North Carolina’s coastal region is a continuum of riverine, estuarine, coastal and oceanic ecosystems that includes the USA’s second largest estuarine complex, the Albemarle-Pamlico Sound system, bounded by the Outer Banks, the Gulf Stream and W. Atlantic Shelf. The NC coast is located at a biogeographic boundary; the intersection of the Gulf Stream and the Labrador current; the leading edge for tropical animals and plants and the trailing edge of temperate species on front line of climate change. These ecosystems are at the interface of human impacted eutrophication, habitat loss and global climatic changes taking place, including warming, sea-level rise and a recent (since the mid 1990’s) upsurge in tropical cyclones (36 at last count), interspersed by more episodic and record-breaking extra-tropical rainfall and major drought events. The rapid rise in these events and trends have had major hydrologic, geologic, biogeochemical, trophic, human health and societal impacts, the combined effect being a major research and management challenge in a rapidly changing structural and functional coastal landscape. In particular, shifting coastal development trends place increased pressures on wastewater, stormwater, and groundwater sources, with profound effects on loading, delivery and effects of nutrients, chemical and microbial contaminants. In this session, we encourage contributions from diverse disciplines (and their interactions) addressing these challenges. Furthermore, we would like to highlight the utilization of new technologies, such as autonomous sensors and rapid contaminant quantification tools, as we aim to understand the ramifications for North Carolina and similarly-impacted coastal regions on larger regional and global scales.
Lead Organizer: Hans Paerl, UNC-Chapel Hill, Institute of Marine Sciences (hpaerl@email.unc.edu)
Co-organizers:
W. Judson Kenworthy, Scientific and Technical Advisory Committee, Albemarle National Estuary Partnership (jud.kenworthy@gmail.com)
Rachel Noble, UNC-Chapel Hill, Institute of Marine Sciences (rtnoble@email.unc.edu)
Reide Corbett, East Carolina University, Coastal Studies Institute (corbettd@ecu.edu)
Presentations
09:00 AM
Biogeochemical and ecological impacts of ~30 years of elevated tropical cyclone activity on North Carolina’s estuarine and coastal waters (9143)
Primary Presenter: Hans Paerl, University of North Carolina - Chapel Hill (hans_paerl@unc.edu)
Coastal North Carolina has experienced 39 tropical cyclones (TCs), including three floods of historical significance since the mid-1990’s (Hurricanes Floyd-1999, Matthew-2016 and Florence-2018). These events caused catastrophic flooding and major alterations of water quality, fisheries habitat and ecological conditions of the Albemarle-Pamlico Sound (APS), the second largest estuarine complex in the USA. Continuous rainfall records for coastal NC since 1898 reveal a period of unprecedented high precipitation storm events since the late-1990s. Six of seven of the wettest storm events occurred in the past two decades. We examined storm-related freshwater discharge, carbon (C) and nutrient, i.e., nitrogen (N) and phosphorus (P) loadings, and evaluated contributions to total annual inputs in the Neuse River Estuary (NRE), a major sub-estuary of the APS. These contributions were highly significant, accounting for >50% of annual nutrient loads. Depending on the magnitude of freshwater discharge, the NRE either acted as a “processor” partially assimilating/metabolizing loads or as a “pipeline” transporting loads to the APS and coastal ocean. Storm discharge events followed by dry periods supported eutrophication, algal bloom events and hypoxia. Event-scale discharge plays an important and, at times, predominant role in C, N and P loadings. We have entered a new climatic regime characterized by more frequent extreme precipitation events, with major ramifications for hydrology, C, N and P cycling, water quality and habitat conditions in NC estuarine and coastal waters.
09:15 AM
ADVANCING THE USE OF REMOTE SENSING TO MEASURE WATER QUALITY AND DETECT SAV AND MARSH HABITAT IN CURRITUCK SOUND (9213)
Primary Presenter: Peggy Mullin, University of North Carolina at Chapel Hill (peggy.mullin1@gmail.com)
In North Carolina (NC), there is a pressing need to understand and quantify dynamics of both salt marshes and communities of submerged aquatic vegetation (SAV), vital habitats increasingly threatened by the effects of climate change. Water quality decline threatens SAV, as these species depend on sufficient water quality for survival. The concurrent presence and absence of SAV and marsh habitat is of interest in Currituck Sound, an oligohaline NC estuary that holds significant ecological and economic value and has exhibited a marked decline in both marsh and SAV area in recent years (Audubon NC, 2021). Recent advances in remote sensing offer an opportunity to explore associated trends in water quality and marsh/SAV presence or absence using both traditional ground-based methods and innovative remote sensing tools to inform coastal management. This work has three aims: to investigate remote sensing measurement of CDOM, to investigate remote sensing identification of SAV presence/absence, and to quantify a relationship between SAV presence/absence and oligohaline marsh habitat change. By investigating these methods and relationships, this work will inform future management of coastal habitat on large spatial and temporal scales, while providing insights into the habitat dynamics of oligohaline environments.
