Final answer:
The two densest patches of seawater are typically found in colder, high-latitude regions, such as the North Atlantic Ocean and potentially the Arctic Ocean, influenced by cold water density and salinity levels.
Step-by-step explanation:
The question is about identifying the two densest patches of seawater based on a sea surface density map. To address this question, we must consider where cold, dense waters are found and where the highest impact of human activities is observed on ocean health. One key factor that influences seawater density is temperature, where colder water tends to be denser. Another factor is salinity; areas with higher salinity also typically have denser seawater.
From the information provided, we know that the Southern Ocean meets with the warmer waters of the Pacific, Atlantic, and Indian Oceans at the Subtropical Convergence. This area is known for upwelling and mixing, leading to higher sea surface density due to the cold and dense waters rising from the depths. Additionally, areas with significant human impact, like the North Sea and East and South China Seas, may experience changes in sea surface density due to pollution and runoff altering salinity levels.
However, without access to a specific sea surface density map and without explicit mention in the information provided, we cannot definitively determine the exact locations of the two densest seawater patches. Generally, though, the densest patches of seawater might be expected in colder, high-latitude regions, such as the North Atlantic Ocean (due to the cold currents) and potentially the Arctic Ocean due to its cold temperatures.