Ocean are turning blue to green

 Our Blue oceans are mysteriously turning Green

The NASA Aqua satellite, it was revealed that 56 per cent of the ocean water had changed its colour from blue to green, especially in the southern Indian Ocean near the equator. The spectroradiometer named MODIS aboard Aqua satellite the researchers analysed data for two decades from 2002 to 2022. This colour change, while subtle to the human eye, provides crucial insights into the health and composition of ocean ecosystems. Following are the some of the important points:-

The study utilised data from the MODIS instrument aboard the Aqua satellite

These colour shifts likely signify broader changes in ocean ecosystems

It has been monitoring ocean colour for two decades

Oceans that cover more than 70 % of our Earth are mysteriously turning blue to green. This is revealed by a study by B B Cael from the UK's National Oceanography Centre, with far-reaching implications for marine ecosystems and the global carbon cycle. The research, which analysed 20 years of data from NASA's Aqua satellite, found that 56 % of the global sea surface has undergone a noticeable change in colour since 2002, primarily turning greener, especially in the southern Indian Ocean near the equator. 

The responsible factor for the change in colour is phytoplankton communities in the ocean. These marine organism plays a vital role in the green colour as they release carbon dioxide that results in the rise of phyto blooms. These phytoplankton contain the green pigment chlorophyll. And their presence in the ocean makes it look green. The greening trend is particularly pronounced in tropical and subtropical regions, indicating potential alterations in phytoplankton communities, microscopic organisms which form the foundation of the marine food web and play a vital role in carbon sequestration.

The study utilised data from the MODIS instrument aboard the Aqua satellite, which has been monitoring ocean colour for two decades. By analysing the full spectrum of visible light reflected from the ocean surface, researchers were able to detect changes which traditional chlorophyll measurements might have missed. B B Cael said, "The colour itself is not something that's easy to describe with human language or that you can even see that well," he further added, "Instead, this might be something that a mantis shrimp or a butterfly could see." Cael is a lead author of the study that has provided the data of NASA satellites for two decades of observation it did on the ocean colour changes.

Cael emphasised that these colour shifts likely signify broader changes in ocean ecosystems, potentially including different assemblages of plankton, increased detrital particles, or changes in zooplankton populations. The research team ruled out widespread pollution or plastics as the cause, noting that these are not prevalent enough to account for the observed changes. He also talked about how human activities impact oceans and mentioned in his statement, "This gives additional evidence of how human activities affect life on earth over a huge spatial extent. It's another way that humans are affecting the biosphere.”

One key factor identified in the study is increased ocean stratification due to climate change. As surface waters warm and become less prone to mixing with deeper, nutrient-rich layers, it creates conditions which favour certain types of plankton adapted to nutrient-poor environments. The findings align with climate model predictions but have been detected much earlier than anticipated. This early confirmation of the trend underscores the rapid pace of climate-induced changes in our oceans and the need for continued monitoring and research. Scientists are observing the phytoplankton growth and their communities as they might be responsible for climate change. So they are tracking their chlorophyll ratio on how blue viruses green surface.

There is an upcoming mission by NASA where the  PACE satellite mission will be launched in 2024 for the further observation of the phytoplankton diversity which will give insights on their growth and possibly scientists may be able to find a solution through data and research on how to slow down the increment of these communities in ocean. There is a report named (European State of the Climate report)  published in April 2024, by the European Union's Copernicus Climate Service that has provided data on the changes in the ocean.