Final answer:
Zebra mussels consume large amounts of phytoplankton, impacting native species in the food web and causing significant economic damage through biofouling.
Step-by-step explanation:
Zebra mussels, an invasive species, have significantly impacted native aquatic ecosystems by outcompeting native species for food resources.
The correct answer to the question of what food source zebra mussels are impacting the native food web through their consumption of is c. Phytoplankton.
These mussels are filter feeders that consume large quantities of phytoplankton, reducing the availability of these primary producers for native species, thereby disrupting the food chain.
The consequences of their feeding habits include the reduction of food sources for larval fishes and native mussels, altering water quality, and causing negative impacts on the aquatic habitat.
Moreover, zebra mussels cause significant economic damage as they are notorious for biofouling of man-made structures including locks and power plants.