Why You and I Need to Care About Phytoplankton–and What We Can Do About Them



Despite my optimistic outlook, there’s one area where I need to search especially hard for positive signs: climate change. To me, it is the existential threat to our planet, and I am infuriated and frightened by those who willfully ignore the important lessons that scientists are teaching us.

Recently, I had an exceptional guide into the impact of climate change on phytoplankton, the tiny organisms at the very bottom of the food chain. And I’m now convinced that we really need to pay attention to the fate of these microorganisms—because our future is intertwined with theirs.

My guide: Terence (Terry) Milligan, PhD, a dear friend who taught advanced placement biology to high school students for many years and now serves as a docent in New York’s American Museum of Natural History. Terry recently took our family through a breathtakingly beautiful exhibit of phytoplankton in the museum.

He’s a gifted educator whose supple knowledge and contagious enthusiasm could probably make any subject fascinating, and with the backdrop of the museum’s exhibits, he wowed us with the magnificence and importance of phytoplankton and the implications of the threats they face. “As they go, so goes the ocean,” Terry says.

First, a brief introduction to phytoplankton. From the Greek words “phyto,” meaning plant, and “plankton,” meaning made to wander or drift, they are a highly diverse group of organisms living in water that’s both salty, as in the ocean, and fresh, as in lakes. Despite the “phyto” nomenclature, they aren’t actually plants, Terry explained.

Most are single-celled bacteria that carry out photosynthesis. And that’s the function that makes them so valuable: Using sunlight and nutrients, they release oxygen into the atmosphere and remove carbon from it. (Terry particularly likes to point out the diatoms –featured at top and below–one of the largest phytoplankton groups; these beautiful microorganisms extract silicon from their surroundings, essentially encasing themselves in glass.)

Pennales–a subdivision of Diatoms



An article by David Biello, Engineering the Ocean, which I’ll return to later (because it offers a bit of hope), captures the essence of these tiny life-factories: “There are more plankton cells in the sea than our current count of stars in the entire universe.”

“Much of the oxygen we breathe comes from just one species of cyanobacteria, Prochlorococcus,” Biello adds. “This species was not even discovered until the 1980s: it is so tiny that millions can fit into a single drop of water and no one had produced a sieve small enough to catch it.” The oxygen they create, Biello says, “dwarfs that produced by the Amazon rainforest and the rest of the world’s woodlands combined.” 



In a phrase I love, Biello says “…these tiny creatures serve as the planet’s lungs, whose steady breathing is limited only by nutrition.” Like plants on land, he notes, “they need nitrogen, phosphorus and other elements to thrive; missing nutrients restrain planktons’ growth.”

Here, somewhat simplified, is Terry’s description of the way that climate change is damaging the phytoplankton and, consequently, the entire ocean’s food chain. The nutrients essential to the phytoplankton’s viability are abundant at the equator in the Atlantic and Pacific Oceans and other so-called “upwelling zones” where the sea is heated and the water currents, helped by the trade winds, pull up to the surface the nutrients found in the deep water coming from Antarctica and the Arctic Ocean.

The “normal” cycle would consist of the water proceeding to the North Pole, getting denser in the colder regions, and sinking to the bottom, where it refreshes its nutrient supply on the way back to the equator. There the nutrients rise to the top and become vital components of the phytoplankton—sustaining the enormous numbers of these creatures found near the surface of oceans throughout the world.

The dangers of climate change are clearly seen in the ocean around Greenland, where the enormous glaciers are already melting rapidly—an average of 270 billion tons of ice each year. (See Umair Irfan in Vox, “Greenland’s ice is melting much faster than we thought. Here’s why that’s scary,” April 11, 2018.)

That huge loss is fresh water, pouring into the ocean around Greenland and making the ocean less dense. The result: the nutrient conveyor belt for the entire North Atlantic slows down, which, in turn, makes it increasingly difficult to sustain the populations of phytoplankton that now exist. Similar activities are inevitably taking place throughout the world.

Obviously, the impacts on plankton and other sea life will be felt by humans on land, from the disappearance of sardines and other fish to the economic calamity on commercial fishing, to name just a few.

But having alerted you to the bad news, I’d like to offer a few rays of hope—though these rays are admittedly filtered by both the complexity of the issue and the many unknowns, including the “laws of unintended consequences.”

