Phytoplankton blooms help scientists understand warming oceans

Humpback whales feed on phytoplankton

Thanks to some ingenious new measurement technology created by the Woods Hole Oceanographic Institution (WHOI), we can get accurate, up-to-date measurements of the phytoplankton Synechococcus, a bacterium that is a key species in some marine ecosystems. Because of this, for example, we’ve learned that this species has been blooming earlier in the year when the water is warmer. Unfortunately, that might be a bad sign.

Over the last 13 years of studying the phytoplankton, ocean temperatures have been rising. Since it is getting warmer earlier, Synechococcus is blooming earlier and faster. Because it is so important to the ecosystem, this might seem like a good thing initially, because it could mean more food. However, the organisms that directly consume the phytoplankton are keeping up with it. For now.

“That was a surprise to us,” says WHOI biologist Heidi Sosik, who initiated the study. “We didn’t expect such a tight lockstep between Synechococcus and consumers as the spring bloom changed.”

“The question is, ‘how stable is that balance?’” says Kristen Hunter-Cevera, lead author of the paper. “In the future, will consumers be able to keep up? A mismatch is a huge concern. If the bloom expands, or moves earlier in the year, higher-level organisms that expect to feed on those consumers at a certain time of year might miss them entirely.”

If there is a positive take-away from this news, it’s the techniques used in the study. They could be applicable to studies done in the world’s other oceans. Ocean observatories are being built off the Atlantic and Pacific coasts of the U.S., and WHOI’s monitoring equipment may be deployed there.

It’s a good thing too that we know more about how warming oceans are affecting marine life, as that can inform future studies and future environmental efforts.

The latter will be especially important, as warming oceans are already having a negative impact on the environment.