I have had success growing turtle grass in my reef/seagrass aquarium at Augsburg College (
http://www.augsburg.edu/biology....yes, the photos of my reef system are now several years old and need to be updated!). Here are some exerpts from an e-mail I sent to the New England Aquarium about 3 years ago when they asked me for advice on growing seagrasses in aquaria (they were about to set up a really large seagrass tank at the time):
Here are some thoughts regarding captive seagrass husbandry. Most of my advice
is based on anecdotal evidence from my reef/seagrass system. Also, I don't
know what you already know about seagrasses, seagrass communities, or reef
aquarium husbandry, so please don't be offended if I've included some basic
info that you already know well!
<snip...some no longer relevant information about sources was here>
As long as I'm on the topic of sources, another source might be Gulf Specimens
(in Pancea, Fl...they are in northern Fl on the gulf
side...they have a web site that you could probably find in a web search if
you are not already familiar with them). They list turtle
grass in their catalog. I think they normally collect only leaves so folks
can look at the diverse epibiont communities, but I'd bet you could get them
to ship you whole "short shoots" (seagrass lingo for the short vertical shoots
with leaves that grow up from the long horizonatal rhizomes), or even better,
some short shoots still attached to sections of rhizome. Short shoots with no
rhizome will grow (this is how I started out), but I'd bet you'll get your
plants established faster if they have some rhizome still present. My short
shoots took a while to really get going well.
I got Augsburg's turtlegrass from a collector in the Keys. <rest of details deleted...no longer relevant>
Another possible source might be Inland Aquatics, in Terre Haute Indiana (I
have links to this company's web site on my web site). I believe thay have
turtle grass growing, and have even listed it for sale at times, though Morgan
Lidster (the owner) tells me his turtle grass doesn't grow all that well for
him (he was amazed by how good the stuff in my tank looked). I have found
Morgan and Inland Aquatics to be great to deal with, and Morgan is very
knowledgeable and skilled in setting up and managing closed system marine
systems.
I'd offer you some of ours, though the few shoots I could spare would not
stock your display very effectively!
OK, now about how to grow the stuff. First of all, a few words about how it
grows in the wild. In the wild, turtle grass generally only grows where there
is a relatively deep buildup of very fine sediment (the other main seagrasses
in the area, manatee grass and shoal grass, neither of which has lasted long
term in my aquaria (don't know why they didn't last), have slightly different
preferences). When one digs up shoots and rhizomes, you are typically digging
into smelly anaerobic regions of sediment. Also, turtle grass is generally
found growing in relatively shallow water where light intensities from the
tropical sun (or I suppose subtropical in the Keys) are quite high. There is
often quite a bit of water motion due to tidal flow or due to rough water on
windy days, though in some areas and at some times (e.g. high or low tide on
calm days), the water flow in seagrass beds can be minimal.
I have been growing turtle grass for about 4 or 5 years now. The first time I
tried this was in a 20 gallon "reef tank on a tight budget" set up with a few
inches of coral gravel in a west window in a lab. These turtle grass short
shoots would photosynthsize rapidly (streams of oxygen bubbles would emanate
from them, just as in the wild) when they recieved direct sun (tank lighting
otherwise was minimal). I had some leaf growth, and one shoot even started to
develop a bit of a rhizome, but as we went into the predominantly cloudy,
short days of winter all growth stopped and the plants gradually died. The
likely moral from this example....turtle grass needs lots of light!
The roughly 60 gallon seagrass tank set up subsequent to the 20 gallon tank
mentioned above is the tank you see on my web site. The substrate is roughly
4 to 6 inches (I'd have a deeper sand bed if i were doing this over again) of
fine oolitic sand (CaribSea brand), and the tank is illuminated by a 5500 K
400W metal halide with a dimpled aluminum reflector (I think there might be
some other name for such reflectors?). The fixture also has 2 28 w
powercompact actinic bulbs, which I suspect are fairly irrelevant for the
turtle grass. This seagrass tank is hooked up to our reef tank, and the whole
system is currently filtered by and algal turf scrubber (from Inland
Aquatics). You can read about the history of our system on my web site, in
particular the fact that initially I was using a protein skimmer and had some
serious algal problems (due to overfeeding) that persisted until I switched to
the algal turf scrubber. During this initial turbulent period of the system
the turtle grass didn't grow all that much (though possibly a lot of root and
rhizome growth was taking place?), and at about the time i set up the algal
turf scrubber it seemed to be declining and I was afraid i was going to lose
it. However, a month or so after the turf scrubber had cured the tank's algae
problems, the turtle grass started growing really well. This could perhpas be
due to the influence of the algale turf scrubber on the system, but the rapid
improvement in growth also coincided with me starting to use a mixed trace
element supplement (Biotrace, purchased from Inland Aquatics). My suspicion
is that the iron in the Biotrace might have been responsible, but this is
really just a guess.
If I were setting up a large turtle grass display, I would set it up as though
it was a reef system for growing corals, except of course that the live rock
that contributes so much to the biological stability and water quality
maintenance in reef systems would need to be in a large sump (or perhaps in an
attached reef system). I see managing this as though it is a reef system as
being important in several respects. First, the intese lighting needed to
keep the turtle grass happy and growing will create horrible algae problems
unless you have pretty pristine water with very low, pretty much undetectable
levels of major macronutrients such as nitrates and phosphates. Secondly, if
you want to have a realistic looking slice of a turtle grass community, you
are going to want to make the various epibiotic coralline algae that live on
wild turtle grass happy, and you'd probably want to include in your system
various calcareous green algae like Halimeda opuntia, Halimeda incrassata,
Halimeda monile, Penicillis sp, Udotea sp, etc. that are characteristic of
turtle grass communities. These coralline red and calcareous green algae will
need the high calcium and alkalinity levels that one typically strives for in
a reef tank for corals.
