AUSTIN (KXAN) — 8 million years of global cooling pushed plankton toward the warmer waters of the tropics where they help sustain various fish population and the surrounding ecosystem. Now, as that gradual cooling gets undone more rapidly by a warming climate and waters that are now too warm, plankton are being forced poleward. This could have the potential for significant impacts to the tropics, where the plankton are leaving and the latitudes, where the plankton are heading.

KXAN Meteorologist Nick Bannin spoke with Dr. Adam Woodhouse, a scientist at UT Austin at the Institute for Geophysics, who helped lead the study recently published in Nature, that documented this migration.

Meteorologist Nick Bannin: Adam Woodhouse joins us, a postdoctoral fellow at UTs Institute for Geophysics. Adam, you were part of a study about the impacts of ocean warming and how it’s impacting tropical plankton. What were your findings?

Dr. Adam Woodhouse, postdoctural fellow at UT Institute for Geophysics: So what we did is we looked back into the fossil record and what we’ve noticed is that over the last 8 million years or so, these plankton communities have actually migrated towards the equator to the equivalent of around 2000 miles or 3200 kilometers. So what we see from that is that the structure of the the vertical structure of the ocean has changed over time and that says the Earth has been cooling and this cooling has been a very slow and gradual process. And why that’s interesting is that if our current trends that we’re estimating are going to continue, then those structural changes, which took a long time, and it took these organisms, these plankton in particular, a very long time to adapt to them. If we suddenly snap back to a world from 8 million years ago {of warmer waters}, we can’t predict what kind of changes that will have on these communities.

Bannin: What were you able to determine as far as seeing a decrease in plankton in the tropical ocean? What would that do to the ecosystem there?

Dr. Woodhouse: So, why this is important, specifically to humanity, is that in the modern ocean, where we have these plankton communities, at the same time, we can have matching communities in higher levels of the food chain, such as tuna, billfish, squid, and krill. And of course, these organisms are organisms, which billions of people around the globe tend to rely on, especially within these low latitude coastal communities. So, if we do revert back to one of these warmer worlds from say, 8 million years ago, in a very fast time, we may expect that these organisms as well as the plankton will move away from the equator again, as things are warming up.

Bannin: Now, as the plankton move poleward they are then moving into places that either don’t have as many plankton or don’t have any at all, what would that do to those areas?

Dr. Woodhouse: So within those areas, we may then be kind of having a species invasion. This could be disrupting the ecosystems and habitats of these, or other organisms, which may be located further from the equator causing more disruptions.