the decoration of choice. The more gnarled, twisted and 'interesting' in shape, the better - especially if this aids management of aspects other than the aesthetic. Those big Cichlids, for example: while they need swimming space, arranging bogwood tangles to break up lines of sight across the aquarium should aid in keeping the flaring Latin tempers of big Guapotes simmering below the flash point. If the fish can always see each other, then the tempers are likely to flare: if they get some rest from seeing each other, internecine warfare is, in my view, less likely, and so compatible communities can be built up with due care and attention (provided of course that the aquarium is large enough to begin with!). Plus, even with smaller, peaceful fishes, bogwood provides shelter for the likes of Corydoras catfishes (my Pandas adore the stuff!), and a substrate for the growing of Java Moss and Java Ferns, all of which help provide interesting repositories of tasty titbits for the Corys and others to explore.

But, it is an entirely different line of thought I wish to dwell upon here.

Let us move for a moment away from freshwater aquaria to marine. There, the principal source of nitrogen cycle management is 'live rock'. This somewhat amusing term describes porous rock that has become colonised by huge numbers of bacteria, all of which perform various functions related to the nitrogen cycle in the aquarium. Some are aerobic, and perform the familiar sequence of breakdown from ammonia through nitrite to nitrate. Some are anaerobic, and reduce the nitrates to free nitrogen. Now, the scope for anaerobic bacteria in a 'live rock' aquarium is somewhat limited, because not all anaerobic bacteria are 'friendly' reducers of nitrates to free nitrogen: some generate hydrogen sulphide, an extremely toxic gas that no-one wants in a marine aquarium at all. In the past, anaerobic reducing chambers were tried in trickle filters, but with a variable degree of success: again, the ever present danger of the 'wrong' anaerobes setting up home made these units problematic. Nowadays, most marine aquarists opt for live rock that is almost exclusively aerobic in operation, and use other means of dealing with nitrates resulting from the bacteria colonies, such as macroalga cultures in refugia regularly harvested to remove the unwanted nitrates. This 'ecosystem' type of aquarium may well become the dominant system in the future, relying upon helpful organisms from Nature to assist our life support management of our fishes and invertebrates, and in my view, deserves to become dominant because successful management of such an aquarium teaches an awful lot about ecology that you won't learn from textbooks!

Why have I diverted to marine aquaria in a post devoted to bogwood? Simple. I mentioned above that 'live rock' contains bacteria colonies of the kind that are of great value in managing the nitrogen cycle in a marine aquarium. Now, while freshwater aquaria tend to rely upon undergravel filters for this, and lush plant growth to mop up at least some of the nitrates, a thought occurred to me.

At least some of my bogwood is porous. Indeed, once it has been made fit for aquarium use, bogwood strikes me as being just as suitable for bacterial colonisation as the 'live rock' of the marine aquarium. And, I suspect that at least some of the bacteria from the filter bed take up residence. Given some of the creatures I've seen take up residence in bogwood, including a colony of little ostracods back around 1996, I would hazard a guess that bacteria are quite ready to do the same.

Which leads me to my latest piece of speculation. Could bogwood be intentionally harnessed as part of the nitrogen cycle management, instead of merely accidentally?

To me, the idea makes sense. The idea that bacteria will colonise rock, but not take advantage of bogwood in the same way, seems absurd. In fact, bogwood should be easier to colonise, being an organic medium itself. Furthermore, a piece of bogwood with its own attached Java Ferns will have, in addition to the usual porosity, at least some mechanism for transmitting oxygen to the deeper medium below the outer integument of the bogwood. I therefore suspect that at least part of the biological filtration in my main community aquarium, which has featured bogwood since it first went 'live' over 10 years ago, takes place within that bogwood. Likewise, once the new Panda Breeding Aquarium™ starts to settle down properly, the 'conceptual artwork' bogwood in there will acquire its own collection of helpful bacteria, along with the Java Moss and Java Ferns I've draped around it.

I am therefore tempted to ask this question: has anyone considered the possibility of deliberately harnessing bogwood in a manner akin to live rock in a marine aquarium?

Perhaps some of the biologists who pass this way can offer some illuminating answers from their researches. I await said contributions eagerly!


Last edited by Calilasseia at 28-Jan-2005 08:48

Panda Catfish fan and keeper/breeder since Christmas 2002

So you are saying that maybe lots of bogwood used in an aquarium could help reduce nitrates, much like how live rock does, and also help in biological filtration in the conversion of ammonia and nitrites?

Yes, this would be the case. But i think the capacity of bogwood to house anaerobic denitrifying bacteria is that great. So wouldn't do much in metabolising nitrates into nitrogen gas. This is just my guess. But this is just me speculating.

-- Gomer

Hi,
I think I am going to have to disagree. Bogwood may provide
additional sites for bacteria but it is a relatively smooth
surface.

Actually, anything added to a tank provides
additional surface area on which bacteria can grow.

It is materials that are porous that offer the most surface
area on which the bacteria can grow. Sponges, and lava
rock are two examples, each offers many more surfaces
than does a smooth log, or a smooth rock.

As the wood leaches the tannins out into the water,
an area of depleted wood will form between the surface
and just under the surface. This "rind" called a weathering
rind, will hinder or slow the release of additional tannins.
Eventually, the rind will enlarge and the tannins will
cease to affect the water.
Likewise the bacteria colonies will grow on the
wood surface, but not penetrate into the inner core.
These benificial colonies require water flow (oxygen)
to function. With out it they die off and anaerobic
bacteria replace them.

The key to enlarging possible bacterial colonies, and
enhance the water purification process is to provide more
surface areas for the bacteria to grow on. We see this
in the addition of Biowheels to filters, or the use of
fluidized filter beds, or ceramic rings or bio balls in
filtration systems.

The question is - Why all the fuss, and desire to maximize
the colonies? The short answer is to provide the maximum
filtration within a given area. Which, by the way, also
allows us to over stock our tanks. The old rule of thumb
of 1 inch of fish/gallon is in modern days debunked because
as is often pointed out one inch of a 12 pound oscar puts
out more waste products than a 1 inch neon tetra. However,
the basic principle of not wanting to over stock the tank
remains and should be heeded.

With todays filtration systems, one can easily exceed
the "standard capacity" by many fold because todays
filters do a far, far, better job of purifying the water.
They pack far more surface area for "good bacteria" to
live and do their job.

Frankly, they allow us to go out on a limb with our
stocking levels. Then Mother Nature steps in and hands
us an ice storm or a careless driver that knocks out the
power for hours, and our fish wind up gasping at the
surface. With the power out, the bactria colonies die
off or are seriously dammaged, and when it comes back on
all that dead bactria is pumped back into the tank, and
conceiveably, the tank have to cycle all over again, this
time with far more fish than when it was first cycled.

Frank


-->>> The Confidence of Amateurs, is the Envy of Professionals <<<--

Actually, most of my bogwood is porous ...

One piece in particular looks as if it's a piece of brown filter foam

Panda Catfish fan and keeper/breeder since Christmas 2002

I would have thought that although the bacteria in a tank would be in equilibrium with the amount of fish waste being produced, the percentage living in or around the bogwood would be lower than elsewhere in the tank due to the fact that both nitrosomonas and nitrobacter prefer alkaline conditions, and therefore settling on the source of the acidic properties of the tank water wouldn't go down all too well with them...