A 31-year-old man is on a scuba diving trip and descends to a depth of 50 m in the Blue Hole off the coast of Belize. After 30 minutes, he has a malfunction in his equipment and quickly returns to the boat on the surface. He develops difficulty breathing within 5 minutes, with dyspnea and substernal chest pain, followed by a severe headache and vertigo. An hour later, he develops severe, painful myalgias and arthralgias. These symptoms abate within 24 hours. Which of the following occluding his arterioles is the most likely cause of his findings?