 |
|
| Home | Marine Aquariums |
Freshwater Aquariums |
Planted Aquariums |
Brackish Systems |
Ponds,
lakes & fountains |
Turtles & Amphibians |
Aquatic Business |
Aquatic Science |
Ask the WWM Crew a Question |
| Please visit our Sponsors | ||||
RE: Collaboration in a live-rock study? Dear Bob <Hey Tim> We are now 2 1/2 weeks through our 4-week live-rock test, and only just now getting preliminary results of nutrient levels (owing to analysts being on sick leave). <Yikes> Ammonia was added at 0.5ppm total-NH3 on day one and 0.25ppm subsequently, and in both rock treatments it disappeared immediately to undetectable levels. Nitrate began appearing in large quantities from day one and built up to 1ppm after 5 days. Nitrite scarcely appeared at all. <Not too surprising> In the control tanks (no rock) ammonia is present at around 1ppm NH3, while nitrate has remained at less than 0.2ppm. <Okay> The difference between rock and no-rock is very dramatic, however there is no difference between the two rock types. <Shouldn't be... if they are/were both stably colonized by nitrifiers to start with> Basically the rock tanks are behaving like an aquarium that has already cycled and is in prime health. They are scarcely being troubled by additions of 0.25ppm daily. I propose we at least quadruple the dose starting tomorrow, and run it like that for another 10 days, to see how they react. <Good idea> Any suggestions? What kind of dose level should we now aim for? <Think your guesstimate is about right here> After this experiment has ended, I'd like to start using fish. I'll start with four per tank, and each week add another two, until some disease or mass-death occurs with one or other rock type. Then, we'll have a rock-type "winner". Would the animal rights people approve, though? <Not pertinent, but do weigh the fish livestock> This experiment is starting to get interesting. <Oh yes> Regards TIM <Bob F, who had din din with the Smiths in Germany, and has been diving in Egypt's Sinai the last couple of weeks... back now> RE: Collaboration in a live-rock study? Thanks for the reply, Bob. We went ahead and quadrupled the ammonia dose. The experiment officially ended last Friday and we expect the full set of data by next Wednesday. <Ahh> We found that, after a few days from the beginning of the experiment, ammonia levels in one control tank separated from the other two and went downwards to join the rock tank treatments. On going back through our records, we realized that a tank breakage right at the start forced us to put some rock into a control tank for an hour as an emergency measure while the broken tank was being replaced. <Oops> After putting the rock back where it belonged, we drained the control tank down to 1-in deep then refilled it. It appears, however, that we inoculated it with the right sort of goodies, so it behaved like a rock tank after a few days lag time. While this event has spoiled that tank as being a "control", it may be rather serendipitous. According to your fine book, people often borrow a cup of "live sand" when cycling a new tank, but maybe they could instead borrow some "live water" (someone's discards after doing a water change on an established tank). Does this bear further investigation? <It seems noteworthy as part of your "discussion"> Will let you know when complete dataset available Regards TIM <Real good. Looking forward to it. Bob Fenner> RE: Collaboration in a live-rock study? Tim, Bob (sounds like a "Waltons" re-run!) <Yes Tim boy?> Still waiting on the ammonia results, but have all the others now. In terms of nitrate build-up, there is no difference between the two rock types at the levels we tested (up to 1ppm NH3 addition per day, which is quite high in hobbyist terms) but a big difference between having rock and not having rock. <Yep, vive le difference!> Tanks without rock went through a nitrite "spike" when we increased the dose from 0.25 to 1.0ppm, i.e went through a "cycling" event, while in the rock tanks the nitrite was hardly noticeable. So its looking good for aquacultured rock as an aquarium product at the moment, though I haven't yet seen what's happening with the ammonia, and subject to any comments Bob may have. <Mmm> Our next move is to try this out with fish, and keep increasing the numbers of fish until they get sick or die. Then we will have a winner (or a first-equal). I attach an application we have just made for $5K from our University research committee to cover this. Tim, would WSI be able to donate a swag of green Chromis or similar fish to use as the live "guinea pigs"? We will need, say, 6 per 80L tank = 54 fish to start with, then increase by another 2 per tank (18 fish) in stages over the weeks to come until something karks it. Is that do-able? <Hopefully, Bob Fenner who will cc Tim McLeod> Cheers TIM RE: Collaboration in a live-rock study? Hi Tim,.....Howdy Bob......I hear from Jason the Red Sea was a blast. <Ah, yes... I know you've dived for thousands of hours in NZ, Fiji and elsewhere... but hopefully aren't "dived-out" quite yet! And will be getting out to make pix someday soon together> Read through the application-nice to see the effort you are putting in here. No problem with the fish, any time you are ready...we should only need a couple of days notice. <Real good> Please note....at present the cultured rock is left in the Ocean for at least 12 months....normally 18-30 depending on the site. <Wowzah, this is getting to be like fine malt scotches...