If it were to be released, the results could be potentially catastrophic for all forms of life.
uncertain
results → release → life
This is why finding out how ecosystems respond to methane leaks is important to ocean scientists.
asserted
ecosystems → find → scientists
Generally, these investigations take place on purpose in controlled environments.
asserted
investigations → take → environments
But in 2018, a drilling incident caused a methane leak in the
South China Sea.
asserted
incident → cause → Sea
But what scientists including those at the University of Bremen, saw next shocked them more.
asserted
saw → include → them
Over the course of the next six years, in situ monitoring of the situation revealed an incredibly rapid response from the ecosystem.
asserted
monitoring → reveal → ecosystem
Within two years, the bacteria and worms had established a methane-munching 'worm bed' as per a study published in National Science Review.
asserted
bacteria → establish → Review
Cracks in the sea rocks allow methane to passively leak out into the ocean.
asserted
methane → allow → ocean
But in 2018, gas hydrate exploration in the South China Sea caused a human-made underwater methane leak.
asserted
exploration → cause → leak
They were trying to figure out how much natural gas might exist in marine sediments, so they drilled a 22-centimetre-wide hole in the deep seafloor.
uncertain
they → try → seafloor
Afterwards, they tried to seal the hole with heavy mud.
asserted
they → try → mud
But their attempt failed.
asserted
attempt → fail → ?
The incident wasn't detected until a year later, but it allowed researchers to study the seabed as the ecosystem quickly underwent a rapid and drastic transformation.
asserted
ecosystem → detect → transformation
A plume of methane gas had shot up from the deep, rising more than a kilometre high into the water column.
asserted
plume → shoot → column
Before the drilling event occurred, the seabed looked pretty much bare, with little in the way of benthic fauna making a living down there.
asserted
fauna → occur → living
Immediately following the leak, there was a further sharp decline in the seafloor life as microbial richness dipped by around 50 per cent.
asserted
richness → follow → cent
Between 2018 and 2023, the team, which included microbiologist Emil Ruff of the University of Bremen, tracked the ecosystem's development.
asserted
which → include → development
They surveyed the site regularly using echo sounders, underwater cameras, chemical sensors, sediment samples and genetic analysis.
asserted
They → survey → sounders
Using echosounders, underwater cameras, and chemical sensors, researchers watched in awe as a swarm of ocean life flocked to the hole and contained the leaking gas with "remarkable speed".
asserted
swarm → use → speed
"Within just one to two years, an effective methane-consuming ecosystem had already formed," said microbial ecologist Emil Ruff of the University of Bremen in Germany as per a report by Sciencealert.com.
asserted
Ruff → consume → Sciencealert.com
According to past models, a fully functioning methane-munching community on the ocean floor can take between 60 and 100 years to develop.
uncertain
community → accord → years
This one was chewing through nearly as much methane in a fraction of the time.
asserted
one → chew → time
Methane-munching bacteria underwater were having a gala time.
asserted
bacteria → munch → time
The anaerobic methanotrophic archaea ANME-2e and ANME-3 had a bonanza, going from scarcely detectable to an expanding population.
asserted
archaea → have → population
These microorganisms paved the way for bigger things to come.
asserted
things → pave → way
These single-celled organisms were then followed by an influx of burrowing invertebrates, which created an extensive 'worm bed' over the hole.
asserted
which → follow → hole
Crustaceans crawled to the scene as well.
asserted
Crustaceans → crawl → scene
Within 1 to 2 years, the once barren sediment was covered in an extensive “worm bed”.
asserted
sediment → cover → bed
"The worms, in turn, benefited from the newly established microorganisms, which likely served as a food source," explains Ruff.
asserted
Ruff → benefit → source
This crew of opportunistic invertebrates are thought to be a good indicator of early-stage seep ecosystems.
asserted
crew → think → ecosystems
The blooming of life – big and small – created a kind of animal-microbe biofilter that was breaking down methane about as effectively as methane seeps that had been going on for decades.
asserted
that → bloom → decades
Reaching 60 to 100 per cent of their methane-degrading capacity, they provided an ecosystem service that formed far quicker than previously thought possible.
asserted
that → reach → service
As tube worms burrowed into the seafloor, they helped mix the sediment, and this probably transported oxygen, nitrate, and sulfate into deeper layers, said Ruff.
asserted
Ruff → burrow → layers
Bubbles of methane were still leaking from the hole in 2023, but as the living filter developed, the plume's height fell from 1,200 meters (0.74 miles) above the seafloor to roughly 800 meters.
asserted
height → leak → meters
However, Ruff points out that the methane filter's rapid formation came at a cost: a marked change to the original ecosystem.
asserted
formation → point → ecosystem
Within a 20-meter (66-foot) radius, the diversity of bacteria and other microorganisms dropped by more than 50% within two years.
asserted
diversity → drop → years
Even 500 meters (1,640 feet) away, researchers detected elevated methane concentrations, along with a more than 30% drop in microbial diversity.
asserted
researchers → detect → diversity
The study, "Rapid de novo assembly of animal-microbe biofilter to mitigate seabed methane leakage," points to two parallel developments: The seafloor developed a strong capacity for methane breakdown in a short period of time, while the original biological community changed significantly in the process.
asserted
community → mitigate → process
