Sea surface microlayers: A unified physicochemical and biological perspective of the air-ocean interface

► The sea surface microlayer is a biogenic film layer at the air-ocean interface. ► Distinct microbial assemblages have defining roles in microlayer functions. ► The sea surface microlayer is fundamentally involved in air-ocean transfer. ► The sea surface microlayer is linked to aerosol production. ► The sea surface microlayer is reservoir of pollutants.