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:
Hi all,
The Neuse River basin had several significant rainfall events prior to the 7 February sampling event and salinity in the upper estuary responded strongly. Surface salinity was < 5 downstream to station 60 and the tip of the salt wedge was between stations 20 and 30. Salinity in the lower estuary dropped about 5 units since January also. The freshwater pulse also caused high turbidity (>10 NTU) at the head of the estuary. Temperature was seasonably cool (8-10 C). Dissolved oxygen was well above levels required for the health of fish and other animals. However, the bottom water dissolved oxygen at station 30 was atypically low (~ 5 mg/L) for this time of year. Strong suppression of mixing caused by the > 10 salinity difference from the surface to bottom layer led to the oxygen sag even though respiration rates were surely very slow in at such cold water temperatures. A localized surface bloom at station 60 was caused primarily by very high densities of a Euglena sp. and secondarily by the dinoflagellate, Prorocentrum minimum. Neither have been linked to fish kills or other toxicity issues in North Carolina.
-Nathan
The Delta Science Program would like to share that the 2022 edition of the State of Bay-Delta Science (SBDS) is now online in the latest issue of San Francisco Estuary and Watershed Science. Seven articles comprise the issue, summarizing the scientific understanding, or “the state of the science,” of plants and algae in the Bay-Delta. Individual articles explore important ecosystem services and disservices, including primary production, the ecology and management of aquatic vegetation, remote sensing methods, harmful algal blooms, and carbon sequestration and subsidence reversal.
Visit the SBDS website to learn more about this ongoing synthesis effort.
Interagency Ecological Program
IEP@wildlife.ca.gov | 2109 Arch Airport Road, Stockton, CA 95206
To learn more about the work that we are doing through ModMon and FerryMon please view our 2022 updates contained in the flyers below!
Hi all,
Here’s an update on the conditions during the first trip in 2023. The estuary was still extremely salty with surface salinity near the mouth well above 20. An oyster farmer friend measured a salinity of 28 in a creek near Bay River. We did have a little rain associated with a strong Christmas time cold front. The salt wedge still extends upstream of New Bern but higher flows have pushed the salt wedge downstream of Streets Ferry Bridge. The water is seasonably cold, < 10C. Dissolved oxygen conditions were normoxic throughout the estuary. Elevated turbidity (>10 NTU) at the head of the estuary likely resulted from higher flows. A subsurface chlorophyll maximum extended from station 30 to station 120 at ~1.5 m depth. Examination of station 50 surface water revealed numerous Prorocentrum minimum cells. Prorocentrum minimum is a shade adapted species that commonly forms subsurface maxima at low light levels. I bet that the observed subsurface chl-a maximum is the beginning of the nearly annual late winter/early spring bloom of Prorocentrum minimum. P. minimum isn’t known to produce toxins/ kill fish but it has been shown to cause problems with oysters. Fortunately, the area where it tends to bloom is too fresh for oysters anyway. The crew plans to be out again later this week and we’ll see how the bloom’s developed.
Best,
Nathan
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