Table Of ContentAdvances in Coral Husbandry in Public Aquariums. Public Aquarium Husbandry Series, vol. 2. R.J. Leewis and M. Janse (eds.), pp. 115-126
© 2008 Burgers’ Zoo, Arnhem, the Netherlands.
Chapter 12
Scientific considerations on a technique of
ecological purification that made possible the cultivation
of reef-building corals in Monaco
Jean M. Jaubert
Musée océanographique de Monaco, Avenue Saint-Martin, MC 98000 MONACO,
Principality of Monaco
[email protected]
AbstrACt
For the last 50 years powerful mechanical filtration and water sterilization techniques
have been driving the evolution of life support systems of most of the public seawater
aquaria. Their recent progresses have made possible the keeping of fish as large as
manta rays and whale sharks. However, by removing all of the plankton and failing
to eliminate all of the wastes produced by the fish and the decomposition of organic
detritus these techniques alter the composition of the water in the tank. Filtered and
sterilized water does not meet the biological requirements of a number of plants and
invertebrates that are much more demanding than fish. A few open-circuit aquaria built
in pristine near-shore areas have overcome the above-mentioned inconveniences by
pumping huge amounts of unpolluted water. But the number of places suitable to
accommodate aquaria of this kind is and will remain very limited. Therefore, efforts
have been made to adapt to public aquaria natural techniques for maintaining closed-
circuit aquaria that hobbyists began to develop empirically in the middle of the fifties.
The present paper analyses the processes that underpin the genesis and evolution
of one of these techniques, which has been implemented in Monaco to cultivate reef-
building corals. Cultivated corals were used to improve the exhibition in the aquarium
of the Oceanographic Museum but also to carry out scientific experiments, which have
resulted in major findings regarding the ecology and physiology of these organisms.
IntroduCtIon
Set up in 1956 by Dr. René Catala, the Symposium. I took this opportunity to inform
Nouméa’s Aquarium was one of the first public Dr. Catala that I had succeeded in keeping
aquariums in the world where reef-building reef-building corals in closed circuit aquaria in
coral were successfully cultivated and kept with the marine laboratory of Tulear (Madagascar).
a number of fishes among which one could see And he was surprised.
quite large specimens of Napoleon wrasses.
It was an open-circuit aquarium situated close At that time all of the public aquarium curators
to the seashore. Water was pumped from a that I knew were thinking that keeping live
neighboring fringing reef and the life support corals with fishes in closed circuit systems
system was reduced to a pumping station and was looking like an inaccessible dream.
a buffer pool that was feeding by gravity open- However, I did not share this opinion because
top tanks illuminated by natural light. In this I had already obtained encouraging results.
regard the Nouméa’s aquarium was a kind of Yet, in the middle of the fifties, while I was
extension of the New Caledonia lagoon. I met living in Algeria, I had kept specimens of the
with Dr. Catala, in August 1973, during a stop zooxanthellate Mediterranean coral Cladocora
over I had made on my way back home from caespitosa (Linnaeus, 1758) using by chance
Brisbane (Australia) where I had participated a simple water management method similar
in the Second International Coral Reef to that of Lee Chin Eng (Eng, 1961). Thirteen
115
J.M. Jaubert
years later, in Madagascar, the same technique out using reef mesocosms enabled us to show
enabled me to keep specimens of several that elevated temperature and carbon dioxide
species of hard and soft corals. These results partial pressure (pCO ) have a synergetic
2
convinced me that there was something to action, which inhibits calcification (Leclercq et
uncover and at the end of a 17 years-long trial al., 2002; Reynaud et al., 2003). This result
and error process complemented by scientific may explain why reefs, which are exposed
experiments I perfected at the University of Nice to warming temperatures and surface water
(France) the method described in the paper I acidification associated to rising concentrations
presented, in 1988, at the Second International of atmospheric CO , degrade worldwide in
2
Aquarium Congress (Jaubert, 1989). This remote areas where they are not directly
method enabled me to set up a 40,000 L reef impacted by human activities.
tank in the Monaco’s oceanographic Museum
and to resume research in this famous
organization by establishing the European MileStoneS on the way of a
oceanographic center (affiliated to the Council diScovery
of Europe) where the ecology and physiology
of cultivated corals was investigated using the Old stories and souvenirs
most advanced scientific techniques. I became an aquarium hobbyist in June 1948.
