Here are the essential elements you need to know for the ecosystem you are researching:
Trueflix Ecosystems - be sure to click on the “explore more” tab for a lot more resources
Gale Kids Infobits - ecosystems
Gale Kids Infobits - bodies of water
30 Cool Things About Rainforests - National Geographic Kids
National Geographic Kids - ecosystems - but dig around on here because there is a lot of cool stuff!
Pebble Go - life sciences - includes plants, animals, adaptations, and food chains/webs
TVES Library Research Resources Page