This month's Special Feature is about the deep sea life that is being discovered off the south coast of Tasmania, and Marther discusses gluconate.

Editorial

Now not messing around this time, straight into it because once again time is short ;-). Doesn't this sound familiar? What we need is for someone out there to lengthen the day, preferably the night as that is when I work best. An extra couple of hours would do fine. ;-) Luckily though not much has really been happening since the last issue.

One thing that I failed to mention last month about the tank move is the algae growth. The Park was without any algae eaters at all for around 2 weeks, what a perfect environment to observe what algae is actually in the tank. I was really quite surprised when I noticed/realised this fact, was just not thinking that this would happen. On the micro scale, such as diatoms and hair algae there was very little noticeable difference. So the growth rate here is not that dramatic. On the other hand macro algae is another story. Various red and green macro algae that had not been visible since the Sailfin Tang, Zebramosa veliferum, began appearing from various nooks and crannies. This demonstrates well the fact that herbivores keep apparent algae growth down to a low level, but it is still there.

OZ REEF Marine Park has a safety switch on all electrical power which comes from the one outlet. I have been having problems with it, as it appears that even the slightest disturbance somewhere else in the house can set it off. Things such as turning off a light switch has tripped it several times. This only occurs occasionally, but I have been unable to determine why it does in fact happen. Anyway, I came home one evening to find the Park at 20^oC with no lights or pumps operating. The power had been tripped off sometime during the day, most likely the morning judging by the temperature. Brrrr, they must have been starting to feel that, it would have been at 26^oC only 8 hours earlier. That is quite a dramatic temperature change. It took until the next day though for the correct temperature to be achieved, with the Park temperature at 24^oC by the next morning. This is good though, because it is rapid temperature changes that causes the stress, and this was, well I would not call it ideal, slightly slower than the pace of the cooling down. The great news is that no losses occurred due to this one day temperature drop, everyone is looking healthy and happy. :-)

And finally have had the first plumbing problem since those encountered during the initial set up period of the Park. The return pump started to fill the enclosure with bubbles, and not just a few either, of a very small size. Size was the main problem, as they were not rising quick enough to the water surface to counter act the currents. So they were spending a long time suspended in the water and take several trips around before they do. The inlet side of the pump was found to be pulling some air though one of the vinyl tubing joins. Tightening the clamp did not stop it, so it was just a case of changing the piece of vinyl tubing. Not a hard thing to do either, it just involved the draining of the sump. This was made much easier by performing a water change at the same time. See, water changes have a 100 and 1 uses. ;-)

Hope you enjoy this months issue, and if you have any comment, requests etc then please don't hesitate to me.

Catch ya,
DBW

Welcome OZ REEF's New Residents

• 3 x Chromis viridi, Green Chromis. These guy are to take the school size back up to 10 after the loss of a couple due to the move and ill health.

Resident of the Month

Dear Marther ReefKeeper

Dear Marther,

What are your thoughts on calcium additives the use complexing agents such as gluconate to increase the amount of calcium present? I have heard from several sources that it just the same as adding sugar to my reef aquarium and it will just cause algae blooms.

From,
Cal C. Ium

Dear, Cal

This topic has been bouncing around for quite sometime and it has come up recently on several of the WWW Boards, News Groups and Emailing Lists. Gluconate, or more precisely polygluconate is present in the Seachem Reef Calcium™. additive. The reason gluconate is used is that it keeps the calcium to solution to higher concentrations than possible without it. I also suspect that is used because it is based on a derivative of glucose, so will easily be broken down by bacteria. Many people have expressed reserve on whether to add such an additive to their aquarium, mainly because of the fact it contains a sugar derivative. It is puzzling too that Seachem actually denies that it is related to sugar, with the following statement off the Seachem website:

Q: I've heard that Reef Calcium has sugar in it and that it will cause algae growth. Is this true?
A: No. This is a faulty assumption based on the premise that polygluconate is the same or similar to glucose.

