Similar but Different - The Microbial Communities of the North and South Poles

In a report last week from an international team of scientists lead by Dr. Alison Murray of the Desert Research Institute, there is a significant difference between the marine microbial communities of the seemingly similar Arctic and Antarctic oceans.  These two areas are as geographically far apart as can be, yet share very similar environmental features. Together they offer a unique opportunity to gain insight on the factors that effect biodiversity and biogeography.   Put more simply, we have a better idea of what lives in these similar areas, and why.  

This study focused on differences in bacterioplankton diversity, between the two regions.  They found that 78% of the microbial population in the Antarctic Ocean was genetically unique to itself while the Arctic has a 70% unique microbial population.   The team of scientists posits that these similar but markedly different areas may exhibit such different microbial biodiversity because of differences in fresh water sourcing between the two areas.  In the Southern Ocean, glacial melt-water accounts for most of the fresh water that flows into the marine system.  In the Arctic, there is some glacial melt water but also fresh water river systems with huge drainage basins that deposit fresh water into the system. 

Dr. Murray and her team specifically compared samples from coastal and open oceans and between winter and summer seasons.  These factors allow the scientists to investigate and compare how environmental conditions and dispersal patterns may shape the two polar marine microbial communities. 

As Dr. Murray points out, now that they’ve identified that there is such a difference in the microbial populations of these two zones, “further research is still needed to address the ecological and evolutionary processes that underlie these unique patterns.” 

This brings to mind the fact that the polar regions are more sensitive than the rest of the planet to the earth’s increasing levels of CO₂. It would be interesting to see how microbial populations in the polar regions may change over time, and whether that change can be linked to increased levels of CO₂ in the atmosphere.