Aquatic ecosystems can be greatly impacted by changes in atmospheric chemistry caused by emissions associated with human activity (agricultural, industrial, energy, urban, transportation) as well as those related to climate change (such as soot from large-scale wildfires, and dust from increasingly drought-prone regions). We invite scientists who are working in a wide range of aquatic ecosystems that are being impacted by atmospheric deposition to participate in this session. We particularly encourage submissions from scientists who are monitoring atmospheric deposition of nutrients from wet and dry sources, and scientists who are monitoring changes in ecosystem nutrient dynamics and assessing how aquatic organisms are adapting. Submissions related to other types of deposition (mercury, emerging contaminants) and how aquatic ecosystems are adapting to them are also welcomed.
Lead Organizer: Diane Lauritsen, LIMNOSCIENCES (ddlauritsen@comcast.net)
Co-organizers:
Janice Brahney, Utah State University (janice.brahney@usu.edu)
Presentations
02:00 PM
RAPID CHANGES IN A SHALLOW SEEPAGE LAKE IN THE NORTH CAROLINA COASTAL PLAIN (USA): THE INFLUENCES OF ATMOSPHERIC DEPOSITION AND BIG RAINS (8096)
Primary Presenter: Diane Lauritsen, LIMNOSCIENCES (ddlauritsen@comcast.net)
Shallow lakes have large surface area to volume ratios, so atmospheric deposition can be more impactful, and change can be relatively rapid. A small, clear water lake (White Lake, >90% rainwater source) in NC has seen 3x increases in Total Nitrogen since the 1970s, while shallow blackwater lakes in the area have seen 2x increases. Total Phosphorus levels in the lakes have remained generally stable over the same period. A nearby National Atmospheric Deposition Program station has measured a 4x increase in ammonium ion deposition while nitrate/nitrite deposition has declined; rainfall pH has increased 1.5 units. Limited rainfall sampling at White Lake found TP ranging from <2 to 45 mg/L, with TN ranges of 190 to 1350 mg/L; DIN ranged from 14-92% of TN. Benthic zone productivity has been and remains relatively high but variable from year to year; hydrilla was widespread in 2017, when pH levels were elevated, but since 2018 its occurrence has been low, and taxa characteristic of the lake have dominated. There has been a notable change in water column productivity, and a cyanobacterial bloom (Planktolyngbya limnetica) developed in 2017 (causing elevated pH) and persisted over that winter; a P-stripping alum treatment was applied in May 2018 and since then cyanobacterial biovolume has remained <5% of total BV. The present phytoplankton community is very dynamic and diverse and is often dominated by taxa groups such as desmids and picocyanobacteria, and short-duration blooms are often associated with high rainfall.
02:15 PM
TRENDS IN ATMOSPHERIC N DEPOSITION SURROUNDING CLUSTERS OF LARGE ANIMAL FARMS IN THE UNITED STATES (8311)
Primary Presenter: Lorrayne Miralha, The Ohio State University (miralha.1@osu.edu)
We compared the spatiotemporal trends in precipitation NH4 and NO3 between HUC8 watersheds that presented spatial clustering and dispersion patterns of Concentrated Animal Feeding Operations (CAFOs). Nationwide, CAFO-clustered watersheds presented greater concentrations of precipitation NH4 (+100 ug/L) and NO3 (+ 600 ug/L) than CAFO-dispersed watersheds (p< 0.05). This relationship held true principally in Indiana, Oregon, and Pennsylvania for NH4 concentrations. NH4 concentrations increased from 1980 onward in CAFO-clustered watersheds in Pennsylvania while CAFO-dispersed ones presented significant negative temporal trends principally during spring. These seasonal trends may be associated with manure application techniques that vary by state, as well as climate differences. In Wisconsin and Michigan, the concentrations of precipitation NO3 were greater in CAFO-clustered watersheds compared to CAFO-dispersed watersheds. We did not have CAFO-dispersed watershed representation in North Carolina for comparison, but we observed that watersheds with a higher density of CAFOs displayed an increasing trend in NH4 in CAFO-clustered watersheds, while no trend was observed in NH4 for watersheds with lower-density of CAFOs. These spatial and temporal patterns may be used to better understand N deposition dynamics in airsheds and bring insights into the role of CAFOs in freshwater nutrient pollution and harmful algal blooms expansion in the US.
02:30 PM
ATMOSPHERIC DEPOSITION OF PFAS IN THROUGHFALL IN AN URBAN ENVIRONMENT, BRONX, NY (8153)
Primary Presenter: Ashley Smith, U.S Geological Survey (amsmith@usgs.gov)
Per- and polyfluoroalkyl substances (PFAS) are a widely used and persistent class of anthropogenic chemical compounds which are emitted to the atmosphere from numerous sources. Contamination of aquatic and terrestrial environments by PFAS is of great concern for human and ecosystem health; however, documentation of the magnitude and flux of atmospheric PFAS contamination remains sparse. In addition, while several studies have quantified PFAS concentrations and deposition in precipitation, the role of tree canopy in PFAS deposition is not well understood. In collaboration with the National Atmospheric Deposition Program (NADP), the U.S Geological Survey collected throughfall samples from April through November 2023 at the Thain Family Forest in the New York Botanical Gardens (NYBG), Bronx, NY to quantify atmospheric PFAS deposition under a tree canopy within an urban environment. PFAS sample collection and analysis was designed to parallel open-air precipitation samples at an adjacent NADP site (NY06) at the NYBG. Seven throughfall collectors were deployed at the study site and collected weekly. Both individual and pooled samples were analyzed for PFAS compounds, dissolved organic carbon, and major ions by the Wisconsin State Laboratory of Hygiene. From September through November 2023, litterfall was collected and analyzed for mercury and PFAS. Preliminary results show that total PFAS in throughfall is higher than in open-air precipitation. Results will advance our understanding of depositional trends and spatial variability of PFAS deposition fluxes in an urban environment.
