During combat, there are other markers on the map besides my squads. What effects do they have?

There are sites with various effects that can be used strategically on the battlefield.
These effects are triggered when you send squads to capture each sites, and each has unique effects.

Ekarium Mine/Large Mine: Increases Ekarium production
Radar Tower: Expands visibility around tower
Bug Hole: Summons units that move toward and attack an enemy base for a certain amount of time
Turret Field: Fires a power missile at an enemy base every 5 minutes