Vertical distribution of enzymatic activities: leucine-aminopeptidase (LAP, ng C L−1 h−1), β-glucosidase (GLU, ng C L−1 h−1), alkaline phosphatase (AP, ng P L−1 h−1), aminopeptidase/β-glucosidase ratio (LAP/GLU) in coastal TNB (upper panels, (A–D)) and offshore RS (lower panels, (E–H)).