Published on April 1st, 2010 | by Steve Savage1
The Genetics of Climate Change: Part 2
As I described in an earlier post, I was privileged to attend a DOE-sponsored scientific meeting last week about how the fast-moving science of “Genomics” is being applied to issues related to climate change. This was a meeting of scientists who are using state-of-the-art genetic technology, and in this post I’ll talk about how they are using that to better understand complex biological systems that really matter for climate change.
One of the reasons that public belief in the reality of Climate Change is eroding is that we cannot be very certain about how all of this will play out. Scientists are used the dealing with uncertainty. The public and the politicians are not. That is something that can, and has been exploited by economic and political forces with reasons to oppose the logical responses to climate change.
One major source of this uncertainty has to do with the vast biological activity that occurs in the oceans. What we do know is that organisms in the oceans have a huge impact on global greenhouse gas levels and that they “buffer” the world from change to some extent. Unfortunately we don’t know nearly enough about these complex biological systems because a great many of them are things that can’t be grown and studied in the lab and/or they function as interlocked communities. How these systems will influence, and be influenced by Climate Change is probably one of the most important questions before us.
Fortunately, “genomics” and the related field of “metagenomics” are beginning to unlock some of the secrets of these gigantic and critical global buffering systems. I’d like to share what I learned about this at the JGI meeting.
Plankton in the Shallow Ocean
For instance, Alexandra Worden of the Monterey Bay Aquarium Research Institute explained that the “plankton” in the oceans do around 1/2 of all the “primary production” on earth – they use photosynthesis to accomplish around 50 gigatons of carbon fixation/year. Much of this is being done by “picoeukaryotes” which are tiny organisms about which we know very little. Genetic profiles from ocean samples have now shown us that the most abundant organism on the planet that can turn sunlight into usable chemical energy (photosynthesis) is a little cyanobacterium called Prochlorococcus. Using genetic tools we can now start to track the fate of this and other key organisms to see whether they can help mediate climate change or whether their critical role in the global carbon balance is being compromised.
Organisms in the “Oxygen Minimum Zones” of the Deep Ocean
Steve Hallam of the University of British Columbia spoke about how he and his colleagues are using “time-resolved metagenomics” technology to probe the poorly understood, but huge biological communities that populate the “Oxygen Minimum Zones” (OMZ) in the intermediate and deep oceans (this is a natural phenomenon different from the “dead zone” at a place like the mouth of the Mississippi river which is a shallow water issue). These organisms are too deep to be involved in photosynthesis, but they are critical for trace greenhouse gas cycling (methane, nitrous oxide) and what they do in response to climate change is hugely important. They could potentially help or they could tip the balance the wrong way. Is the OMZ expanding, contracting, intensifying? It matters! Fortunately, the tools of genomics are making it possible to begin to understand what is happening in this critical biological system in a way that was never possible before.
Organisms Near the Ocean Floor
Victoria Orphan of CalTech talked about how she and her cooperators are using advanced genetic tools to understand a “consortia” of organisms that grow near the ocean floor that use methane as an energy source and combine it with sulfur and also do a bit of “nitrogen fixation.” The balance of this system is also important for “Climate Change,” and it can now be studied in greater detail.
Viruses Matter Too
Finally, there was a talk by Forest Rohwer of San Diego State University about the viruses that are involved in the dynamics of organisms in coral reefs and the open ocean. He presented data from tracking genetic sequences that showed how dynamic the interaction was between the viruses and their hosts.Actually, it turns out that certain cyanobacterial communities that are important for atmospheric carbon flux do more of that because their viruses always keep changing which species is growing the fastest and which are in decline. He called it the “kill the winner” phenomenon. If we are going to understand the biological systems that influence climate change, we also must understand the interaction with their “predators.” In this case, tracking genes is the only way to do that.
The climate of earth is an incredibly complex system and much of that complexity comes from the biological side. The best hope we have of unraveling the biology comes from the fact that all living things (and even their viral parasites) can be studied based on their DNA – a universal code across all biological entities. I’m not saying we have the answers, but the technology explosion in this area is making it possible to ask and answer questions that were never before feasible.
I’m really glad that there is DOE money going into these important fields. This is an excellent example of where public funding for basic science is a very good thing.
(I’m sending a link to all these authors to make sure I haven’t misinterpreted their talks, so I reserve the right to edit this post)
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DNA image from Tony Atkin