In Engineering the Ocean, David Biello describes what he calls an “ambitious new pursuit” by a marine biologist named Victor Smetacek, who set about to provide plankton with the iron nutrient they need to survive. “Fertilizing the waters could promote blooms that help sea life thrive all the way up the food chain, even to whale populations, which are still recovering from overhunting,” Biello writes.

Biello notes that environmentalists—“the very people who care the most about climate change”—tried to stop this effort because of concerns about possible toxic algae bloom, poisoning of sea life, or the creation of the kind of dead zones that developed in the Gulf of Mexico, “where the fertilizers that support Midwestern cornfields gush out of the Mississippi River’s mouth and into the ocean.” A UN body said in 2008 that iron fertilization should be prohibited “until there is an adequate scientific basis on which to justify such activities.”

But, Biello says, Smetacek’s research was successful, albeit briefly, and the science on which it was based was vetted in the journal Nature in 2012. Still, there are no current efforts, though Smetacek thinks commercial interests may hold the key.

Terry finds the idea intriguing, though the duration of the iron fertilization has thus far been limited. He foresees the need for a massive international cooperative effort for anything like that to have a chance to succeed, assuming the effort has first been proven to be safe.

He does see positive signs for reversing the negative trends in such efforts as New York Mayor Bill De Blasio’s agreement with London’s Mayor Sadiq Khan to switch New York and London from oil-based energy sources to wind and solar. “It would be very good if more mayors deliberately try to develop non-hydrocarbon energy mechanisms,” he stresses.

And he emphasizes that individuals also have an important role to play. That’s where you and I come in. “I own a car that gets 52 miles per gallon,” Terry says. “More people are turning away from incandescent lighting.” If more of us consciously buy things and do things of that nature, there is reason to be hopeful.

Biello believes the kind of “expansive thinking” that Smetacek showed with his iron fertilization plan is essential. “A land animal [humans] has come to tame the heaving, alien world of the sea,” he writes, “and, though doing so can make us uncomfortable, in the end it might undo a great deal of the damage we have already done.”

And there may be another source of hope. An article in Pacific Standard quotes Oscar Schofield, an oceanography professor at Rutgers University, who points out that at Palmer Station, a US research site located north of the Antarctic Circle, “there’s been a decline in the Adelie penguin population by an order of magnitude. But sub-polar penguins that live in the Falkland Islands…are increasing. Species have a lot of unknown capacities for adaptation. They can evolve and change their characteristics—but it happens slowly.”

Schofield does wonder whether organisms can adapt to climate change in time to survive. Says Sarah Watts, who wrote the article, “For phytoplankton, marine life, and humans alike, that remains to be seen.”

Terry notes that most smaller fish are increasing in numbers. “Is that a good thing?,” he asks. “The ecology of the ocean is actually changing. What’s happening in the Falklands could be a result of the impact of overfishing on the larger predator fish. Time will tell if it’s good or bad.”

Obviously, we don’t know. But wouldn’t it be wonderful if, after we humans have apparently done our damnedest to mess up our environment, we apply our ingenuity a la Smetacek to reverse the damage and save the phytoplankton—and we’re helped by the penguins and other forms of marine life, using their innate “ingenuity” to find their own ways to adapt?


Note: I added this non-phytoplankton image of a gang from the Falkland Islands because…why not?

Your thoughts?


18 thoughts on “Why You and I Need to Care About Phytoplankton–and What We Can Do About Them

  1. Well, these little tiny breathing creatures you have brought to life as I sit here at my regular table in Starbucks are riveting. Their endangered, stressed status is another terror to consider when I weary of wringing my hands over the demise of my country as I know and love it. (There, then: the elephant in the room, called out!) Thank you for the science you laid out. It’s so elegant in its logic and beautifully articulated by you. (Your use of language always captivates: “supple knowledge,” “contagious enthusiasm,” and “encasing . . . in glass.”) As an educator of late (a chapter I never saw coming), I am with students of all ages, high school through post-doc, and pay attention to their shorthand mottos for moving ahead with their careers. Here are three from last week alone that left an impression: “Science will never betray us,” “Get over it, and get on with it,” and “You don’t need to know everything, just your next step.” Words by which to set one’s course. My next step is to pass your blog around in an effort to raise awareness. I can’t think of a better summary, more persuasively stated, to wake people up. Thank you for your work.


    1. Denise,

      You are a blogger’s/writer’s dream. I wondered whether this post might be a bit too long and too arcane to appeal to many people, but I plunged ahead because I find the topic fascinating and so very important. I’m most grateful that you feel the same way–and that you plan to continue the effort to raise awareness by sharing this post. And thanks so much for your generous praise.

