Merdav,
I have no experience with what I'm about to tell you, but here it goes: they have flaoting islands on the market now. You might look into these. I saw a pretty interesting presentation at last year's Pond Boss conf from the guy who developed them. Quite simply, you install the island (different sizes available) and plant whatever you want on it. The plants grow and draw the nutrients from the pond. It's essentially nutrient harvesting. You can then remove the plants from the island. Maybe you grow flowers and pick them. Maybe you grow vegetables and eat them. Maybe you grow other plants and smoke them or sell them for the purchase of the bog system! Actually, they were able to grow terrestrial grasses, corn, tomatoes, wetland plants, and even cacti.
Really, though, you should consider doing some research on the floating islands. They seem pretty cool. I will have real-world experience with them this time next year. We're going to use them on two, separate neighborhood association ponds beginning next spring. Get this, both clients came to me about using them so there must be some good stuff about them on the internet.
Let me know if you find anything interesting. Since the presentation last year, I haven't had time to further research them (price, brands, etc). This is one of my winter to-do tasks since we will be using two of them. The underlying theories behind they do and how they work make a lot of sense. Like most things, fine-tuning the technique to each system takes patience (types of plants to plant, how big of an island, the degree of nutrient saturation in the pond, etc).
