Marine Bacteria - do you know you're soaking in them?
Next time you head down to the beach for a swim scientist Els Maas would be delighted if you spare a thought for the
invisible workhorses of the ocean.
The NIWA microbiologist is the only person in New Zealand studying the processes of billions and billions of tiny
invisible bacteria in the oceans that play a crucial role in how the planet works.
“Bacteria are major players in the ocean but when we think about what’s important in the sea, we tend to think of
something like fish or whales. While they are important, it’s really the bacteria that keep everything going.
“They’re just there all the time, breaking down anything that’s already dead and recycling the nutrients for all the
other organisms to use again.”
To get an idea of the sheer volume of marine bacteria, imagine a single drop of sea water. It contains about one million
bacteria, each no more than one millionth of a metre long. And a litre can contain more than 20,000 different types of
bacteria.
Dr Maas is particularly interested in the processes bacteria use to do their job and what controls these processes.
Take iron, for instance. For humans consuming the right amount of iron is important for good health. It’s the same for
bacteria but there is a limited amount of iron in the ocean and bacteria have to compete with other organisms to get
enough.
“Luckily they’re very adaptable.”
Different bacteria do different things but the same bacteria can also behave differently in different environments.
For instance, in the upper ocean bacteria exist that can use light and in polar regions they must be able to withstand
the cold. In hydrothermal vents – where they provide all the energy for big organisms - they need to stay alive at
350°C.
Studies have found that following the oil spill into the Gulf of Mexico in 2010, bacteria on the gulf beaches were able
to feed – and thrive – on a diet of oil. The oil, although low in the nitrogen bacteria need to function, did provide
them with a rich food source resulting in a population explosion.
One scientist commented that it was surprising how fast they consumed the oil. “In some locations it took only one day
for them to reduce a gallon of oil to a half gallon.”
The bacteria compensated for the lack of nitrogen by getting it from the air – and the enthusiasm with which they took
to consuming the oil is likely to provide valuable insight into future oil spill clean-up techniques.
As Dr Maas says: “These guys can exist in small numbers but when the conditions are right, or they change by getting new
genes, they just go for it.”
She is also studying how climate change affects bacterial processes and what any change to the acidity and temperature
of the ocean might mean in the future.
“We are predicting that less carbon from the upper ocean will get into the deep ocean. More and more is being recycled
in the upper ocean and at the same time producing more carbon dioxide.
When there is less carbon in the deep ocean it affects the organisms in the deep that rely on the carbon as a food
source.
“And with more carbon dioxide in the upper ocean, it adds to the CO2 already absorbed by the ocean and leads to an
increase in ocean acidification. Until we make sure the microbial processes are okay, there will be consequences further
up the food chain.”
So while you’re swimming, surfing or boogie boarding this summer remember that all around you nature’s recycling bin is
busy taking in waste products and dead plant and algae material before returning useful nutrients to the environment.
“The bacteria are very important and we don’t think enough about them,” says Dr Maas. “They really are dealing with
everything no one else wants.”
Bacteria breakdown
• Bacteria are the oldest living organism on earth with evidence going back at least 3.5 billion years.
• The largest known species of bacteria was found in 1999 in the ocean sediments of Namibia where cells were as
large as 0.75mm.
• There are more bacteria in six litres of seawater than people on earth.
• Bacteria decompose dead things as big as whales and as small as other microbes.
• Bacteria can communicate with each other and coordinate their actions.
• Bioluminescent bacteria produce light and can be found in some fish.
• Some bacteria can reach puberty about 10 minutes after birth. That makes them theoretically able to produce one
billion offspring in an afternoon.
• Because they are constantly evolving, the majority of bacterial species remain undiscovered.
• Without marine bacteria, life as we know it would cease to exist.
ends