Revealing the Identity of

Oil-Degrading Microorganisms

at Deepwater Horizon….and a little more

Overview

1. Deepwater Horizon oil spill in the GoM. Where did most of the oil go? Who’s responsible?

2. On the formation of ‘Oily Snot’ during DWH spill.

3. FISH’n for oil-degrading bacteria.

4. Knowns and Unknowns about the DWH spill.

Deepwater Horizon Mucondo well site

B Incubation of sample on labeled 13C PAHs

Whole DNAextract

DNAAssimilation of labelby active microbes

“ light ”

“ heavy ”

- PCR of 16S rRNA- Cloning- Sequencing

A

OH

COO-

O

Uniformly-labeled 13C Naphthalene

trans-2-hydroxy-benzylidenepyruvate

Degradation Further metabolism

Incorporation of the 13C atoms into cellular biomass

(e.g. DNA)

“ Heavy ” DNA

Identifying Who Degraded the Oil by Stable-Isotope Probing (SIP)

Gutierrez, T. (2011) Rev Environ Sci Bio/Technol.

10 mmP

erc

en

t c

ha

ng

e

-100

0

100

200

300

400

500

7

0 0

2

PE5

B6 B11

B1

What about that ‘Oily Snot’

Polymer concentration (mg/mL)

0.0 0.2 0.4 0.6 0.8 1.0

Hyd

roca

rbo

n c

on

cen

trat

ion

(m

g/L

)

0

10

20

30

40

50 A

FISH’n for Oil-Degrading Bacteria

G-T-G-C-C-G-C-T-A-T-C-G-A-A-T-T-C-G

( Fluorescence In Situ Hybridization )

Alpha-proteobacteria associated with Pseudonitzschia diatom

Probes used: EUB-Cy5 / Alpha-Cy3

Marinobacter (green) + DAPI (blue)Marinobacter (green/yellow)

vs. others (red)

Beginning of enrichment 4 days later

Gulf of Mexico Plume Water Enriched with Oil

Overview about the DWH Oil Spill: a microbial perspective

Knowns:- Mobility / Fate of the oil- Bacteria largely responsible in ultimate removal of the oil- The types of bacteria that dominated and were likely responsible for degrading much of the oil- We know that all of the oil is now gone from the water column; but residual oil remains in the sediment.

Not-So-Well Knowns:- Detail on the microbial response and succession of this response over the course of the spill- What diversity of bacteria contributed, and by how much? What was their function?

Acknowledgements

Colleagues/Collaborators• Prof. Mike Aitken (UNC, Chapel Hill)• Prof. Andreas Teske (UNC, Chapel Hill)• Dr. Kirk Semple (Univ. Lancaster)• Dr. Alexander Loy (Univ. Vienna, Austria)• Luke McKay (UNC, Chapel Hill)• Tingting Yang (UNC, Chapel Hill)• Sara Mishamandani (UNC, Chapel Hill)

Funders• European Commission (Marie Curie Programme)• NSF Rapid Response Grant• UNC fellowship program