Paerl Lab Photo

The Paerl Lab took a lab photo last week in front of IMS’s brand-new mural!

Pictured from left to right:

Back Row

Maxfield Palmer, Hans Paerl, Jeremy Braddy, Haley Plaas, Nathan Hall, Mingying Chuo

Front Row

Madison Sholes, Alex Sabo, Karen Rossignol, Leah Nelson, Randy Sloup 

The Hall Lab, who we often collaborate on projects with, also got a lab photo.

Pictured from left to right: Maxfield Palmer, Nathan Hall, Mingying Chuo

Investigating Associations between Air and Water Quality in Eastern North Carolina

This past week PhD student Haley Plaas and intern Madison Sholes deployed PurpleAir Sensors at pre-established sites along the Chowan River, where Cyanobacterial Harmful Algal Blooms (CHABs) are known to occur. In recent years, communities in northeastern North Carolina surrounding the Chowan River and Albemarle Sound have faced degraded water and air quality tied to a suite of environmental issues, including increased incidences of toxin-producing harmful algal blooms. Previous work done by Plaas et al. found that several aquatic cyanobacterial genera were detected in sampled particulate matter (PM), including two toxin-producing strains, Dolichospermum and Microcystis. These findings suggested a need for further research on the link between HABs and HAPs, i.e., the presence of Harmful Air Pollutants, in this region. The goal of this project is to investigate the association between indicators of CHABs and corresponding PM mass concentrations via the deployment of several PurpleAir sensors throughout the Chowan River and Albemarle Sound basin.

Haley and Madison deploying sensors in the field:


Photos taken by: Tom Brennan

Research in the Bay Delta, CA

The Paerl Lab was in the Bay Delta, California last week to kick off Haley Plaas’ PhD thesis research, which focuses on assessing the linkage between nutrient enrichment, phytoplankton community composition, cyanobacterial harmful algal bloom toxin production, and aerosol formation in the Sacramento-San Joaquin River/Bay Delta estuarine ecosystem. Research Technician, Leah Nelson, accompanied Haley to California where they met up with Seyong, who is one of the Paerl Lab’s summer interns. The bioassay went off without a hitch! We saw surface scums of cyanos at both of our sample locations, Discovery Bay and Stockton. Upon filtering toward the end of the week it appeared as if the P and N+P treatments responded the most, suggesting P limitation at both sites. Early aerosol findings showed Microcystis and other cyanobacterial cells collected from the air. The data will tell us soon, so stay tuned! We want to thank our collaborators at CA-DWR, USGS, and Restore the Delta (and more)!


Lake Erie Research – June 2022

Over the past week, members of the Paerl Lab were busy at Lake Erie in Put-In-Bay, Ohio as part of a research project called the Lake Erie Center for the Great Lakes and Human Health Project supported by the National Institutes of Health (NIH) and the National Science Foundation (NSF).

The Paerl Lab partners with Justin Chaffin of the F. T. Stone Laboratory Ohio Sea Grant School of Environment and Natural Resources at Ohio State University as well as Chris Ward who is a professor at Bowling Green State University, and his students. Hans Paerl, Karen Rossignol and Randy Sloup were accompanied by Madison Sholes, our Scientific Communication Intern, to collect samples and conduct a bioassay. While at Lake Erie, Hans also gave a talk about eutrophication to students and faculty at the Stone Lab. We are excited to go back to Lake Erie in August to conduct another bioassay for this project! Thank you to all of our scientific collaborators which make this research possible!

Neuse River Estuary Conditions 15 June, 2022

Hi all,

As I’m sure you’re all aware, it’s still really dry. The Neuse River flow is less than half its seasonal norm. Salinity is still high along the estuary and salinity is >20 in the surface waters near the mouth. The tip of the salt wedge is still upstream of New Bern. The estuary is moderately stratified with surface to bottom salinity differences of ~8 at station 30 to ~ 2 at station 180. Warm bottom water temperatures (> 25 C) and stratification promoted hypoxia (< 2 mg/L) from stations 30 to 120 and even the lower stations had bottom water DO < 4 mg/L. A small subsurface maximum of chlorophyll a occurred along the pycnocline at ~ 1.5 m depth at stations 30 and 50. Microscopic examination of station 50 surface water revealed a phytoplankton community dominated by the summer bloom forming dinoflagellate, Levandarina fissa (formerly known as Gyrodinium instriatum). Its not known to produce toxins and hasn’t been associated with fish kills.


