Cold no curb on appetite

Sep 11, 2013

Living in a low temperature environment does not affect bacteria's appetite for hydrocarbons, according to recent research. This new knowledge could affect environmental risk assessment in the Arctic.

Many people have expressed environmental concerns as the offshore petroleum industry moves further north, citing fears about the consequences of possible pollution in icy seas

Water temperature plays a key role in this type of , both for the behaviour of spilt hydrocarbons and for the speed at which toxins in the are broken down naturally.

Findings in a recent doctoral thesis at the University of Stavanger may lead to changes in such risk assessments.

New method

Experiments carried out by doctoral research fellow Andrea Bagi show that Arctic bacteria "eat" the oil component naphthalene just as quickly as their counterparts further south, provided they get necessary nutrients.

Similar trials conducted earlier have involved cooling down North Sea water, adding oil and seeing how long degradation takes. The results clearly show that the bacteria consume more slowly.

Bagi has taken a different tack by sourcing her both off south-west Norway and north of the Arctic Svalbard islands.

Different properties

These specimens have been contaminated with naphthalene, an important (and toxic) crude oil component, and tested at 0.5°C, 4°C, 8°C and 15°C.

Environmental toxins turned out to be broken down just as rapidly in the water taken from the Arctic as in the North Sea sample, even at low temperatures.

The explanation is actually fairly simple – the bacterial flora found off Svalbard has different properties than the forms found off Stavanger.

Adjusted bacteria

"Bacteria in these two sea areas are adjusted to their respective environments," observes Bagi. "They thereby manage to do the same job under differing conditions."

Her PhD supervisor, associate professor Roald Kommedal, admits to being a little surprised when she reported these results.

"We expected to see some effect from the environmental adjustment, but not that natural breakdown would be just as fast as in warmer waters," he says.

Eaten by enzymes

Bacterial degradation is one of the most important mechanisms for natural removal of hydrocarbons from the marine environment. Many oil spills have proved less damaging than feared because nature itself cleaned them up to some extent.

That is because the seas contain a multitude of bacterial types. Some produce enzymes which can convert hydrocarbons to food by turning sticky oil into carbon dioxide.

Bagi emphasises that she has only researched a single component (naphthalene) and that bacterial action is only one of several factors involved when assessing the risk of Arctic oil spills.

New understanding

Her work could nevertheless have consequences for Oil Spill Contingency And Response (OSCAR), the main model used for on the Norwegian continental shelf. This is based on the old understanding of temperature effects.

Kommedal hopes to secure backing for further research with a larger number of crude oil components and different types of seawater.

"Oil operations in the Arctic are a political hot potato, and many people have strong views on this issue," he points out. "That makes it all the more important to learn as much as possible."

Andrea Bagi defended her PhD thesis at the Faculty of Science and Technology on June 20th.

Explore further: Two-armed control of ATR, a master regulator of the DNA damage checkpoint

More information: Estimation of hydrocarbon biodegradation rates in marine environments: A critical review of the Q10 approach, Marine Environmental Research, vol. 89, August 2013, DOI: 10.1016/j.marenvres.2013.05.005

Naphthalene biodegradation in temperate and arctic marine microcosms, Biodegradation, April 2013, DOI: 10.1007/s10532-013-9644-3

add to favorites email to friend print save as pdf

Related Stories

Magnetic rocks aid oil exploration

Jul 03, 2013

A new study has pinpointed the relationship between oil reservoirs and magnetic rocks, which could lead to more accurate oil exploration.

Greenpeace says Russia denies it Arctic access

Aug 21, 2013

Greenpeace said Wednesday that Russia had denied its ship access to Russian Arctic waters to hide the extent of its lucrative energy exploration work in the fragile ecosystem.

Recommended for you

Japanese scientist resigns over stem cell scandal

Dec 19, 2014

A researcher embroiled in a fabrication scandal that has rocked Japan's scientific establishment said Friday she would resign after failing to reproduce results of what was once billed as a ground-breaking study on ...

'Hairclip' protein mechanism explained

Dec 18, 2014

Research led by the Teichmann group on the Wellcome Genome Campus has identified a fundamental mechanism for controlling protein function. Published in the journal Science, the discovery has wide-ranging implications for bi ...

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.