qualité de l'eau (1) échantillonnage (1) fleuve (1) papier (1) fer (1) indicateur (1) habitat (1) eau douce (1) Europe (1) indicateur environnemental (1) diatomées (1) conductivité (1) Europe (1) Colonies (1) Forms (1) Identification (1) Northern Hemisphere (1) Water quality (1) Water (1) Shields (Geology) (1) Sampling (1) Rivers (1) Photography--Films (1) Paper (1) Motion pictures (1) Microfilms (1) Lakes (1) Iron (1) Identity (Philosophical concept) (1) Identification (1)