Today we had a day of navigation, and National Geographic Explorer was full of interesting happenings. On-board scientist Lucas Kamiski taught us about the incredible symbiosis between ants and some butterflies, and naturalist and expedition diver Alice Skehel explained the incredible world of plankton and how some people are using the small creatures to compose art. Later in the afternoon, our hotel manager and our chef explained the complexity of the ship supply operation. As we navigated along the coast of South America, we noticed the change from blue water to green and then to murky water as we entered the region influenced by the mighty Amazon River.