Ecological Effects
Until recently, the NAO had been in an overall more positive regime since the late 1970s, bringing colder conditions to the North-West Atlantic, which has been linked with the thriving populations of Labrador Sea snow crabs, which have a low temperature optimum.
The NAO+ warming of the North Sea reduces survival of cod larvae which are at the upper limits of their temperature tolerance, as does the cooling in the Labrador Sea, where the cod larvae are at their lower temperature limits. Though not the critical factor, the NAO+ peak in the early 1990s may have contributed to the collapse of the Newfoundland cod fishery.
On the East Coast of the United States an NAO+ causes warmer temperatures and increased rainfall, and thus warmer, less saline surface water. This prevents nutrient-rich upwelling which has reduced productivity. Georges Bank and the Gulf of Maine are affected by this reduced cod catch.
The strength of the NAO is also a determinant in the population fluctuations of the intensively studied Soay sheep.
Read more about this topic: North Atlantic Oscillation
Famous quotes containing the words ecological and/or effects:
“The question that will decide our destiny is not whether we shall expand into space. It is: shall we be one species or a million? A million species will not exhaust the ecological niches that are awaiting the arrival of intelligence.”
—Freeman Dyson (b. 1923)
“Trade and commerce, if they were not made of India-rubber, would never manage to bounce over the obstacles which legislators are continually putting in their way; and, if one were to judge these men wholly by the effects of their actions and not partly by their intentions, they would deserve to be classed and punished with those mischievous persons who put obstructions on the railroads.”
—Henry David Thoreau (1817–1862)