I was seven years old and my anniversary gift
Research completed in this center resulted in was a freshwater aquarium. At that time, the
major findings, particularly the mechanisms most popular way to set up aquariums was
which underpin: (a) the uptake and transport extremely simple (Boucher, 1946). My 50 liters
of bicarbonate and calcium ions (Tambutté et tank (Figure 1a) was made of glasses sealed to
al., 1995 and 1996; Al Moghrabi et al., 1996; zinc coated steel angles using a putty containing
Bénazet-Tambutté et al., 1996; Goiran et al., minium (red lead oxide). The soil was composed
1996); (b) the metabolic fractionation of stable of one layer of humus covered with one layer of
isotopes of oxygen, carbon and nitrogen quartz sand. With a dense population of plants
(Reynaud-Vaganay et al., 1999 and 2001; the tank was a kind of naturally balanced micro
Muscatine et al., 2005); (c) the synthesis of the pound. Water stirred by a flow of bubbles was
skeletal organic matrix (Allemand et al., 1998); not filtered but remained crystal clear.
and (d) the uptake and excretion of organic
carbon (Al Moghrabi et al., 1993; Ferrier-Pagès The same year I had the opportunity to see
et al., 1998a and 1998b). Experiments carried the first film of Jacques Cousteau (18 m below
a b
1948: freshwater aquarium 1958: seawater aquarium
live marine rocks
live calacareous marine sand
rubber pipe
rubber pipe
Quartz sand
humus
air pump
Figure 1: Freshwater and seawater aquarium, using the same basic natural principles, respectively set up in 1948 and
1958. The seawater aquarium set up in 1958 is similar to that of Lee Shin Eng.
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Chapter 12: SCientifiC ConSiderationS on a teChnique of eCologiCal purifiCation to Cultivate CoralS in MonaCo
the surface). Imitating Cousteau I started to sophisticated seawater-compatible equipment
snorkel in the Mediterranean Sea and admire did not exist at that time and they were living
the aquatic life, which was more attractive close to the sea where they could collect live-
than that of my freshwater aquarium. I was rocks and live-sand. At that time I ignored and
fascinated and several years later I decided also Eng and Coutant ignored I presume, that,
to try to set up a seawater aquarium by in the middle of the Victorian Era (nineteenth
transposing the above-described freshwater century), a number of amateurs were using
aquarium technique. For this purpose I used almost the same technique to keep marine fish
live sand, live rocks and Caulerpa prolifera and invertebrates in glass jars where algae
(Forsskål) Lamouroux 1809 (Figure 1b). (especially Ulva sp.) illuminated by sunlight
were the main source of oxygen. This technique
My first experiments quickly resulted in is described in two handbooks (Gosse, 1855;
disasters. Their primary cause, the toxic Taylor 1910). According to (Verwey, 1930),
compounds released by the corrosion of zinc, quoted by Delbeek and Sprung (2005), the
remained enigmatic during several years curators of an open-circuit aquarium built in
but became understandable when I used 1928 in Indonesia were using live-rocks and
successfully, by chance, a small all-glass tank full sunlight to keep corals and anemones and
recovered from a dismantled lead battery. In even breed clownfish.
this small tank I could easily keep small fishes,
shrimps and anemones. Situated in front of a My coral keeping experiments in France
window the tank was receiving enough natural and Monaco
light to meet the requirements of the alga In 1973, Jacques Cousteau was preparing an
Caulerpa prolifera and of small colonies of the exhibition dealing with reef-building corals in
zooxanthellate coral Cladocora caespitosa. the Monaco’s Museum. To make this exhibition
more attractive, Cousteau who knew that I was
At that time I did not know that my technique was keeping live coral in Nice asked me to set up
similar to that of Lee Shin Eng who published a live coral tank in his Museum. At that time
in the Tropical Fish Hobbyist magazine an almost no coral was available on the market.
article entitled “Nature’s system of keeping Therefore I went to Eilat (Israel) with one of
marine fishes” (Eng, 1961), which I uncovered my colleagues (Dr. Marc Lafaurie) to collect
two decades later. colonies of various species. Thanks to the
logistic support of the Weisman Institute and of
Two years later, during summer vacations in the Heinz Steinitz Marine Biological Laboratory
France, I met by chance with René Coutant. we succeeded in bringing back about fifty
This pioneering seawater aquarist (who colonies belonging to fifteen different species
founded in 1970 the Aquarium de La Rochelle, of corals. Lafaurie and I had designed the 1,500
France) was manufacturing seawater tanks in L closed-circuit tank inside which these corals
a quite small shop situated close to the bank were kept in Monaco. Height VHO daylight
of river Charente in the city of Saintes. In the fluorescent tubes fixed inside a cover ventilated
Coutant’s tanks water was filtered trough glass by electric fans provided enough light to meet
wool, calcareous sand and activated carbon. the photosynthesis requirements of the corals.
