Anna Szynkiewicz | University of Tennessee Knoxville (original) (raw)
Papers by Anna Szynkiewicz
AGU Fall Meeting Abstracts, Dec 1, 2012
ABSTRACT
Lunar and Planetary Science Conference, Mar 1, 2013
ABSTRACT
Lunar and Planetary Science Conference, Mar 1, 2017
AGU Fall Meeting Abstracts, Dec 1, 2017
Chemical Geology, May 1, 2010
The preservation of the primary stable isotope compositions of peat-forming plants in peat was te... more The preservation of the primary stable isotope compositions of peat-forming plants in peat was tested along a short (b 3.5 km), steep (739-1393 m asl) altitudinal transect. The stable isotope compositions in plant cube samples taken from the surface of mires were compared with the stable isotope compositions in cube samples of the underlying young peat for the following elements: hydrogen, carbon, nitrogen, oxygen and sulfur (HCNOS). Electron paramagnetic resonance (EPR) measurements were also compared. Statistically significant correlations (p ≤ 0.03) for the pairs of plant-peat samples among all analyzed elements suggested that the stable isotope compositions of peat are primarily determined by the stable isotope compositions of the peat-forming plants. This implies that preservation of the plants' primary stable isotope variations (e.g., from the time of plant growth) is well preserved in young peat and that the overall decomposition during peat formation has only a secondary influence on the final peat stable isotope composition. We were able to detect relative variations in stable isotope composition between plants growing in different conditions and/ or at different times. The EPR results confirmed the more anoxic conditions of decomposition at lower altitudes and more oxic conditions at higher altitudes, which involved an increase in oxygen centered free radicals. The observed correlations between the stable isotope compositions of plants and altitude indicated that the δ 13 C value of peat-forming plants is primarily controlled by growing season temperature, while the δ 2 H and δ 18 O values are controlled by stable isotope composition of surface water. The δ 15 N and δ 34 S values appear to reflect different distributions and concentrations of anthropogenic pollution at the sites of peatforming plant growth. A strong and statistically significant correlation between altitude/temperature and δ 13 C of plants and peats indicates a good preservation of primary stable carbon isotope composition. Thus, the analysis of peat stable isotope compositions could be useful for paleoclimate and paleoenvironmental evaluations.
New Mexico Geological Society Annual Spring Meeting, Apr 18, 2008
Pleistocene/Holocene gypsiferous lake sediments of the Tularosa Basin (White Sands area) and Esta... more Pleistocene/Holocene gypsiferous lake sediments of the Tularosa Basin (White Sands area) and Estancia Basin were studied, using sulfur isotope methods, to try and identify primary sulfate sources and determine the hydrologic cycle during the Holocene tectonic evolution of these basins.
New Mexico Geological Society Annual Spring Meeting, Apr 12, 2013
The Rio Grande flows from Southern Colorado through New Mexico and West Texas down to the Gulf of... more The Rio Grande flows from Southern Colorado through New Mexico and West Texas down to the Gulf of Mexico. It serves as an important water supply for agricutural and municipal needs. In Rio Grande waters, total dissolved solids (TDS) increase from ~40 mg/L at the headwaters to 500-1500 mg/L at El Paso, Texas. The elevated TDS values in downstream water cause various problems such as reduction in crop productivity and deterioration of soil quality due to salt loading. A number of natural and anthropogenic factors may lead to increased salinity, so the exact sources and their relative contributions to the salt load remain unclear. U isotopes (e.g., 234 U and 238 U) fractionate naturally when released from rocks to waters during chemical weathering processes at Earth's surface. It has been suggested that the degree of U isotope fractionation depends largely on local lithology and climate conditions, which affect chemical weathering and U release rates. U isotopes in natural waters thus have great potential to serve as natural tracers for chemical weathering processes, which in turn can help to determine the origins of dissolved solids (i.e., salts) and their history.
LPICo, May 1, 2016
Metabolic 34 S-32 S isotope biosignatures-characteristic imprints upon the environment of the pro... more Metabolic 34 S-32 S isotope biosignatures-characteristic imprints upon the environment of the processes by which life extracts energy and material resources to sustain itself. 2) Molecular (genomic) biosignatures-structural, functional, and information-carrying molecules that characterize life forms and their metabolism. Between 2007 and 2014, water and sediment samples were collected from hot spring, stream and crater lake sediments affected by hydrothermal H 2 S gas emission. The method of S sequential extraction was used to characterize isotope composition of mineral phases containing S 6+ , S 0 , and S 2-[4]. To link microbial metabolic potential with observed metabolic isotope signatures, we examined the presence of adenosine-5phosphosulfate (APS) reductase, a gene involved in both dissimilatory (i.e. energy yielding) sulfate reduction or S oxidation reactions.
