Vegan Manhattan Clam Chowder

Name: Vegan Manhattan Clam Chowder
Ingredients: 8 cup vegetable broth; 1 large piece of kelp (also known as kombu); 1/4 cup dried wakame (optional, for more briny flavor); 1 tbsp extra-virgin olive oil; 2 medium carrots, peeled and cut into 1/4-inch pieces; g 2 celery ribs, cut into 1/4-inch pieces; 1 medium onion, finely chopped; 3 cloves garlic, minced; 2 tsp dried thyme; 1 1/2 tsps Old Bay Seasoning; 2 to 3 medium waxy potatoes, about 1 pound, peeled and cut into 1/2-inch pieces; 8 oz shiitake mushrooms, stemmed and sliced into thin strips; 28 oz can crushed tomatoes; 3 tbsp tomato paste; 2 tsp maple syrup or granulated sugar; 2 bay leaves; Salt and ground black pepper, to taste; Oyster crackers, for serving (optional)