Climate change making world's oceans 'green', suggests new study
According to new research, the colour of the Earth's oceans is changing because of climate breakdown. The report suggests that the deep blue sea is actually turning greener over time and added that climate change is also affecting areas in the low latitudes near the equator.
“The reason we care about this is not because we care about the colour, but because the colour is a reflection of the changes in the state of the ecosystem,” stated BB Cael, a scientist at the National Oceanography Centre at the University of Southampton and author of the study which was published in Nature.
Earlier research has focused on the changes in the ocean's greenness, using the verdant chlorophyll present in its plankton, to know more about the impacts of climate change. However, the team led by Cael has studied the observations recorded by NASA's Modis-Aqua satellite which is an exhaustive data repository and searched for patterns of change in the colours of the ocean using a fuller colour spectrum, which included red and blue.
Plankton of various sizes have been scattering light in different ways and plankton, which have different pigments, have been absorbing light in various ways.
More than 56 per cent of the oceans facing 'greening effect'
By studying the colour changes, scientists can provide clarity over changes in plankton populations across the world. Phytoplankton is important for ocean ecosystems because it remains at the base of many of its food chains.
“We do have changes in the colour that are significantly emerging in almost all of the ocean of the tropics or subtropics,” stated Cael. The changes have been noted in more than 56 per cent of the oceans across the world, which is an area more than all of the land spread on the globe.
In many areas there’s a clear “greening effect”, stated Cael, however, he added that there are also water bodies where the blue or red colourings are falling or rising.
“These are not ultra, massive ecosystem-destroying changes, they may be subtle,” stated Cael. “But this gives us an additional piece of evidence that human activity is likely affecting large parts of the global biosphere in a way that we haven’t been able to understand," he added.
A researcher of ocean productivity at Oregon State University, Michael J Behrenfeld, said that the study extensively documents another consequence of changing climate. However, it remains unclear how strong these changes are and what exactly is taking place inside the ocean which is causing them.
“Most likely, the measured trends are associated with multiple factors changing in parallel. With answers to these questions, we can then begin understanding what the ecological and biogeochemical implications are,” stated Behrenfeld.
An advanced satellite mission called Pace (plankton, aerosol, cloud, ocean ecosystem) will be launched by NASA in January 204 which will measure hundreds of colours in the ocean. “Making more meaningful inferences about what the changes actually are ecologically is definitely a big next step,” stated Cael.