Everything is Connected, sometimes by dust

A River of Dust: The Life-Giving Link Between North Africa and the Amazon 

by Jilanne Hoffmann; illus. by Eugenia Mello 

48 pages; ages 5-8 with interest for older kids

‎Chronicle Books, 2023  (July 25)

theme: ecology, nonfiction, air

Millions of years ago, no ocean lay between us. You and I were one.

Even though the continents are now separated by miles of ocean, the dust of the Sahel travels across Africa and the Atlantic Ocean to reunite with its ancient home in the Amazon basin. The combination of lyrical language and richly colored illustrations take readers on a journey of thousands of miles. 

What I like about this book: Ecologists often say that everything is connected. In this book, Jilanne Hoffman shows how small particles from a thin slice of land between the Sahara and the savannah are essential to the plants and animals of the Amazon. I like how she infuses the text with a sense of longing: When I reach you, we become one once again.  And there is enough Back Matter to satisfy even the most curious minds.

After reading A River of Dust I knew I needed to talk with Jilanne.

Me: Your back matter provides tons of information - and just as many questions - about how dust and climate are connected. How long did you spend researching this topic before you knew you were ready to write the book?

Jilanne: My initial research spanned about six months, starting with the information provided on NASA’s website, and then using JSTOR, the amazing online journal database. I wrote the initial rough draft, which was way too much like a travelog, within the first six months. That version contained no reference to plate tectonics, and it had no back matter. I wanted to put the narrative in place before shaping what turned out to be an overwhelming amount of information. 

Over the next three years, I followed dust trails everywhere, and discovered the man I call “the grandfather” of dust collection, Joseph Prospero, Professor Emeritus in the Department of Atmospheric Sciences at the University of Miami. He’s been collecting the dust that crosses the Atlantic for decades, and he kindly reviewed sections of my back matter. He even sent me a pre-published paper describing the history of research involving African dust transport. I followed his trail of journal articles, and then branched out to study everything from the effects of phosphorus and iron in plants and animals to how drought in the Sahel affects the quantity of dust that ends up in the Saharan Air Layer (a 2 to 2.5-mile-thick layer of the atmosphere starting a mile above the surface of North Africa). 

some of the research papers I read...

I followed trails of scientists who used data from NASA’s earth observation satellites (including CALIPSO) to model how rainfall, or lack thereof, affects climate in the short and long term and more! But eventually, I was able to shape the research into “Questions for Curious Minds,” that included plate tectonics, too! After all, the book is also about separation and reconnection. 

After the book was acquired, I kept researching because: 1) I wanted to lean more into plate tectonics so the narrative could come full circle; 2) I needed to respond to the fact checker questioning specific flora and fauna choices in each biome; and 3) I wanted to respond to a sensitivity reader who pointed out that I hadn’t mentioned how human inhabitants have altered some of the soils in the Amazon over thousands of years. There’s also the question of how much phosphorus comes from burning vegetation from Southern Africa, not just North Africa. So once again, I delved into journal articles discussing  anthropogenic sources of phosphorus and soil studies, and found that while the soils in certain Amazonian corridors, usually along rivers, have been purposefully enriched by human activity, the majority of the soils in the Amazon have not. But the amount of phosphorus provided by burning vegetation is still—ah—up in the air. 

And as we went into final, I found a new study suggesting that a larger proportion of the dust crossing the Atlantic may come from a spot in the Sahara to the west of the Sahel’s Bodélé depression. It’s a difficult analysis. So I decided to include a sentence about that, and we changed the title to include North Africa, not just the Sahel. Writing about science is a race to stay current!

Me: Wow! That is a lot of work! Not only does dust blow from Africa, but you mention that dust from the Gobi Desert feeds the trees of the Sierra's. Where does this river of dust end up?

Jilanne: Yes, the Gobi Desert is also a major source of a river of dust on Earth, especially in the spring in the Northern Hemisphere. The dust causes significant air pollution (like all dust storms) in northern China and Mongolia and even further south while spreading across the North Pacific and spilling over the Western United States. A study conducted by UC Merced researchers suggests that the Gobi provides 18-45% of the dust deposited in the Sierras, depending on location. The remainder of the dust originates from California’s Central Valley. The Los Angeles Times likened the whole process to the way a dirty sponge gets rinsed out by rain and snow along the western slopes of the Sierras. 

Me: Are there any citizen/community science projects that encourage people to collect dust falling onto their rooftops? This is a hot topic (so to speak) because the smoke from Canadian wildfires left lots of dust and ash on my roof - which came down in the rain. I usually collect rainwater to water plants, but not this stuff - it was black!

Jilanne: Yes, “ash rain” is a big problem during fire season! You don’t want to be collecting that! 

A variety of citizen science projects collect and analyze dust around the globe. But from my understanding, they tend to be adult-oriented. One recent project was spurred by the enormous dust transported from North Africa in 2021 to Europe. Citizen scientists collected dust samples on snow in the Pyrenees and French and Swiss Alps and found differences related to mineral content, particulate size, amounts on south vs. north-facing slopes, etc. and recorded their findings. The results have not yet been published. 

Other citizen science projects focus more on specific contaminants that can be found in dust, including lead. Breathing air that contains heavy metal particles is especially concerning for children and their brain development. But all sorts of contaminants and even viruses hitchhike their way around the globe on the vehicle of dust, so there’s really no way to avoid it. Wearing a filtration mask during fire season or Spare the Air days may become more the norm in the future as our world heats up. 

Me: Thank you for joining us today. Jilanne has created a downloadable educator guide that includes a group of cross-curriculum activities, including one that asks kids to monitor and report on the air quality where they live. And the guide offers a wonderful “Simon says” PE activity that involves throwing “dust particles” in different directions, depending on the time of year and wind direction name called out by the teacher. You can find it at her website here.

Beyond the Books:

You can monitor the air quality in your area using the AirNow website or app. Sometimes the air quality changes throughout the day, so you might want to check a couple times a day. Are there times of the year when air quality is worse or better? 

Make a simple dust monitor. All you need is some graph paper (I use centimeter ruled), an index card (or panel of milk carton), Vaseline, and a few common supplies. Then tie them to a tree or tape to a lamp post or the outside of a window. A perfect way to collect wildfire dust and pollen! Here’s how to make the card. 

Jilanne Hoffman is a member of #STEAMTeam2023. You can find out more about her at her website. 

We’ll join Perfect Picture Book Friday once they resume. It’s a wonderful gathering where bloggers share great picture books at Susanna Leonard Hill's website. Review copy provided by the publisher.