Dallas Warren

Just thought I would share a few things that I have read about and been thinking that goes with the sand fauna discussion that has been going on of late.

I was just reading an article in New Scientist, an issue in the last month, about bacteria communities on teeth. It was very interesting, and I suggest that anyone with access to it have a look for it. The good thing about it is it talks quite a bit about dynamic populations, which applies to all ecosystems. I have been drawing a parallel to that which occurs in our sand beds, and reefs in general.

Anyway, what the article says (and this makes perfect sense, it has been shown in other areas including reef tanks, and you can see it yourself) is after a disturbance, such as brushing your teeth ;-), the type of organisms present and relative populations go through a cycle. The presence of some is dependent on the presence of others, i.e. they feed on them, the other organism creates a suitable environment, they are in direct competition with each other and so on. As the community develops it is continually changing until an equilibrium is reach, and in the case of your teeth this is after three weeks (and try this out at your own peril due to your partner ;-) ). With any larger ecosystem i.e. implying larger number of different organisms, then the time frame is going to be much larger. Note that most people really see this type of occurrence with algae.

The article also points out that if a particular organism misses its chance to join the community then if it tries to in the future then it is really an up hill battle. It can be very difficult for it to gain a foot hold with all the competition with others in the same niche, preditation etc. And this makes perfect sense for a sand bed too and I think has consequences for how you seed a reef tank. Just adding a small amount of live sand, i.e. low number of organism, to the system when it is stable will not amount to much. You have to add a large amount to give them a fighting chance against competition from other organisms that are acclimatised to the particular conditions, preditation etc. I suppose this only really applies when there is existing fauna in the sand, and most people it seems to be desperately lacking in this department so it is not so much of an issue. Another issue too is if there is any organisms currently present that will compete, eat etc the organism trying to gain a foot hold....... now ain't this complex ;-)

Oh well, there you have it, just thought I should think out loud and hopefully get some feedback on these thoughts......and note that you can find some very good information in areas where you least expect it ;-)

Eric Borneman

great post...

Very true, too. I have long been saying that the reason there was so much "negativity" areound sand beds for so long is that no one was giving their benthic community a chance to satbilize, grow, diversify, etc... My first sand bed was set up in 1993 using all live sand that was actually of incredibly good quality....following the loss of , IMO, high quality sand suppliers, I had started to set-up systems with "dead" sand and soon learned tht six months was still not a long time to get a fully functional, well populated, stable sand bed...most were putting in a couple inches of sand and waiitng three or four weeks, not seeing miracles, and jumping on the naysyaer bandwagon....sigh...its all about patience.

Anyway, even more than perfect homeostasis, I have found that there is, pending new inputs, of course, a flux of communities...cycles of increase and decreease as smaller populations row, thrive, and decrease along with their food supply... IMO, this is a very natural progress of things, and has been very fulfilling to see happen. If we would quit messing with the sand so much, stirring, adding, siphoning, washing, changing, worrying, etc, we would be in a vastly better place, I think.

Ron Shimek

Would one get the same effect of a large concentration if one added the new sand in a corner by it's self, moveing aside the sand that was there all ready? I would think so.

Probably. It would be a "balancing" game where you would have to take into account the amount of added habitat and fauna and the total volume of the system. In my tanks the sand fauna is dense and diverse. A newly added portion of sand would be subject to colonization from the present population which is continually producing larvae and juveniles.

Small amounts of new sand would likely simply get overwhelmed by the present fauna. Keep in mind as well, that the sand containing a diverse established assemblage likely contains predators as well. The newly added sand fauna will be stressed by the collection and transport process and may well be easy pickings for both competitors and predators from the established populations.

If the established population is not diverse or dense, a small localized addition would likely succeed as long as the general conditions in the system were pretty good.

However, one should look at WHY there is not a diverse population present in the first place. If it is because no live sand fauna was added previously, the innoculation would likely succeed. If it is because an initial attempt has failed (due to lack of adequate feeding, the presence of sand-sifting predators, or ...) then those conditions will need to be remedied first.