nia, a major funder of the institute, raised
concerns about the climate impact of rice.
The company asked Moskowitz if her group
could do anything about the methane rising
off the fields.
Moskowitz began to scour the scientific
literature. She found evidence from Asia
suggesting that fish grown in rice fields—
an ancient practice in that region—could
substantially reduce methane. But the find-
ings weren’t consistent, and no one could
explain how fish pulled this off. So when
Moskowitz came across a paper in the jour-
nal Nature Communications that investi-
gated the fish-methane relationship in a
different context—a lake—she was ecstatic.
For three summers, Shawn Devlin, the
lead author of that paper, had divided a
small Finnish lake in two with a curtain-
like barrier. Because it was shallow and cov-
ered in ice every winter, the lake naturally
lacked fish. Devlin introduced perch on one
side and left the other side fish-free. Then,
once a month, he measured the greenhouse
gases coming off the lake. The side with fish
produced 90 percent less methane than the
side without.
How? The food chain. Aquatic ecosys-
tems host a veritable Serengeti of micro-
scopic organisms: Some microbes, like the
problematic methane producers, grow fat
on dead plant material. Others, however, eat
methane. These methane lovers are known
as methanotrophs.
When the perch showed up, they feasted
on the methanotrophs’ main predator, little
creatures called zooplankton. With fewer
zooplankton around, the methane-eating
bacteria proliferated, capturing much of the
lake’s emissions before they could bubble
into the atmosphere.
“It set me back on my heels,” Moskowitz
says of the paper. “I thought, ‘Why should
this lake be that much different from a
flooded rice paddy?’”
Devlin, who’s an ecologist at the Uni-
versity of Montana, didn’t initially see how
his findings might turn into a method for
reducing emissions. He thought of the
research as purely descriptive of certain
lake dynamics. So when Moskowitz called
him with her pitch to apply the idea to rice
paddies, he was gobsmacked. “As an ecol-
ogist,” Devlin told me, “to have the concept
applied somewhere is such a rarity that it’s
mind-blowing.” He headed to California.
The results of the collaboration so far
have been promising. In California rice
fields, golden shiner minnows introduced
by the project have reduced methane com-
ing off fallowed rice paddies by 64 percent.
By trying different species and densities of
fish, Devlin thinks he can get that number
closer to the 90 percent he saw in Finland.
For Oswald Schmitz, an ecologist at the
Yale School of Forestry and Environmen-
tal Studies (he’s not involved in the proj-
ect), the big lesson of Devlin’s research is
that “animal diversity drives the carbon
cycle,” he says. With a large predator pres-
ent, carbon from decaying plant material
gets shunted into fish meat instead of flow-
ing into the atmosphere as methane. Ani-
mals might even be useful in conservation
generally, helping ecosystems wilder than
rice paddies sequester carbon and aiding in
the fight against climate change. “We view
animals as passengers on a sinking ship,”
Schmitz says, “when in fact, they’re driv-
ers of the ship.”
On a wet, drizzly December day in Cal-
ifornia’s Sacramento Valley, the Resource
Renewal Institute launched its most ambi-
tious test yet of this idea. Chance Cutrano,
the organization’s director of programs,
emptied buckets of golden shiner min-
nows, their underbellies flashing silver,
into a 7-acre paddy. Between 2,500 and
3,000 fish would enter the turbid water;
later 13,000 more fish were plopped into
two other locations. “This is as good as it
gets for fish,” Cutrano said. “Go forth and
grow!”
For the rice farmers, Fish in the Fields
offers the additional enticement of a sec-
ond possible income stream from paddies
that don’t have much use in the winter. The
paddies provide all the food the fish need,
and the fish are harvested before rice plant-
ing season, so they don’t interfere with the
summer crop.
Where could farmers sell minnow pro-
tein? That winter day, Moskowitz had a
proof of concept: pouches full of dried-
fish dog treats. She’d baked them at home.
“My kitchen smelled interesting after I made
them,” she told me with a smile. But her dog
loved them.Fungus:It’s What’sfor DinnerBYAdam Rogers↙
Meat is murder—of Earth’s climate, at least.
More than a quarter of the planet’s ice-free
land is inefficiently used for grazing, a third of all
farmland grows food for animals, and livestock
are prodigious belchers of greenhouse gases.
Global demand for meat is spiking at exactly
the moment it’d be really good for all of us to
eat less of it.
Alas, meat is also freakin’ delicious. High-tech
plant-based replacements aspire to replicate its
proteinaceous umami yumminess and texture,
but pea-based Beyond and soy-based Impossi-
ble face technical challenges. So maybe it’s time
to look to a whole otherkingdom of life for meaty
not-meats: fungus.
Fast-growing meshworks of mycelial
filaments can replicate meat’s texture, and it’ll
eat pretty much any carbon source, including
waste from various industrial processes.
Decades ago, British-based Quorn was the
beginning of this idea, but this year the number
of startups planning to put fungus-based alter-
native proteins in stores and on plates is mush-
rooming.PRIME ROOTS
FUNGUS: ASPERGILLUS ORYZAE
You’ve already eaten Berkeley, California–based
Prime Roots’ substrate. It’s better known as
koji, the fungus that gets the starches in rice
and soy ready for fermentation into sake
and soy sauce, producing all sorts of meaty
flavors along the way. Prime Roots grows a
particular variety of koji and adds fats and
flavors for eatin’.MEATI FOODS
FUNGUS: PROPRIETARY MYCELIAL
STRAIN “ROSITA”
Boulder-based Meati pored through libraries
of filamentous fungi used to make other stuff—
citric acid, antibiotics—to find one that could
grow directly in bioreactors. The resulting har-
vest is good enough to fry up in vegan butter
and garlic all on its own.SUSTAINABLE BIOPRODUCTS
FUNGUS: FUSARIUM SPP
Found in a Yellowstone hot spring, the fast-
growing fungus that underpins Sustainable’s
products grows in open trays, no bioreactor
required. Then it’s just a matter of drying, press-
ing, and adding flavor.MOISES VELASQUEZ-MANOFF
(@moisesvm) writes about health and
science.