North Sea between and among rivers, artificial harbours, and the sea. The Kiel Canal, connecting the North Sea with the Baltic Sea, is the most heavily used artificial seaway in the world reporting an average of 89 ships per day not including sporting boats and other small watercraft in 2009. It saves an average of , instead of the voyage around the Jutland peninsula. The North Sea Canal connects Amsterdam with the North Sea. North Sea The North Sea is a marginal sea of the Atlantic Ocean located between the United Kingdom (particularly England and Scotland), Denmark, Norway, Sweden, Germany, the Netherlands,
Baltic Sea hypoxia can occur. the total area of bottom covered with hypoxic waters with oxygen concentrations less than 2 mg/l in the Baltic Sea has averaged 49,000 km over the last 40 years. In the Baltic Sea, the input of salt water from the North Sea through the Danish Straits is important in determining the area of hypoxia each year. Denser, saltier water comes into the Baltic Sea and flows along the bottom. Although large salt water inputs help to renew the bottom waters and increase oxygen concentrations, the new oxygen added with the salt water inflow is rapidly used to decompose