A new study has revealed a significant shift in ocean colors worldwide, with water turning greener at the poles and bluer at the equator. The change in color is attributed to declining chlorophyll concentrations in tropical regions and increasing levels of the green pigment in polar waters. This alteration could have substantial implications for fisheries, which provide sustenance for millions of people globally.
Chlorophyll, a green pigment found in plants and algae, serves as an indicator of phytoplankton populations – microscopic organisms that form the base of the ocean’s food chain. Phytoplankton convert sunlight into energy through photosynthesis. The study’s authors, led by Dr. Haipeng Zhao, analyzed two decades’ worth of satellite data to track changes in chlorophyll concentrations.
The research found that more than half of the world’s fish catch originates from tropical and subtropical regions, which are now experiencing declining chlorophyll levels. This decline could have a profound impact on low- and middle-income nations, such as Pacific Island countries, that heavily rely on fisheries for food and economic development.
However, the study did not investigate the potential correlation between the changes in chlorophyll concentrations and climate change. Researchers noted that warmer ocean temperatures, which are widespread, may be contributing to these changes. To gain a deeper understanding of this phenomenon, the authors emphasize the need for further research using more diverse data collection methods, including physical field observations.
This study highlights the complexity of studying the global ocean, with currents and sediment movements playing significant roles. Dr. Zhao stressed that continued support is necessary to advance this research, as it could provide crucial evidence on the impacts of climate change on our oceans.
Source: https://coastalreview.org/2025/06/ocean-water-is-changing-colors-getting-warmer-study