Summary

On June 21, 2015, the summer solstice, thousands of scientists will join together to participate in Ocean Sampling Day (OSD), an international collaboration to collect water samples from the ocean and rivers around the world. Within the water samples, scientists will also be collecting things so small that, in most cases, they are invisible to the naked eye. Some, in fact, are so tiny that up to a million of them can live in just one milliliter of seawater!