Nematode species richness in the southern North Sea

For this assignment, first create a map of nematode species richness in the southern North Sea. Do this on a 0.1 degree resolution, and indicate richness levels with a color and/or size scale. Start with visualizing richness, adding land polygons is optional.

Then overlay this map with gastropod species richness. Use point size to indicate richness, and use a different color for each of the layers. Tip: to make points transparent, add opacity = 0.3 for example.