Answer
Most of what the second buddy says is correct.
Work Step by Step
Gas solubility reduces as pressure drops. At atmospheric pressure, the bubbles are gas molecules that have dissolved in the water. As a result of the lower pressure, bubbles began to emerge. Water vapor would be the second bubble because when the pressure drops, the quantity of vapor pressure (vapor leaving the liquid's surface) matches the external pressure, causing water to boil. As a result, the second bubbles must be vaporized water.
