The ocean is full of mysterious deep-sea life, sunken historical artifacts … and a whole
lot of pee.
I’m not just talking about those of you who think the ocean is his personal port-a-potty.
There are millions of animals that live, eat, and make lots of waste in there.
It might sound kind of gross, but a recent study in Nature Communications showed just
how much the nutrients in fish pee help keep coral reefs healthy.
Coral reefs get plenty of energy from the sun, but nutrients – like compounds rich
in nitrogen and phosphorus – are harder to come by.
Fish are like mobile nutrient reservoirs – storing them in their bodies, or spreading them around.
See, fish excrete waste through their gills, pee, and poop, creating a delicious nitrogen
and phosphorous bath for the reef!
So a team, led by a researcher from the University of Washington, wanted to study how fishing
affects the nutrients in 43 Caribbean reefs.
Specifically, they analyzed around 73,000 fish, representing 143 species, to learn how
the fish excretions changed the chemistry of a sample of ocean water.
Using statistical models, they estimated that heavily-fished coral reefs had around half
the measured nutrients of well-protected areas.
And the key to a healthy cycle of nutrients?
Balance.
Just like a company needs the right mix of employees, a coral reef needs the right mix
of fish, because different fish excrete different amounts and kinds of waste.
Some smaller fish, for example, have higher metabolisms and excrete nitrogen faster.
Hungry predators like groupers and barracuda, on the other hand, store more nutrients and
pee out more phosphorus thanks to the food they eat.
Unfortunately, these big fish also happen to be very popular with fishermen.
That’s bad news for coral ecosystems, because they’re losing a lot of nutritious waste.
Conservation efforts usually focus on maintaining numbers of different species – and that’s
still important.
But these reefs also need the right balance of fish: big fish, small fish, predators,
and prey.
According to these researchers, if we really want to protect coral reefs, we need to consider
how all these organisms interact and share nutrients.
Even – and especially – through their pee.
But, you know what else is in seawater, and soil, and your body?
Viruses!
There might be more viruses on Earth than there are stars in the observable universe,
and we think they can infect every known lifeform.
Bacteria ... humans ... nothing is safe.
We know a lot about a few viruses, mostly the ones that infect humans.
But, now, thanks to some powerful computing and a tool called CRISPR, the global scope
of viruses is becoming clearer than ever before.
A research team at the US Department of Energy analyzed over five trillion DNA bases – that’s
five terabases – looking for new viral genes.
They took 3000 DNA samples from around the world: from seawater to soil, and hot springs
to the human body.
And they combed through those samples using software that recognized viral DNA sequences.
Viral genes could be anywhere in those terabases – usually embedded in the DNA of some infected
organism.
After years of searching and improving their software, we now know of around 16 times more
viral genes than we used to!
Using those genes, the researchers wanted to figure out which viruses infect which species
– mostly focusing on bacteria hosts.
So, they used CRISPR.
Recently, CRISPR’s been hitting the headlines as a revolutionary gene-editing tool.
But in the wild, bacteria use CRISPR to defend themselves against their viral enemies: bacteriophages.
Whenever they defeat a virus, the bacteria snip out a gene fragment and store it in a
special part of their DNA called a CRISPR locus.
Like a row of “most-wanted” posters, CRISPR helps them find and destroy bacteriophages
if they return.
The team of researchers compared these “most-wanted” posters to their viral database, and found
nearly 10,000 new matches.
But what’s the point of knowing which viruses can affect which bacteria?
Turns out, we have our own uses for bacteriophages.
A couple types are used in FDA-approved treatments for meat and cheese, keeping bacteria at bay
so the food is safe to eat.
Others can screen for bacterial infections like the deadly MRSA.
Or these bacteriophages could eventually be used as phage therapy, instead of antibiotics:
to target, infect, and kill certain harmful bacteria without destroying our friendly microbes.
Not to mention, with a huge viral database, it might be easier to fight off a new virus
that infects humans – especially if we’ve seen something like it infecting other species.
Thinking beyond human health, bacteria are really important for global nutrient cycles
– kind of like the fish pee in coral reefs, but everywhere!
And viruses that infect these bacteria could have a major influence on these cycles, but
we barely know anything about them right now.
So these researchers are working on expanding their database, and creating an open resource
for scientists worldwide.
With a catalogue of genes that encode nearly 3 million new viral proteins, they’ve made
a strong head start!
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