Open Access Theses and Dissertations

Advanced search options

Advanced Search Options 🞨

Browse by author name (“Author name starts with…”).

Find ETDs with:

in
/  
in
/  
in
/  
in

Written in Published in Earliest date Latest date

Sorted by

Results per page:

Sorted by: relevance · author · university · date | New search

You searched for +publisher:"Virginia Commonwealth University" +contributor:("Dr. S. Leigh McCallister"). Showing records 1 – 3 of 3 total matches.

Search Limiters

Last 2 Years | English Only

No search limiters apply to these results.

▼ Search Limiters


Virginia Commonwealth University

1. Koren, Lindsey Michelle. Assessment of Microbial Carbon Processing and its Implications to the Carbon Budget of Lake Superior.

Degree: PhD, Integrative Life Sciences, 2019, Virginia Commonwealth University

URL: https://doi.org/10.25772/R80T-0542  ; https://scholarscompass.vcu.edu/etd/6007 

Over the past few decades, there has been increased research focus on carbon cycling within aquatic systems, especially with the changing global climate. Inland waters play a major role in the global carbon cycle, but the fundamental features remain poorly understood, particularly the large lakes of the world. Our experimental approach assessing the carbon budget of Lake Superior, the largest freshwater lake by area, provides spatial and temporal variability that has been previously overlooked but may be critical to our understanding on the biogeochemical processes controlling the lake. Multiple stations were chosen across the lake, both nearshore and offshore, to evaluate the variability in physical mixing regimes and biogeochemical processing. Short and long-term carbon consumption measurements were coupled to assess the heterotrophic activity relative to the lability of dissolved organic carbon. Partial pressure of carbon dioxide (pCO2) was directly measured to determine the metabolic nature of the lake and the amount of carbon dioxide (CO2) that fluxes across the air-water interface. The pCO2 results were further coupled with an isotopic approach measuring oxygen-18 (δ18O) to evaluate how the metabolism of Lake Superior has changed over a decadal scale. A range of environmental factors, including temperature, photodegradation and source/quality of organic carbon, influenced short and long-term carbon consumption. In-situ pCO2 observations supported a temporal switch in metabolism from the lake being a source of CO2 in the spring to being a sink in the summer driven by biological components of the system. When the pCO2 results were coupled with the isotopic measurements over the past decade (1999-2011), Lake Superior was dominated by respiration during isothermal conditions and production during stratification. In the past decade, Lake Superior has experienced increased surface water temperatures, shifting the metabolic state to a shorter net heterotrophic period in the spring and a longer net autotrophic period in the summer. This research highlights fundamental aspects of Lake Superior’s metabolism that have been previously understudied, as well as providing key information about processes controlling its carbon budget, and giving a better understanding of how climate change will continue to impact Lake Superior. Advisors/Committee Members: Dr. S. Leigh McCallister.

Subjects/Keywords: Lake Superior; Carbon Cycling; Metabolism; Biology; Life Sciences; Terrestrial and Aquatic Ecology

Record Details  Similar Records    Google PlusoneFacebookTwitterCiteULikeMendeleyreddit

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Koren, L. M. (2019). Assessment of Microbial Carbon Processing and its Implications to the Carbon Budget of Lake Superior. (Doctoral Dissertation). Virginia Commonwealth University. Retrieved from https://doi.org/10.25772/R80T-0542 ; https://scholarscompass.vcu.edu/etd/6007

Chicago Manual of Style (16th Edition):

Koren, Lindsey Michelle. “Assessment of Microbial Carbon Processing and its Implications to the Carbon Budget of Lake Superior.” 2019. Doctoral Dissertation, Virginia Commonwealth University. Accessed January 26, 2021. https://doi.org/10.25772/R80T-0542 ; https://scholarscompass.vcu.edu/etd/6007.

MLA Handbook (7th Edition):

Koren, Lindsey Michelle. “Assessment of Microbial Carbon Processing and its Implications to the Carbon Budget of Lake Superior.” 2019. Web. 26 Jan 2021.