> I'm hoping to get it down to 6 months with some research into propagating the coralline spores, and introducing the rock to a heavily infected bath of the coralline in its planktonic (sp.??) stage. (over to you--how busy did you want to get?) I'm also going to swing by Suva sometime to check the rock and coral samples you have. Will call when I can find a break. All the best Tim <Hope to see you soon (maybe August). Bob Fenner> RE: Collaboration in a live-rock study? Dear Tim-Bob <Howdy> Please find attached our preliminary results (mean data and graphs) for the live rock experiment, in the attached Excel spreadsheet. We welcome your comments on how to interpret these results, now that we are in write-up mode on this experiment. <All seems to be "about right"... for Walt.S sake would like to run a series of experiments with a few formulations I have in mind... for maintaining pH through the "run in period" of establishing biological cycling...> Please let know if any problems opening the file. TIM <As stated, all seems about as predicted/anticipated. Bob Fenner> RE: Collaboration in a live-rock study? Bob, my take on it is that, in terms of ability to convert ammonia into nitrate, the two rock types are "evens-for-Stevens" at the conc.s tested. <Agreed... no need even for chi-square testing... they're within my "confidence limits" this same functionally> But note that when the ammonia dose was increased from 0.25ppm to 1.0ppm, there was a nitrite "spike" in the artificial-rock tanks. So ability to withstand the triggering of a new cycling event in a tank may be marginally higher with natural rock. Do you think the observed nitrite spike was high enough to warrant being described as a "spike", i.e did it reach a nitrite conc. that may be troublesome to fish? <A spike is a fine, descriptive, useful and common term> Regarding the new formulations you have in mind for initial tank cycling and pH, let us know in more detail what you're thinking, so we can plan the new experiments accordingly. <Mmm, a mix of sodium bicarbonate, calcium chloride, calcium carbonate and a little borate. I gave the formulation for this "Fiji Gold" (delicious, export) to Walt.S sometime ago and strongly suggested he market same and place a sample in each box of live rock, faux and natural... Bob Fenner> Regards TIM Collaboration in a live-rock study? I am writing to ask if you wish to collaborate with us in a research project in our laboratory to compare the efficacy of an aquacultured "artificial" live rock with that of natural Fiji live rock. I am Lecturer in Aquaculture at the Marine Studies Programme of the University of the South Pacific in Suva, Fiji, and am supervising a Post-graduate student Dilpreet Kaur on this topic for a one-semester project. We are collaborating with Walt Smith International based at Lautoka, Fiji, who will supply us with the rock. <Will gladly help, assist. Do know Walt and family... and visit Fiji a couple of times most years> Though I have a background in aquaculture, I am relatively new to the aquarium hobby and am teaching myself about it by maintaining a 90- gallon marine aquarium in our reception area. I am also supervising Masters students on aquaculture of corallimorphs and fire shrimp Lysmata debelius. <Good practice> Being new to this, I would appreciate your input, if you wish to make any, on matters of experimental design for this live rock project, particularly on achieving realistic doses of nitrogen to the system and realistic stock densities of live rock. We intend to publish the work, and would credit you with a co-authorship. Your recommendation as to a suitable journal for publication would also be welcomed. On the other hand (with articles on biological and chemical aquarium matters to your credit) you may think this is a bad idea, or its already been done before? <There is the Journal of Aquariology and Aquarium Science... John Farrell Kuhns... we can talk this over further> In brief, the study can be summarized thus: Objective - to compare the effectiveness of a cement-based artificial "live rock" (manufactured by Walt Smith International and left in the sea for several months) with natural Fiji rock, in terms of ability to contribute to the cycling of nitrogen in an aquarium. Prediction on - more nitrate will build up in the artificial-rock treatment, because of its less porous nature thus less habitat for anaerobic bacteria. Null hypothesis - there is no difference in levels of ammonia, nitrite and nitrate between aquaria stocked with natural live rock and artificial live rock. Treatments - (1) Tank stocked with natural Fiji rock (2) Tank stocked with artificial live rock (3) Control (no rock at all) Replicates - Two tanks per treatment Tank size - approx 100L (30 gal), in glass. Kg of rock per tank, for this water volume? (Read "Conscientious Tank-keeper" to find out!) Sand on bottom, say, one-inch deep? Yes, or no? Experimental protocol: Set up tanks