When I said that I did not use any filter Coutant A prototype of chiller built in the Museum’s
gave me a specimen of the little booklet he workshop and a thermo regulated heater were
had published (Coutant, 1958). In this booklet used to maintain the temperature between 23
I could read (page 2) “Filtration, an important and 26 °C. But we made the error to equip this
topic that will cause much ink to flow, is not tank with an under-gravel filter operated with
indispensable in a well balanced tank”. a powerful airlift. During one year, with almost
Thus, in the middle of the fifties at least 3 no fish in the tank, the corals remained in good
aquarists, living in different countries, Lee Chin condition. But 6 month after we had added fish
Eng in Indonesia, René Coutant in France filamentous algae started to grow. The same
and Jean Jaubert in Algeria, had empirically phenomenon occurred in the tanks I had set up
discovered that a closed-circuit seawater at the University of Nice. At the beginning this
aquarium could function very well without a algal growth was discrete. I didn’t pay enough
filter and perhaps even better than with a filter. attention to this sign of eutrophication it and
None of them knew why. They used simple wrote a too optimistic article regarding the
techniques likely because polymers as well as performances of the system (Jaubert, 1976).
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J.M. Jaubert
When the growth of nitrophilous algae became layer in my aquariums I could make use of this
uncontrollable I understood that nitrate was process to eliminate nitrate.
causing the trouble. But I did not know how to
get rid of it. If I had known the book of Peter A simple way to create a hypoxic layer in my
Wilkens (Wilkens, 1973) I would most likely aquarium was to turn off the under-gravel filters.
have used the technology promoted by the I disconnected the airlift of the under-gravel
group that gave birth to the Berlin method and filter of one of the aquariums inside which I was
set up a powerful protein skimmer to reduce keeping corals. But since this airlift was also
nitrate formation by eliminating dissolved used to stir and aerate the aquarium water I
organic matter before bacterial degradation. kept it and connected it to a strainer fixed above
But I did not read the book and took another the sand (Figure 2). As PVC T connections
path. were fixed to its upper extremity this airlift was
also doing the work of a basic protein skimmer
Although I was keeping reef-building corals (Figure 2). This light skimming may have played
in the laboratory I could not use them to a significant role. By discarding brownish foam
investigate their physiology because they were it may have contributed to remove colored
neither healthy enough nor enough numerous organic matter from the water of this aquarium
to allow valuable scientific experiments. In this (as well from that of other tanks I equipped later
regard I decided to carry out experiments on with this simple system), which never became
the seafloor. For this purpose I designed and yellowish although I never used activated
built respirometers (Jaubert, 1977) and other carbon to filter it.
underwater devices. During experiments
carried out in Aqaba (Jordan) in 1979 I Eight months later the “miracle” occurred. The
uncovered that reef sediments were sinks corals that were surviving in this aquarium
for nitrate (unpublished results). From the started to grow. Measurements made with a
literature (Koike and Hattori, 1978; Sorensen, spectrophotometer confirmed that nitrate had
1978) I understood that heterotrophic virtually disappeared from a concentration of
denitrifying bacteria living in hypoxic and 70 mg.L-1 of NO - (representing a theoretical
3
anoxic layers of organic-rich marine sediments rate of removal of 0.2 mg a day). To repeat
were responsible for this phenomenon. this experiment I decided to dismantle a
By “respiring” nitrate to oxidize organic 2,000 liters tank and restock it from scratch
compounds these bacteria were converting with live sand, live rocks, corals and fish that I
nitrate into molecular nitrogen. Immediately I had collected in the Red Sea. The first results
thought that by creating a hypoxic sediment were excellent (Jaubert, 1981) but the tank
airlift live marine rocks
foam live coral sand
Plenum
water
strainer
Perforated
Pvc plates
Figure 2: Airlift for water stirring and skimming in the Jaubert System (Jaubert, 1989). Arrows illustrate schematically
water movements. Grey arrows simulate the circulation of the oxygen-rich water in the aquarium. White arrows
simulate the circulation of pore-water throughout the sediment and that of the hypoxic water in the plenum.
