The balmy waters of the Caribbean could turn into a deadly heat trap for countless tiny creatures. Authors of a new study conducted at the Smithsonian Tropical Research Institute (STRI) in Panama discovered that microscopic sea urchin eggs and larvae may suffer stunting or death when the water temperature spikes just a couple of degrees above normal, adding to the impact of climate change in already warm tropical oceans.Sea urchins, pincushion-shaped relatives of the starfish, graze the sea floor from shallow coastal areas to deep ocean vents from pole to pole. Their young look nothing like them. Adults release millions of eggs and sperm into the water, which develop into pinprick-sized free-swimming larvae. Only a minute fraction will survive and metamorphose into adults. Scientists think the developmental stages from egg to larvae are extra sensitive to temperature changes, but very few studies compare the vulnerability of the offspring to that of the adults.