| The reason for this is that the rich soil as well as the rest of the ecosystem has evolved a fairly balanced symbiosis. |
| It stands as a living entity in an ecosystem dependent on a participatory reciprocity. |
| Nothing like this vast, circumpolar ecosystem occurs in the Southern Hemisphere. |
| Human harvesting of shellfish has raised concerns over ecosystem sustainability. |
| They are the producers of the river ecosystem such as the alga or the hygrophyte. |
| Marine vertebrates including tunas, seabirds, sharks, sea turtles, pinnipeds and cetaceans use a pelagic ecosystem we barely understand. |