Gluconate not related to glucose, I don't think so! To back this statement up, here is the structure of calcium gluconate, which is not the polymeric form of the compound.

The only difference between glucose and gluconate is the terminal -COO^- at the top of the above structure, glucose has a terminal -CHO instead. Note that glucose is in equilibrium with the cyclic structure, where the terminal groups react together forming a six membered ring when dissolved in water. I am unsure if gluconate undergoes a similar ring formation reaction, but it is not out of the question. It could form the same ketone ring joint and have two -OH groups instead of one which is present for glucose.

Granted the above is the monomer of the compound, not polygluconate as Seachem states is contained in the Reef Calcium™. But all this means is that there is a chain of the molecules joined together, the "base" structure is still the same. The way that it would be fitted together is most likely as a type of polysaccharid or natural sugars. When you make a polymer, the reactive properties of the base component does not change that dramatically, there are still the same reactive groups minus those that reacted together to form the polymer. I really have a problem with Seachem's statement that in effect says poly-gluconate is not similar to Glucose or sugar, it is actually a derivative.

Note that sugar does not just apply to glucose, it is used as a term to denote a monosaccharide that are pentoses or hexoses i.e. 5 and 6 carbon atoms respectively, e.g. fructose, deoxyribose, maltose, lactose etc.

What happend to this gluconate when you add it to the reef system? Most likely it is just metabolised by saccharide processing organisms. I suspect that something related to glucose that close would be fairly easily used up. Seachem states on their site that it is a carbon source, assisting in denitrification. Which would make sense, bacteria could use it as a carbon source and accelerate the rate of nutrient processing. Though it may not have that much of an effect compared to the other carbon sources that are present in a well feed aquarium.

Eric Borneman had some things to say about how gluconate will be utilised in the aquarium:

Gluconate is the salt of gluconic acid, if I recall? Yes, we do have a glucose derivative.

As far as reactions go, obviously sugars can be oxidized, reduced, cleaved, etc., although glucose is pretty stable. They are subject to enzyme attack, and with all the acids, bases and microbes in the tank, I would not want to venture a guess. I would imagine that, barring the many, bacteria would be the first to take up any sugar molecules. I would also imagine that the facultative aerobes and anaerobes would be the ones to benefit most. Bacteria phosphorylate sugars as they cross the cell membrane and can then use it in the respiration. Sugars are used by fermenters and in glycolysis. Animals, plants and bacteria can all utlize the sugar source.

Well thats that, basically it comes to that polygluconate is a derivative of glucose and would be rapidly used up by bacteria in the reef aquarium. And as whether to use in your aquarium, well all I can say is that the performance is variable. There are those the swear by it, and others that think that it cause algae blooms. Personally I would stay clear of it though, no need to add some additional variable to your reef. There are other techniques that you can use that are just as good or better.

From,
Marther ReefKeeper

Special Feature

Deep Discoveries

by Katherine Johnson, pictures by Karen Gowlett-Holmes, CSIRO Marine Research.

Reprinted from CSIRO's science and environment magazine, ECOS.

Mention coral reefs, and most people picture colourful fish darting between corals, sponges and shells in the tepid waters of the tropics. Few of us envision reefs where the sun never shines. A place where, amid an inky blackness, deep-sea corals provide refuge for a host of slow-moving and often remarkable species, many of which are new to science.

But such a place does exist, founded on extinct volcanic cones known as seamounts which rise steeply from the seafloor, their summits often more than a kilometre from the ocean's surface. Sometimes the seamounts are clustered together in ranges; other times they are solitary. Whatever their form, they provide a unique environment in an otherwise watery wasteland.

Most of the seafloor at depths below 1000 metres is an open plain marked only by the burrows of marine worms and other animals. In contrast, seamounts host a rich and diverse assemblage of life forms. The reason is the unusual abundance of food. Ocean currents converge at the pinnacles, concentrating plankton and dissolved organic material near the mountain slopes, supplying a travelling smorgasbord to anything able to live there.

