Diverse Universe

2. Referring to feeding relationships among species in a ***
5. Mixed community of fungi and bacteria found on rocks in streams, also known as biofilm
8. Donor-controlled resource across habitats
10. Type of diversity measure looking at between-habitat diversity
11. Fish that migrate from salt water to freshwater to reproduce
12. Dead or decaying animal flesh
13. Fresh to partly decomposed plant and animal matter
14. Major primary producer in aquatic systems
15. Breakdown of nitrates & nitrites into nitrogen, mainly by bacteria
19. Living, active, occurring, or existing in the absence of free oxygen
21. Nutrient essential to plants and animals but lacking an atmospheric pool
22. Distribution of abundance across the species in a ***

1. association of species that co-occur in the same place and time, and the word represented by *** throughout clues for this puzzle
3. River ___ Concept: a conceptual model that predicts biological *** responses to change along lengths of rivers
4. Hypothesized that at intermediate levels of this, there will be the highest species richness
6. Nutrient enrichment into a body of water
7. Keystone predator in the Pacific Ocean that exerts top down control on urchin populations, helping maintain kelp forests (2 words)
8. Gradual change in *** structure through time
9. Type of diversity measure looking at total species diversity across a landscape
15. Strength of interaction in a trophic web with lots of complexity
16. Number of species in a ***
17. Form of primary productivity: overall photosynthetic rate per unit area per year (before respiration)
18. Type of diversity measure looking at within-habitat diversity
20. Aquatic dead zones lacking oxygen