Papers by Karen Johannesson
Applied Geochemistry, Mar 1, 2023
AGU Fall Meeting Abstracts, Dec 1, 2008
Rare earth element (REE) concentrations were analyzed in surface water and submarine groundwater ... more Rare earth element (REE) concentrations were analyzed in surface water and submarine groundwater within the Pettaquamscutt Estuary, located on the western edge of Narragansett Bay in Rhode Island. These water samples were collected along the salinity gradient of the estuary. Rare earth element concentrations in the majority of the groundwater samples are substantially higher than their concentrations in the surface waters. In particular, Nd concentrations in groundwater range from 0.43 nmol kg -1 up to 198 nmol kg -1 (mean ± SD = 42.1 ± 87.2 nmol kg -1 ), whereas Nd concentrations range between 259 pmol kg -1 and 649 pmol kg -1 (mean ± SD = 421 ± 149 pmol kg -1 ) in surface waters from the estuary, which is, on average, 100 fold lower than Nd in the groundwaters. Groundwater samples all exhibit broadly similar middle REE (MREE) enriched shalenormalized REE patterns, despite the wide variation in pH of these natural waters (4.87 ≤ pH ≤ 8.13). The similarity of the shale-normalized REE patterns across the observed pH range suggests that weathering of accessory minerals, such as apatite, and/or precipitation of LREE enriched secondary phosphate minerals controls groundwater REE concentrations and fractionation patterns. More specifically, geochemical mixing models suggest that the REE fractionation patterns of the surface waters may be controlled by REE phosphate mineral precipitation during the mixing of groundwater and stream water with incoming water from the Rhode Island Sound. The estimated SGD (Submarine Groundwater Discharge) of Nd to the Pettaquamscutt Estuary is 26 ± 11 mmol Nd day -1 , which is in reasonable agreement with the Nd flux of the primary surface water source to the estuary, the Gilbert Stuart Stream (i.e., 36 mmol day -1 ), and of the same order of magnitude for a site in Florida.
AGU Fall Meeting Abstracts, Dec 1, 2013
Science of The Total Environment, Dec 1, 2022
Sedimentology, Jul 18, 2011
... reactions occurring during REE transport to the oceans in rivers and estuaries (Ronov et al.,... more ... reactions occurring during REE transport to the oceans in rivers and estuaries (Ronov et al., 1967; Nesbitt, 1979; Duddy, 1980; Hoyle et al ... Bau, M., Alexander, B., Chesley, JT, Dilski, P. and Brantley, SL (2004) Mineral dissolution in the Cape Cod aquifer, Massachusetts, USA: I ...
Fems Microbiology Letters, Oct 9, 2020
Research in the last decade has illuminated the important role that lanthanides play in microbial... more Research in the last decade has illuminated the important role that lanthanides play in microbial carbon metabolism, particularly methylotrophy. Environmental omics studies have revealed that lanthoenzymes are dominant in some environments, and laboratory studies have shown that lanthoenzymes are favored over their calcium-containing counterparts even when calcium is far more abundant. Lanthanide elements are common in rocks but occur at exceedingly low levels in most natural waters (picomolar to nanomolar range) with the exception of volcanic hot springs, which can reach micromolar concentrations. Calcium is orders of magnitude higher in abundance than lanthanide elements across natural settings. Bacteria that use lanthanides for growth on simple carbon compounds (e.g. methanol and ethanol) grow optimally at micromolar concentrations. It is highly likely that bacteria in the environment have evolved specialized lanthanide sequestration and high-affinity uptake systems to overcome lanthanide deprivation. Indeed, we identified genes in soil metagenomes encoding the lanthanide-binding protein lanmodulin, which may be important for cellular differentiation between calcium and lanthanides. More research is needed on microbial adaptations to lanthanide scarcity.
Journal of Hydrology: Regional Studies, Jun 1, 2017
Study region: The groundwater influenced coastal waters along the arid Kona coast ofthe Big Islan... more Study region: The groundwater influenced coastal waters along the arid Kona coast ofthe Big Island, Hawai'i. Study focus: A salinity-and phase partitioning-based mixing experiment was constructed using contrasting groundwater endmembers along the arid Konacoast of the Big Island, Hawai'i and local open seawater to better understand biogeochemical and physicochemical processes that influence the fate of submarine groundwater discharge (SGD)-derived nutrients and trace elements. New Hydrological Insights for the Region: Treated wastewater effluent was the main source for nutrient enrichment downstream at the Honok ōhau Harbor site. Conservative mixing for some constituents, such as nitrate + nitrite, illustrate the effectiveness of physical mixing to maintain oceanic concentrations in the colloid (0.02-0.45 m) and truly dissolved (<0.02 m) forms. In contrast, the nonconservative behavior of phosphate highlights the importance of surface complexation reactions that can lead to higher concentrations based on conservative mixing alone. Results from this physiochemical mixing experiment demonstrate how relative availability of P can shift with adsorption behavior, affecting the mobility of phosphate in the environment. With a proposed 8-hectare wastewater treatment facility (WWTF) to be constructed upslope of the Kaloko-Honok ōhau National Historical Park (NHP), treated effluent is projected to add additional nutrients. Combined with high permeability, rapid discharge, and increased nutrient loading SGD will likely continue to serve as a persistent source of nutrients and potential contaminant to coral ecosystems.