AGU Fall Meeting Abstracts, Dec 1, 2020
AGU Fall Meeting Abstracts, Dec 1, 2018
Abstracts with programs, 2022
Geological Society of America Abstracts with Programs
American Mineralogist
Understanding past and present aqueous activity on Mars is critical to constraining martian aqueo... more Understanding past and present aqueous activity on Mars is critical to constraining martian aqueous geochemistry and habitability, and to searching for life on Mars. Assemblages of minerals observed at or near the martian surface include phyllosilicates, sulfates, iron oxides/hydroxides, and chlorides, all of which are indicative of a complex history of aqueous activity and alteration in the martian past. Furthermore, features observed on parts of the martian surface suggest present-day activity of subsurface brines and at least transient liquid water. Terrestrial analogs for younger and colder (Hesperian–Amazonian) martian geologic and climatic conditions are available in the McMurdo Dry Valleys (MDV) of Antarctica and provide opportunities for improved understanding of more recent aqueous activity on Mars. Here, we study the VXE-6 intermittent brine pond site from Wright Valley in the MDV region and use coordinated spectroscopy, X-ray diffraction, and elemental analyses to charact...
Geological Society of America Abstracts with Programs, 2017
Introduction: The main objective of this project is to determine whether elemental sulfur (S) is ... more Introduction: The main objective of this project is to determine whether elemental sulfur (S) is a significant constituent to the total S present in terrestrial acidic hydrothermal systems. Subsequently, this knowledge will be applied to Mars to improve the interpretation of in situ geochemical measurements. The geologic history of Mars was likely dominated by complex S cycling between the mantle, lithosphere, hydrosphere, and atmosphere [1-4]. Meteorites suggest that Mars’ mantle and lithosphere may be intrinsically more abundant in S than the Earth [5, 6]. In situ analyses by rovers, as well as remote sensing data, support an overall enrichment in S as well as wealth of S-bearing minerals [7, 8]. Sulfates are common minerals measured on the surface, and sulfides have also been detected in situ at Gale Crater [9, 10]. Although an excess of S has been observed in situ in places like Meridiani Planum and Gusev Crater, the nature of S, whether it be elemental, is unclear [11-13]. Clim...
Geological Society of America Abstracts with Programs, 2021
Geological Society of America Abstracts with Programs, 2018
Geological Society of America Abstracts with Programs, 2018
Glacial retreat is changing biogeochemical cycling in the Arctic, where glacial runoff contribute... more Glacial retreat is changing biogeochemical cycling in the Arctic, where glacial runoff contributes iron for oceanic shelf primary production. We hypothesize that in Svalbard fjords, microbes catalyze intense iron and sulfur cycling in loworganic-matter sediments. This is because low organic matter limits sulfide generation, allowing iron mobility to the water column instead of precipitation as iron monosulfides. In this study, we tested this with high-depth-resolution 16S rRNA gene libraries in the upper 20 cm at two sites in Van Keulenfjorden, Svalbard. At the site closer to the glaciers, iron-reducing Desulfuromonadales, iron-oxidizing Gallionella and Mariprofundus, and sulfur-oxidizing Thiotrichales and Epsilonproteobacteria were abundant above a 12-cm depth. Below this depth, the relative abundances of sequences for sulfate-reducing Desulfobacteraceae and Desulfobulbaceae increased. At the outer station, the switch from iron-cycling clades to sulfate reducers occurred at shallower depths (ϳ5 cm), corresponding to higher sulfate reduction rates. Relatively labile organic matter (shown by ␦ 13 C and C/N ratios) was more abundant at this outer site, and ordination analysis suggested that this affected microbial community structure in surface sediments. Network analysis revealed more correlations between predicted iron-and sulfur-cycling taxa and with uncultured clades proximal to the glacier. Together, these results suggest that complex microbial communities catalyze redox cycling of iron and sulfur, especially closer to the glacier, where sulfate reduction is limited due to low availability of organic matter. Diminished sulfate reduction in upper sediments enables iron to flux into the overlying water, where it may be transported to the shelf. IMPORTANCE Glacial runoff is a key source of iron for primary production in the Arctic. In the fjords of the Svalbard archipelago, glacial retreat is predicted to stimulate phytoplankton blooms that were previously restricted to outer margins. Decreased sediment delivery and enhanced primary production have been hypothesized to alter sediment biogeochemistry, wherein any free reduced iron that could potentially be delivered to the shelf will instead become buried with sulfide generated through microbial sulfate reduction. We support this hypothesis with sequencing data that showed increases in the relative abundance of sulfate reducing taxa and sulfate reduction rates with increasing distance from the glaciers in Van Keulenfjorden, Svalbard. Community structure was driven by organic geochemistry, suggesting that enhanced input of organic material will stimulate sulfate reduction in interior fjord sediments as glaciers continue to recede.
