Slime: How Algae Created Us, Plague Us, And Just Might Save Us

A much-needed and hopeful exploration of algae, which is increasingly found in our food, clothing and household products, its overall importance to the environment and the possibility algae could help mitigate the impacts of the climate crisis

They live in your bathroom, inhabit your aquariums, create coastal dead zones by thriving on agricultural runoff, and form an especially dense (yet invisible) layer that blankets the world’s oceans, where they are more numerous than all the stars in all the galaxies in the universe. Who are these seemingly ubiquitous beings? They are algae.

Algae comprise a diverse array of photosynthetic organisms — but they are not plants. Algae include microscopic cyanobacteria whose entire length is just one-tenth the diameter of a human hair to giants that are 150 feet tall. In fact, algae is a catchall category for unrelated organisms that lack a common ancestor but are united by their ability to harness the sun’s energy — an ability they acquired by incorporating friendly photosynthetic cyanobacteria into their cells and forming a mutually satisfying relationship. In the case of green algae, these photosynthetic tenants are chloroplasts, whereas endosymbiotic red algae dwell within diatoms and brown algae.

There are three main types of algae. These include the tiny blue-green algae (or cyanobacteria), which are amongst the most ancient living things on Earth and whose photosynthetic activities eventually oxygenated the entire planet, the somewhat larger single-celled microalgae that have a distinct cell nucleus and other internal structures, and the kelp and other giant macroalgae that most people lump together into “seaweed”.

In her book, Slime: How Algae Created Us, Plague Us, and Just Might Save Us (Houghton Mifflin Harcourt USA, 2019: Amazon US / Amazon UK), science writer Ruth Kassinger takes us on a journey through time and space as she tells us the story of algae beginning more than three billion years ago, when life on the planet was in its infancy, to its many uses today, from Korean seaweed farmers hoping to increase the world’s consumption of seaweed to American entrepreneurs using algae to produce oils that could work as a fossil fuel replacement (we’re still decades away from that development, but the possibility gives hope).

After providing us with an overview of the evolution of algae, Ms Kassinger then devotes three sections of the book to exploring the various uses of algae, from the culinary to the industrial. We learn, for example, that algae are very healthful and rich in omega-3 oils, and thus, are consumed widely around the world, as well as being used for fertilizer and as a nutritional supplement in livestock feeds. Ms Kassinger’s enthusiasm for the nutritional benefits of algae will likely motivate her readers to at least consider increasing their overall consumption of “seaweed” in their diets.

We also learn that algae are being developed as a lightweight substitute for plastics in the soles of running shoes and then we are provided a detailed treatise on the boom-and-bust nature of biofuel startup companies that are genetically engineering algae to create biofuels and ethanol.

In the last section of the book, we learn about algae’s symbiotic relationship with corals, the human causes that lead to algae blooms and oceanic dead zones, which are massive and growing problems around the world, and the possibility that algae may play a significant role in environmental cleanups and in mitigating climate change.

The book represents a lot of promise and hope, but it only partially delivered. For example, the writing was generally accessible and included a few special treats, such as algae recipes in one of the book’s appendices. The artwork was lovely, but the reader would have benefitted from a few more illustrations alongside of some of the discussions in the book so, for example, the evolutionary history and relationships between the different types of algae and to plants was made clearer. On one hand, the book design itself was generally respectful of the reader’s time, including a useful and well-referenced chapter-by-chapter bibliography for those who might be interested in pursuing particular topics in greater depth, but on the other hand, the index itself was not particularly useful.

Ms. Kassinger included brief accounts of her many international travels to visit scientists and entrepreneurs, which provided a sense of immediacy and an interesting framework of personalities throughout the book. However, I became quite disturbed by the substantial carbon footprint created by this book, a fact that the author is no doubt aware of since the entire last section (six chapters) is devoted to the worsening climate crisis. Even supposing that the author’s attention on startup companies was initially interesting, this focus soon transformed into a parade of corporate press releases and stock portfolios, particularly when discussing oils and fuels derived from genetically engineered algae. Last but certainly not least, I was especially surprised that the author discussed the disproven “tongue map” (pp. 79-80) to explain — erroneously — the tongue geography of various tastes when clearly, this was not only inaccurate, but completely unnecessary to develop the discussion of umami.

In short, there is much to like about this book but I was concerned by its scientific errors and disappointed by the corporate hype it dutifully reports.