THE MARTIN KARLSEN, A CANADIAN SHIP, IS A FLOATING LABORATORY FROM WHICH SCIENTISTS ARE ANALYZING PHYSICAL, CHEMICAL BIOLOGICAL AND METEOROLOGICAL CONDITIONS IN LAKE SUPERIOR. SUCH COMPLETE STUDY OF FRESH WATER IS CALLED LIMNOLOGY. LIMNOLOGIST ATTACHES A NANSEN BOTTLE TO A DROPLINE. THE NANSEN BOTTLE, WHOSE OPENING AND CLOSING IS CONTROLLED BY A BRASS WEIGHT, TAKES WATER SAMPLES AT SPECIFIED DEPTHS

---

Size: 3677px × 5439px
Photo credit: © Alpha Stock / Alamy / Afripics
License: Licensed
Model Released: No

Keywords: