First thing every morning, I take coffee and medicines. Maia usually jumps on the bed and supervises my intake of the daily meds. Then there is usually a small pastry or biscotti and the remainder of the coffee. Maia watches intently until I reach for her bag of Tuna-flavored feline treats. She vacuums up her kitty treats and then leaves us. Her entire ritual has a distinctly mercenary design. Sometimes, after reading a few pages of email on my phone, I snuggle down into the comforter and take an hour-long nap.
This morning was one of those nap mornings. “I awoke with a nagging question on my mind. “How much do all the earthworms on the planet weigh?” I don’t recall dreaming about earthworms or gardening or Roland Emmerich’s 1998 movie Godzilla which opens with Dr. Niko Tatopoulos harvesting earthworms from the Chernobyl exclusion zone. Nonetheless, there was this question that insisted on an answer, “How much would they weigh?” It didn’t occur to me then that the answer might depend on whether we were talking live, wiggly worms or desiccated worms. Science can be a fickle mistress.
I went straight to Google, of course – the Encyclopedia Mundi. There I found numerous scientific articles, earthworm databases, meta-analyses, and articles for the laity on the matter of earthworm diversity, density, distribution and biomass. None of them provided a simple answer regarding the earth’s biomass of earthworms. Merde!
I did encounter several interesting pages and articles. One, in particular, tickled my fancy. A four-year old asked which weighed more – all the people in the world or all the bugs. Only a four-year-old can conjure up such profound questions; many of the questions that children pose are Fermi problems. We should all try to keep that part of our curiosity alive no matter our chronological age. The bugs, in case you are wondering, won out.
The best I could find regarding the biomass of earthworms was an estimate of 51.18 g/m^2. Of course, this depends on where you sample for worms. We aren’t going to find as many earthworms in the desert or in the boreal forests of North America as we find in Western Europe or the warmer parts of the United States. It turns out that most of the North American earthworms perished during the last ice age. Our red wigglers down South are the progeny of European invaders. Worse still, our northern conifer forests are becoming infested with earthworms whose digestive activities are contributing to global CO2 and hence to climate change. Nasty little annelids.
Okay, I didn’t find a reasonable estimate for the worldwide earthworm biomass. But I am now a little more in touch with my inner four-year-old. That’s worth something.