Language Lab, Science Faculty, University of Nice - Sophia Antipolis

 

Home / Earth Science / Lake Nyos - Part II

Prepositions.

In this part of the exercise, fill each blank with a correct preposition. Each of the prepositions shown below are used at least once, with some used multiple times. When you are finished with the exercise, go on to part III of the activity here. Also, if you don't manage to find all the answers, a complete version of the text, with all the prepositions included, can be found here.

   behind      below      in      into       of       on      through      to      toward  
The science the disaster is fairly simple. Lake Nyos is a deep pool water sitting the throat of a dormant volcano. The real culprit is a pool of hot magma, lying almost 50 miles the lake. The magma releases the carbon dioxide and other gases, which travel upward the earth. The gases gets trapped natural spring water, which eventually rises (in the direction of) the surface and feed the crater lake.

The carbon dioxide, instead being harmlessly released the atmosphere, gets trapped the cold water at the bottom of the lake. The amount of gas that can be dissolved the water is dependent water temperature and pressure. The greater the pressure, the more gas that can be trapped. None of this would be particularly hazardous if the water at the bottom of the lake were to regularly rise the surface, where the gas could be safely released. The problem is that the waters of Lake Nyos, like many tropical lakes, are steady and still, with little annual mixing of the water layers.