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Chapter 12: SCientifiC ConSiderationS on a teChnique of eCologiCal purifiCation to Cultivate CoralS in MonaCo
needed more than 2 years of maturation to this closed-circuit tank for 15 years and would
fully equilibrate. be likely still thriving if I had not dismantled
it in 1994 when I had to move full time to
Monaco where I had founded the European
oceanographic center.
the Jaubert’S SySteM
Sand bed, plenum, stirring and pore-water
During 8 years I improved the system. I did circulation
this in a more or less empirical way because The thick layer of sand and the plenum, which
my academic responsibilities of research team Lee Shin Eng did not use, characterizes
leader, my in situ experiments in the Red Sea the Jaubert’s system (Figure 2 & 3). The
as well as the Pacific Ocean (French Polynesia) plenum is the void space situated under the
and my lectures at the University of Nice plastic screen that supports the coarse coral
were consuming most of my time. In fact, my sand on the aquarium floor. The plenum
aquarium activities never fell within the scope contains a layer of hypoxic water. Its role is
of my “official” research activities and thus not substantiated by scientific data. I could
remained marginal. However, in 1988, I took the never find enough time and money to carry
time needed to describe the system in Monaco out the experiments needed to compare the
at the Second International Aquarium Congress denitrification yield of aquariums functioning
(Jaubert, 1989). At that time my aquarium was with and without plenums. Indeed, to comply
looking like a small Red Sea coral patch and in with the statistical constraints of scientific
the opening address of the Congress, Jacques experiments, I should have set up a minimum
Cousteau acknowledged this achievement and of 3 aquariums with a plenum and 3 aquariums
its prospects (Cousteau, 1989). without a plenum. Nevertheless I presume that
Soft and hard corals have been thriving in the plenum facilitates pore-water circulation
light
n
2
cirratulid
n
worm 2
organic waste
n2 nh4+ no- aerobic
Plenumdenitrificatio2n nnoo3-- hypoxic Plenum
3
screen
Figure 3: Basic functioning principles of the Jaubert NNR System.
119
J.M. Jaubert
through the sediment in aquaria within which and of the minute organic particles that are
stirring is moderate (Figure 2) and that pore- captured and incorporated into the sediment
water circulation plays a key role. Indeed, by pore-water circulation. In this regard
by increasing fluid exchanges between the generalizing the claim suggesting that the role
sediment and the overlying water several fold of sediment in-fauna in nutrient processing
relative to simple molecular diffusion (Precht is minimal (Toonen and Wee, 2005a) seems
and Huettel, 2003): premature. On the other hand, inadequate
(1) it brings to the deeper layers of the stirring-induced pore-water circulation as well
sediment some oxygen, which prevents them as limiting concentrations of organic carbon in
from becoming completely anoxic and by way the sediment of deep sand bed aquaria with
of consequence toxic pockets of hydrogen or without a plenum may explain the relatively
sulfide from forming; high final concentration of nitrate and low
(2) it brings more nitrate to the bacteria and concentrations of dissolved calcium carbonate
more calcium to the aquarium water than a found by these authors. From the photos of the
simple process of diffusion. experimental set up published in the Advanced
Aquarist’s Online Magazine (Toonen and Wee,
During years I have underestimated both 2005b) one can infer that the current generated
the intensity as well as the role of the by the submersible pumps visible on these
stirring-induced pore-water circulation and the photos and the resulting pore-water circulation
adjective “confined” I used to qualify the plenum were too intense to maintain adequate hypoxic
water (Jaubert, 1989) was inappropriate. To conditions in coarse sand-beds with or without
keep the intensity of pore-water circulation a plenum. Pore-water circulation carries minute
within limits compatible with the maintenance particles captured at the aquarium water
of hypoxic conditions in the plenum (average sediment interface (Huettel et al., 1996). This
concentration of oxygen: 0.5 mg.l-1) stirring process generates some mechanical filtration,
in the aquarium should be moderate. Indeed which may explain why water remains crystal
a strong stirring increases turbulences and clear in aquaria equipped with a deep coarse
pressure oscillations at the sediment-water coral sand bed in spite of the absence of any
interface and cause more seawater to infiltrate classical mechanical filter.
