Hi! My name is Francisco Spaulding-Astudillo, and I’ve been working with Dr. Beth Orcutt this summer on a project related to crude oil degradation in marine environments at Bigelow Laboratory for Ocean Science. At my home institution – The University of Chicago – I am enrolled as a Geophysical Sciences major and Creative Writing minor. I was first introduced to the exciting world of marine research when I took a geophysics course on mid-ocean ridges, the moving underwater mountain systems that are responsible for seafloor spreading. I was most interested in how the geology of deep-sea marine environments – especially, mid-ocean ridges – changes over time. That’s when I tangentially discovered the immense role that biology plays in altering the geochemistry of the earth. “Microorganisms impacting the environment” is a story we’ve all heard before; of course, I’d never actually discounted it, but I’d also never entirely considered them as a major driving force of geological change. Only a couple months after my rediscovery of microorganisms, I was drawn to the research Dr. Orcutt conducts at Bigelow Laboratory.
Dr. Orcutt specializes in an area of research known as geomicrobiology. In her study of microorganisms, she inspects a variety of marine environments, from sediments deep beneath the ocean floor to frozen Arctic lakes. The microorganisms found in these environments directly mediate the geochemistry there in remarkable ways. My project, in particular, seeks to elaborate on the primary biochemical pathways microorganisms use to break down their food in different environments.
The microorganisms that I’m studying eat, or degrade, crude oil. More specifically, they degrade hydrocarbons – compounds composed primarily of hydrogen and carbon. In doing so, they gain the energy necessary to fuel their other metabolic functions. Many of the hydrocarbons they eat are toxic and carcinogenic, and not at all the kinds of things we want floating around the environment. Nevertheless, hundreds of millions of tons of crude oil enter the marine environment every year via anthropogenic and natural means.
So, where is all this crude oil going? Most importantly, what is the ultimate fate of hydrocarbons in the marine environment?
We can’t answer this grand question all at once, but we can diagnose at least part of the riddle. Through the investigative research and lab work I’m doing this summer, I will help define:
- Which microorganisms break down hydrocarbons across a variety of marine environments
- Which hydrocarbon degradation pathways are potentially being used in each environment
We’ll tackle the first question by coupling bioinformatics with empirical data from past experiments. In these experiments, samples were collected from four different sites in North America: the Beaufort Sea, Gulf of Alaska, Portland Habor, and the Gulf of Mexico. Each sample was treated to a suite of variable conditions – e.g. oil or no oil, cold or warm, aerobic or anaerobic, etc. The purpose of these experiments was to monitor the changes in the microbial community over time in response to crude oil exposure. From the 16s rRNA data collected then, I am compiling a log that represents the most abundant microorganisms in each microbial community.
The REU student from that year also looked at which hydrocarbons in particular were degraded in each sample. Cross referencing their hydrocarbon degradation data with fluctuations in the microbial population helps tell us which microorganisms might be involved in crude oil degradation.
To answer the second question, I read literature for genes involved in two very specific types of hydrocarbon degradation – long chain n-alkanes and polycyclic aromatic hydrocarbons. Several genes have been used in the past as biomarkers, or biological evidence, for each type of hydrocarbon degradation. In these papers, accomplished scientists have designed primers, or tests, for locating the genes suspected to be involved in hydrocarbon degradation within a variety of microorganisms. Essentially, if the gene is present in an organism’s DNA, we know that the organism has the potential for metabolizing hydrocarbons.
The next step for this research is to conclude our site-specific analysis of each environment and take away the following information:
- Organism X is eating Hydrocarbon Y and using Degradation Pathway Z at Site 1
- Organism A is eating Hydrocarbon B and using Degradation Pathway C at Site 2
With this knowledge, we can better predict how long it would take for an oil-polluted environment to recover. Additionally, this research may contribute significantly to the development of more effective bioremediation treatments, a form of waste-removal that uses microorganisms to break down environmental contaminants.
Louisiana (USA). May 6th, 2010. A ship cuts through a band of oil on the surface of the water. Asubstantial layer of oily sediment stretches for dozens of miles in all directions from the wellhead, suggesting that a large amount of oil did not evaporate or dissipate, but may have instead settled to the seafloor. Photo by Daniel Beltra for Greenpeace
My overall experience in Maine and at the Bigelow Laboratory has been fantastic. Evenings spent at Ocean Point are chilly, but lovely. I’ve also become attached to the Opera House in Boothbay Harbor, where Bigelow puts on the weekly Café Sci seminars; it’s some of the best entertainment around. After my summer at Bigelow, I hope to end up in Marine Science.