with live rock obtained from Walt Smith, add a power head to provide water circulation (but no water flow-through). Daily add Mel of XM ammonium chloride solution (what is a realistic quantity of daily ammonia addition?) Daily or once every two days, collect water sample and analyze for ammonia, nitrite and nitrate concentrations. Run experiment for at least 6 weeks. Statistical tests: Analysis of covariance to test for differences in concentrations of each species of nitrogen through time. Follow-up experiment - try it again, this time with real fish! Any comments? Since we have a research laboratory at our disposal, with algal-culture facilities under construction and tropical oceanic seawater supply available, and the Walt Smith people just down the road to advise us, our institution is well-placed to conduct some reasonably rigorous scientific research on any topics of interest to your hobby. I'd be glad to hear of any other labs doing likewise, and hear of any other suggestions you may have for worthwhile research topics. Best regards Dr Tim Pickering Lecturer in Aquaculture <Tim, have been visiting in Australia this last month. Sorry for the delay in correspondence. Allow me a few days to return to the West Coast (US) and I'll gladly cooperate with you. Be chatting. Bob Fenner> Re: Collaboration in a live-rock study? Thanks very much Bob, for your positive response. <A pleasure to be of assistance, work with you> We plan to set up this experiment in the next one to two weeks. Key issues for us now are: (1) How many kg of rock to stock per L seawater? <I would try a series of densities, test organism populations for these assays. Something of a range that reflects that used by aquarists. Likely 0.1, 0.2, 0.3 kg/l in my estimation> (2) What's a realistic daily dose of ammonia? <Remind me sometime to relate to you the couple of years I worked at a bioassay lab in San Diego (another in Kaneohe Bay in O'ahu) on testing anti-fouling paints (copper and organo-tin cpd.s) where the folks left out this important measure... Oh, 0.05 on the low end, perhaps 0.5 to 1.0 ppm on the high> (3) Should we have any sand in there too? <Not in the test model, experiments... unless you/we have hundreds of tanks to employ, plenty of time for replicate testing. One variable to manipulate/test at a time as you know> Any guidance you can give will be most appreciated. Thanks TIM <Looking forward to the further collaboration. Be chatting, Bob Fenner> Re: Collaboration in a live-rock study? Thanks Bob, that's good advice, we'll work around those numbers. <Real good. Is there a more "full-text" version of the test-model? Am curious as to what sorts of animals, densities, exogenous sources of nutrients, measures of transport/conversion... procedures you might be using. Bob Fenner> Re: Collaboration in a live-rock study? Hi Bob <Hey Tim> That's the fullest-text version of the experimental method so far. We are still developing our ideas. <Okay, me too> Our plan at the moment is to not use any real fish, at least, not this time (maybe next time). Instead, we'll add ammonia daily as NH4Cl. Not as realistic as real fish, but more controllable. <Yes... perhaps "Phase 2" can/will employ live-livestock...> It does, however, leave us with the problem of knowing just how much ammonia to add each day. While 1.0 ppm may be a typical ammonia concentration, that figure tells us nothing about the *rate* of ammonia addition and subtraction in the system. After establishing 1ppm of ammonia on Day One, what amount should we be adding daily thereafter? <Mmm, good question as in "I don't really know"... something to the point of it (the NH3/NH4OH) being appreciable/detectable... there are a few concerns here... at or about one ppm systems can be poisoned in ways that forestall nitrification, and its very establishment... Not to throw more wrenches in to your considerations... I would add some guess to the amount that a token bioload would produce under "aquarium conditions"... Experimentally, to a starting point of 0.1 ppm or so. If desired and there being plenty of rep.s/time available, attempts might be made to "peg" the amount of exogenous ammonia added... such that there would be detectable ammonia hours, a day later.> This problem would be circumvented if we *did* use real fish, since they themselves already know how much ammonia (urea, or whatever) they're going to be adding, as they go about their business of doing what comes naturally. <Yes... or, another idea/possibility... to drip/add the diluted ammonia over the trial period> We could use any of the fish that Walt Smith keeps in stock. Green Chromis is one candidate fish that springs to mind. And we could just feed them weighed amounts of the Fenner Shrimp/Oyster/Seaweed recipe, to input nitrogen to the system. <A good choice of specimens (cheap, readily available in good numbers, very popularly used in experiments, by hobbyists... and ammonia tolerant compared with many other species/groups> What's your preference for this experiment - real fish, or a chemical source of ammonia? <For the first go of experiments, ammonia solution... Cheaper, easier to do, control... then bioassays later if time, money, interest exists> If the latter, then what *rate* of ammonia turnover should we expect, that we can base a daily dose upon? (Maybe a preliminary experiment is needed to determine this). <Highly variable as you will find...