Neuse River Estuary conditions 31 May, 2022

Hi all,

We finally got some rain in the basin on 26 May that sent river flows to nearly twice their seasonal norm. On May 31, the estuary was still really salty though. The salt wedge was upstream of New Bern and bottom water at New Bern (station 30) was ~ 10. Surface salinity at the mouth of the estuary was ~20. Water temperatures ranged from low 20s C in the bottom waters to nearly 30 C at the surface. The strong temperature gradient reinforced the vertical density gradient caused by salinity. Surface to bottom salinity differences ranged from about 10 upstream to 2 at the mouth. Hypoxic bottom water conditions were observed from the tip of the salt wedge at station 30 downstream to station 160. A subsurface zone of elevated chlorophyll (~40 ug/L) occurred at ~ 1 m depth at station 50. Microscopic observation of station 50 surface water indicated the phytoplankton community was dominated by small centric diatoms and cryptophytes. Generally, both small centric diatoms and cryptophytes are highly edible fuel for the estuarine food web. Elevated turbidity (15-20 NTU) at the freshwater head of the estuary is indicative of the elevated discharge conditions.


Neuse River Estuary conditions 17 May, 2022

Hi all,

Conditions on 17 May 2022 were very similar to the previous sampling in April. The estuary is very salty with surface salinity almost 20 at the mouth. The tip of the salt wedge was upstream of New Bern which usually only happens during summer and fall drought. The estuary was normoxic with the exception of near the tip of the salt wedge at station 30 where dissolved oxygen was low < 4 mg/L but still sufficient for most estuarine fish. A small zone of elevated chlorophyll a (~25 ug/L) was observed at station 50. Microscopic analyses showed dominance by small centric diatoms and a few cryptophytes.


Neuse River Estuary conditions 5 April, 2022

River flow has been below normal for most of the spring but there were some high flows in late March. On April 5, the upper estuary was freshened by those high flows with surface salinity < 5 downstream to station 70. Surface salinity at the mouth was ~18 which is unusually salty for spring. Despite cool water temperatures (< 20 C), low bottom water dissolved oxygen (< 4 mg/L) was observed in the upper estuary at stations 30 and 50 and within the high salinity intrusion of bottom water from the intercoastal waterway at station 160.

A subsurface zone of high chlorophyll a was observed along the pycnocline at ~ 2 m depth at stations 60 and 70. Microscopic analysis of surface water from station 60 showed a mixed bag of spring dinoflagellates, Prorocentrum minimum, Heterocapsa rotundata, Heterocapsa triquetra, small centric diatoms, and cryptophytes. These dominant species are not known to produce toxins. Karlodinium veneficum, a toxic fish killing dinoflagellate, was present in low numbers. Turbidity was highest (8-10 NTU) at the head of the estuary. Throughout the rest of the estuary turbidity mainly ranged from 2-3 NTU except at stations 60 and 70 within the zone of high phytoplankton biomass where turbidity was ~5 NTU.


Welcome Madison!

The Paerl Lab welcomes Madison as our Science Communication Intern for the summer of 2022! Madison is a rising junior at NC State studying marine science. She will be assisting Haley in disseminating scientific information to the public, especially regarding Asphyxiation by Algae. Welcome Madison!

Neuse River Monitoring

Last week, Jeremy, Alex, and Madison conducted biweekly water quality monitoring on the Neuse River! Jeremy is using a Multiparameter Water Quality Sonde to collect data on the water at each station. This instrument records information such as salinity, pH, temperature and in-situ Chl a concentrations. Alex is collecting water samples for filtering and further analysis back at the lab.

Photos by our Science Communication Intern, Madison Sholes!

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