Vancouver:

Koren LM. Assessment of Microbial Carbon Processing and its Implications to the Carbon Budget of Lake Superior. [Internet] [Doctoral dissertation]. Virginia Commonwealth University; 2019. [cited 2021 Jan 26]. Available from: https://doi.org/10.25772/R80T-0542 ; https://scholarscompass.vcu.edu/etd/6007.

Council of Science Editors:

Koren LM. Assessment of Microbial Carbon Processing and its Implications to the Carbon Budget of Lake Superior. [Doctoral Dissertation]. Virginia Commonwealth University; 2019. Available from: https://doi.org/10.25772/R80T-0542 ; https://scholarscompass.vcu.edu/etd/6007


Virginia Commonwealth University

2. Tassone, Spencer. A comparison of computational methods for estimating estuarine production and respiration from diel open water dissolved oxygen measurements.

Degree: MS, Biology, 2017, Virginia Commonwealth University

URL: https://doi.org/10.25772/5906-DS96  ; https://scholarscompass.vcu.edu/etd/4988 

Diel dissolved oxygen (DO) data were used to characterize seasonal, inter-annual, and longitudinal variation in production and respiration for the James River Estuary. Two computational methods (Bayesian and bookkeeping) were applied to these data to determine whether inferences regarding DO metabolism are sensitive to methodology. Net metabolism was sensitive to methodology as Bayesian results indicated net heterotrophy (production < respiration) while bookkeeping results indicated net autotrophy (production > respiration). Differences in net metabolism among the methods was due to low seasonal variation in respiration using the Bayesian method, whereas bookkeeping results showed a strong correlation between production and respiration. Bayesian results suggest a dependence on allochthonous organic matter (OM) whereas bookkeeping results suggest that metabolism is dependent on autochthonous OM. This study highlights the importance in considering the method used to derive metabolic estimates as it can impact the assessment of trophic status and sources of OM supporting an estuary. Advisors/Committee Members: Dr. Paul Bukaveckas, Dr. Scott Neubauer, Dr. Daniel McGarvey, Dr. S. Leigh McCallister.

Subjects/Keywords: Metabolism; Estuary; Ecosystem respiration; Primary production; Net ecosystem metabolism; James river; Marine Biology; Terrestrial and Aquatic Ecology

Record Details  Similar Records    Google PlusoneFacebookTwitterCiteULikeMendeleyreddit

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Tassone, S. (2017). A comparison of computational methods for estimating estuarine production and respiration from diel open water dissolved oxygen measurements. (Thesis). Virginia Commonwealth University. Retrieved from https://doi.org/10.25772/5906-DS96 ; https://scholarscompass.vcu.edu/etd/4988

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Tassone, Spencer. “A comparison of computational methods for estimating estuarine production and respiration from diel open water dissolved oxygen measurements.” 2017. Thesis, Virginia Commonwealth University. Accessed January 26, 2021. https://doi.org/10.25772/5906-DS96 ; https://scholarscompass.vcu.edu/etd/4988.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Tassone, Spencer. “A comparison of computational methods for estimating estuarine production and respiration from diel open water dissolved oxygen measurements.” 2017. Web. 26 Jan 2021.

Vancouver:

Tassone S. A comparison of computational methods for estimating estuarine production and respiration from diel open water dissolved oxygen measurements. [Internet] [Thesis]. Virginia Commonwealth University; 2017. [cited 2021 Jan 26]. Available from: https://doi.org/10.25772/5906-DS96 ; https://scholarscompass.vcu.edu/etd/4988.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Tassone S. A comparison of computational methods for estimating estuarine production and respiration from diel open water dissolved oxygen measurements. [Thesis]. Virginia Commonwealth University; 2017. Available from: https://doi.org/10.25772/5906-DS96 ; https://scholarscompass.vcu.edu/etd/4988

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


Virginia Commonwealth University

3. Koren, Lindsey Michelle. Influence of Salinity Variations on the Desorption and Lability of Soil Organic Carbon Associated with Tidal Freshwater Marshes.

