Antarctic Bottom Water

Definition

Antarctic Bottom Water (AABW) is a dense, cold water mass that forms in the Southern Ocean, particularly around Antarctica, as surface waters cool and sink. This process creates one of the most significant contributors to global thermohaline circulation, influencing oceanic currents and nutrient distribution in the open ocean, ultimately affecting global climate and marine ecosystems.

5 Must Know Facts For Your Next Test

1. Antarctic Bottom Water is formed primarily near the Weddell Sea and Ross Sea when cold, salty water sinks due to its high density.
2. AABW contributes significantly to global ocean circulation by flowing northward along the ocean floor, influencing climate and nutrient dynamics far from its source.
3. The formation of Antarctic Bottom Water is sensitive to changes in climate; warming temperatures can impact its density and formation processes.
4. This water mass plays a crucial role in storing carbon dioxide, impacting global carbon cycles and climate change.
5. Antarctic Bottom Water is recognized as one of the most important water masses in the world's oceans due to its influence on both marine life and climate patterns.

Review Questions

• How does Antarctic Bottom Water contribute to thermohaline circulation and why is this important for global climate?
  • Antarctic Bottom Water contributes to thermohaline circulation by providing a dense water mass that sinks and flows northward along the ocean floor. This movement helps drive the global conveyor belt of ocean currents, which regulates temperatures and transports nutrients throughout the world's oceans. The importance of this process lies in its influence on climate regulation and marine ecosystem health, as it connects polar regions with equatorial waters.
• Evaluate the potential impacts of climate change on the formation of Antarctic Bottom Water and its implications for oceanic systems.
  • Climate change poses a risk to the formation of Antarctic Bottom Water by increasing surface temperatures and altering salinity levels. As warmer waters reduce the density of surface water, the sinking process may slow down or even halt, disrupting thermohaline circulation. This can lead to significant consequences for oceanic systems, such as altered nutrient distribution, changes in marine biodiversity, and shifts in global climate patterns.
• Analyze the relationship between Antarctic Bottom Water formation and marine life productivity in nutrient-poor regions of the open ocean.
  • The formation of Antarctic Bottom Water is intrinsically linked to marine life productivity through processes like upwelling. As AABW moves northward, it can create conditions that promote upwelling of deeper waters rich in nutrients to the surface. This nutrient influx supports phytoplankton growth, forming the base of the marine food web. The relationship between AABW and marine productivity underscores the importance of this water mass in sustaining ecosystems even in nutrient-poor areas of the open ocean.

Related terms

Thermohaline Circulation:

A large-scale ocean circulation driven by differences in temperature and salinity, which influences global climate patterns and nutrient distribution.

Upwelling:

A process where deep, cold water rises to the surface, bringing nutrients and supporting high biological productivity in marine ecosystems.

Salinity:

The concentration of dissolved salts in water, which affects water density and plays a crucial role in ocean stratification and circulation.