Likewise, the more abundant they are, the less blue the water will be.
Costa hopes this latest report will reinforce the importance of understanding the effects of climate change on the world's oceans, noting phytoplankton are "very important in the carbon cycle". Climate change will fuel the blooming of some phytoplankton in some areas, while reducing it in other spots, leading to subtle changes in the ocean's appearance.
"What this study is trying to explain is that in parallel to measuring the amount of phytoplankton in the water, we should also be measuring the light coming from the water", Maycira Costa, professor and coastal oceanography researcher at the University of Victoria, told CTV News. "So it's a complicated process, how light is reflected back out of the ocean to give it its color".
However, Earth's oceans are not comprised of water alone.
So the team looked to satellite measurements of reflected light, instead.
The best example is phytoplankton - an aquatic micro-organism. More algae means more green because their chlorophyll pigments - the ones that absorb sunlight for photosynthesis - absorb more of the blue end of the electromagnetic spectrum, and less of the green. The changes won't be dramatic, in fact, they likely won't be visible to the naked eye, but it suggests that the hue of the ocean could be an important marker for scientists watching to see how climate change will affect our seas. "Everything in the ocean requires phytoplankton to exist".
However, it is sometimes challenging to isolate the driving force behind an observed change in phytoplankton levels.
Climate change doesn't just happen in the air, in the dirt, or in the fearsome pages of damning studies.
At the heart of the phenomenon lie tiny marine microorganisms called phytoplankton, which are crucial to ocean food webs and to the global cycling of carbon - and sensitive to the temperature of ocean waters.
According to a research, phytoplankton will reduce in ocean as a result of increasing global warming and high temperatures. The model took into account phytoplankton characteristics such as feeding and growth behaviors, and was capable of simulating ocean currents and mixing dynamics.
According to Nasa, when sunlight hits the ocean, some of the light is reflected back directly, but most of it penetrates the ocean surface and interacts with the water molecules it encounters.
They started with a computer model used previously to predict phytoplankton changes caused by rising temperatures and ocean acidification.
The team allowed their model to simulate conditions up to the end of the present century. This water is "barren", and the typical oceanic blue is seen in open waters.
Numbers of phytoplankton in areas such as the subtropics are predicted to fall, causing oceans to take on a much bluer colour.
A new study by researchers at the Massachusetts Institute of Technology (MIT) has claimed that earth may not appear as blue by 2100. "That basic pattern will still be there. Different types of phytoplankton absorb light differently, and if climate change shifts one community of phytoplankton to another, that will also change the types of food webs they can support".
"Looking at just the colour of the ocean, and how that is going to change in the future by monitoring it from satellites, is actually going to give us an early warning signal of changes in the phytoplankton", said Hickman.