Where the heck does the time go? Last time I prepared a Reef Ramblings it was back in August 2008 and all of a sudden Christmas has come and gone and we’re well into 2009!!
We’ve been tremendously busy at Midland Reefs, expanding our range and getting all our new products out into the market place. With of things that have been going on it has been difficult to find time to do much writing. I hope things have now settled down enough to let me get back to carrying out research and preparing articles.
As far as I’m concerned the most interesting bits of news of late are my latest coral spawning! On Monday 17 February 2009, whilst I was doing my morning round of feeding my eye was caught by a number of small particles drifting in a group in one of my soft coral tanks. This is a low flow aquarium with moderate light levels, home to a collection of large specimens of Klyxum species, various assorted polyps, and a number of large mushroom corals, probably Rhodactis inchoata. It took me some time before I was able to identify the source of the eggs or egg/sperm bundles floating around the tank – and to my surprise it turned out that a single specimen of R. inchoata was responsible.
The mushroom coral Rhodactis inchoata is a broadcast spawner, spasmodically ejecting small numbers of egg/sperm bundles, say 5 or 6 at a time (I’ve seen a reference somewhere to separate sexes so it could be just eggs) These gametes were similar size to Briareum and of a cream to grey colouration.
I’m also seeing indications that it may have spawned on a number of different days without me witnessing the event.
From the research I’ve managed to carry out so far it looks as if this is quite an unusual event. Indeed this sort of spawning event seems to be rarely recorded even in the wild.
There was a repeat of this event 12 days later on Saturday the 28th February and again around a month later during the last week of March.
But that’s not all …
Shortly after the Rhodactis inchoata spawning I noticed that in another of my tanks I’d had a Briareum species, Star Polyp, spawning; this isn’t too unusual occurrence in this particular tank where there’s been half a dozen or so spawnings in the last few years. What makes this spawning event unusual is that the planula larvae have actually settled this time! The daily hunt for primary polyps proved quite exciting and it was immensely rewarding to eventually find numerous primary polyps scattered about the tank. I believe I may now have enough information to induce spawning in this species but this will have to wait until the baby corals have grown large enough for me to safely remove them to another system.
Curiously, at around the same time, I’ve also noticed newly settled sponges on the glass of a couple of my tanks. Perhaps it’s a sign of Spring!
Why Sexual Reproduction in Corals Matters.
You may wonder why sexual reproduction of corals is so important an aim. There are two main reasons to be considered.
Primarily it may help to preserve genetic variability. New, emerging coral diseases are often associated with loss of coral in the wild during bleaching events. Corals that spread by growth, in a manner similar to the way reefkeepers frag corals, are identical clones, which could be vulnerable to emerging diseases, whereas different genetic strains might demonstrate resistance to new diseases, allowing a species to survive possible extinction.
If one day it becomes possible to induce coral spawning on demand it may become an important tool for reef restoration. Some scientists are looking at species of corals that demonstrate resistance to bleaching, so being able to produce these species through sexual reproduction could be immensely important for preserving reefs in the future.
The Briareum has continued to spawn, the latest event taking place over 2 days with the same polyps being seen to eject planula on the 14th and 15th April. I started to see settled primary polyps from this spawning from the 21st April, 7 days after the spawning took place.
Reef Ramblings FAQs and Reef Ramblings Q & A
I’ve added the new category of FAQ’s to address some of the queries that are apparent from the search key phrases I see when I take a look at the statistics for Reef Ramblings. In this way I hope to answer some of the questions relating to Reefkeeping, aquarium hardware, etc., that aren’t already being covered within the existing articles posted at Reef Ramblings. Some of these search phrases seem a little brief but it’s usually pretty obvious what the query relates to. From the mix of queries I’m seeing it’s obvious that all the things we’ve learned about reef aquaria over the last 10 years are not being passed on to new reefkeepers …
Reef Ramblings Reef Aquarium Q & A has been added to address some of the more common problems afflicting new reefkeepers in a lengthier format than that used in print magazines. Some of these are from past print articles, others are new generated by the constant stream of reefkeepers asking me for advice.
