11. It is thus a major sink for "'fixed "'nitrogen and so limits oceanic primary productivity . 12. These include primary productivity ( production of trophic interactions. 13. The fern is a keystone species in Hawaiian ecosystems, and primary productivity in some areas. 14. Changes in the temperature ranges will also change the location of areas with high primary productivity . 15. Net primary productivity ( NPP ) is the primary measure of biomass accumulation within an ecosystem. 16. This may affect regional temperatures and primary productivity . 17. Only if the concentration is extreme will it decrease the light level sufficiently for impacting primary productivity . 18. Freshwater influences primary productivity in two ways. 19. An oligotrophic lake is a lake with low primary productivity , as a result of low nutrient content. 20. Heavily shaded pools have colder water, where as lightly shaded pools have increased levels of primary productivity .
