Live Rock Variances

[Scouse]

What is the difference in live rock throughout the world, especially difference between warm and cold water.

When considering setting up a native species tank, the first thought towards live rock is that the rock is not as porous as that you get in the Live Rock we purchase for warm temperature tanks.

Therefore logic leads me to beleive that the biological filtration will not be very good.

Surely there is sufficent biological filtration in cold parts of the world in the sea, but is this taken over by something else rather than live rock?

Any thoughts on how to overcome the matter, as natural as possible, with a native tank?

Cheers

[SCOOB]

a Very interesting topic and looking forward to 'the panels' response.

as a guess tho' i would say that the highly porous live rock of which you see in shops and reef tanks has come from highly volcanic atols and so would have been filled with air and gasses when formed to create the sponge like texture think this is called igneous but i may be way off. other live rock is actually just dead coral skeleton and therefore is made up of aragonite. if you look at somewhere like the maldives for instance. the actual islands are the peaks of mountains and out of the atolls is incredibly deep open ocean. up here around the uk we are on a very shallow plate meaning the sea bed has more exposure to the sun and therefore algaes have taken on the project of nutrient export. plus our seas are much colder than in the tropics, i imagine all these factors come into play.

like i said i'm just guessing, looking forward to what someone with half an idea might say tho' :)

[danny]

I`m not a panel member:p but I would go for dried reef rock for a temperate set up, as you say this would offer better filtration.
Remember that in the sea the stocking density is miles lower than in our tanks and as such there does not need to be as much biological fitration as in our tanks. Bacteria will colonise any available surfaces given the opportunity.
Danny

[jez]

Hi
This is probably a question for a geologist rather than a reef keeper but I will take a good stab as to how I see it. I should have paid more attention in geography at school.

Live Rock as we know it.
The primary rock used by the aquarium industry and branded live rock, is simply pieces of coral skeletons that have over time been smashed off the reef, by the action of wind and waves. These pieces of living or dead reef fall to the seafloor as rubble, given time they will be colonised by a range of organisms, which will bore burrow and generally make the rock a bit more porous than it was when it was living. By rock standards the aragonite formation of coral calcification is pretty soft and porous; the addition of erosion and boring animals gives us the stuff we want as aquarists. This porosity allows effective filtration of our aquariums.

NB: On a natural coral reef the rock is not the main form of filtration, as it is in most reef aquariums. The dynamics of how a coral reef cycles its nutrients is fairly complex but in essence the whole thing operates on very tight cycling of nutrients by a vary diverse range of organisms.


The STM plating rock can easily be identified as plates of very large Pavona, which in certain parts of the world grows to a massive size and is frequently shattered by storm wave action. Fiji live rock is more mixed in its origin but it’s usually possible to spot a few well known corals. The Caribbean rock that was popular up to the arrival of Fiji rock was largely made up of eroded pieces of Acropora palmata.

Coastal rock
Rock around the UK coast is of totally different origin to live rock. As I recall most of the rock that lies around the UK shore came from prehistoric times, from up welling, volcanic activity etc etc. As you travel the coast, the composition of near shore rocks will tend to match the local geology, so if you pick up rocks on the south coast they will be mainly chalk and flint. Although there are cold water reefs off parts of the UK coastline, these are too distant to allow the collection of rock made from skeletons of corals.

In terms of filtering a native marine species aquarium, finding live rock as we know it, is probably not going to happen. What you will find in certain parts of the country where the local stone is soft and porous will be rocks with a good few holes in. These may offer filtration abilities. Most of the people I have met who keep native marines do not go to the lengths tropical reefers do. Most seem to at best use a canister, some under gravel filters. There seems to be a tendency to rely on the hardiness of rock pool creatures, that can handle varying water quality, usually combined with regular trips to the coast to collect seawater. It is quite possible, in fact probably desirable to offer the level of care we lavish on tropical specimens to some of our native species. The biggest cause of failure with many native marines is temperature and lack of oxygen saturation.

Hope that helps


Regards Jez