Chemosphere, Feb 1, 2022
We evaluated groundwater quality, pollution, and its effects on human health in the eastern part ... more We evaluated groundwater quality, pollution, and its effects on human health in the eastern part of the Lake Urmia basin, the largest lake in the Middle East. Although groundwater quality is suitable for drinking and irrigation purposes, an index-based approach quantifying heavy metal pollution revealed that most sampling sites exhibited moderate to high pollution levels in the northern and southern regions. The positive matrix factorization (PMF) and principal component analysis-multi linear regression (PCA-MLR) receptor models suggest that the main contributors to the observed groundwater pollution, expressed as percentages by model, were: lake water infiltration and dissolution of minerals and fertilizers (46% and 63%), infiltration of leachates from solid wastes (29% and 15%), mixing with industrial-municipal wastewaters (18% and 13%), and vehicular emissions (7% and 9%). The PMF model indicated better correlations between observed and predicted concentrations (R2 = 0.96) than the PCA-MLR (R2 = 0.89). Our results from the human health risk assessments (HHRA) highlight non-carcinogenic and carcinogenic risks for Pb and Cr, respectively. Also, the PMF-based assessment of human health risk indicated that wastewaters and solid waste leachates are responsible for the cancer risk from Cr for children.
GSA 2020 Connects Online, 2020
AGU Fall Meeting Abstracts, Dec 1, 2014
GSA Annual Meeting in Denver, Colorado, USA - 2016, 2016
Online access for this thesis was created in part with support from the Institute of Museum and L... more Online access for this thesis was created in part with support from the Institute of Museum and Library Services (IMLS) administered by the Nevada State Library, Archives and Public Records through the Library Services and Technology Act (LSTA). To obtain a high quality image or document please contact the DeLaMare Library at https://unr.libanswers.com/ or call: 775-784-6945.Three manuscripts are presented describing the rare earth element (REE) concentrations and behavior in terrestrial waters. These studies suggest that the pH, rock geochemistry, and the formation of stable REE complexes control for the REE concentrations and normalized REE patterns observed in the water bodies under investigation
Chemical Geology, Dec 1, 2021
Abstract The distribution and accumulation of rare earth elements (REE) in the labile fraction of... more Abstract The distribution and accumulation of rare earth elements (REE) in the labile fraction of sediment cores collected from salt marshes in the Patos Lagoon estuary from southern Brazil were investigated. Sediment cores (ca. 40 cm) were obtained from three locations within the estuary to capture possible changes in REE content across the salinity gradient (i.e., where saline, brackish, and freshwater dominate). Salt marsh sediments from all three coring locations were enriched in the light REE (LREE) over the heavy REE (HREE) when normalized to the North American shale composite (NASC). Shale normalized values for the LREE of marsh sediments from sites M2 and M3 in the mid- and upper estuary commonly approximates unity indicating these sediments chiefly exhibit a terrigenous signature. In contrast, all 14 naturally occurring REE are depleted in the sediments from the M1 coring location in the lower estuary compared to shale. Sediments from the mid-estuary (M2 core location) where typical salinity values are ca. 10 practical salinity units, exhibit the greatest shale normalized LREE enrichments. The higher LREE contents of the M2 sediments likely reflect preferential removal of LREE from the water column owing to salt-induced coagulation of river-borne colloids that occurs during estuarine mixing processes. Sediments samples collected from the salt marsh in the lower estuary nearer the Atlantic Ocean (i.e., M1), have substantially lower REE contents than salt marsh sediments from sites M2 and M3 in the mid- and upper estuary, respectively. The more sand-rich lower estuary sediments are exposed to higher salinity water from the South Atlantic compared to the generally finer grained sediments from the mid- and upper estuary, which are dominated by brackish and freshwater conditions, respectively. Negative Ce-anomalies (i.e., Ce/Ce* 1) for much of the sediment from the M1 core, the mid depths of core M2 (i.e., 9 cm to 27 cm), and shallower than 13 cm in sediments from core M3 support oxic conditions where Ce is enriched in sediments from these depths by preferential scavenging from pore waters onto Fe/Mn oxides/oxyhydroxides. These trends in Ce/Ce* with depth in each sediment core are also consistent with known bioturbation that occurs within these marsh sediments. The relatively high REE contents of the sediments from location M3 are also related to the fact that these sediments are dominantly composed of clay-silt deposits that are enriched in organic matter. Finally, we find no conclusive evidence that the studied salt marsh sediments have been impacted by addition of REE from the local fertilizer manufacturing industry.
AGU Fall Meeting Abstracts, Dec 1, 2013
AGU Fall Meeting Abstracts, Dec 1, 2012
AGU Fall Meeting Abstracts, Dec 1, 2017
AGU Fall Meeting Abstracts, Dec 14, 2015
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Papers by Karen Johannesson