Yesterday we welcomed another new Research Technician to our team, Lily Goerlitz! Lily received her BS in Oceanography from the University of Miami in 2022 and comes to us from the Mote Marine Laboratory where she worked as an Ocean Acidification Intern! We are excited to have you!
The Paerl Lab is back in the Bay Delta, CA this week, and the 2023 California Bioassay is well underway!
Haley Plaas and Leah Nelson are working to continue Haley’s dissertation research which focuses on assessing the linkage between nutrient enrichment, phytoplankton community composition, cyanobacterial harmful algal bloom toxin production, and aerosol formation in the San Francisco Bay Delta Estuarine ecosystem. This research has been accomplished by completing a combination of aerosol measurements and nutrient addition bioassay experiments.
Despite a few minor hiccups, everything is going great. Haley and Leah have had lots of help from our awesome interns, Cheyenne and Deborah!
The aerosol samplers are all up and running now at both Discovery Bay and Stockton and the bioassay experiment will be completed tomorrow. We look forward to seeing the results from both the bioassay and aerosol samples! We will be sure to keep you updated as we analyze the data in the weeks to come.
Thanks for all your help, Cheyenne and Deborah, as well as to all of our collaborators at CA-DWR, USGS, and Restore the Delta (and more)!
The Paerl Lab welcomes another new intern, Caroline Lorio, this week! There will be lots of new faces around the lab this summer. Caroline is currently pursuing her undergraduate degree in Biology and Environmental Science at UNC – Chapel Hill. We are so excited to work with you!
Hi all,
The winter and early spring saw flows that were always below normal and usually only about half of the seasonal norm. That changed starting on 10 April when flows began to rapidly increase. By the time of sampling 19 April, flows peaked at nearly twice the seasonal norm. Dumping that much freshwater into a really salty estuary caused very strong salinity based stratification with surface to bottom salinity differences of ~15 in the upper estuary from station 30 to station 120 and ~10 further downstream. Bottom waters were cool (< 15 C) and certainly the low temperatures helped prevent bottom water hypoxia. High turbidity (>10 NTU) flood water penetrated downstream to station 60 and turbidity was < 5 NTU throughout the rest of the estuary. A large mid-estuary chlorophyll maximum (> 20 ug/L) was observed from station 60 to 140 and was concentrated vertically just above the pycnocline at ~1.5 m depth. Microscopic examination of station 100 surface water revealed that small solitary centric diatoms and chain-forming centric diatoms were the dominant taxa. There was a relatively high concentration (~1000 cells/mL) of the toxic dinoflagellate, Karlodinium veneficum. Although 1000 cells/mL is higher than normal, Karlodinium doesn’t usually cause fish kills until the concentrations reach about 10,000 cells/mL.
-Nathan
This week the Paerl Lab welcomes Jack Cheshire, a new technician, and Elizabeth Norris, a new intern! Jack comes to us from NC State, where he received his B.S. in Ecology, Evolution and Conservation Biology in May 2023. Elizabeth is currently pursuing a B.S. in Marine Biology at UNCW. We are excited to work with you!
Elizabeth Norris – egnorris@unc.edu
Jack Cheshire – jcheshi@unc.edu
Hi all,
Despite a few rain events, river flows in late March and the first few days of April were still only about half their seasonal norm. The recent freshwater inputs lowered surface salinity values to less than 2 upstream of station 70. The tip of the salt wedge was still upstream of New Bern and bottom waters of the lower estuary were still greater than 20. The estuary was strongly stratified with vertical salinity differences greater than ~5 and temperature differences greater than ~3 C along most of the estuary. A small zone of very salty and hypoxic water occurred at the very bottom at station 160 and likely resulted from saltwater intrusion from the intercoastal waterway. A subsurface maximum of chlorophyll up to ~ 30 ug/L occurred along the pycnocline from station 50 to 160. No samples were collected at these depths to determine the dominant organisms but previous sampling events found an ongoing bloom of the dinoflagellate, Prorocentrum minimum, which has been commonly observed to form subsurface maxima. Turbidity was < 5 NTU except for at the head of the estuary where river inputs had turbidity of ~ 10 NTU.
Best,
Nathan
Are you interested in working with the Paerl Lab at UNC Institute of Marine Sciences?
We have a Research Technician position available! This position is temporary with the possibility of becoming permanent. We are seeking an enthusiastic individual with an interest in water quality research. Includes opportunities to conduct fieldwork across North Carolina and in other US locations!
Application deadline is 5/23/2023
Link to apply: https://unc.peopleadmin.com/postings/255583
Hi all,
Not much has changed since the last report. A spring cold front cooled temperatures by about 5 degrees and now temperature are near their seasonal norm. River flow has been low all March at about half its seasonal norm. Salinity at the mouth was about 17 at the surface and above 20 at the bottom. The tip of the salt wedge is still upstream of New Bern (station 30). Supersaturated oxygen levels at stations 60 and 70 were produced by a dense surface bloom (chl > 40) at those stations. The bloom extended upstream as a subsurface bloom to above station 50. I looked at station 60 under the microscope and saw a near monoculture of the dinoflagellate Prorocentrum minimum, the same dinoflagellate species that’s been blooming in this region of the Neuse for the past two months. Colleagues, Drs. Rick Stumpf and Alexandria Hounshell, at NOAAs National Centers for Coastal Ocean Science have provided us a bird’s eye view of bloom with their chlorophyll a product derived from Copernicus Sentinel-3 satelite imagery. It shows the highly concentrated nature of the bloom with maximum biomass just where the estuary starts to widen and residence time increases. It also shows an extension of the bloom along the north shore of the estuary down stream to Beard Cr. P. minimum hasn’t been associated with fish kills or toxin production. If history is a good predictor, the P. minimum bloom will be gone in the next few weeks. The satellite derived chlorophyll also shows other co-occurring blooms in the Pamlico River, Pungo River, and on Lake Mattamuskeet. I wouldn’t be surprised if the Pamlico River and Pungo River blooms were also P. minimum. I’ve sampled Mattamuskeet recently and its bloom is a 50:50 mix of diatoms and cyanobacteria.
Best,
Nathan
Hi all,
Late winter has been unusually warm and water temperatures in the estuary are about 5 C warmer than normal. High salinity conditions are still in place with salinity near 20 at the estuary mouth. The tip of the salt wedge is still upstream of New Bern. No hypoxic bottom waters were observed. Super saturated oxygen conditions were observed near the surface at station 60 where high chlorophyll (>40 ug/L) indicated a bloom. The intense surface bloom at station 60 was part of a broad region with high (~25 ug/L) subsurface chlorophyll that stretched from station 50 to 120. Microscopic examination of station 60 surface water revealed a mix of the winter/spring bloom forming dinoflagellate, Prorocentrum minimum, and a Euglena sp. These are the same two species that were found blooming in the same area in February. Neither is thought to be problematic in regards to toxins and fish kills.
Best,
Nathan
Come work with the Paerl lab at UNC Chapel Hill’s Institute of Marine Sciences.
We have 2 research technician positions available. These positions are temporary with the possibility of becoming permanent. We are seeking enthusiastic individuals with an interest in water quality research.
Includes opportunities to conduct fieldwork across North Carolina and in other US locations!
Application deadline is 03/30/2023.
Links to apply below:
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