Heat oil in heavy large pot over medium heat.
Add onion and garlic and stir 1 minute.
Add celery, carrots and red bell pepper and sauté until vegetables are tender, about 8 minutes. Add broth and Oregano and bring soup to a boil.
Reduce heat to medium-low; simmer to blend flavors, about 20 minutes.
Add turkey, lemon juice and lemon peel into soup.
Season soup to taste with salt and pepper
Placed a handful of chopped spinach into bottom of each bowl..
Ladle soup into bowls.