Scientist-Educator Collaborative Workshop
What Role Do Microbes Play in the Carbon Cycle?
Held at the Darling Marine Center in Walpole, ME
Friday, November 22, 2008 through Saturday, November 23, 2008
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Original concept map created by Michael Sieracki
Digital concept map created in the COSEE Concept Map Builder
Consensus concept map created using the COSEE-OS Concept Map Builder
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Presentation Videos & Maps

About this Workshop:
For this workshop, 14 educators from the New England area were matched with ocean and climate scientists from the University of Maine to improve their collective understanding of how the ocean can impact climate change. [more]

About this Scientist:
Michael Sieracki studies marine microplankton and their ocean ecosystems using advanced technologies that can record activities and sizes of individual plankton microbes. [more]
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Who Worked on this Concept Map
Paul McGuinness
Margo Murphy
Susan Richman
Michael Sieracki
Scientist Michael Sieracki explains the concept map and its development:

The challenge in concept mapping for me was to simplify my topic enough for the target audience (e.g., college freshman with no marine science background), but also remain scientifically accurate. I chose to focus on an oceanic process called the "biological pump", a component of the global carbon cycle that is included in all ocean carbon models, but it is really a model itself. The biological pump represents how we believe that organisms, microbial plankton in particular, can affect the flow of carbon in the ocean. To begin, I recalled first time I saw the biological pump model, almost 20 years ago. Even though scientists have added details over time, it is still a good general model upon which I have "mapped" my own research ideas.

I chose to divide my "For Educators" map into sectors divided by horizontal and vertical lines. Above the horizontal line is the upper layer of the ocean that interacts directly with the atmosphere. Below this line is the deeper ocean that doesn't interact directly with the atmosphere, except on very long time scales. The vertical line represents a divide in the size of phytoplankton and how they affect carbon flow in the upper ocean. To the left of the vertical line, large phytoplankton fuel the "traditional food web." To the right of the line, small phytoplankton fuel the recently discovered "microbial loop" which includes micrograzers, bacteria, viruses and DOC (Dissolved Organic Carbon).

On the right side of the map, I added two labels -- "Slow" and "Fast" -- to show that there are different speeds for carbon to return to the atmosphere after uptake by marine biological organisms. The "Slow" path (left of vertical line) represents carbon uptake and flow through the traditional food web. This includes biomass sinking to the deep ocean - e.g., as "marine snow" or "fecal pellets" - where it will likely not return to the atmosphere for a long time. The "slow process" has a net removal of carbon from the atmosphere - often described as carbon being "pumped" down to the deeper layers. The "Fast" path (right of vertical line) represents carbon uptake and flow through small phytoplankton and the microbial loop. This includes fast-growing microbes and quick respiration of carbon dioxide that can remain in the upper ocean and eventually return to the atmosphere. It is believed that this "fast process" results in no net removal of atmospheric carbon. My own research is focused on determining the conditions that favor either of these pathways - i.e., traditional food web vs. the microbial loop -- and how they affect, or are being affected by, climate change.

The workshop educators and I streamlined my original map, both in terms of vocabulary and linking lines. In our "Group Final Map," we chose to keep the bold lines separating the ocean layers (horizontal) and sizes of phytoplankton (vertical). We also added more detail to the food webs. We emphasized the important role of dissolved organic carbon (DOC): just about all organisms produce DOC, some bacteria consume it, and its production enhances the microbial loop. We added the concept of "sedimentation" but also agreed that - for high school students -- it could be augmented by another concept map for "carbon sequestration" that would emphasize sinking and burial.
View All Concept Maps Created at this Workshop
Concept map