Final answer:
Density currents in warm waters like the Mediterranean Sea are formed due to increased salinity. High evaporation rates contribute to the increase in salinity, making the water denser, which then sinks below less dense surface water.
Step-by-step explanation:
Density currents in warm waters, such as those found in the Mediterranean Sea, can form due to increased salinity. When water evaporates, salt is left behind, increasing the water's density. This denser, saltier water sinks beneath the less dense surface water, creating a density current. This process is particularly common in semi-enclosed bodies of water where high evaporation rates can increase salinity substantially. In contrast, temperature variations often cause density changes in open ocean settings, but in warm, high-salinity regions like the Mediterranean, the salinity factor is more significant.