The BATS satellite data show that the Sargasso Sea is not uniform but instead varies substantially in temperature and abundance of phytoplankton . Some of this variability is due to ocean eddies that move through the BATS area. Other eddies are more like an underwater wave.
Some eddies form when meanders in the Gulf Stream are pinched off and wander into the Sargasso Sea .
Thus the passage of an eddy past the BATS site can dramatically alter its chemical, physical, and biological characteristics. We understand little about how the biological community at BATS might respond to the different conditions brought on by the eddies. While scientists take measurements once a month at the BATS site, some episodic events occur that monthly sampling does not always capture. One example is hurricanes . These often move through the Sargasso Sea in the late summer and early fall.