This is an example of hyperbole.
Hyperbole is a figure of speech which authors use when they want to show some exaggeration. So, Hamlet wouldn't really drink up Eisel, or eat a crocodile - he is just trying to say that he loves Ophelia very much and that he would do anything for her. This turned out to be a lie because he didn't really love her and she did kill herself.
Criteria such as salinity, depth,and whether the water is flowing or standing are used by scientists to classify aquatic system.
Explanation:
Hydrologist and Oceanographer used to test salinity, depth, temperature of ocean water and whether the water is flowing or standing in case of large water mass or stagnant water body to classify aquatic system. To know the aquatic system very well one must have idea about the photic zone of the water i.e. up to which level sun rays can penetrate into the water.
In photic zone the phyto planktons and all the vegetative life of water mass do exist. Beyond this level plant life can't exit in dark zone. Likewise with increasing depth salinity of water increases, nature of water mass (stagnant or flowing) also have influence in classifying aquatic system.