It is now possible to go to a beach, scoop up a jar of water, and determine everything that’s living in the spot where that particular water sample was taken. Usually, when scientists want to know which plants and animals live in an ocean or a lake, they have to don scuba gear, deploy nets and physically count things to create an accurate picture of that particular environment. This work can be expensive and time consuming. It also may no longer be necessary. Every living thing sheds DNA.