Answer
Temperature and Salinity
Step-by-step explanation:
The two key factors that determine the density of ocean water are the temperature of the water as well as the salinity of the water.
Theoretically the density of ocean water at the sea surface is usually about 1027 kg/m3. When the temperature is low then the density of ocean water increases until freezing of the water occurs.When there is also increase in Salinity if water the density of water also increases. However the temperature of an ocean have more impact on the density than the salinity of the ocean.
Density of ocean is usually calculated through the situ measurements of temperature, salinity by taking the sample of the ocean and taking it to laboratory