Life in these frigid, deep-sea waters, where light no longer penetrates, and water pressure exceeds 100 atmospheres, cannot be called easy. If a person were to descend the depths in a submersible, and place a polystyrene coffee cup on the seafloor, it would shrink under the weight of water to thimble size. At these depths, extreme evolutionary adaptations are essential and creative life forms emerge.

Deep-sea life is characterised by bizarre body forms and extraordinary physiologies. Add isolation to the list, as is often the case with seamounts, and endemism emerges: evolution of unique life forms that are found nowhere else. A cluster of seamounts 80 km south of Tasmania is attracting particular interest.

The seabed south and west of Tasmania was first surveyed in early 1994 by the French research vessel L'Atalante for the Australian Geological Survey Organisation (AGSO). The cruise produced detailed maps of the seabed to depths of 4500 m, covering a total area three times the size of Tasmania.

The study was led by AGSO's Dr Neville Exon. It found the region consisted of a number of extinct volcanic cones, 65 of which peak at depths between 660 m and 1940 m from the sea surface. The average height of these undersea mountains is 400 m, and the gradient of their slopes ranges from 20 to 30 degrees.

The first maps of the seamounts off Southern Tasmania, produced for the Australian Geological Survey Organisation by L'Atalante using a multibeam sonar system. The maps revealed a number of extinct, submarine volcanic cones which have since yeilded a treasure trove of previously unknown species.

Many of the shallower seamounts in the area closest to Tasmania are known intimately to orange roughy fishers who have harvested the region since the 1980s. A number of the newly mapped hills, however, with summits 1200 m or more from the sea surface, are new to fishers and scientists.

"We knew there were fishing grounds in this area, but we didn't know there was this whole swarm of little volcanoes -thought to be about 30 million years old - that were very pristine in structure," Exon says.

"As the research vessel travelled over the seabed, the maps literally rolled out at your feet, in real time, showing perfect little cone-shaped hills that none of us had expected to see. For me that was incredibly exciting."

The pilot study aboard the French research vessel showed that this sort of marine-bed mapping, so important for management of offshore areas, is feasible for the whole of Australia's Exclusive Economic Zone. But the most exciting for Exon is the prospect of Australia developing the capability to do this research using its own facilities, either by putting the mapping equipment onto an existing Australian vessel, or having a boat specifically designed for marine sea bed survey work.

A haul of surprises

At about the same time as the L'Atalante expedition, researchers from CSIRO Marine Research in Hobart, led by Dr Tony Koslow, conducted an acoustic survey of the orange roughy fishing grounds in the area. Orange roughy congregate on the seamounts around southeastern Australia and New Zealand between 700 and 1400 m. Together with deep-water oreos, they form the basis of one of the largest and most valuable fisheries in these countries, with more than half a million metric tonnes landed since the 1980s.

Using the FRV Southern Surveyor, the only Australian vessel capable of supporting research to depths of 2000 m, the CSIRO scientists also did three experimental trawls on lightly-fished seamounts to sample the seabed fauna. The haul was surprising.

Under the artificial lighting of the Southern Surveyor, creatures from the deep, dark sea were spilled out onto sorting tables.

Among them were several tonnes of deep-sea coral and a dozen specimens of four previously undescribed species of fish: two deep-water cod from the genus Paralaernonema, and two deep-water lings. Paralaemonetna had previously only ever been found on seamounts in the South Atlantic. The find highlighted how little was known about the seamounts south of Australia.

CSIRO fish biologist Dr Peter Last says the excitement of exploring unknown ecological communities is unparalleled. "There is a general perception that the Australian seas are well-explored," Last says. "However an indication of how little is known about the deep-sea is that new species are being discovered faster today than the early explorers recorded fishes from our seas two centuries ago.