Hints ‘n’ Tips.
At the recent meeting of the Coventry & Warwickshire Reefers Club I had a great time talking with the many reefkeepers who attended the evening. Thanks for coming along and making it an enjoyable event. I hope to cover some of the stuff that came up in conversation that night in my articles here at Reef Ramblings. To start off lets have a look at the subject of water changes, this came up in conversation with John Thomas who followed up our chat with this email.
Hi Tim I spoke to you after your talk at Coventry Aquatics, I can still see the look of horror on your face when I said I don’t do water changes (almost 5 years now) anyway after listening to your reasons for them I’ve decided to do 10 litres a week, this is only about 2% of my system because I don’t want to upset the balance but it’s a start, I’ll let you know if I notice any improvement.
I’ve added a few photos of the tank just to give you an idea of how the tank is doing at the moment, the only added filtration is an algae scrubber deep sand bed and Chaetomorpha.
Thanks for the email John.
OK, so why am I so adamant that water changes are a good thing? The practice of water changes seems to have originated with fresh water aquariums, indeed before aquarists fully understood the concept of the nitrogen cycle and started to apply the idea of biological filtration this was the only way of maintaining good water quality. The idea behind water changes is very simple and summed up in the mantra. “The solution to pollution is dilution” When biological filtration began to be applied to freshwater aquariums and people started to use test kits to monitor water quality it soon became apparent that water changes were still required as levels of nitrate were seen to continue to accumulate – in this situation it’s very easy to determine a water change regime by deciding what the maximum nitrate level is that you’re prepared to tolerate, then carrying out regular water changes to maintain this level.
Unfortunately this method doesn’t quite translate to the reef aquarium, as a properly constructed reef should naturally keep nitrates to acceptable levels. So if you don’t see a steadily increasing nitrate value, indicating pollution over time do you still need to carry out water changes? I believe the answer to this question is a resounding YES!
Even though we no longer have a convenient indicator of pollution in the form of nitrate, the water in a closed system is still deteriorating in quality due to biological processes, and the concentration and depletion of various elements, major, minor, and trace. This deterioration is difficult, if not impossible, to quantify and, furthermore, will vary from reef to reef depending on the organisms present.
John’s reef uses a DSB for natural filtration along with Chaetomorpha, which is presumably being regularly harvested as a means of nutrient removal. I don’t know what his feeding regime is or what supplementation is being used, but going into the tank will be food and, I’d guess, Calcium and Carbonates. These will be taken up by the organisms inhabiting the reef along with the various minerals and trace elements they contain. Not all of these minerals and trace elements will be used and there is evidence that some of them may accumulate in the reef aquarium to unnaturally high levels. Corals, particularly octocorals (or soft corals), produce an arsenal of chemical weaponry to wage war on the other species of corals that they share the tank with – again these chemical compounds can accumulate within the aquarium if no steps are taken to deal with them – if carbon is used to filter out these compounds it may also remove some desirable ones, producing a depletion. The harvesting of macro-algae, while removing some undesirables such as nitrate and phosphate, will also deplete other elements such as Iodine, depending on species.
Now we could try to supplement for every thing being depleted but it would be next to impossible to accurately determine what should be added and in what quantity. Aquarium test kits can be best described as a guide and many of the more esoteric tests such as those for Iodine, Strontium are of questionable utility.
Part of my general philosophy of reefkeeping is the belief that for best results you need to do the following:
- Supply water movement and lighting appropriate to the requirements of the species being kept.
- Feed high quality nutrition i.e. natural foods containing no additives or artificial preservatives.
- Maintain Calcium and Carbonates according to the biological demand of the reef.
- Perform water changes on a regular basis to dilute pollutants and to replenish minor and trace elements.
It’s worth noting that the cost of doing regular water changes is far lower than that of supplementing with the very many supplements offered by so many manufacturers. And that on the natural reef, with very few exceptions, reef organisms are continually exposed to, what is in effect, fresh clean seawater.
Any questions or comments, or if there are any particular topics you’d like to see covered here, please feel free to get in touch with me: email@example.com
©2004 – 2009