AGU Fall Meeting Abstracts, Dec 1, 2012
ABSTRACT
Lunar and Planetary Science Conference, Mar 1, 2013
ABSTRACT
Lunar and Planetary Science Conference, Mar 1, 2017
AGU Fall Meeting Abstracts, Dec 1, 2017
Chemical Geology, May 1, 2010
The preservation of the primary stable isotope compositions of peat-forming plants in peat was te... more The preservation of the primary stable isotope compositions of peat-forming plants in peat was tested along a short (b 3.5 km), steep (739-1393 m asl) altitudinal transect. The stable isotope compositions in plant cube samples taken from the surface of mires were compared with the stable isotope compositions in cube samples of the underlying young peat for the following elements: hydrogen, carbon, nitrogen, oxygen and sulfur (HCNOS). Electron paramagnetic resonance (EPR) measurements were also compared. Statistically significant correlations (p ≤ 0.03) for the pairs of plant-peat samples among all analyzed elements suggested that the stable isotope compositions of peat are primarily determined by the stable isotope compositions of the peat-forming plants. This implies that preservation of the plants' primary stable isotope variations (e.g., from the time of plant growth) is well preserved in young peat and that the overall decomposition during peat formation has only a secondary influence on the final peat stable isotope composition. We were able to detect relative variations in stable isotope composition between plants growing in different conditions and/ or at different times. The EPR results confirmed the more anoxic conditions of decomposition at lower altitudes and more oxic conditions at higher altitudes, which involved an increase in oxygen centered free radicals. The observed correlations between the stable isotope compositions of plants and altitude indicated that the δ 13 C value of peat-forming plants is primarily controlled by growing season temperature, while the δ 2 H and δ 18 O values are controlled by stable isotope composition of surface water. The δ 15 N and δ 34 S values appear to reflect different distributions and concentrations of anthropogenic pollution at the sites of peatforming plant growth. A strong and statistically significant correlation between altitude/temperature and δ 13 C of plants and peats indicates a good preservation of primary stable carbon isotope composition. Thus, the analysis of peat stable isotope compositions could be useful for paleoclimate and paleoenvironmental evaluations.
New Mexico Geological Society Annual Spring Meeting, Apr 18, 2008
Pleistocene/Holocene gypsiferous lake sediments of the Tularosa Basin (White Sands area) and Esta... more Pleistocene/Holocene gypsiferous lake sediments of the Tularosa Basin (White Sands area) and Estancia Basin were studied, using sulfur isotope methods, to try and identify primary sulfate sources and determine the hydrologic cycle during the Holocene tectonic evolution of these basins.
New Mexico Geological Society Annual Spring Meeting, Apr 12, 2013
The Rio Grande flows from Southern Colorado through New Mexico and West Texas down to the Gulf of... more The Rio Grande flows from Southern Colorado through New Mexico and West Texas down to the Gulf of Mexico. It serves as an important water supply for agricutural and municipal needs. In Rio Grande waters, total dissolved solids (TDS) increase from ~40 mg/L at the headwaters to 500-1500 mg/L at El Paso, Texas. The elevated TDS values in downstream water cause various problems such as reduction in crop productivity and deterioration of soil quality due to salt loading. A number of natural and anthropogenic factors may lead to increased salinity, so the exact sources and their relative contributions to the salt load remain unclear. U isotopes (e.g., 234 U and 238 U) fractionate naturally when released from rocks to waters during chemical weathering processes at Earth's surface. It has been suggested that the degree of U isotope fractionation depends largely on local lithology and climate conditions, which affect chemical weathering and U release rates. U isotopes in natural waters thus have great potential to serve as natural tracers for chemical weathering processes, which in turn can help to determine the origins of dissolved solids (i.e., salts) and their history.
LPICo, May 1, 2016
Metabolic 34 S-32 S isotope biosignatures-characteristic imprints upon the environment of the pro... more Metabolic 34 S-32 S isotope biosignatures-characteristic imprints upon the environment of the processes by which life extracts energy and material resources to sustain itself. 2) Molecular (genomic) biosignatures-structural, functional, and information-carrying molecules that characterize life forms and their metabolism. Between 2007 and 2014, water and sediment samples were collected from hot spring, stream and crater lake sediments affected by hydrothermal H 2 S gas emission. The method of S sequential extraction was used to characterize isotope composition of mineral phases containing S 6+ , S 0 , and S 2-[4]. To link microbial metabolic potential with observed metabolic isotope signatures, we examined the presence of adenosine-5phosphosulfate (APS) reductase, a gene involved in both dissimilatory (i.e. energy yielding) sulfate reduction or S oxidation reactions.
