In "Marine Layer", intentional blur or defocusing allows the viewer to focus on the image holistically, without distraction from crisp detail and features. 

In coastal towns, the marine layer is a density of fog that accumulates at the shore when cooler water temperatures and warmer air meet. It can be a subtle haze or a thick fog bank; those images represent the spectrum - those where you can almost make out the detail, and those where only the beach context gives away the subject.