South Pacific Gyre
The South Pacific Gyre is a major oceanic gyre located in the South Pacific Ocean. It is one of the five major ocean gyres on Earth and is characterized by its clockwise circulation pattern formed under the influence of the trade winds and the Coriolis force. The gyre is bounded by the Antarctic Circumpolar Current to the south and the continent of South America to the east.
Oceanic Pole of Inaccessibility
The center of the South Pacific Gyre is notable for being the oceanic pole of inaccessibility, which is the point in the ocean farthest from any landmass, making it one of the most remote locations on Earth. This area is often referred to as the "oceanic desert" due to its exceptionally low productivity.
Characteristics
Covering an area of approximately 37 million square kilometers, the South Pacific Gyre makes up about 10% of the Earth's ocean surface. The unique circulation pattern of the gyre isolates its center from nutrient upwelling, which is typically necessary for supporting marine life. Unlike other oceanic regions where nutrient-rich sediments are common, the gyre's central area receives minimal nutrient input. This is partly due to the lack of significant land masses in the Southern Hemisphere that could supply dust and nutrients via eolian processes.
Biological Productivity
The low nutrient levels in the South Pacific Gyre lead to extremely low primary productivity at the ocean's surface. Consequently, there is a minimal flux of organic material settling to the ocean floor as marine snow. This results in a sparse accumulation of sediments on the ocean floor, with sedimentation rates ranging from 0.1 to 1 meter per million years.
Environmental Concerns
The South Pacific Gyre is not immune to environmental challenges. The South Pacific garbage patch, similar to the infamous Great Pacific Garbage Patch in the North Pacific Gyre, has become a significant concern. This accumulation of marine debris and plastic pollution threatens the local marine ecosystem and highlights the broader issue of oceanic pollution.