Final answer:
To calculate the percent change in Arctic sea ice extent and the average change per decade, we would need specific data for the years in question. However, we can mention that several species, including polar bears and Arctic foxes, depend on Arctic sea ice for their habitat.
Step-by-step explanation:
To calculate the percent change in the area of September Arctic sea ice extent between 1980 and 2015, we need the data for both years. Unfortunately, the given information does not include the specific data for those years. However, if we had the data, we could use the following formula to calculate the percent change:
Percent Change = ((New Value - Original Value) / Original Value) * 100
To determine the average change in Arctic sea ice extent per decade, we would need to have data for each decade from 1980 to 2015. By calculating the difference between the ice extent at the beginning and end of each decade and dividing it by the number of years in the decade, we can find the average change.
As for the organisms that may depend on Arctic sea ice, several species rely on it for survival, including polar bears, Arctic foxes, walruses, seals, and various types of seabirds. The sea ice provides them with a habitat for hunting, breeding, and resting.