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CyanoHAB video

Dr. Paerl & Haley Plaas (PhD candidate) worked with collaborators in UNC’s visual communications master’s program to create this video explaining the importance of CyanoHAB research. Haley’s work in the Paerl lab at UNC-IMS will work towards preventing the expansion of harmful algal blooms to protect  people, pets, wildlife, and our environment.


Hans W. Paerl presentation at 2019 Vernberg Lecture

Dr. Paerl  presented the keynote address, “Mitigating harmful cyanobacterial blooms in a hotter, hydrologically more-extreme world,” for the 2019 Winona B. Vernberg Distinguished Lecture Series on Wednesday, November 13, 2019. Dr. Paerl discussed the importance of continued research of harmful algal bloom management on the Neuse River with environmental health and fisheries management staff as well as academics from North and South Carolina at an invited seminar at the University of South Carolina.

Check out the YouTube video linked above to watch the full presentation

Neuse River Estuary Conditions 27 October 2020

Hi all,

The fish kill that started in late September was still occurring on 27 October. Dying and dead peanut sized (~3″) menhaden were observed from station 70 to station 100. This area seems to be where most of the fish kill activity has been observed. Many of the fish had sores consistent with infection by the water mold, Aphanomyces invadans. In the fish kill zone, water temperatures near 20C and salinities of 5 or less are optimal for growth of A. invadans.

The estuary was highly stratified from New Bern to station 160 and hypoxic bottom waters extended downstream to station 160. Anoxic conditions, indicated by the smell of sulfide, occurred at station 50 through 100. Anoxia is unusual but occasionally occurs during the hottest, calmest periods of the summer when there is moderately high river flow. I don’t recall ever seeing anoxic conditions this late in the season. High chlorophyll a levels were observed near the surface from stations 60 to 160.

Surface waters from station 70 were observed microscopically. The bloom was primarily dominated by the dinoflagellate Gyrodinium instriatum which is not known to be toxic or cause fish kills. Lesser cell densities of the potentially harmful raphidophyte, Heterosigma akashiwo, were also observed. While Heterosigma akashiwo has been repeatedly associated with fish kills in other estuaries, this fall is the first time I am aware of that it has been associated with a fish kill in NC waters. I strongly caution that this association does not imply that H. akashiwo was responsible for the fish kills.

State funding for ModMon has expired. ModMon monitoring activities and these associated reports will be suspended while we pursue other funding options. 

Stay well,


Clean Waters and SAV: Making the Connection

Dr. Hans Paerl and Dr. Nathan Hall discussed the Status of NC’s estuarine water quality yesterday at the Clean Waters and SAV (submerged aquatic vegetation) workshop. Their presentations focused on existing and developing water quality management strategies, past and present estuarine water quality challenges, and water quality monitoring and assessment. Their participation in this workshop helped provide input for the NC Coastal Habitat Protection Plan revision to develop collaborative management strategies to preserve and improve water quality suitable for SAV growth in NC coastal waters. Click the links below to view their presentations.

Paerl SAV Conference presentation

New Decade, Neuse Blooms

Happy New Year.
The Neuse has kicked off the new decade with an impressive bloom of Prorocentrum minimum. We saw the beginnings of this bloom a month ago in December but it’s a lot more dense now. The surface water at station 100 was actually scummy (see attached photo taken by Melissa LaCroce) and the YSI measured 200 ug/L chl-a at 0.3 m depth. The bloom extended throughout the water column at station 100. Upstream to station 50, the bloom was concentrated just below the surface, and downstream at station 120 the bloom was concentrated along the pycnocline. Subsurface aggregations are really common for Prorocentrum minimum, but in my experience such dense surface scums are less common. However, there is a nice photo from an airplane of a Neuse River P. minimum bloom in Springer et al. (Harmful Algae 2005). P. minimum is not know to be toxic, and despite the high biomass levels there aren’t reports of problems associated with these blooms (e.g. hypoxia, fish kills, etc.). While we await further laboratory measurements, I think it’s safe to assume that such high biomass levels are at least partly the result of physical concentration of highly motile cells along a frontal zone.  Other than the bloom, the river is about 4-6 degrees warmer than normal for this time of year. The river is also quite salty with salinity near 20 at throughout the water column at the lower stations.
Best regards,

Hans Talks About HABs

Dr. Hans Paerl spoke with EOS about a new harmful algal bloom study showing that HABs are getting worse with climate change. Click the photo below to read the article or here for the pdf.

2009 HAB on Lake Erie

Photo Credit: NOAA Great Lakes Environmental Research Laboratory

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