Quote:
Originally posted by mojoreef
To funny DOug those meds must be working.
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Yeah Doug will be the source for a few weeks now, Mr. Comedy!
Quote:
Originally posted by mojoreef
Well the sand bed is about 8 months old and if you add in the swap of it, it would be about 3 years.
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nope, the swap is just like starting over, although you have a BIG head start in seeding the sand bed and you have the advantage of mature adults in the sand bed capable of reproducing, you still have clean sand grains without the periphytonic communities established on the surface of each grain. Competition will occur to colonize these new "real estates" for optimal growth of the corresponding organisms. Maturity will occur when competiton for this space reaches a standoff and only occasional sand bed population fluxes will occur.
Quote:
Originally posted by mojoreef
For critters, I have all the usuals, pods , worms, about a 150 nass. snails, 3 conches and the mother of all serpant stars. I am not a big fan of cukes, but I figured I was OK.
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now there ya go Mikey, got to think outside the box of "Normal" leftovers for the sand bed cleanup...
This is where I get to hang on a bit more to the fishpoop!
REMEMBER: Think Food chains.
If you want remote sand beds that work appropriately, they would need five things:
- appropriate sand granule size and depth
- water current slow enough to allow regenerative sediment settling (accomplished with wide shallow tanks)
- good lighting
- appropriate benthic populations and speciation
- appropriate grazers and optionally, nitrate consumers (especially with shallow sand beds)
All of us are familiar with the need for the detritus to settle out where bristleworms,
brittle stars, etc., can consume the initial organic "humus", if you will (PhD Reefchow...
), that contribute to the initial carbon cycles and some of the raw materials for deammonification of nitrogenous substances. Depth of the bed will help establish those areas where low O2 tension will be capable of processing the nitrogen compds to nitrogen gas, and the upper layers will provide the mechanisms to make organics into CO2 and water, but this is NOT where it stops.
The available CO2 can either supply acidity to the water column, or it can be the raw material for photosynthesis for benthic microalgal populations. Coral reef sands harbor huge dense populations of microalgae capable of prodigious primary production, with chlorophyll A contents in the hundreds of mg per square meter of substrate area. Measurements of the production rates by Sorokin et.al., demonstrate that in addition to the heterotrophic activity of such sans, that the primary production of these soft sediments attains levels of 1-3 gms of Carbon per meter squared per day!!!. In this manner, many of the nutrients that would otherwise become end detrital components are recycled back into the food chain, where they are then converted by sand consumer/cleaners into biomass, often capturing many of the substances that we find accumulating in DSB without such cleansing. These are not sand stars, not fishes, rather they are the
Holothurian spp. of sea cucumbers and related Echinoderms that consume sand for it's benthic periphytonal communities (biofilms). Not surprisingly, areas in the wild that are in close proximity to dense coral populations have the highest production of benthic carbons, due to the high nutritive value of shed coral mucus in feeding these same benthic populations (the heterotrophic portion).
As these populations are high, so is their corresponding consumption of oxygen in the absence of light and the benthic algal pops, hence their need for good current, both in terms of supplying fresh detritus and O2. This respiration rate has been measured at 0.1-0.6mg of Oxygen per gram of substrate per day, which translates into the ability of 20 gms of sand and its bacterial pops have the ability to completely remove all oxygen from 1 litre of seawater in one day. This accounts for the relatively rapid development of anaerobic layers of sands in areas that are deep enough and have sufficient populations of heterotrophs.
Soft sediments (coral sands) cover 60 to 80% of the total reef-bottom area in the wild, and account for primary production at rates of 2 to 3 grams of Carbon per sq meter in flourishing reef sands, 1 gm of sand will produce 100 to 150 micrograms of carbon per day, very close to the levels produced by living thriving corals per gram of gross colony weight! These production rates account for the huge biomass of the bacterial and algal microbenthic communities resulting from the conversion of regenerative sediments (detritus made up of mucus, leftover food, plant material and "fishpoop") in the presence of light. These become the food for many benthic sand grazers such as the
Holothurians, various worms, and clams in addition to the many representatives of the microbenthos and meiobenthos (Sorokin 1973, Moriarity et al, 1985, Hansen 1985, Hansen and Skiller, 1988; documentation on request), and are responsible for conversion of the primary production of these sediments into biomass. Many studies have demonstrated the visible effect in the reduction of bacterial populations (Sorokin 1978, etc.) by holothurians, clams, microbenthic copepods, and (especially) the harpacticoids in addition to the nematodes, protozoans, and turbellarians. It is this group of heterotrophic consumers that allow us to keep sand beds and keep them relatively free of detritus accumulation (the key is
relatively)
Over time, this slow accumulation of substances may end up requiring the replacement of DSBs in the long run, but in my personal experience, I have yet to exceed those limits (testing will be done on the 6 plus year old beds on the tank still running in Wellford when it is taken down)
More later, I have to go to court this afternoon...
