>I am researching growing a Turtle Grass saltwater Tank as a
>semi-natural environment for Seahorses. I plan to set this up in a
>greenhouse. That should handle most of the light requirements. Can
>anyone tell me where to start? Montana is a long way from any
>saltwater and university libraries are 2-4.5 hours down the road.
I am a marine biologist with the Texas Parks and Wildlife Department.
We have five species of seagrasses in Texas--Thalassia testudinum
(turtle grass), Syringodium filiformae (manatee grass), Halodule
wrightii (shoal grass), Halophila engelmannii (no common name), and
Ruppia maritima (widgeon grass). All grow in shallow, clear water
(except Halophila, which can grow in deeper water and needs less
light). All grow in sandy soil with a very low organic content (1-4%
organics), except Ruppia, which I have seen growing in mud. Ruppia
can also tolerate low salinities; the other grasses do best at
salinitites from 20-40 parts per thousand.
Eel grass, Zostera marina, is not native to the Gulf, but is common in
the Chesapeake Bay. It can tolerate lower temperatures than the Gulf
species; perhaps you should check into it. I have a greenhouse, and
it is hard to keep a fairly constant temperature; daytime temperatures
can easily break 100 F inside, even in January, and I have to use a
heater to keep my greenhouse over 50 F on a cold winter night (our
idea of "cold" is +40 F). Your seahorses probably wouldn't like 50
degree temperature swings, either.
The Smithsonian keeps a living reef aquarium, with turtle grass
planted in the fore reef. Maybe one of Walter Adey's books will
describe their setup. They have a complicated system, and use banks
of metal halides for lighting.
Another good general reference is "The ecology of the seagrass meadows
of the west coast of Florida: A community profile" by Zieman and
Zieman, 1989. This is published by the U.S. Fish & Wildlife Service,
Biological Report 85(7.25). It does not cover cultivation, but it has
a lot of good information on their physical environment.
There has been a lot of work here in Texas on seagrass cultivation,
but it is mostly concerned with replanting them in the wild, not
In my experience, marine macroalgae such as Caulerpa are much easier
to grow, and the seahorses will do just as well. There are also more
species to choose from, need less light, and would be easier for you
to get in Montana (even mail order). You could grow these indoor,
under flourescent lights. I recommend them.