| Human harvesting of shellfish has raised concerns over ecosystem sustainability. |
| It is an unavoidable fact that one of the consequences of increasing the external energy input to an ecosystem is an increase in population. |
| Due to Israel's diverse ecosystem and terrain, each outing was more exciting than the last. |
| Marine vertebrates including tunas, seabirds, sharks, sea turtles, pinnipeds and cetaceans use a pelagic ecosystem we barely understand. |
| Nothing like this vast, circumpolar ecosystem occurs in the Southern Hemisphere. |
| But the ecosystem is too interdependent for GM and non-GM crops to coexist without cross-fertilising. |