> For ammonia, nitrite and nitrate measurement, we have secured the services of our Institute of Applied Science water monitoring lab, who routinely use colorimetric methods to analyze reef water samples and can do so with great accuracy. <Okay... though Horiba et al. companies make very good "live" instruments, recorders... but can be expensive to purchase, operate... and you already have the other gear, personnel.> Our plan is to just measure ammonia, nitrite and nitrate in the tank water, and compare their levels every two days over a month time span in tanks with natural, artificial, or no live rock. Hopefully this will tell us which type of rock is most efficient in cycling the initial ammonia spike, and which is most efficient in ultimately disposing of nitrate through conversion into N2 gas. <Do add testing for temperature, pH, alkalinity, and Calcium to these parameters (please). Much to be discussed (as in cause-effect, Discussion) in your scientific paper/s here.> Regards TIM <Be chatting my friend. Bob Fenner> Re: Collaboration in a live-rock study? Dear Bob The best plan may be to review the amount of ammonia addition every two days when we obtain each nitrogen test result, by checking its current level and then calculating how much needs to be added to restore ammonia to the predetermined figure (be it 1 ppm, or 0.5 ppm, or whatever). This is what we New Zealanders call the "Suck it and see" approach ... <A good approach and apt descriptor. Bob Fenner> Regards TIM Re: Collaboration in a live-rock study? Dear Bob I've been staring into space again, deep in thought about the ammonium levels we administer to the rock. Essentially this is a "fishless cycling" exercise, for which there are a host of web articles explaining. You'd already be well versed, naturally, but I'm just getting up to speed on it ... <Perhaps I can help you get into the jogging mode, or at least tie up your tennis shoes> Problem is, the writers of these WebPages are imprecise in their descriptions of ammonia added (measured in "drops", and used in lots of different brands and formulations). Most seem to aim for initial conc.s. of 1 - 2 ppm (Meyer 1999), 5ppm (Cow), or 3 - 5ppm (McGregor-King) measured by testkits, add enough ammonia daily to maintain this level until nitrite peaks, then cut the ammonia dose back by 1/2 until cycling is complete. <Sigh... I know this all too well> The purpose of "fishless cycling" is, however, different from our purpose. A "fishless cycler" wants to go for overkill, on the basis that having *too* many nitrifying bacteria present when they finally add fish to their tank is better than not having enough (lest adding the fish triggers further cycling). The die-off of bacteria that might ensue, due to fish-ammonium input being less than the preceding chemical-ammonia input, does not seem to be regarded as a problem. <Yes... a good, fair lesson in the ying-yang of the real universe... let's see, an equivalent in physics is... the Schrodinger Principle> Our own purpose here is not to cycle a tank as fast as possible to as high a bacteria population as possible. Rather, it is to compare (1) how two different types of rock deal with cycling (nitrification), and (2) how effectively each deals with denitrification to eliminate the pool of nitrate which emerges from the nitrification. <Yes, agreed. While "stoking the nitrifiers" with chemical feeder stock necessarily, expediently> Since our purpose is to compare, we don't want differences to be obscured by "overkill" in the amount of ammonia (especially if nitrification can be impaired by high ammonia levels). Nor do we want the level of ammonia to be so low that it is easily handled by both types of rock, and neither gets sorely tested. <Yes> So we need a "middle ground", some level of ammonia that mimics the level actually added into water by the fish in a tank. Which, in a closed system, could be assumed to be the same as the number of N atoms contained in the food we feed to our fish. <Yes> This approach, if adopted, differs from what I proposed earlier. It is a "fish-driven" daily addition of ammonia in an amount that remains constant between tanks and over all days of the experiment. The data we collect is the levels in seawater of ammonia, nitrite and nitrate, with the "winner" being (1) the rock that is soonest (measured in days from the start of the experiment) to reduce ammonia level to zero (or to reduce an ammonia spike to zero within 24hr of addition?), and (2) the rock with the lowest concentration of nitrate in the tank after, say, one month of daily ammonia additions. <Mmm, well... as a series of preliminary experiments, one could just count on endogenous sources of ammonia from catabolism... the conversion, consumption of peptides by the life in/on the rock itself...