Research has shown that Arctic plants are more injured by ...

[altibaby]

Research has shown that Arctic plants are more injured by increased ultraviolet radiation than by global warming (see Ch. 17).
 
  (77) The authors of the study say there is a growing belief that ozone depletion is of only minor environmental concern because the impacts of UV-B radiation on plant communities are often very subtle. Here we show that 5 years of exposure of a subarctic heath to enhanced UV-B radiation both alone and in combination with elevated CO2 resulted in significant changes in the C:N ratio and in the bacterial community structure of the soil microbial biomass. What might this mean about the future Arctic ecology? Explain.

Question 2

If no one has ever seen a molecule, how do we know that there are molecules in fluids?
 
  What will be an ideal response?

[trog]

Answer to Question 1

The fact that increased UV alone causes problems in Arctic plants means that this
alone could be a harbinger of ecological problems there. The main point of the quote is that
the while effects at lower latitudes may not show that problems arise, the neglect of possible
differences in the various biomes (tropical, temperate, boreal, etc.) could be leading scientists
astray.
A central point of scientific experiments is the existence of control of variables. Sometimes,
assumptions are made that certain variables are unimportant. In this case, that occurred. The
results of Ref. 77 show that the question of control is more complex than it looked at the
beginning.
Arctic ecology seems from this research to be quite sensitive to the effects of ozone
depletion. This might enhance the deleterious effects of global warming, or cause different
problems. Perhaps the soils in the Arctic could become sources of climate change if the
plant communities die off. In any case, Mother Nature seems to be saying that it is
dangerous to fool around with things when the outcome is so possibly problematic.

Answer to Question 2

We infer that there are molecules from the behavior of the fluids. The kinetic
theory describes the characteristics of fluids very well. Many predictions made assuming
this is true supported the inference.

[altibaby]

Thank you!

[trog]

Always glad to help...