What is the average deep ocean temperature

The average temperature of the ocean surface waters is about 17 degrees Celsius The deep ocean is not well mixed. The deep ocean is made up of horizontal layers of equal density. Much of this deep ocean water is between degrees Celsius The authors note that there are several possible causes for this deep warming: a shift in Southern Ocean winds, a change in the density of what is called Antarctic Bottom Water, or how quickly that bottom water is formed near the Antarctic, where it sinks to fill the deepest, coldest portions of the ocean around much of the globe.

The scientists found the strongest deep warming around Antarctica, weakening with distance from its source as it spreads around the globe. While the temperature increases are small about 0.

Purkey and Johnson note that deep warming of the Southern Ocean accounts for about 1. The highly accurate deep-ocean temperature observations used in this study come from ship-based instruments that measure conductivity through salinity, temperature and depth. In low latitude tropical regions the sea surface is much warmer, leading to a highly pronounced thermocline Figure 6. Additionally, there is not much seasonal change in surface temperature in tropical regions, so there is little seasonal change in the profiles.

In high latitude polar regions, there is little difference between the surface temperature and the deep water temperature, and temperature is fairly constant and cold at all depths. Polar waters therefore lack a strong thermocline, and as with tropical water, there is little seasonal change in temperatures. In temperate regions, the surface water is much warmer in the summer and the thermocline is more pronounced compared to the winter months.

But in the winter the thermocline is deeper at mid-latitudes than it is in the summer. This is because winter storms churn up the surface water more than occurs in the summer, creating a deeper mixed layer and thus a deeper thermocline Figure 6. Due to the high heat capacity of water, daily fluctuations in ocean temperature are fairly insignificant. Skip to content Generally ocean temperatures range from about -2 o to 30 o C o F.

At depths below 4, meters 14, feet , temperature fluctuations were more minute, but changes followed an annual pattern, indicating seasons still have a measurable impact far below the ocean surface. The average temperature at all four locations went up over the course of the decade, but the increase of about 0.

According to the authors, these results demonstrate that scientists need to take the temperature of the deep ocean at least once a year to account for these fluctuations and pick up on meaningful long-term trends.

In the meantime, others around the world who have used the same moorings to study deep sea ocean currents could analyze their own data and compare the temperature trends of other ocean basins. A better understanding of temperature in the deep sea could have implications that reach beyond the ocean. Because the world's oceans absorb so much of the world's heat, learning about the ocean's temperature trends can help researchers better understand temperature fluctuations in the atmosphere as well.

Materials provided by American Geophysical Union. Note: Content may be edited for style and length. Science News. Journal Reference : Christopher S. Meinen, Renellys C. Perez, Shenfu Dong, Alberto R. Piola, Edmo Campos.