Hans W. Paerl is Kenan Professor of Marine and Environmental Sciences at the UNC-Chapel Hill Institute of Marine Sciences in Morehead City. He studies phytoplankton and nutrients, important factors that dictate water quality, in coastal waters, estuaries, and lakes. His research includes microbially-mediated nutrient cycling and primary production dynamics of aquatic ecosystems, environmental controls of harmful algal blooms and assessing the causes and consequences of man-made and climatic (storms, floods) nutrient enrichment and hydrologic alterations of inland, estuarine and coastal waters. His studies have identified the importance and ecological impacts of land-based and atmospheric nitrogen inputs on estuarine and coastal eutrophication and harmful algal blooms. He is examining the impacts of increasing frequencies and intensities of tropical cyclones and extra-tropical storms and their floodwaters on the resiliency and sustainability of coastal ecosystems using microbial and biogeochemical indicators of aquatic ecosystem condition and change.
Paerl leads the Neuse River Estuary Modeling and Monitoring Program, ModMon, and ferry-based water quality monitoring program, FerryMon, which employs environmental sensors and various microbial indicators to assess near real-time ecological condition of the Pamlico Sound System, the second-largest estuarine complex in the U.S. and key southeast fisheries nursery.
Industry Expertise (3)
Areas of Expertise (17)
Harmful Algal Blooms
Fellow of the American Geophysical Union (professional)
The Fellows program recognizes AGU members annually who have made exceptional contributions to Earth and space sciences as valued by their peers and vetted by a committee of Fellows. The Fellows program serves to meet the need for identified authorities who could advise, upon request, the various government agencies and other organizations outside the Earth and space sciences.
Odum Award (professional)
Awarded by the Coastal and Estuarine Research Federation, the Odum Award recognizes the lifetime achievements of an outstanding estuarine scientist whose sustained accomplishments have made important contributions to the understanding of estuaries and coastal ecosystems.
G. Evelyn Hutchinson Award (professional)
Awarded by the Association for the Sciences of Limnology and Oceanography, the G. Evelyn Hutchinson Award has been presented annually since 1982 to recognize excellence in any aspect of limnology or oceanography.
University of California: Ph.D., Ecology-Limnology 1973
University of California: B.S., Biological Sciences 1969
College of San Mateo: B.A., Biology-Biochemistry 1967
- American Association for the Advancement of Science
- American Society Limnology and Oceanography
- Phycological Society of America
- Ecological Society of America
Media Appearances (6)
Lessons from Dorian: UNC hurricane expert warns storms are ‘getting wetter and more frequent’
WRAL TechWire online
Citing data accumulated since 1898, the researchers noted that six of the “highest precipitation events” such as hurricanes and tropical storms have taken place over the last 20 years – including hurricanes Floyd (1999), Matthew (2016) and Florence (2018). It’s still unclear where Hurricane Dorian ranks on that scale, but Paerl is determined to find out.
What Parents Need to Know About Blue-Green Algae Poisoning
Blue-green algae is commonly found in lakes and ponds. The tiny organisms that make up blue-green algae—also called cyanobacteria—are billions of years old, says Hans W. Paerl, Kenan Professor of Marine and Environmental Sciences at the UNC-Chapel Hill Institute of Marine Sciences in Morehead City.
North Carolina tropical cyclone-driven coastal flooding is worsening with climate change, population growth
UNC-Chapel Hill online
“North Carolina has one of the highest impact zones of tropical cyclones in the world, and we have these carefully kept records that shows us that the last 20 years of precipitation events have been off the charts,” said Hans Paerl, Kenan Professor of Marine and Environmental Sciences at the UNC-Chapel Hill Institute of Marine Sciences.
Uncharted waters ahead for Albemarle’s returning algae blooms
North Carolina Health News online
Paerl began his work in North Carolina in 1978. The first big project he worked on was figuring out how [to] control blooms in the Albemarle. “They were having pretty large blooms like they’re having now that were causing problems,” Paerl said. “Not only this issue of surface scum but also toxicity associated with the blooms.”