02:45 PM
Insights into the Profile of Atmospherically Deposited PFAS: PFAS in Wet Deposition and a Seepage Lake Sediment Core (7861)
Primary Presenter: Samantha McClung, University of Minnesota Duluth (mcclu348@d.umn.edu)
Per- and polyfluoroalkyl substances (PFAS) are a large family of persistent contaminants with diverse and poorly characterized sources. Our understanding of their environmental cycling is improving, but is still quite limited, and the presence of PFAS in environmental media (e.g., sediments, surface water, ice) from remote areas emphasizes the significant gaps in our understanding of the sources, fate, and transport of PFAS. In particular, the importance of atmospheric transport and transformation of PFAS as a pathway into surface hydrologic systems is poorly understood. To investigate the magnitude and profile (fingerprint) of PFAS characteristic of atmospheric deposition, wet deposition (rain and snow) samples were collected from a suite of National Atmospheric Deposition - National Trends Network (NADP-NTN) precipitation monitoring sites around the upper Great Lakes, and analyzed for 37 target PFAS. To further investigate the role of atmospheric deposition as a source of PFAS to terrestrial and aquatic ecosystems, in the Great Lakes region, a sediment core from Loaine lake - a remote Minnesota lake with primarily atmospheric inputs - was age dated and analyzed for target PFAS. This presentation will share initial results from the wet deposition samples and seepage lake sediment core. These preliminary data sets are just one component of a larger effort to constrain PFAS wet-deposition across the Great Lakes.
03:00 PM
POLLEN INFLUX INTO THE LAURENTIAN GREAT LAKES IS A SIGNIFICANT SOURCE OF CARBON (7841)
Primary Presenter: Kathryn Schreiner, University of Minnesota Duluth (kschrein@d.umn.edu)
Pollen deposition is often overlooked as a source of allochthonous carbon and nutrients in lacustrine systems. Although pollen is degradation resistant, it has been shown to provide substantial carbon and nutrient subsidies to communities of aquatic consumers in both saline and freshwater environments. The input of pollen and other allochthonous organic matter (OM) imports to the Laurentian Great Lakes (LGLs) remain a relatively understudied component of the carbon cycle of each lake. As part of the Great Lakes Sediment Surveillance Program, we characterized the chemical composition and source of allochthonous OM across surface sediments of Lakes Superior, Huron, and Ontario. Surface sediments were collected from approximately 30 sites in each lake and analyzed for bulk elemental and stable isotope content as well as lignin-phenol biomarkers using cupric oxide oxidation and gas chromatography-mass spectrometry (GCMS). Lignin-phenol proxy ratios allowed us to trace pollen-derived OM, as pollen is much higher in cinnamyl phenols than other terrestrial OM. These proxies indicated that airborne pollen was a major contributor to offshore sedimentary OM in each lake, while soil and vegetative runoff were major contributors to nearshore sedimentary OM. Previously overlooked aeolian influx of pollen into the LGLs may constitute a significant carbon input, especially in offshore sediments, which in turn has significant potential impacts on our knowledge of carbon and other nutrient sourcing into the LGLs.
03:15 PM
HISTORICAL CHANGES IN TERRIGENOUS ORGANIC MATTER IMPORTS TO THE LAURENTIAN GREAT LAKES (7832)
Primary Presenter: Jake Zunker, University of Minnesota Duluth (zunke018@d.umn.edu)
Lacustrine sediments act as archives that can be used to reconstruct historical changes in the environment. Terrigenous organic matter (OM) that is incorporated into aquatic sediments is relatively stable and provides insights into current and historical conditions of the surrounding watershed. Allochthonous OM imports to the Laurentian Great Lakes (LGLs) are a relatively understudied component of the overall carbon cycle, especially questions surrounding how those carbon inputs have changed over time. As a part of the Great Lakes Sediment Surveillance Program, we have characterized the source of allochthonous OM from a series of sediment cores taken from LGLs Superior, Huron, and Ontario. Sediment cores dating to the early 1800s were collected at three sites in each lake and analyzed for bulk elemental and stable isotope content as well as lignin-phenol biomarkers using cupric oxide oxidation and gas chromatography-mass spectrometry (GCMS). Lignin-phenol proxy ratios in offshore sediment organic matter (SOM) indicate that airborne pollen is a major source of allochthonous SOM in each lake. The effects of urbanization on the watershed and subsequent deforestation were traced as a decrease in pollen input offshore and concomitant “pulses” of soil-derived SOM nearshore. LGLs Huron and Ontario received a larger proportion of their SOM from terrestrial sources than Superior due to differences in watershed to lake surface area and the amount of past human development. These results are the first to show the historical importance of aeolian pollen inputs to multiple LGLs.
SS41 - Airborne: Assessing the Impacts of Atmospheric Deposition on Aquatic Ecosystems
Description
Time: 2:00 PM
Date: 6/6/2024
Room: Meeting Room MN