09:30 AM
IMPACTS OF MODERATE TO EXTREME STORM EVENTS ON MICROBIAL PLANKTON IN A LARGE TEMPERATE NORTH CAROLINA ESTUARY. (9252)
Primary Presenter: Ryan W. Paerl, NC State University (rpaerl@ncsu.edu)
Microbial plankton (prokaryotes, eukaryotes) have important roles in food webs, biogeochemical cycling, and altering the health of coastal ecosystems. Storms, and a lack thereof, are of increasing concern regarding their links to climate change as well as their future regional-dependent intensity and frequency. In North Carolina (NC), wetter conditions are predicted and furthermore much of the state is vulnerable to extreme storms such as cyclones – which are also predicted to increase in frequency and intensity. Recently, we found within the Neuse River Estuary (NRE) – a major component of the larger Albemarle-Pamlico Sound System- small phytoplankton (picophytoplankton, cells <3 µm in diameter) composition and biomass are significantly altered by moderate to extreme storms (Hurricane Florence). Here we expand on that analysis to investigate how abundances of other microbial populations (e.g. bacterioplankton) and the metabolic potential of the microbial community are impacted by storms. Time series sampling in collaboration with the MODMON program (UNC-CH) and flow cytometry, PCR amplicon sequencing, and metagenomic analyses were employed to assess storm impacts as well as broader trends within the NRE (since 2017). Dispersal of populations pre/post storm is of particular interest – especially ‘cryptic’ species or poorly studied cyanobacterial populations that may impact ecosystem health or function. Last, NRE data will be compared to similar datasets from other coastal systems impacted by storms (e.g. cyclones) to investigate if similar consequences emerge from moderate to extreme storms in temperate regions.
09:45 AM
ANTIMICROBIAL RESISTANCE AND THE STRESS OF CLIMATE CHANGE-DRIVEN COASTAL FLOODING ON WASTEWATER SYSTEMS (9257)
Primary Presenter: Emma Dempsey, UNC Chapel Hill (edemps@ad.unc.edu)
Antimicrobial resistance (AMR) is an intensifying public health concern demanding a One Health research approach, considering zoonotic reservoirs and bacterial pathogenesis. Our research indicates that coastal municipalities with wastewater treatment plants (WWTPs) are likely discharging antimicrobial-resistant bacteria (ARB) and genes (ARGs) into estuaries, threatening recreational and fisheries services. NC WWTPs are overburdened by aging infrastructure, tourism, and development, leading to increased fecal contamination in estuaries, exacerbated by climate change. By leveraging an active NC wastewater surveillance program, we have optimized methods to test for clinically relevant ARGs in influent, effluent, and environmental water samples. To further our understanding of AMR risks, influent samples are collected weekly from five coastal, rural WWTPs serving 600-8,000 people. Additionally, differences in ARG/ARB trends are being characterized by a longitudinal influent-effluent study, comparing microbial communities across the disinfection process using weekly and adaptive collection under varying conditions (storms, floods, King Tides), resulting in 30 distinct events and over 180 samples. Metagenomic sequencing is also being used to identify AMR groups for the development of a ddPCR panel. This assessment of WWTPs under various climate change-driven conditions will be a key step in understanding current and future AMR risks.
10:00 AM
INCORPORATING UNOCCUPIED AERIAL SYSTEM DATA INTO COASTAL MONITORING AND RESTORATION (9759)
Primary Presenter: Rachael Cronin, University of North Carolina (rlouise@ad.unc.edu)
The marshes of North Carolina provide valuable ecosystem services, including habitat for imperiled migratory birds, mitigating damage from storm surge, and contributing to water quality. The Carolina Drone Lab at UNC Chapel Hill, in partnership with North Carolina Audubon and Elizabeth City State University, uses unoccupied aerial systems (UAS) to characterize marsh resilience and monitor change through time in the marshes in Currituck Sound, NC. Collected RGB and multispectral imagery is analyzed in tandem with ground-level observations to characterize vegetative communities, habitat types, and marsh edge retreat. UAS-derived digital elevation models and high-precision GPS datasets are also used to track changes in marsh elevation to identify areas most vulnerable to fragmentation and inundation from sea-level rise - allowing coastal managers to prioritize restoration and management efforts. UASs offer finer spatial and temporal resolution imagery than satellite and plane-collected imagery, capturing site-specific changes that are of most interest to project managers. The wide variety of available drone platform types, sensors, and data collection methods gives researchers and managers the freedom to customize approaches to meet their specific research and monitoring goals. UAS can serve as efficient and strategic tools to enhance restoration efforts in North Carolina’s marshes, helping strengthen coastal resilience.
10:15 AM
Long-Term Analysis of Gulf Stream Variability at Cape Hatteras Using High-Frequency Radar Surface Current Observations (9459)
Primary Presenter: Yubeen Jeong, University of North Carolina - Chapel Hill (ybjeong@unc.edu)
Long-range high-frequency radar observations collected offshore of Cape Hatteras, North Carolina, can play a pivotal role in monitoring the Gulf Stream (GS) separation point and orientation angle. We present an analysis of the long-term variation of the GS, using radar-measured ocean surface currents for 18 years at three coastal sites: Duck, Buxton, and the Core Banks of NC (DUCK, HATY, CORE). This is the first measurement program to obtain an hourly, high-resolution GS time history spanning decades, documenting the spatial and temporal variability of the GS at various time scales. A consistent database has been created by reprocessing all existing radar observations from these sites. We here focus on monthly and longer temporal variability, utilizing the month-averaged radial component of surface velocity to extract the Gulf Stream’s separation location, path, and speed. Using high-frequency data spanning nearly two decades, this study demonstrates the GS’s long-term variability, particularly in relation to climate-driven changes, including shifts in ocean circulation, and coastal sea level rise. Our analysis reveals significant offshore and nearshore shifts in GS position, with major offshore displacements observed in 2010 and 2019. Additionally, changes in orientation angle, especially near Cape Hatteras, suggest variations of GS transport, which have implications for regional sea levels and coastal ecosystems. These findings highlight the importance of long-term monitoring for assessing the resilience of North Carolina’s coastal ecosystems to ongoing climatic changes.
SS45 - North Carolina’s coast at the doorstep of climate change
Description
Time: 9:00 AM
Date: 29/3/2025
Room: W205CD