Phytoplankton Decline in the North Pacific - August 2002

Phytoplankton Decline in the North Pacific - August 2002

NASA (National Aeronautics and Space Administration) and NOAA (National Oceanic and Atmospheric Administration) have analyzed satellite observations over the past 20 years and reported that phytoplankton levels in the North Pacific have decreased by approximately 30%. In addition, a 14% decrease was also observed in the North Atlantic Ocean. On the other hand, an increasing trend was observed in the northern Indian Ocean and near the equator, and it is highly likely that these changes are related to ocean warming and changes in nutrient supply.

Phytoplankton forms the basis of marine ecosystems and plays an important role as food for fish and marine mammals. Therefore, a decrease in plankton levels could lead to a decline in fishery resources and a collapse in the balance of the ecosystem. In addition, since phytoplankton absorbs CO₂ from the atmosphere through photosynthesis, its decline could also accelerate the progression of global warming.

Researchers have pointed out that the plankton decline may have been caused by changes in the ocean's stratification due to rising sea surface temperatures, which reduced the supply of nutrients from deeper layers. Changes in ocean currents due to climate change may also have had an impact. Further observations and analysis are required to elucidate the detailed mechanism.

**Related Information**.
- Long-term changes in nutrients and lower-order ecosystems in the subarctic western North Pacific
- Report on Elucidation of the Mechanisms that Nurture "Abundant Ocean" in the North Pacific
- Research on the Effects of Climate Change on Basic Production in the Western North Pacific Subtropical Ocean