      It’s also great that you’re learning from your students! But why not? We all have stuff to teach and to learn, don’t we?




    1. Fran,

      Thanks so much for your kind words–and for citing two sources that help advance our understanding of the amazing world of phytoplankton. This is exactly the kind of dialogue I seek with this blog, and I’m grateful to you for taking the time to pursue the topic further and enrich this exchange.




      1. Thank you. But I have to confess that I totally misconstrued the point of the NASA hurricane link. In no way does the article imply anything positive about hurricanes and their having a positive impact on climate change. It was a big mistake for me to have read anything scientific after 8:00 pm. Oy!


      2. No, hurricanes don’t have a positive effect on climate change—their increasing ferocity does seem to be another negative. But they do, as the article you cited states, give a temporary boost to Phytoplankton by churning up the waters. So the article is relevant to our discussion. All these climate change issues are so complicated!


    2. Hi Fran!
      Read your articles and found them very interesting, especially the hurricane/phytoplankton connection which I had not come across. It is a side issue here but still of interest to note that the effect of a hurricane on the atmosphere has somewhat parallel effects to those on the phytoplankton in the redistribution of water from ocean to land via evaporation from the ocean into the hurricane, and as rain (fresh water!), of course, from the hurricane to the land. This replenishes the land side of the water cycle and ensures blooms of land plant life in the wake of a passing hurricane in that fresh water (as with the much needed micronutrients in the ocean) would be far less abundant in those areas without hurricanes.

      Terry Milligan

      Liked by 1 person

      1. Hello, Terry–and Welcome!

        So now, thanks to the NASA article Fran cited and your mini-lesson, we have a greater understanding of the positive impact of hurricanes on both phytoplankton in the ocean and land plant life. But as we’re watching the devastation of Hurricane Michael, I thought it might be helpful to introduce some articles about the climate change link and its impact on the destructive power and increased precipitation associated with hurricanes (though probably not greater frequency).

        From the Union of Concerned Scientists:


        From the Center for Energy and Climate Solutions:


        And this one, from FiveThirtyEight, provides a bit of the optimism I’m always seeking. It points out that climate change research has made five-day forecasts of hurricane predictions as accurate as 2-day forecasts had been decades ago. I am assuming that could provide life-saving information.


        Thanks so much for advancing our dialogue!

        Liked by 1 person

  2. Good articles Annie! The thing is It all makes so much sense … common sense!!! Hurricanes are driven by the heat in ocean water!!! As the earth gets warmer (the evidence for this is overwhelming and incontrovertible) the water of the ocean gets warmer. This greater heat causes more water to evaporate and get sucked into the storm. The warmer temperature of this additional water does at least 3 very dangerous things: 1. It increases the size of the storm so more area will be affected. 2. The greater energy in it causes the winds of the hurricane to increase in speed causing more wind destruction. Michael INTENSIFIED to a category 4 (possibly 5!) as it approached the shore due to the storm moving over water that was shallow and hotter than the deeper water further out in the Gulf. Something the hurricane experts HAD NOT SEEN before. Take a good look at the before Michael and after Michael footage of the Mexico Beach area and others on the Florida panhandle to see what effect the added energy had. 3. The additional water will be returned to the earth as greater amounts of rain causing greater damage by rising tides and larger waves at the shore and cataclysmic flooding inland wherever the storm goes.


    1. Yes, this all makes common sense. But there’s clearly a need for common sense and much policy and pragmatic discussion about both the increasing density of people in the hurricane-prone zones and the decisions governing where and how rebuilding should occur following the devastation. Perhaps a topic for another time…


  3. “ But wouldn’t it be wonderful if, after we humans have apparently done our damnedest to mess up our environment, we apply our ingenuity to reverse the damage….” Yes, it would be, but WILL we? Great, informative post.

    Liked by 1 person

    1. WILL we? Is the operative question. Thanks so much for your encouraging remarks. I know this post can be a challenge to read all the way through. And thanks, again, for helping me broaden its readership.

      Liked by 1 person

    1. Good question, Marleen. As I understand it, it’s a matter of balance, and climate change is disrupting the balance. So yes, as I mentioned in my more recent post about climate change, there are lakes in the US (and I’m sure elsewhere) that have become overgrown with toxic algae blooms that have killed people’s dogs and led to closures of recreational activities. That’s why although there’s some excitement about the iron nutrient fertilization plan described above, some urged caution due to concern it could become out of control.


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