AGU Fall Meeting Abstracts, Dec 1, 2020
AGU Fall Meeting Abstracts, Dec 1, 2018
Abstracts with programs, 2022
Geological Society of America Abstracts with Programs
American Mineralogist
Understanding past and present aqueous activity on Mars is critical to constraining martian aqueo... more Understanding past and present aqueous activity on Mars is critical to constraining martian aqueous geochemistry and habitability, and to searching for life on Mars. Assemblages of minerals observed at or near the martian surface include phyllosilicates, sulfates, iron oxides/hydroxides, and chlorides, all of which are indicative of a complex history of aqueous activity and alteration in the martian past. Furthermore, features observed on parts of the martian surface suggest present-day activity of subsurface brines and at least transient liquid water. Terrestrial analogs for younger and colder (Hesperian–Amazonian) martian geologic and climatic conditions are available in the McMurdo Dry Valleys (MDV) of Antarctica and provide opportunities for improved understanding of more recent aqueous activity on Mars. Here, we study the VXE-6 intermittent brine pond site from Wright Valley in the MDV region and use coordinated spectroscopy, X-ray diffraction, and elemental analyses to charact...
Geological Society of America Abstracts with Programs, 2017
Introduction: The main objective of this project is to determine whether elemental sulfur (S) is ... more Introduction: The main objective of this project is to determine whether elemental sulfur (S) is a significant constituent to the total S present in terrestrial acidic hydrothermal systems. Subsequently, this knowledge will be applied to Mars to improve the interpretation of in situ geochemical measurements. The geologic history of Mars was likely dominated by complex S cycling between the mantle, lithosphere, hydrosphere, and atmosphere [1-4]. Meteorites suggest that Mars’ mantle and lithosphere may be intrinsically more abundant in S than the Earth [5, 6]. In situ analyses by rovers, as well as remote sensing data, support an overall enrichment in S as well as wealth of S-bearing minerals [7, 8]. Sulfates are common minerals measured on the surface, and sulfides have also been detected in situ at Gale Crater [9, 10]. Although an excess of S has been observed in situ in places like Meridiani Planum and Gusev Crater, the nature of S, whether it be elemental, is unclear [11-13]. Clim...
Geological Society of America Abstracts with Programs, 2021
Geological Society of America Abstracts with Programs, 2018
Geological Society of America Abstracts with Programs, 2018
Glacial retreat is changing biogeochemical cycling in the Arctic, where glacial runoff contribute... more Glacial retreat is changing biogeochemical cycling in the Arctic, where glacial runoff contributes iron for oceanic shelf primary production. We hypothesize that in Svalbard fjords, microbes catalyze intense iron and sulfur cycling in loworganic-matter sediments. This is because low organic matter limits sulfide generation, allowing iron mobility to the water column instead of precipitation as iron monosulfides. In this study, we tested this with high-depth-resolution 16S rRNA gene libraries in the upper 20 cm at two sites in Van Keulenfjorden, Svalbard. At the site closer to the glaciers, iron-reducing Desulfuromonadales, iron-oxidizing Gallionella and Mariprofundus, and sulfur-oxidizing Thiotrichales and Epsilonproteobacteria were abundant above a 12-cm depth. Below this depth, the relative abundances of sequences for sulfate-reducing Desulfobacteraceae and Desulfobulbaceae increased. At the outer station, the switch from iron-cycling clades to sulfate reducers occurred at shallower depths (ϳ5 cm), corresponding to higher sulfate reduction rates. Relatively labile organic matter (shown by ␦ 13 C and C/N ratios) was more abundant at this outer site, and ordination analysis suggested that this affected microbial community structure in surface sediments. Network analysis revealed more correlations between predicted iron-and sulfur-cycling taxa and with uncultured clades proximal to the glacier. Together, these results suggest that complex microbial communities catalyze redox cycling of iron and sulfur, especially closer to the glacier, where sulfate reduction is limited due to low availability of organic matter. Diminished sulfate reduction in upper sediments enables iron to flux into the overlying water, where it may be transported to the shelf. IMPORTANCE Glacial runoff is a key source of iron for primary production in the Arctic. In the fjords of the Svalbard archipelago, glacial retreat is predicted to stimulate phytoplankton blooms that were previously restricted to outer margins. Decreased sediment delivery and enhanced primary production have been hypothesized to alter sediment biogeochemistry, wherein any free reduced iron that could potentially be delivered to the shelf will instead become buried with sulfide generated through microbial sulfate reduction. We support this hypothesis with sequencing data that showed increases in the relative abundance of sulfate reducing taxa and sulfate reduction rates with increasing distance from the glaciers in Van Keulenfjorden, Svalbard. Community structure was driven by organic geochemistry, suggesting that enhanced input of organic material will stimulate sulfate reduction in interior fjord sediments as glaciers continue to recede.