There is an effect on this whole bass line. G|----------------------| D|----------------------| A|0---------------------| D|----4---3---3--3--5-5-| 1:52 G|-------------| D|-------------| A|0------------| D|----3--3-5-5-| 2:00 G|-------------| D|-------------| A|0-(Ring out)-| D|-------------| Speeds up gradually to the point where you're playing fast 16th notes and gets an interesting sound from the effect that you can't replicate on a normal bass.