"It is a startling statistic, but we know more about the types of fishes living around Antarctica and Heard Island than we do about the fish species around much of Australia. And at ocean depths below 1500 m - which is more than 70% of the entire Australian marine jurisdiction -we know almost nothing."

In 1995, Environment Australia, the Australian Fisheries Management Authority and the fishing industry agreed to provide interim protection to the group of newly mapped seamounts pending further investigation of their environmental and economic significance. The decision provided the time needed to assess the impact of fishing on previously fished seamounts, and to determine whether the deep-water reserve would protect the fauna found on the shallower, fished seamounts.

The reserve status is unique on a world scale. There is only one other deep-water reserve, a deep-sea area in Hawaii set aside to help conserve the black coral communities fished for making jewellery.

In January 1997, the CSIRO team of researchers, again led by Koslow, did their first biological survey of the newly discovered seamounts in research funded by Environment Australia and the Fisheries Research and Development Corporation.

"We feel like first explorers, travelling to unknown corners of the globe," Koslow says. "But this is the 1990s, and we are still discovering great areas of unexplored territory."

Koslow says the researchers expected to find a relatively diverse deep-sea community and, if they were lucky, even a few new species. But what they discovered was more exciting than anyone had anticipated.

Wearing overalls and wellington boots, and looking more like fishermen than the stereotypical scientist, the researchers excitedly sorted through the samples: an urchin here, a fish there, coral fragments scattered across the sorting bench and a myriad of weird and wonderful unidentified creatures, all carefully preserved and sent to experts for identification.

"We found so many new species that taxonomists around Australia, and several from overseas, are still identifying them," Koslow says. "There are new species in virtually every animal group that we are examining, from corals and hydroids to crabs and fish."

For example, of 13 species of hydroids - corals without skeletons found on the seamounts, nine appear to be new to science.

The exact number of new species found in the other groups will be known by the end of the year. But what is proving to be as interesting as the sheer number of new species is the high level of endemism: these new species are found on these particular seamounts and nowhere else, not even off the coast of New Zealand.

The tip of a single frond of black coral. Such colonies can reach more than 12m in length.

"This is surprising because organisms in the deep-sea generally have fairly wide distributions - on the order of the ambit of an ocean basin - because there are few barriers to dispersal," Koslow says.

But seamounts are unique deep-sea environments: like islands in the ocean. One false move and offspring are lost to the deep blue-yonder with little chance of finding another seamount. As a result, many of these species seem to have evolved mechanisms to restrict their range to the seamounts that support them.

For example, an urchin retrieved in the January samples was found to brood its young beneath it, appearing to have bypassed the need for a larval stage altogether. "It is a strategy that makes sense in an environment where a larval stage - which can see the animal drift in ocean currents for weeks, months or years, depending on the species - is a liability", Koslow says.

A sea urchin brooding young. Animals living in the deep ocean usually adopt one of two survival strategies: lay many eggs and hope they survive as they drift about in a current, or lay a few and keep them close to protect them. This sea urchin has adopted the latter strategy.

The high level of endemism apparent on these seamounts has important conservation implications. Koslow says it means that the seamount fauna of each region will have many unique elements, and local disturbances may be enough to threaten entire species.

The big picture filters out

As well as studying the seamount specimens individually, the scientists are picturing the deep-sea community as a whole by taking photographs with a drop camera as the research vessel drifts over the seamounts. The camera can withstand the enormous pressures of the deep ocean, filming the underwater scene from less than a few metres from the seafloor.

The photographs are the first images of these reefs more than a kilometre beneath the sea surface and reveal the sheer abundance and diversity of life on the seamounts.

They show that filter feeders - animals that draw the water around them into their bodies and filter out tiny animals and plants for food - dominate the community. In particular, the colonial stony coral Solenosmilia variabilis is particularly prevalent and forms a dense matrix of living and dead coral as new members of the colony grow up and over older members to reach as far into the current as possible.

