Assertion: salt marsh | /r/HasProperty | bottom
Facets:
value: historically
type: TEMPORAL
Source sentences:
text: Bertness and Silliman have also suggested that while salt marshes may have historically been nutrient limited and bottom up controlled, human disturbances such as eutrophication and predator depletion has shifted these systems to top down control in recent decades (Bertness and Silliman 2008).