为啥 “海水的密度比纯水大，还会随温度变化”？

海水中含有盐分，使海水密度（约 1.025 克 / 立方厘米）大于纯水（1 克 / 立方厘米）。温度对海水密度影响显著：温度升高，海水密度减小；温度降低，密度增大。在 4℃时，纯水密度最大，但海水因含盐分，最大密度出现在冰点（约 - 2℃）以下，这种特性影响着海水的垂直环流和分层。

Why is "the density of seawater greater than that of pure water and changes with temperature"?

Seawater contains salt, making its density (about 1.025 g/cm³) greater than that of pure water (1 g/cm³). Temperature has a significant impact on seawater density: as temperature rises, seawater density decreases; as temperature decreases, density increases. Pure water has the highest density at 4℃, but due to the salt content, seawater's maximum density occurs below the freezing point (about -2℃). This characteristic affects the vertical circulation and stratification of seawater.