Why coastal Carolina may never recover from its intensifying hurricanes
For the last 24 years, Hans Paerl has been a guardian for water quality along North Carolina’s coast. As part of his duties as a marine scientist at the University of North Carolina-Chapel Hill, Paerl oversees two projects that monitor the Albemarle-Pamlico Sound system, which is the second-largest estuary in the United States behind the Chesapeake Bay.
Hurricanes and water quality
UNC-Chapel Hill Well Said Podcast radio
Once hurricanes subsides and waters return to their normal height, another risk lurks: pollutants in the watershed. Carolina researcher Hans Paerl has spent decades understanding the environmental side effects of the powerful storms.
Recent increase in catastrophic tropical cyclone flooding in coastal North Carolina, USA: Long-term observations suggest a regime shiftScientific Reports
Hans W. Paerl, Nathan S. Hall, Alexandria G. Hounshell, Richard A. Luettich Jr., Karen L. Rossignol, Christopher L. Osburn, Jerad Bales
Examination of continuous rainfall records for coastal NC since 1898 reveals a period of unprecedentedly high precipitation since the late-1990’s, and a trend toward increasingly high precipitation associated with tropical cyclones over the last 120 years.
Extreme weather events modulate processing and export of dissolved organic carbon in the Neuse River Estuary, NCEstuarine, Coastal and Shelf Science
Alexandria G. Hounshell, Jacob C. Rudolph, Bryce R. Van Dam, Nathan S. Hall, Christopher L. Osburn, Hans W. Paerl
Following such extreme weather events, the estuary acts as a pipeline for direct export of terrestrial dissolved organic carbon, drastically altering the amount and quality of dissolved organic carbon loaded to downstream coastal systems. This has important implications under future climate scenarios, where extreme weather events are expected to increase.
CO2 limited conditions favor cyanobacteria in a hypereutrophic lake: An empirical and theoretical stable isotope studyLimnology & Oceanography
Bryce R. Van Dam, Craig Tobias, Andreas Holbach, Hans W. Paerl, Guangwei Zhu
We propose that the ability of many cyanobacteria to access otherwise limiting pools of inorganic C is intrinsically linked with their capacity to cope with CO2 limiting conditions, and may be a key factor in their dominance during harmful algal blooms.
Two decades of tropical cyclone impacts on North Carolina’s estuarine carbon, nutrient and phytoplankton dynamics: implications for biogeochemical cycling and water quality in a stormier worldBiogeochemistry
Hans W. Paerl, Joseph R. Crosswell, Bryce Van Dam, Nathan S. Hall, Karen L. Rossignol, Christopher L. Osburn, Alexandria G. Hounshell, Randolph S. Sloup, Lawrence W. Harding Jr.
Nutrient loading and flushing jointly influenced spatio-temporal patterns of phytoplankton biomass and composition. These findings suggest the importance of incorporating freshwater discharge and C dynamics in nutrient management strategies for coastal ecosystems likely to experience a stormier future.
Mitigating cyanobacterial harmful algal blooms in aquatic ecosystems impacted by climate change and anthropogenic nutrients (Review)Harmful Algae
Hans W. Paerl, Wayne S. Gardner, Karl E. Havens, Alan R. Joyner, Mark J. McCarthy, Silvia E. Newell, Boqiang Qine, J. Thad Scott
Here we examine the suite of current mitigation strategies and the potential options for adapting and optimizing them in a world facing increasing human population pressure and climate change.
Nutrient limitation dynamics examined on a multi-annual scale in Lake Taihu, China: implications for controlling eutrophication and harmful algal bloomsJournal of Freshwater Ecology
2015 From 2008 to 2013, a series of in situ microcosm and mesocosm nutrient addition bioassays were conducted that were focused on the heavily polluted northern region (i.e., Meiliang Bay) and other lake locations.