Meaghan - I certainly dont mind if you'd want to use it, BUT, your professors might mind using an internet source, even if it is a lovely published magazine like Reefkeeping. Check with them. If you're in a lower level than say undergrad in college you're probably just fine to go ahead.
Probably this format is good:
Lardizabal, S. 2006. Beyond the Refugium: Seagrass Aquaria. Reefkeeping. vol 5 issue 3. [Or.. "5(3)"]
I am a weeee bit rusty on the particulars of reference format. Probably they gave examples in the syllabus, mine usually did, of how they want it to appear.
The papers/grants I write are usually far more relaxed on this sort of formatting etiquette.
It would also be completely fine to cite the original sources I list at the end of the article, particularly if your professors/teachers are uncomfortable with you using an internet source. 95% of the article is information from scientifically refereed papers and if you wanted to use something specific, you could quote the original paper. (Follow the numbers.)
There is also an excellent comprehensive seagrass biology text out now -- Larkum AWD, Orth RJ and CM Duarte. 2006. Seagrasses: Biology Ecology and Conservation. Springer / USA. That would be another good source to consider using if you have the time to check your library. It was just released in February, I adore my copy.
At any rate, I hope something of what I said above is useful to you! I'm glad you found the article helpful!
Just for curiosity, is your paper a comprehensive treatment of 'grass communities, or something in specific?
>Sarah