ephemeral

Carries a poignant, often poetic quality. It doesn't just mean 'short', but suggests a fleeting beauty or a fragile existence that is destined to vanish quickly. Commonly used in artistic, philosophical, or scientific contexts. While 'temporary' is neutral and functional (like a temporary job), 'ephemeral' implies a certain delicacy or inevitability of loss. In biological terms, it describes organisms that complete their entire life cycle in a burst of activity triggered by specific conditions, emphasizing the contrast between a brief existence and a long dormant period.