Degree: MS, Biology, 2009, Virginia Commonwealth University

URL: https://doi.org/10.25772/SCXS-HC51  ; https://scholarscompass.vcu.edu/etd/1772 

Tidal freshwater marshes (TFMs) are unique ecosystems that bridge the gap between terrestrial and aquatic ecosystems and are important in the sequestration of soil organic carbon. With the ever changing global climate, TFMs are left vulnerable to downstream effects of rising sea level and salt water intrusion due to increases in flooding by saline waters. These changes often act over large spatial and temporal scales resulting in significant impacts to local and regional environments. This multidisciplinary study assessed the amount and lability of desorbed organic carbon in tidal freshwater marsh soils from the Waccamaw River Marsh, South Carolina and Sweet Hall, a marsh on the Pamunkey River, Virginia. Soils from each marsh were extracted at 0-35 practical salinity units (psu) and the dissolved organic carbon (DOC) concentration, and carbon lability of the leachates were measured. At increasing levels of salinity, soil desorption amounts were higher in the Waccamaw River marsh interior and similar between the Waccamaw River creekbank and Sweet Hall levee. A larger fraction of desorbed DOC was consumed in the more organic soils from the Waccamaw River marsh in comparison to the more mineral soil from Sweet Hall Marsh. Finally, the rate of decay of the desorbed carbon was highest in the Sweet Hall levee soils, indicating more labile desorbed carbon, while the Waccamaw River Marsh soils had lower decay rates indicating less labile desorbed carbon. By understanding how salt water intrusion affects desorption and lability of soil organic carbon, in coastal marshes, we may be able to better understand how increasing sea levels may affect carbon storage in coastal ecosystems. Advisors/Committee Members: Dr. S. Leigh McCallister.

Subjects/Keywords: Tidal Freshwater Marshes; Soil Organic Carbon; Salt Water Intrusion; Waccamaw River Marsh South Carolina; Sweet Hall Marsh; Virginia; Carbon Lability; Biology; Life Sciences

Record Details  Similar Records    Google PlusoneFacebookTwitterCiteULikeMendeleyreddit

❌

APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Koren, L. M. (2009). Influence of Salinity Variations on the Desorption and Lability of Soil Organic Carbon Associated with Tidal Freshwater Marshes. (Thesis). Virginia Commonwealth University. Retrieved from https://doi.org/10.25772/SCXS-HC51 ; https://scholarscompass.vcu.edu/etd/1772

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Koren, Lindsey Michelle. “Influence of Salinity Variations on the Desorption and Lability of Soil Organic Carbon Associated with Tidal Freshwater Marshes.” 2009. Thesis, Virginia Commonwealth University. Accessed January 26, 2021. https://doi.org/10.25772/SCXS-HC51 ; https://scholarscompass.vcu.edu/etd/1772.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Koren, Lindsey Michelle. “Influence of Salinity Variations on the Desorption and Lability of Soil Organic Carbon Associated with Tidal Freshwater Marshes.” 2009. Web. 26 Jan 2021.

Vancouver:

Koren LM. Influence of Salinity Variations on the Desorption and Lability of Soil Organic Carbon Associated with Tidal Freshwater Marshes. [Internet] [Thesis]. Virginia Commonwealth University; 2009. [cited 2021 Jan 26]. Available from: https://doi.org/10.25772/SCXS-HC51 ; https://scholarscompass.vcu.edu/etd/1772.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Koren LM. Influence of Salinity Variations on the Desorption and Lability of Soil Organic Carbon Associated with Tidal Freshwater Marshes. [Thesis]. Virginia Commonwealth University; 2009. Available from: https://doi.org/10.25772/SCXS-HC51 ; https://scholarscompass.vcu.edu/etd/1772

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.