the sediment. Increased pore-water circulation
brings too much oxygen to the deeper layers of In coastal areas, strong pressure oscillations
the sediment breaking or stopping the work of generated by waves and currents control
the denitrifying bacteria. pore-water circulation and oxygen dynamics
in permeable sediments. Precht and Huettel
Toonen and Wee (2005a) have completed an (2003) and Precht et al. (2004) have shown that
experimental comparison of sediment-based coastal sediments form a gigantic filter, which
biological filtration designs for re-circulating recycles nutrients in permeable reef sediments
aquarium systems and concluded that there (Wild et al., 2004) and more generally purifies
was no detectable advantage to the inclusion of coastal waters. Extremely complex catalytic
a plenum beneath sediments. The quality of this processes and metabolic pathways mediate
excellent work is not questionable. However, the biogeochemical processes responsible
their experimental set up was too different for this purification. These processes and
from the system dealt with in the present paper their ecological role are still poorly known
to allow a relevant comparison. Firstly their because during many years scientists have
tanks were significantly smaller. Secondly their been investigating fine muddy sediments with
“live” animal experiment was conducted under no or negligible pore-water circulation rather
unspecified indoor ambient light condition, than permeable sediments. In this regard,
which I presume was significantly lower than elaborating on this topic in the present paper
that of current reef tanks. Thirdly their tanks would be speculative and premature.
might have not been sufficiently biologically
mature. The sediment meiofauna may require Mineralization of organic matter
more than 12 months to multiply and form a During the day, zooxanthellae and macro-algae
diversified population, which equilibrates produce enough oxygen to create conditions
according to the amount of organic matter on of super-saturation in the water column and
which they feed. This matter is composed of the the contiguous layer of sand. Consequently,
debris that falls at the surface of the sediment organic and inorganic nitrogen are converted
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Chapter 12: SCientifiC ConSiderationS on a teChnique of eCologiCal purifiCation to Cultivate CoralS in MonaCo
into nitrates and the aquarium remains virtually by the Ocean is produced by the anaerobic
free of ammonium and nitrite. In a similar oxidation of ammonium (anammox), a process
way particulate (POP) and dissolved organic mediated by autotrophic planktomycete-like
phosphorus (DOP) are mineralized into micro-organisms, which were unknown 10
dissolved inorganic phosphorus (DIP). DIP is years ago. Annamox prokaryotes have been
an essential chemical for life. In many marine found in almost all of the terrestrial and marine
environments it is a bio-limiting macronutrient environments but not yet in reef sediments.
because its availability is related to the Hence, in the light of the above-mentioned
insolubility of phosphate salts (Pratt, 2006). considerations it is unlikely that they do not
However, in aquaria opposite conditions tend exist in a naturally purified reef tanks where
to prevail. DOP and DIP are highly undesirable they may participate with their heterotrophic
substances, which promote blooms of counterparts in the reduction of the reactive
cyanobacteria and algae. Since my aquarium forms of inorganic nitrogen.
never experienced such blooms during
decades I presume that the basic skimmer Heterotrophic nitrate reduction, respiration
discarded part of DOP before mineralization and calcium dissolution
and that DIP was fixed in the sediments and/or In addition to pore-water circulation, which
in the plenum by biogeochemical processes. carries minute particles originating from the
Anschutz et al. (2007) have found that a aquarium water (Huettel et al., 1996), the
portion of the phosphate and ammonium sediment fauna and meiofauna plays a key role
released during mineralization does not in the nitrate reduction process by transferring
escape the carbonated sediment of a coastal to the hypoxic layers of the sediment organic
lagoon (Thau, near the city of Marseille, matter on which denitrifying bacteria feed.
France), since the concentration gradient This transfer results both from bio-turbation
was close to zero between 1 and 25 cm depth and the release of fecal pellets, which
below the sediment water interface. But since contain undigested organic compounds. By
highly complex processes of adsorption and moving continuously sand grains, organisms
desorption controlled by magnesium, iron responsible for bio-turbation transport and
and other minerals drive the adsorption and discard into the plenum microscopic mineral
desorption of DIC (Millero et al., 2001) the and stable organic particles, which otherwise
above-mentioned presumption is a working would clog the sediment after a while. The
hypothesis rather than an explanation. On the most efficient animals are small cirratulid
other hand, one has to consider that recent worms (Figure 3, first row) that collect and
findings reviewed and put into an “Earth-system swallow, using their sweeping tentacles, all
perspective” by Gruber and Galloway (2008) kinds of edible detritus that fall at the surface
are being resulting in important revisions of the sand.
