In a medium pot, combine the water and the kombu. Simmer gently, without boiling, for 10 minutes. Remove the kombu. Add the scallions, carrots, ginger, and garlic and simmer until the carrots are soft, about 20 minutes.

Scoop ½ cup of the hot broth into a small bowl with the miso paste. Stir until combined and return it to the soup pot. Add the turmeric, black pepper, lemon and lime juice, coconut oil, tamari, sriracha, tofu, noodles, and bok choy. Simmer for 10 minutes. Season to taste with ¼ teaspoon sea salt, if desired, and serve with fresh herbs, if desired.