A conversation with "Ocean Outbreak" author Drew Harvell

When Cornell University ecologist Drew Harvell wrote her book "Ocean Outbreak," she couldn't have known that 2020 would be the year of COVID-19. But even as people around the world grapple with the effects of that disease, scientists are keeping watch on potential disasters from viruses and other pathogens for species in the world's oceans. As the oceans warm due to climate change, scientists expect incidences of disease to increase in marine ecosystems including the Salish Sea. We asked Harvell about her new book and the need to address this rising challenge.

Ocean Outbreak" cover courtesy of University of California Press.
Ocean Outbreak" cover courtesy of University of California Press.

EoPS: Right now, the topics of disease and the coronavirus are on everyone’s mind. Can disease have the same effect on the ecosystem as it does on human populations?

Drew Harvell: You know, it’s very similar. I call myself a disease ecologist, and that’s essentially the quantitative study of how diseases act and how they outbreak, what the resistance factors are and how they are transmitted. We really study the same parameters whether it is a human coronavirus that’s newly emerging or whether it’s a new virus in a sea star. We’re interested in how rapidly a disease spreads, how resistant are the hosts, what are the environmental factors that govern the spread rates of these diseases.

EoPS: Is disease ecology a new field in science?

DH: I would say it’s not new to be studying the environmental causes and consequences of disease, but we do have new tools. We are able to study it with a little bit more control and quantitative perspective than perhaps we could have 20 years ago.

EoPS: Are there new environmental factors that are increasing the outbreaks of disease in the ecosystem? Your book talks a lot about the impact of climate change, for example.

DH: Yes.  I think here in our waters in Puget Sound and into the Salish Sea, we’re caught a bit in a vice grip. One arm is rapid climate change -- our waters are warming and they’re becoming more acidified. At the same time, we’re piling on human population. Those two factors act synergistically, and both put a lot of stress on our marine ecosystem. Both factors contribute to an increasing risk of disease as well as other problems with sustainable ecosystems.

EoPS: I think you said in your book something to the effect of ‘warmer seas are sicker seas.’

DH: That is actually a quote from a paper that we published in 2002 in Science where we said a warmer world is a sicker world. We talked about this across the board, whether it is in the ocean, or agricultural systems or whether it is with human disease. Of course, not all diseases are temperature sensitive, but in general warmer conditions can create more stress for a host. They also create higher replication rates for lots of infectious microorganisms. In the case of humans, that can also increase some of the vectors like mosquitos which have a wider range under warmer conditions.

EoPS: With climate change and disease high on the radar, what are people trying to do in response?

DH: Well, we’d really like to see political change and see a slowing of our carbon dioxide emissions. It’s certainly very worrisome to me that we are not really slowing it down enough. In the absence of that, surveillance is vital. Fortunately, we have NOAA, which does phenomenal satellite remote sensing. They provide us with minute by minute temperature forecasts that we can use to forecast and ground truth [ocean conditions]. I think we need to work much harder to improve our diagnostics for marine disease so we’re in a better place where we really can pick up these rapidly expanding diseases.

I think everybody is very impressed — shocked and amazed — at the pace and the unexpectedness of the coronavirus outbreak. But you have to realize that things like that happen in the ocean too.


"Ocean Outbreak" is published by University of California Press. Drew Harvell is a Professor of Marine Ecology at Cornell University and an affiliate faculty member at the University of Washington School of Aquatic and Fishery Sciences where she conducts research at Friday Harbor Laboratories. 

Related articles:

Warming oceans fuel viruses among species in the Salish Sea

Virus related to measles could push Puget Sound orcas to extinction, study says

About the Author: 
Jeff Rice is the managing editor of the Encyclopedia of Puget Sound.