of the scientific concepts that underpin the
current understanding of the global nitrogen By respiring nitrate and oxidizing organic
cycle and of the way it interacts with the other compounds the heterotrophic denitrifying
major biogeochemical cycles, particularly that bacteria release carbon dioxide into the
of carbon and phosphorus. interstitial water between the aragonite grains
of the sand. This carbon dioxide hydrates
One of the most surprising discovery concerns and forms carbonic acid (H CO ), which
2 3
new Crenarchaeota microorganisms bearing dissolves aragonite and releases calcium
the ammonia monooxygenase encoding genes ions. Other, perhaps more important sources
(amoA). Their abundance in shallow (300 m) of carbon dioxide in the interstitial water
marine waters and sediments is 1–2 orders of are the respiration of the dense meiofauna
magnitude higher than those of the “classical” that populates the sediment and that of the
β- and γ-Proteobacteria, which are commonly aerobic bacteria, which degrade their feces.
thought to mediate nitrification in marine In this regard, the oxygenated and hypoxic
environments (Wuchter et al., 2006). The sand layers function like calcium reactors.
exact role of these nitrifying Crenarchaeota Carbon dioxide (CO ) hydration forms carbonic
2
is still unknown but may be important. Other acid (H CO ). Carbonic acid dissociation forms
2 3
recent findings reviewed by Op den Camp et bicarbonate ions (HCO -) as well as carbonate
3
al. (2006) and Kuenen (2008) have shown that ions (CO 2-) and releases protons (H+). A
3
more than 50 % of the molecular nitrogen lost thorough description of these processes and
121
J.M. Jaubert
The basic equations, which illustrate the above-mentioned chemical processes, are:
Nitrate respiration
NO - + carbohydrates N + CO + H O
3 2 2 2
Heterotrophic denitrifying bacteria
Photosynthesis
CO + H O O2 + carbohydrates
2 2
Respiration
CO + H O H CO HCO - + H+ and CO 2- + 2H+
2 2 2 3 3 3
of the associated pH variations can be found in by the decrease in their rate of calcification, I
Andersen (2002). uncovered this phenomenon by chance when I
Total alkalinity and pH show important diurnal broke by mistake a branch of Acropora hemprichii
variations. In the small volume of a reef (Ehrenberg, 1834) and noticed that the skeleton
aquarium these variations are higher than in of this branch was abnormally porous. At that
nature (Jaubert et al., 1995). They reflect those time the calcium concentration of the aquarium
of the partial pressure of CO (pCO ) and O water was 350 mg.l-1. This observation agrees
2 2 2
(pO ), which are correlated and depend on the with the experiment of Gattuso et al., (2000)
2
metabolic activity of bacteria, algae, corals, fish, who showed that artificial seawater with a low
etc. At night calcium carbonate dissolution is calcium concentration lowered calcification
higher than calcification. Total alkalinity, pH and rate of Stylophora pistillata. It suggests that the
pO decrease while pCO increases. Opposite adaptation capacity of many reef corals to low
2 2
conditions prevail during the day. In a balanced calcium concentrations is higher than usually
aquarium, dissolution releases enough calcium accepted. This assumption is supported by
ions to replace those taken up by corals and the experimental results of Fine and Tchernov
calcareous algae. Empirically, I succeeded in (2007) who showed that Oculina patagonica
establishing a robust and lasting balance in the (Angelis, 1908) and Madracis pharensis (Heller,
2,000 liters aquarium I had set up in my office 1868) were able to survive and recover from
at the University of Nice (Jaubert, 1989) by complete decalcification.
covering less than one third of the surface of
its floor with live rocks supported by perforated Oxygen balance, sediment fauna and fish
shelves (Figure 2). The thickness of the biomass
sediment bed, made of coarse coral sand (2-4 Under conditions of reduced aeration gas
mm) was 8-10 cm. A perforated PVC plate (hole exchanges at the atmosphere water-interface
diameter 1 cm) buried under 2-3 cm of sand of a reef aquarium have a negligible effect on
prevented fishes from connecting the aquarium the oxygen concentration of the water, which
water with that of the plenum by digging holes depends essentially on the photosynthetic
in the aquarium floor. This aquarium has been production and the heterotrophic consumption
functioning perfectly well for 15 years without (Leclercq et al., 1999). In this regard, the fact
any addition of calcium. that in the above-described aquarium the
minimum pO (recorded at the end of the night)
2
However, after a decade the calcium was stable and close to saturation indicated
concentration of the aquarium water started to that this aquarium was balanced with respect
decrease. This depletion was likely due to the fact to oxygen over a cycle of 24 hours. In other
that dissolution was no longer able to compensate words, photosynthesis (essentially that of photo-
the calcium taken up by calcifying organisms, calcifying organisms) was producing enough
which had significantly increased their biomass, oxygen to meet the biological and chemical
particularly branching Acropora (unpublished demands of the system. Decomposers (aerobic
result). Fortunately, corals were able to adapt bacteria and sediment meiofauna) are major
to this decreasing calcium concentration by oxygen consumers. Since these organisms
decreasing their rate of calcification. Since the feed mostly on fish faeces and unconsumed
growth rate (branch elongation) of branching particles of food their biomass reaches
Acropora colonies was not significantly affected equilibrium slowly according to that of fish.