The meshwork colony structure of the colonial coral, Solenosmilia variabilis. Huge colonies of this coral form reefs on the tops of the seamounts, and are the basis of the seamount community.

Once in the current, these corals can feast on the ready supply of food carried by ocean currents that concentrate at the pinnacle of seamount slopes.

The dense coral matrix provides the perfect platform for other filter feeders, such as hydroids and sponges, several species of solitary stony corals, and various bamboo, gold and black corals, some of which grow to several metres in height and more than 100 years old.

More motile feeders, such as crinoids (or feather stars), use the coral platform as a perch from which to reach up into the deep-ocean currents the lifeblood of the deep-sea.

A crinoid. This type of crinoid lacks a stalk, but all crinoids feed by catching drifting food particles in their feathered arms.

The thick coral matrix also provides invaluable shelter to animals that would otherwise be unable to live on the exposed seamounts.

Various galatheid or slipper lobsters hide within the coral matrix, using their long feeding appendages to reach out for food from the relative safety of their burrows.

It is a unique ecological community, where togetherness is the name of the game. But it is also fragile.

"Given the slow rates of growth of many of the deep-sea organisms, and the low recruitment rates from outside the local seamount environment, even small-scale disturbances can disrupt the balance," Koslow says. "And once disturbed, these deep-sea reefs could take centuries to regenerate."

The first stage in conserving the biodiversity of the deep-sea is understanding what is there.

"The fact that it will take a team of taxonomists a full year to identify all the new species we found during one research cruise is an indication of how little we still know about the reefs of the deep-sea," Koslow says.

Who would have thought that more than a century after the first major marine expedition - the Challenger Expedition of 1872-1876 when British scientists took the first samples from the deep-sea - that marine biologists aboard modern research vessels would still be exploring unknown areas of ocean and discovering new species on such a scale?

More about the deep sea

Broad W., The Universe Below, Simon and Schuster:New York, 1997.
Koslow J.A., Seamounts and the ecology of deep-sea fisheries, American Scientist, 85, (1997), 168-176.

You Wouldn't Believe It!

..... the Pseudoceros bifurcus flatworm found on the Great Barrier Reef at depths of around 15-20 metres undergoes a strange mating dance when it comes across another of the same species. The flatworms are hermaphrodites, so have both male and female reproductive organs. Upon encountering another worm they partake in what is called "penis fencing" which can last from 20 to 60 minutes. They both attempt to inject sperm under the skin of the other worm, with the winner (the worm that manages to inject its sperm) becoming the male for that particular mating. With hermaphrodites they usually just exchange sperm, such as earth worms and most other flatworms. But this particular species, that is about 4-6 centimeters long, bends back and displays it penis when encountering another worm. Repeatably they strike at each other until one succeeds, with both maneuvering to avoid being pieced. This bizarre mating duel can be explained in terms of evolutionary selfishness. Sperm are biologically cheaper to produce than eggs, so males can produce more decendents than females over a lifetime. The loser gets the added burden of fertilised eggs to care for. This finding was published by Nicolaas K. Michiels and Leslie J. Newman in the February 12^th, 1998, issue of Nature.

Bereavement Notices

1 x Chromis viridis
This one is a real puzzle. The second day after he moved in I spotted him hanging around the top of the reef structure not showing much interest in any of the food floating past. He was swimming very gingerly in a low flow spot, but on an angle that made it difficult to see what was wrong. It appeared that the back half of his scales had been rasped off, either totally removed or rubbed back in the wrong direction. There was no chance of catching him, so I could only cross my fingers and hope. And as I am sure you realise, you are reading the Bereavement Notices after all, he did not make it to the next evening. What could have done such a thing to a fish? Would have to be something that has some strength, but it was so even, the entire length of the back half body, top to bottom. That is too regular for an attach of a mantis shrimp. Anybody have an idea? I would love to hear any you have at all.

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