Ruth Kassinger Takes Readers on an Algae Adventure

Today’s guest review is by Alison Gilchrist, who previously reviewed Carl Zimmer’s She Has Her Mother’s Laugh for Read More Science. Alison Gilchrist is a PhD candidate at the University of Colorado Boulder, where she studies how dengue virus infects humans and nonhuman primates with Dr. Sara Sawyer. She is currently Editor in Chief at the Science Buffs STEM Blog, a graduate student-run blog at CU, and has written for Massive, Scientific American, and the Colorado Arts and Sciences Magazine. Follow her on Twitter at @AlisonAbridged

Photo by Alison Gilchrist

When I made a note to read Ruth Kassinger’s book Slime: How Algae Created Us, Plague Us, and Just Might Save Us, I didn’t know much about it. I knew the book was about algae, I knew that it was highly recommended on Science Friday’s summer books list, and I knew that I was probably going to learn something about biofuels—my only real working knowledge of what algae was good for. So when I finally picked it up from the bookstore, I was surprised to find illustrations of seaweed on the cover. Seaweeds are algae?

Sure enough, I learned that seaweeds are considered a type of algae called “macroalgae”—big algae. The hard, dry lichens stuck to boulders and trees all over the mountains where I live are also partly composed of algae—again, very different from the slimy pond scum I was picturing. Even cooler, algae are some of the organisms that make up corals in coral reefs all over the world. Are you, like me, having to edit your internal picture of what algae are? Suddenly I wasn’t thinking about slime at all.

My confusion is excusable (I argue, into the void of the internet) because of the fact that “algae” is a term without much biological meaning. Unlike “cat” (Felis catus, a species), or “Carnivora” (an order), or “Mammalia” (a class), the term “algae” doesn’t describe a single branching-off point on the tree of the life. Instead it includes different species from a bunch of different branches on the tree of life. Phylogenists (people who study the relationship between species) call this a “polyphyletic group.” It means that the things we call algae have been grouped together under one name, but they don’t share a single common ancestor—at least, not to the exclusion of things that don’t get to be called “algae.” 

All this to say that Slime is a far-reaching book that isn’t quite as filled with, well, slime, as I expected. Instead I read about seaweeds, lichens, corals, and more. And Kassinger infuses the book with her personality from beginning to end as she writes about her own personal quest to understand algae. To research Slime, she went all over the world in search of people growing, manipulating, and using many different types of this diverse group of organisms. For example, she travels to Wales and Korea to learn about the seaweeds that humans eat, and how those macroalgae are farmed—yes, farmed! 

The cultivation of seaweeds is tricky because they like to grow in the ocean, not in man-made pools. But the ocean is a treacherous, unpredictable, and sometimes polluted place to grow food. Kassinger talks to the people who are farming or collecting seaweed and learns how they do it, why they do it, and what they think the future of edible seaweeds is. The answer to that last question is this: we, as a species, will probably be eating more algae in the near future. As farming practices improve and more companies discover this rich source of nutrients, it’s likely to become a product with more reach.

The good news: many seaweeds are high in fiber and protein, and they taste pretty good! Most of us have likely eaten nori, the seaweed that shows up in a lot of sushi. But there are plenty of other species of macroalgae to experiment with. Kassinger even includes seaweed-featuring recipes in her book so you can try them for yourself. 

The reviewer took Slime on a camping trip. Photo by Alison Gilchrist.

Kassinger also traveled to San Diego, Fort Myers, and other cities around the world to learn about the companies making biofuel and plastics from algae-derived products—did you know that there are already shoes made with algal plastic? Some kinds of algae are masters of production: genetically manipulate the right biochemical pathways and put them in the right nutrient environment, and they will frantically churn out useful chemicals in response.

Kassinger writes about the scientists and entrepreneurs who are working out how to make special kinds of algae grow quickly and produce the right kind of oils. For some, this means biofuels. For others, it means edible or pharmaceutical compounds. Regardless of the final product they’re looking for, these people are all want rapidly-growing and hyper-productive algae. 

But hyperactive algae are not always useful or helpful. Kassinger also travels to places where algae have multiplied like crazy due to warming water and increased nutrient runoffs from agriculture. The effect is scary: large “dead-zones” where algae have used up all the available oxygen, and accumulations of algal toxins in the food chain. As the subtitle of Kassinger’s book suggests, even as people are manipulating algae to save us, they continue to plague us. 

These passages about algae “plagues” are made more surreal by the names given to the pestilent species. “Watermelon snow” is the cute name given to a pink alga found in high latitudes. Unfortunately, it has a large impact on climate change by settling on icefields and spurring snowmelt. “Rock snot” is a much less pleasant name given to an alga that is overrunning tributaries in countries all over the world. These names mean that Kassinger gets to create sentences that strike a careful balance between humor and pessimistic observation. Describing how one species of algae extends its territory, she writes: “A grotesque invasion of rock snot ensues.” 

Watermelon snow in the Pacific Northwest mountains. Source

Slime is a book full of emotional ups and downs—Kassinger doesn’t shy away from talking about the connection between global warming and algal blooms, or the problematic dependence on plastic that’s motivating us to find new ways to make it, or the fact that algae-derived biofuels simply aren’t economically competitive right now, and probably won’t be in the next decade. But she also delights in the hunt for unusual lichens, munches on tasty seaweeds, and is hopeful about the work being done to make algae useful producers of interesting compounds. It’s a pleasure to join her for the ride. 


If you enjoyed Alison’s review, leave a comment thanking her! And if you’re interested in writing a guest review for Read More Science, reach out to Sarah at sciencebookreviews (at) gmail (dot) com to let her know what book you’re interested in reviewing.

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