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Maturation time influx of fresh water due to the mistake of the
The development of the sediment meiofauna, technician who was responsible for maintaining
which is a key component of the system, the salinity within the range 38-40 ‰ it was
requires 12 months. Furthermore, in most of decided to operate it in a semi-closed mode with
my aquaria a period of two years maturation a rate of water renewal of 5 % a day.
was necessary to enable the system to reach
robust and lasting balance. Then these aquaria Today, 18 years later, this reef tank is still a
were virtually maintenance free. Modifications semi-closed tank full of coral and fish. Colonies
of the permeability of the coral sand due to the of Echinopora fruticulosa (Ehrenberg, 1834),
slow accumulation of minute refractory particles Montipora danae (Milne Edwards and Haime,
between the sediment grains may also play a 1851) and Stylophora pistillata (Esper, 1797) as
role in this long maturation process. well as several species belonging to the genus
Acropora have tremendously increased in size
Applications to a public aquarium and given birth to a several generations of cloned
In 1989, Professor François Doumenge who had colonies that populate many other tanks.
become Director of the Monaco’s Museum after
the retirement of Jacques Cousteau asked me Applications to scientific research
to design and set up a 40,000 L reef tank for its In 1990 I was commissioned by H.S.H. Prince
public aquarium. At that time it was impossible to Rainier to found the European oceanographic
find enough coral and live stones to stock such a center. This center, which was part of a Council
large tank. Therefore I had to collect them in the of Europe network, was dedicated to the
sea. I completed this work in Djibouti with only physiology and ecology of reef-building corals.
2 technicians of the Monaco’s Museum (Gilles Most of the experiments were carried out using
Pérez and Philippe Maurel) thanks to the strong cultivated corals and reef mesocosms.
logistic support of the local authorities. I also
designed and set up a 12,000 L storage pool At the community level (reef) experiments were
inside which corals were recovering during one carried out using reef mesocosms. One of them
week before being transferred to the reef tank. was the above mentioned reef tank I had set up
At the rate of one shipment a week, 2 months in the Monaco’s Museum. Jaubert et al. (1995)
were needed to gather enough material to build showed that the global metabolic features
and populate a nice reef. After the inauguration of this captive reef kept in a semi-closed
of the reef tank the storage pool became the circuit tank were similar to those of the most
first piece of a farm where corals were asexually productive natural reefs. This finding, which
propagated. has been recently confirmed in a closed circuit
During 6 months this tank functioned in closed Jaubert system (Ikeda et al., 2004; Table 1),
circuit. Then subsequently to an accidental enabled researchers of the European center
Table 1. Global metabolic features of a captive reef kept in a closed circuit tank compared to those of natural reefs
(from Ikeda et al., 2004). This closed circuit tank is a typical Jaubert NNR System set up under license by the
organization Monaco Kenkyusho (Himonya 3-16-21 – Meguro-ku – Tokyo 152-0003) in the National Museum of
Emerging Science and Innovation, Tokyo.
