- Title Information
- Title
- Investigating the role of atmospheric nitrogen deposition and biogeochemical changes in cryospheric environments
- Name:
Personal
- Name Part
- Clark, Sydney C
- Role
- Role Term:
Text
- creator
- Name:
Personal
- Name Part
- Hastings, Meredith
- Role
- Role Term:
Text
- Advisor
- Name:
Personal
- Name Part
- Russell, James
- Role
- Role Term:
Text
- Reader
- Name:
Personal
- Name Part
- Fischer, Karen
- Role
- Role Term:
Text
- Reader
- Name:
Personal
- Name Part
- Prell, Warren
- Role
- Role Term:
Text
- Reader
- Name:
Personal
- Name Part
- Baron, Jill
- Role
- Role Term:
Text
- Reader
- Name:
Corporate
- Name Part
- Brown University. Department of Earth, Environmental, and Planetary Sciences
- Role
- Role Term:
Text
- sponsor
- Origin Information
- Copyright Date
- 2020
- Physical Description
- Extent
- , None p.
- digitalOrigin
- born digital
- Note:
thesis
- Thesis (Ph. D.)--Brown University, 2020
- Genre (aat)
- theses
- Abstract
- Reactive nitrogen gases (e.g., NOx = NO + NO2) emitted to the atmosphere eventually return to the surface environment as nitrate (NO3-) deposition, which causes a variety of ecological impacts due to excessive inputs of this important nutrient. Dramatic climatic and hydrological changes, along with changes in external inputs of atmospheric NO3- have been suggested to be major drivers of environmental change in remote environments with cryospheric features (e.g., Arctic and alpine). The ability to quantify the extent and persistence of atmospheric reactive nitrogen deposition is critical for understanding connections between external contributions of reactive nitrogen, ecosystem biogeochemistry and environmental change. Nutrient concentrations and stable isotopes of NO3- allow for tracking the environmental fate of atmospherically oxidized NO3- in addition to internal cycling. Specifically, a unique and conservative tracer of atmospheric NO3- Δ17O) was used to quantify its role in these sensitive ecosystems. Using a suite of isotopic tracers, and modeling of isotope mixing and/or processes, the provenance of NO3-was quantified in late-summer Arctic Ocean sea ice and in glacier ice, snow and surface waters in the Colorado alpine. This work revealed that in both environments, internal microbial cycling is critical to the nitrogen cycle. In Arctic sea ice, 40% or less of the NO3- was atmospherically-derived; in two proximal alpine watersheds of the Colorado Front Range, atmospheric NO3- only makes up 20-11% of the NO3- observed in surface waters from early to late summer, respectively, while 80-89% reflects microbial nitrification. Moreover, historical surface waters collected in CO reflected a decline in atmospheric NO3- from the mid-90s to present. Long-term trends in atmospheric transport suggest that a shift in localized westerly transport has increased in importance over a 20-year period, along with a significant increase in ammonium deposition from the atmosphere that might be stimulating today’s abundant microbial processes. Finally, very low concentration samples of limited volume from this work influenced the development of a new isotope dilution method enabling the characterization of Δ17O in low concentration samples that otherwise would not have been possible.
- Subject
- Topic
- Atmospheric chemistry and biogeochemistry
- Subject (fast)
(authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/01131235")
- Topic
- Stable isotopes
- Subject (fast)
(authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/01038072")
- Topic
- Nitrogen cycle
- Language
- Language Term (ISO639-2B)
- English
- Record Information
- Record Content Source (marcorg)
- RPB
- Record Creation Date
(encoding="iso8601")
- 20200720
- Access Condition:
rights statement
(href="http://rightsstatements.org/vocab/InC/1.0/")
- In Copyright
- Access Condition:
restriction on access
- Collection is open for research.
- Identifier:
DOI
- 10.26300/8z1g-7549
- Type of Resource (primo)
- dissertations