Satellite Eye on Earth: April 2017 – in pictures

Europe by night, Canada's vanishing river and the Netherland's tulip fields are among the images captured by European Space Agency and Nasa satellites last month

From space, the strait of Gibraltar appears tiny compared to the continents it separates. At the strait's narrowest point, Africa stands just 14km (nine miles) from Europe. But the narrow waterway is a complex environment that gives rise to striking phytoplankton blooms when conditions are right. The intricate swirls of phytoplankton trace the patterns of water flow, which in this region can become quite turbulent. For example, water moving east from the North Atlantic into the Mediterranean has created turbulence in the form of internal waves. These waves - sometimes with heights up to 100 metres - occur primarily deep within the ocean, with just a mere crest poking through the surface. At the same time, water flowing west helps stir up water in the North Atlantic, including the Gulf of Cidiz. While most of the swirls of colour are phytoplankton, the ocean scientist Norman Kuring of Nasa's Goddard Space Flight Center notes that some of the colour near coastal areas could be due to sediment suspended in the water, particularly near the mouths of rivers.