Net photosynthesis Net calcification Ratio of
(mmolC.m-3.d-1) (mmolC.m-3.d-1) photosynthesis
to calcification
The Monaco
Aquarium 74.3 ± 7 56.6 ± 10.4 1.3
Reef Flat of Palau
Barrier Reef (from
Ikeda 1997) 83.5 65 1.3
Moat of Shirao,
Ishigaki Island, Japan
(from Hata 2003) 48.5-65.5 35-60.5 1.1-1.4
123
J.M. Jaubert
to use mesocosms of this type as models to several years of an exhausting fight would
investigate the consequences of increasing likely be necessary to reach my objectives I
content of carbon dioxide in the atmosphere decided to give up and resigned. Now and I
and the subsequent acidification of surface will try to dedicate a significant part of my time
water on the metabolism of reefs (Leclercq and efforts to carry out scientific experiments
et al., 1999; 2000 and 2002; Reynaud et al., aimed to improve methods for setting up
2003). naturally balanced and more self-sustainable
aquaria. Popularizing this type of aquaria and
explaining how they function might contribute
concluSion to enhance public awareness on marine
conservation as well as other key ecological
The Jaubert’s system and systems derived issues and to change behaviors.
from it have significantly contributed to
the development of reef tanks in Monaco
(Oceanographic Museum) and Taiwan (National
acknowlegMentS
Museum of Marine Biology and Aquarium).
It has also contributed to make possible
laboratory experiments that have resulted in Comments made by anonymous reviewers
striking improvements of the knowledge of the were extremely constructive and helpful in
biology and ecology of reef-building corals. improving this manuscript.
However, several aspects of the functioning of
this system are still poorly known. In particular
the pattern and intensity of pore-water
referenceS
circulation as well as the flux of chemicals and
energy at the sediment- water interface are
Allemand, D., É. Tambutté, J.-P. Girard and J.Jaubert,
unknown and should be quantified. Recent
1998. Organic matrix synthesis in the
findings concerning the filtration process driven Scleractinian coral, Stylophora pistillata: role
by pore-water circulation in coastal sediments in biomineralization and potential target of the
and new microbial processes involved in the organotin TBT. Journal of Experimental Biology,
201:2001-2009.
nitrogen cycle have shed some light on the
Al-Moghrabi, S., D. Allemand and J.Jaubert, 1993. Valine
biogeochemical processes that may take place
uptake by the Scleractinian coral Galaxea
in the aquarium floor. A significant amount of fascicularis: characterization and effect of light
work and time as well as fairly sophisticated and nutritional status. Journal of Comparative
Physiology, 163:355-362.
equipment are needed to investigate these
Al-Moghrabi, S., D. Allemand, C. Goiran, N. Speziale
biogeochemical processes and to elucidate
and J.Jaubert, 1996. Inorganic carbon uptake
the exact role of the plenum. So far my for photosynthesis by the symbiotic coral-
scientific carrier never provided me with the dinoflagellate association II. Mechanisms for
opportunity to develop research on naturally bicarbonate uptake. Journal of Experimental
Marine Biology and Ecology, 199(2):227-248.
balanced aquaria. Hence, developing this type
Andersen, C.B., 2002. Understanding carbonate
of research was my major objective, in July
equilibria by measuring alkalinity in experimental
2004, when I became Director of the Monaco’s and natural systems. Journal of Geoscience
oceanographic Museum. Unfortunately, at that Education, 50(4):389-403.
Anschutz, P., G. Chaillou, P. Lecroart, 2007. Phosphorus
time, the Museum was in a critical financial as
diagenesis in sediment of the Thau Lagoon.
well as social situation and I had to dedicate
Estuarine, Coastal and Shelf Science 72(3)
all my time and efforts to reorganize it and 447-456.
increase its incomes. At the end of 2006 the Bénazet-Tambutté, S., D. Allemand and J. Jaubert, 1996.
annual number of visitors had gone above the Permeability of the oral epithelial layers in
Cnidarians. Marine Biology, 126:43-53.
symbolic threshold of 600,000. Hence, I started
Boucher, M., 1946. L’aquarium équilibré. Imprimerie de
to make plans to renovate the exhibitions and
l’Est, Paris : 78 pp.
resume research, a major mission given to the Cousteau, J-Y., 1988 (1989). Opening address of the
Museum by its famous founder H.S.H. Prince Second International Aquarium Congress.
In: Proceedings of the second International
Albert I. Sadly the project was rejected by the
Aquarium Congress, Monaco. Bulletin de
Board of the Oceanographic Institute, which
l’Institut Océanographique Monaco, 5:21-22.
owns the Monaco’s Museum. When I realized Coutant, R., 1958. L’aquarium marin d’appartement en
that I had underestimated the bureaucratic circuit fermé. Imprimerie Savary, Saintes : 15
weight of this French Foundation and that pp.
124
Description:were fixed to its upper extremity this airlift was Figure 2: Airlift for water stirring and skimming in the Jaubert System (Jaubert, 1989). Cnidarians.
