The Puck Lagoon is an essential area of research and management. It consists of two main parts divided by a shallow barrier: a shallow part with a rich environment of seagrass meadows and a deeper part where local upwelling and influence of fresh water play an important role in hydrology. In the winter, the shallow part of the Lagoon is covered with ice. In comparison with the coast of the open Baltic, this complex environment has a great biological diversity. The Puck Lagoon is designated to be a green star spot in the European biodiversity research program. Several species, like the common seal or Baltic sturgeon are currently being reintroduced. The Lagoon is also a place of many conflicts between man and environment. Strong erosion is a threat to coastal infrastructures in some parts of the Lagoon. Nearly half a million people live in vicinity of the Lagoon with the coasts flooded by tourists every summer. For several research institutes the Puck Lagoon is a place of diverse research projects.