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Rossco
01-05-2010, 02:52 PM
Hi All,
I have recently been in a few debates with people about the use of an ATS. I think the concept is sound. The latest comeback was a video showing the results of a study by USF. It seems legitimate. I have asked for some more details on the vid and await a reply.
http://www.marine.usf.edu/videos/2007-01-26.wmv
Anyhow, after watching the results of the studies I felt even more inclined to use turf algae as a method of excess nutrient removal. Others have taken it all a bit differently and are saying that it shows any algae in our system is killing the corals we are trying to maintain. Have a watch and see what you think.
If you are interested in the opinions of others it started here: http://www.masa.asn.au/phpBB2/viewtopic ... 627#724627 (http://www.masa.asn.au/phpBB2/viewtopic.php?p=724627#724627)
As I'm no marine biologist, undergoing studies to prove a point, I can only go on what I learn from others experience. This makes it hard to convince others.
I just thought you guys and girls should have a chance to defend yourselves and your methods. I noticed a lot of people that were going to give this method a try have been scared off by the above video( mainly one idiots interpretation). If someone with some real experience could add to the debate it would be very helpful.
Thanks for your time.
Ross.

ChrisD
01-05-2010, 04:06 PM
I'm no marine biologist either but I can look in my tank and see coral with algae on the old skeleton adjacent to the coral tissue and the coral has been fine for months and not died within the 24 hours that he is claiming. In the questions at the end someone queries that particular experiment and questions whether the corals were simply dying from something else and, as a scientist myself, I am amazed that he didn't reply with confirmation that a control without exposure to the algae was performed. Why couldn't they have taken a single piece of coral, divided it and used the same water etc and put in an identical tank minus the algae and see if the other piece died too. A control is fundamental to any science experiment of this nature!

Also, how were the test tanks lit? Maybe the algae was dying or going asexual and affecting water chemistry. Also, I do recall seeing something about some algae releasing compounds that are toxic to coral, particularly sps.

So many questions / holes in the experiment from a very brief view from me that, in the absence of any further explanation, I will simply look in that little glass box of mine and judge for myself.

Rant over.
Chris

SantaMonica
01-05-2010, 05:15 PM
Is old news.

A research video from the College of Marine Science (U of S. FL, St. Petersburg) is sometimes used as proof that "algae kills corals". If you watched only 5 or 10 minutes of it, that's what you'd think it was saying. The video starts out appearing to make the point of "algae kills corals", but this first part of that presentation is just a setup for the presenter's further explanations, and is not the point itself.

It's a similar situation to a presentation for beginners about how rock, sand, and the nitrogen cycle works: You would start by saying "If I have a fish in a bucket of water, and I pour in ammonia, the fish will die." This is true, but it's only used to set up later explanations of how rock and sand come into the picture to stop the death of the fish.

So it turns out that if you watch the whole research video, the presenter/researcher not only makes the point that algae does NOT kill corals in the wild, but also counters the "high-DOC's are bad" arguments. The presenter, in the beginning, is trying to show how "algae kills corals" was what they were expecting to see in the ocean, so that later he can show you what they really found in their diving research. The crux of his presentation is basically: "We thought higher DOC's were the cause of coral death; We were wrong. Lower DOC's are" (these are my words).

So here is the video, with rough quotes of what the video says, along with the minutes and seconds into the video where you can see it for yourself:

http://www.marine.usf.edu/videos/2007-01-26.wmv

23:30 "Bulk DOC does not correlate with coral decline; higher DOC areas have healthier corals; lower DOC areas have weaker corals. The opposite of what we predicted".

24:40 "The DOC to DIN ratio's are higher on healthy reefs, and lower on less-healthy reefs".

25:45 "Microbial numbers are elevated with a lower DOC to DIN ratio" (!) (even I got that one wrong).

34:00 "Christmas Island, with the really low DOC, has the highest pathogens, while Kingman Island, with the highest DOC, has the lowest pathogens."

37:00 "On Kingman Island you have high hard-coral coverage and the lowest disease [and highest DOC]. That's weird! What you SHOULD find is that as hard-coral coverage reduces, it should be harder for the pathogens to find hosts, so you should see a pathogen decrease. But we're not seeing that, which means there is SOMETHING ELSE going on."

49:20 "The DOC definitely always goes down, in the really bad coral areas".

52:39 "You can actually put the corals where the nutrients are really high, and the corals are not dying; in some cases they tend to grow better, which is also true in our [???].

So I submit to them, using their own evidence, that not using a skimmer, with the resultant increase in DOC's (and now apparent decrease in microbes), is not in-itself a coral killer. Something else is. And this explains why some people using algal-only filtration can grow great sps.

Amphiprion
01-05-2010, 05:36 PM
Well, it is open to some interpretation. It is well known that various types of algae do release carbohydrates into the water, particularly sugars, which foster bacterial growth. This is also applicable to refugia, which have been well accredited to the creation of bacterioplankton, a vital food source. Do also keep in mind that corals excrete carbohydrate-rich mucus, which also fosters quite a bit of bacterial growth. It also depends upon the amount of algae and its proximity, as well--which is also mentioned several times in the study. Something that others may not have noted in the presentation, is that when they mentioned "turf species" it also included "cyanobacteria," which are largely regarded to be toxic and implicated in many diseases. Basically, there are too many variables and too many possibilities to start blaming one particular algae or ATS in general. Given the popularity of refugia, it seems quite unreasonable that remote setups are an issue. Of course, we already know when algae is growing practically on top of a coral, it isn't going to do as well in many cases. There are also a lot of variables in the study's setup. I doubt these people set this particular experiment up like an aquarist would. I wouldn't doubt it if they managed to overlook something relatively simple, like the amount of water motion involved, etc.--all of which influence bacterial activity. In the end, I think more needs to be done in this particular area while covering more grounds and other potential factors. I hate to use it as an example, but there are too many successful scrubber setups that show the contrary. There are far more replications in that regard than in that study. I think people are too quick to jump on bandwagons, but that's jmo. I've noticed, also, that many of these folks (though not necessarily on that site) that like these newer bacterial driven nutrient reductions systems. These systems are no different and, in fact, represent an even more elevated situation in regard to bacterial growth and activity.

Edit: SM beat me to much of it. In response to part of that, there are explanations to that, which include greater bacterial assimilation, hence lower DOCs (kinda like inorganic N and P and lots of algae in the tank), in addition to less corals overall, which would also result in less DOC. I just think something isn't necessarily adding up and/or the situations aren't necessarily equal, hence some of the unfounded blame. There's too much contrary evidence and other inconsistencies to say that this USF study is THE answer.

Rossco
01-06-2010, 03:34 PM
Thanks for the replies.
I have watched the video all the way through and agree with your take on it Santamonica. To me it was just proving that if you allow algae to overrun a tank it will out compete coral. The whole point of the talk was to show how overfishing was the greatest noticable impact on reef decline. Not nutrients.
My problem is that I'm dealing with someone who is well educated in marine science and who is well respected amongst my local society. He is smart and has helped a lot of people. He also believes that tanks should have no live rock or sand and just coral/fish and a skimmer. It's like dealing with a religious nut.
The bloke Saltydog or Chris really does not like you Santamonica( not personally) and has basically discredited most of what your site explains. I just thought you should know as he is well respected by many on the forums here in oz. Most reefers use the RTAW site for information.
Gotta run for now.
Ross.