microalgae
Technical term in botany and environmental science for microscopic algae, often discussed in contexts such as biofuels, ecology, and nutrition.
Microalgae are attracting attention as a raw material for biofuels.
A variety of microalgae inhabit this lake.
藻類 is the broader term for algae in general, while 微細藻類 specifically refers to microscopic algae.
Compound of 微細 (bisai, 'microscopic') and 藻類 (sōrui, 'algae'). The exact historical derivation is uncertain; the term is a modern scientific coinage.