If I were doing this, I think I'd want more light than I have on my seagrass
tank now. For my current system, possibly the use of one of the high quality
polished aluminum reflectors (e.g., the Spyder light reflector) would do it,
or maybe I'd even try a 1000w metal halide. On your presumably much larger
system I think you are going to want some pretty powerful lighting, and you'll
need to make sure the lights are relatively close to the water, and you'll not
want to have a really deep tank (personally, I would not exceed 3 feet of
depth). Yes, our turtle grass grows well with its current lighting (including
good rhizome growth and production of new short shoots), but it is taller than
any wild turtle grass I have seen and the blades are narrower than a lot of
wild turtle grass. This suggests to me that we have a bit of etiolation.
Also, my impression has been that the Udotea, Penicillis, Avrainviella
(spelling?), and certain other macroalgae I have grown in this tank have been
etiolated as well, some species severely etiolated (and they eventually died
out...though who knows, maybe this was some sort of nutrient or trace element
issue instead???).
This overly elongated growth form of my turtle grass might in part be due to
water flow issues though, since the shoots that have grown up after the
addition of an additional large powerhead have been shorter and more natural
looking. At any rate, you are going to want to have some decent water
movement in this tank. Though I wouldn't normally expect to see waves
crashing on a real seagrass bed, I think the back and forth water motion
created by a dump bucket style wavemaker (e.g., like the algal turf scrubber
unit we have on our reef tank) would be beneficial to the health of the
system. If you want to make your display really cool, I'd think simulated
tidal flow (changing directions according to time of day) would be cool and
also pretty useful. Regardless of how this is set up, you need water
movement, and you need it to be fluctuating somehow so that you don't end up
with dead spots where detritus will accumulate. Proper water flow will also
be essential to some of the other creatures (Condylactis or Bartholomea
anemones, etc.) that you might want to keep in your seagrass tank.
You are also going to want to promote the development of a good, healthy "live
sand" bed, with lots of little worms and other critters. Most reef aquarium
experts agree these days that this is critical for the health and well being
of reef aquaria. Inland Aquatics could provide you with starters of a variety
of sand bed creatures (e.g. terrebellid worms, etc) that reproduce in their
systems (incontrast, some wild collected critters do not last long, for
whatever reason), but you also would probably want to start out with a certain
proportion of wild-collected "live sand" to get your sand bed community off to
a good start.
Also, if I were doing this (actually, I HAVE been contemplating a 500-1000
gallon reef and a connected 300-500 gallon seagrass tank if we can get the
funding), I'd want to include a number of the other organisms characteristic
of seagrass beds. This might include the algae and anemones mentioned above,
as well as queen conchs (captive propageted ones are available), silversides
and sheepshead minnows (might not be compatible with the anemones, if you
catch my drift!), Pederson's cleaning shrimp (which hang out on the anemones),
the snapping shrimp that live with the Bartholomea, brittle stars in
abundance, and others. I would NOT put horseshoe crabs in this display unless
the display was huge, since they would eat up the critters important to your
live sand bed. There are a number of sponges that would probably do well too,
including chicken liver sponges (which often are found on turtle grass
blades). If you are lucky, you might be able to get some of the red
macroalgae to grow long-term as well. Incidentally, I have not been very
successful in maintaining very many of the turtle grass epibionts other than
certain coralline algae, though if you have a much larger system you might
have better success (?).
If you have carefully protected overflows (i.e. behind a large-area screen
partition) and if your water flow patterns don't toss them around too much,
Cassiopea jellyfish would do well, especially if you feed live baby brine or
have abundant mysids, etc. reproducing in the system (though if you have many
large anemones, the jellyfish might tend to get injured (or eaten??) by
occassional contact). If adequately fed, I'm told that Cassiopea will even
reproduce and can even become pests in aquaria.
Also, I would be sure to include Caulerpa paspaloides, which is common in
seagrass areas in the Keys, and is an absolutely spectacular Caulerpa species
in my opinion. It gets too big for me to manage in my system ( eventually
gave up on it because it was shading things to much), but in a larger tank it
would be wonderful.
Finally, if you have the good water quality I think you'll need anyway, some
of the stony corals and gorgonians found in nearshore waters would be nice
additions, though I don't know if you can legally get some of them. Gulf
Specimens lists a few (they have a permit that allows their collection for
educational purposes). Alternatively, you could use ecological analogues from
the IndoPacific. For example, we have a green Montipora digitata growing in
our seagrass tank (loose on the sand) that is very reminiscent of the way one
of the porites corals found in nearshore waters often grows loose on the
sediment in the Fl. Keys.
Well, this is probably more than you were expecting...I guess I got a bit
carried away here (I guess I'm a little jealous of your opportunity to set up
a display like this!). I'm not sure if I covered everything I planned to
mention, but I need to call it quits for now.
Let me know if I can be of any more assistance,or if I left out any critical
issues that you wnted to know about.
Bill
P.S. Though turtle grass can grow fairly fast when it is happy with its
conditions, don't expect it to spread in the speedy way that the superficially
similar freshwater Vallisneria does. Turtle grass has big tough rhizomes and
very substantial leaves, and these take a bit longer to grow and spread.
