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How Phytoplankton Rule The World

How phytoplankton rule the world

When it comes to climate change, let’s start with the small. The really, really small.

Take a look at the Ocean. What do you see? A whole lot of water. Ok. Waves? Yep. I bet if you look even closer there’s a beautiful creature coming up to say hello somewhere out there. Overwhelmingly though - our eyes scan across the ocean and see the vast blue, that’s it. For something that makes up nearly three-quarters of the earth’s surface, the ocean is to most of us surprisingly mysterious and seemingly separate - another world underneath it all.

photos from  Claire

photos from Claire

The separateness of anything however, is an illusion that is being quickly shattered as we face the effects of climate change. No better organism illustrates this than the microcosmic but mighty phytoplankton! The story of phytoplankton in the face of global warming demonstrates just how interconnected life on land is to the ocean, and how the balance of both is under constant threat in the anthropocene.

Phytoplankton are microscopic organisms that exist in the sunlit upper layer of the ocean, an area called the Euphotic Zone. They are the invisible vacuum cleaners of our climate - playing a pivotal role in regulating the carbon cycle, and the overall temperature of our planet. Phytoplankton draw in carbon dioxide from the atmosphere and through photosynthesis, generate oxygen in the ocean. The boundary between ocean and air is a permeable one in the exchange of carbon. Phytoplankton come to the rescue - regulating an over abundance of carbon levels in the air. Like trees and plants, they are a built in filtering system that we cannot live without. Phytoplankton are the unsung hero. It’s that simple. Well, sort of.

Historically, the ocean has played a pivotal role in ensuring that the balance between carbon in the ocean and in the atmosphere is maintained at inhabitable levels. When phytoplankton die, they and the carbon they have absorbed from our atmosphere sink to the bottom of the ocean. There, the carbon is stored in the ocean sediment for just about 100 years before it is unearthed by ocean currents and felt in our atmosphere. In fact, the effects we are feeling now are from carbon that would have been released from, for example, the coal that your grandparents burned in the early 1900’s. We won’t begin to see the effects of our current carbon emissions for a similar duration of time.


“How inappropriate to call this planet earth, when clearly it is Ocean” - Arthur C. Clarke


Managing the levels of carbon dioxide in our atmosphere is essential to mitigating rising temperatures. We can’t do this without phytoplankton! The problem is, phytoplankton lose their capacity to photosynthesize the carbon dioxide from the atmosphere if they are too hot. The conditions under which phytoplankton thrive require a highly sensitive chemical equilibrium. This balance is constantly being tested as CO2 emissions continue to rise from the agricultural sector, human respiration and the burning of fossil fuels from transportation and energy production - among other things.

Carbon Dioxide is one of the leading greenhouse gases in addition to Nitrous Oxide (N2O), and Water Vapour, among others. These greenhouse gases “warm the Earth by absorbing energy and slowing the rate at which the energy escapes to space; they act like a blanket insulating the Earth.” (EPA) On the one hand we couldn’t live without greenhouse gases, our planet would drop to freezing conditions and become uninhabitable. But with too many greenhouses gases, “earth would be like Venus, where the greenhouse atmosphere keeps temperatures around 400 degrees Celsius (750 Fahrenheit).” (Earth Observatory, 2011)

As carbon dioxide levels rise, our atmosphere and ocean temperatures rise right along with it. The phytoplankton work tirelessly to maintain the status quo in our environment, but this has reached a threshold. When carbon emissions interact with ocean water, acidity rises. Phytoplankton prefer cooler, less acidic water. Without that, they just stop doing their job of pulling in carbon from the air and in turn - through photosynthesis - generating oxygen in the ocean. A warmer ocean means that the phytoplankton have begun slowing down and dying. Once the ocean has gone in this direction, it’s difficult to turn around. The tipping point quickly results in a domino effect that touches nearly every system on earth.


Our ecosystems reveal their inherent sensitivity when we look at the ways in which an incremental change in one organism, affects the rest. Microorganisms  build the foundation upon which ocean life thrives! As phytoplankton production and CO2 vacuuming ability slows down in warm waters, a critical piece of the marine food chain is either removed entirely, or migrates to a different region. Migration or death of phytoplankton results in marine life following suit. Not only is that devastating for the ecosystem, but it would greatly affect local industry based off of marine life.

Without phytoplankton to regulate carbon levels in the atmosphere the air and ocean begin to warm, resulting in a new breed of storms and coastal region impacts. Warmer air instigates water evaporation from the ocean, increasing humidity in the air, ice melt from increasing temperatures and subsequent sea level rise. Storms such as the recent Hurricane Florence become unpredictable and tend to linger much longer over coastal regions. With no cold air or currents to break up the building energy that the storm generates, it gains momentum at an unprecedented rate.

When addressing climate change, looking at the domino effect of the smallest organism is a great starting point. It illustrates the crux of the issue. Global warming cannot be addressed in categories isolated from one another. The wounds of our earth cannot be treated separately from the whole. Phytoplankton remind us of the incredible force and impact of even the smallest organism on this planet. They are a reminder of the natural wisdom within each element of our biosphere - a natural wisdom that is being threatened by the choices and actions of our species.



Cervino, James (2018). Hurricanes, Nor'easters, and Sea Level Rise: Implications for Coastal Eco-Systems. ENVB0386. Columbia University.

Lovelock, James.1979. Gaia. Second Edition. Oxford, UK. Oxford University Press.

The Global Carbon Cycle. Science Compass: Review. October 2000. (via courseworks)

Watts, Sarah. Global Warming is Putting the Ocean’s Phytoplankton in Danger. Pacific Standard. December 2007.

The Importance of Phytoplankton. NASA, Earth Observatory. July 2010.

Effects of Changing the Carbon Cycle. NASA, Earth Observatory. July 2010.