NOAA just featured the Sargasso Sea in a short article. There is in the article an awesome animation showing currents that surround the Sargasso, including Gulf Stream Rings. They also mention sargassum, an amazing holopelagic algae.
A timely article indeed since we just completed Chap. 7 on ocean currents.
Click here to read and see more from NOAA: Sargasso Sea Article - NOAA