> My earlier concept was a "bacteria-driven" amount of ammonia, whereby we simply replace the ammonia that the bacteria consume. This might be different between tanks in the experiment, so they'd end up getting different daily doses. In fact, under this regime, the data we'd record and analyze would be (1) the size of the daily dose required to restore ammonium to a level of 0.5ppm, and (2) the concentration of nitrate after 1 month. <Yes... though not mimicking what goes in a typical captive system, this is a close approximation> To determine a "fish-driven" ammonia level, what I propose to do is get a %N test done on the "Fenner Milkshake" food ration I am currently giving to our display aquarium. <Yum, am getting hungry now> I've no idea if this food ration follows correct practice or not - its a 1in. x 1in. x 0.5in. ice block of blended shrimp tails (Penaeus), clams (Anadara) and seaweed Hypnea pannosa, shared between 1 clownfish, 2 algae blennies, 6 green Chromis, 1 sleeper goby, 3 pajama cardinals, and about 7 other small fish I don't know the names of. All food gets consumed within about 3 mins. <Faster if I get hold of it...> Once we know the %N of a typical ration, we can calculate the no. of N atoms we have to add to our experimental system per L, and can thus come up with a quantity of NH4Cl for addition on a daily basis, after an initial "spike" of 0.5ppm on Day One. <Easy enough to digest, run tests for in the lab> Alternatively, we could just add the food daily and let it rot (see http://www.algone.com/fishless_cycling.htm) <Yes, a possible approach. Worth trying> Do you have any thoughts on which approach you'd prefer - "fish- driven" or "bacteria-driven" daily ammonia amounts? <Mmm, may seem disingenuous, but "both"> Logistically the "fish-driven" constant-amount approach is easier than continuous recalculation and adjustment of different N doses for different tanks in the experiment (there will be 6 tanks). <Yes... and only six rep.s?> The other issue is how frequently we analyze the water for the three forms of nitrogen. I had it in mind to do this three times a week (Mon, Wed and Fri) for logistical reasons. However some fishless cycling articles, for example http://www.csupomona.edu/~jskoga/Aquariums/Ammonia.html say that the cycling end point is reached when ammonia which is added goes to zero within 8-12hr after addition. Would it be sufficient for us to test every 2 to 3 days and still be able to observe when ammonia hits zero? <Yes... close enough for me, the intended applications> Appreciate your thoughts, thanks for the time it takes to consider these issues. Simple experiments never seem to stay simple for very long ... <Agreed. Press on my friend. Bob Fenner> TIM Re: Collaboration in a live-rock study? Dear Bob I'll adopt the "fish-driven" constant-dose model for now, but regard this as Round One in the bout (and hoping there'll be no TKO before Round Two). <Okay> Regarding your comment below: "Logistically the "fish-driven" constant-amount approach is easier than continuous recalculation and adjustment of different N doses for different tanks in the experiment (there will be 6 tanks). <Yes... and only six rep.s?>" We planned to use three treatments ("wild" live rock, aquacultured live rock, and a control with nothing in the tank at all except water), with two replicates per treatment. <Wish there were more tanks, time, money... while I'm in the wishing biz...> Are you nervous about only two replicates per treatment? We could increase it to three if need be. <I would do so... the within group variance in results could be considerable... Bob Fenner> Regards TIM Re: Collaboration in a live-rock study? Okay, three it is. While I've got you on the line, are your ppm figures quoted earlier for "ppm as N" (ppm N-NH3), or "ppm as ammonia" (ppm NH3)? <As NH3... a bit of historical conflict with the hobbyist and scientific literature... which you/we should mention/offer a conversion factor for. Bob F> TIM Re: Collaboration in a live-rock study? Dear Bob <Hey Tim> I've struck a logistical problem - our order for 1 dozen powerheads to use for water circulation in this live-rock experiment is unlikely to be filled for another 1 -2 weeks, and I'd really like to get this show on the road or the student will not finish before the semester ends (another 7 weeks). We can create some water circulation by aeration, but wonder if this will cause ammonia to be bubbled off and thus bias our results. <Mmm, should be no problem. But do check with Walt Smith... and I'll cc friends at Sea Dwelling Creatures to see if friends, associates have powerheads on hand in Fiji for your use> Should I use air, or wait for the power heads to arrive? <If no powerheads available in the short term, I would go ahead with the airstones... a standard in the world of bioassays. Bob Fenner> Regards TIM RE: Collaboration in a live-rock study? Bob, I get from this
message that "Tim" needs power heads that will run in
Fiji. <Yes, Tim Pickering is a fisheries scientist there,
doing some baseline studies of Live Rock> I currently don't have
any in Fiji that will work there. The best option is via Australia or
New Zealand. I can get some sent over there quickly via post from my
Australian cronies. Let me know if I can help out. <Will send your
note on. Thank you for your quick attention, offer of help Scott (Sea
Dwelling Creatures). Bob Fenner> Thanks,
|
|
|
Features: |
|
| Featured Sponsors: |
