The influence of changing environmental conditions on biological contributions to elevation in brackish marshes threatened by sea-level rise

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dc.contributor McKee, Karen L.
dc.contributor Benstead, Jonathan P.
dc.contributor Krauss, Ken W.
dc.contributor Mortazavi, Behzad
dc.contributor.advisor Cherry, Julia A. Jones, Joshua 2017-03-01T17:35:49Z 2017-03-01T17:35:49Z 2015
dc.identifier.other u0015_0000001_0001975
dc.identifier.other Jones_alatus_0004D_12375
dc.description Electronic Thesis or Dissertation
dc.description.abstract Coastal wetlands provide human populations with a multitude of ecosystem services, but they are increasingly threatened by sea-level rise and other simultaneously changing environmental conditions. To avoid drowning as water levels rise, coastal wetlands must maintain their surface elevations relative to mean sea level through feedbacks between physical and biological processes. Environmental changes that alter biological processes of production and decomposition will likely affect the capacity of these ecosystems to regulate their elevation and keep pace with sea-level rise. Changing environmental conditions such as elevated CO2, eutrophication, and hurricane sediment deposition have the potential to change production – decomposition dynamics by changing patterns of primary production, biomass allocation, community composition, or litter chemistry. To investigate the effects of climate change and nutrient enrichment on biological contributions to elevation maintenance, I conducted a series of multi-factor experiments, in both the field and greenhouse, which were designed to elucidate mechanistic pathways involved in elevation maintenance. The first study revealed that the biological response to storm sediment deposition was largely dependent on the position of the soil surface relative to sea level, and that elevated CO2 may help stabilize the new sediment addition in the long-term. Additionally, species-specific responses to flooding largely dictated the extent to which experimental wetland sods gained elevation over time. The second and third studies demonstrated that elevated CO2 may indirectly alter rates of decomposition of plant organic matter by driving shifts in biomass allocation to belowground organs or by altering community composition to favor the C3 species. Furthermore, the last study revealed that microbial decomposition was less than expected given the strong influences of plant species, tissue type and nutrient growth conditions on litter quality, suggesting that macrodetritivores also play an important role in litter processing, especially for shoot material. Collectively, these findings suggest that the capacity for biological contributions to elevation are largely determined by species-specific responses to changing environmental conditions, including CO2, storm-sediment inputs, sea-level rise, and nutrient enrichment. Thus, environmental changes that alter plant community composition or biomass allocation may have important consequences for biological feedbacks to elevation through their effects on plant production and organic matter decomposition.
dc.format.extent 104 p.
dc.format.medium electronic
dc.format.mimetype application/pdf
dc.language English
dc.language.iso en_US
dc.publisher University of Alabama Libraries
dc.relation.ispartof The University of Alabama Electronic Theses and Dissertations
dc.relation.ispartof The University of Alabama Libraries Digital Collections
dc.relation.hasversion born digital
dc.rights All rights reserved by the author unless otherwise indicated.
dc.subject.other Ecology
dc.subject.other Climate change
dc.title The influence of changing environmental conditions on biological contributions to elevation in brackish marshes threatened by sea-level rise
dc.type thesis
dc.type text University of Alabama. Dept. of Biological Sciences Biological Sciences The University of Alabama doctoral Ph.D.

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