|
阅读理解
For many creatures, the danger of global warming is more than too much heat．You can get temperature-related effects that may not be what you expect．Slight environmental change can affect physiological(生理的)needs and weaken the ability of animals to keep a large enough population for them to live on even when the temperature rise is too mild to kill any creatures．
Biologists usually don't know enough about an animal to assess this risk．Their knowledge comes largely from laboratory research on bits and pieces of a creature's physiology．This method doesn't tell how an animal as a living whole responds to climate change in where it lives．
Now, 10 years of research that joined laboratory study with field work has explained the decrease in the populations of eelpout, a kind of fish in the southern part of the North Sea．Dr．Portner and Knust have shown that a mild rise in water temperature can reduce the water's ability to hold oxygen, and, at the same time, it increases the fish's need for more oxygen to keep active, otherwise they will be killed or have to move away．
The researchers discovered that, over the past five decades, eelpout populations decreased when summer temperatures rose．They also found that warmer summers reduced eelpout populaion the following year．
Danish scientists noted that “it remains difficult to determine that increased temperature is the cause for the eelpout population decrease．”Yet they accepted the connection between temperature and population size as recorded in the field with the effect of temperature on the fish's oxygen needs as recorded in the laboratory．They found this connection between laboratory and field data to be “persuasive”．
| 