Pixel Tracker

Saturday, November 17 , 2018, 10:36 pm | Fog/Mist 53º

 
 
 
 
Advice

UCSB Oceanographer Studies Effects of Dispersants on Oil Spills and Indigenous Microbial Communities

UCSB research oceanographer Uta Passow.
UCSB research oceanographer Uta Passow. (Sonia Fernandez / UCSB photo)

When the Deepwater Horizon (DWH) oil rig exploded in the Gulf of Mexico in 2010, scientists knew the fallout would be far-reaching — both geographically and temporally.

What investigators didn’t know until now is that the millions of gallons of chemical dispersants meant to stimulate microbial crude oil degradation in some cases inhibited the microorganisms that naturally degrade hydrocarbons.

A team of marine scientists, led by the University of Georgia and including UC Santa Barbara biological oceanographer Uta Passow, discovered this in laboratory experiments when they mimicked the conditions of the Gulf of Mexico’s deep waters immediately following the DWH oil spill. Their findings appear today in the Proceedings of the National Academy of Sciences.

“This paper shows that the species composition completely changes in the presence of chemical dispersants such as Corexit,” said Passow, a researcher at UCSB’s Marine Science Institute. Corexit works by emulsifying crude oil into minuscule droplets that scatter in seawater.

The study examined microbial oil degradation in the DWH plume by simulating concentrations of oil and dispersant as observed during the incident. The team found that the dispersants significantly altered the microbial composition of gulf deep water by promoting the growth of Colwellia, a group of microorganisms themselves capable of dispersant degradation.

However, when oil alone was added to parallel samples in the absence of chemical dispersants, the growth of natural hydrocarbon-degrading Marinobacter was stimulated.

During the spill, Passow noted, Marinobacter were not abundant in deep water plume samples, possibly as a consequence of dispersant applications. Study results demonstrate that the naturally occurring communities of oil-degrading microorganisms — particularly Marinobacter — are quite proficient at degrading oil and are even more so in the absence of chemical dispersants.

“Although the most stunning result is obviously that Corexit impacted bacterial composition, and thus oil degradation, the results on marine oil snow production in the different treatments are very intriguing as well,” said Passow, an expert on marine snow, a naturally occurring formation of aggregated oil and organic matter.

“It appears that the formation of microbial oil snow is much more complex than we initially thought,” she added. “Not only do different bacteria lead to different types of marine snow, but nutrients and the type of oil addition matter as well. Still, there is much we need to learn about the formation of marine snow in the presence of oil.”

This research was supported by the Ecosystem Impacts of Oil and Gas Inputs to the Gulf (ECOGIG) research consortium, which is funded by the Gulf of Mexico Research Initiative

Julie Cohen is a science writer for the UCSB Office of Public Affairs and Communications.

 

Support Noozhawk Today

You are an important ally in our mission to deliver clear, objective, high-quality professional news reporting for Santa Barbara, Goleta and the rest of Santa Barbara County. Join the Hawks Club today to help keep Noozhawk soaring.

We offer four membership levels: $5 a month, $10 a month, $25 a month or $1 a week. Payments can be made using a credit card, Apple Pay or Google Pay, or click here for information on recurring credit-card payments and a mailing address for checks.

Thank you for your vital support.

Become a Noozhawk Supporter

First name
Last name
Email
Select your monthly membership
Or choose an annual membership
×

Payment Information

Membership Subscription

You are enrolling in . Thank you for joining the Hawks Club.

Payment Method

Pay by Credit Card:

Mastercard, Visa, American Express, Discover
One click only, please!

Pay with Apple Pay or Google Pay:

Noozhawk partners with Stripe to provide secure invoicing and payments processing.
You may cancel your membership at any time by sending an email to .(JavaScript must be enabled to view this email address).

  • Ask
  • Vote
  • Investigate
  • Answer

Noozhawk Asks: What’s Your Question?

Welcome to Noozhawk Asks, a new feature in which you ask the questions, you help decide what Noozhawk investigates, and you work with us to find the answers.

Here’s how it works: You share your questions with us in the nearby box. In some cases, we may work with you to find the answers. In others, we may ask you to vote on your top choices to help us narrow the scope. And we’ll be regularly asking you for your feedback on a specific issue or topic.

We also expect to work together with the reader who asked the winning questions to find the answer together. Noozhawk’s objective is to come at questions from a place of curiosity and openness, and we believe a transparent collaboration is the key to achieve it.

The results of our investigation will be published here in this Noozhawk Asks section. Once or twice a month, we plan to do a review of what was asked and answered.

Thanks for asking!

Click Here to Get Started >

Reader Comments

Noozhawk is no longer accepting reader comments on our articles. Click here for the announcement. Readers are instead invited to submit letters to the editor by emailing them to [email protected]. Please provide your full name and community, as well as contact information for verification purposes only.