Ecosystem metabolism in salt marsh tidal creeks and ponds : applying triple oxygen isotopes and other gas tracers to novel environments
Howard, Evan M.
MetadataShow full item record
Salt marshes are physically, chemically, and biologically dynamic environments found globally at temperate latitudes. Tidal creeks and marshtop ponds may expand at the expense of productive grass-covered marsh platform. It is therefore important to understand the present magnitude and drivers of production and respiration in these submerged environments in order to evaluate the future role of salt marshes as a carbon sink. This thesis describes new methods to apply the triple oxygen isotope tracer of photosynthetic production in a salt marsh. Additionally, noble gases are applied to constrain air-water exchange processes which affect metabolism tracers. These stable, natural abundance tracers complement traditional techniques for measuring metabolism. In particular, they highlight the potential importance of daytime oxygen sinks besides aerobic respiration, such as rising bubbles. In tidal creeks, increasing nutrients may increase both production and respiration, without any apparent change in the net metabolism. In ponds, daytime production and respiration are also tightly coupled, but there is high background respiration regardless of changes in daytime production. Both tidal creeks and ponds have higher respiration rates and lower production rates than the marsh platform, suggesting that expansion of these submerged environments could limit the ability of salt marshes to sequester carbon.
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution February 2017
Suggested CitationThesis: Howard, Evan M., "Ecosystem metabolism in salt marsh tidal creeks and ponds : applying triple oxygen isotopes and other gas tracers to novel environments", 2017-02, DOI:10.1575/1912/8654, https://hdl.handle.net/1912/8654
Showing items related by title, author, creator and subject.
Howarth, Robert W. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1979-02)The rate of sulfate reduction in stands of dwarf Spartina alterniflora in the Great Sippewissett Salt Marsh is approximately 75 moles S04 m2 year-1. This is the highest rate reported for any natural ecosystem. Sulfate ...
Distribution of hydrocarbons in a salt marsh ecosystem after an oil spill and physiological changes in marsh animals from the polluted environment Burns, Kathryn A. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1975-06)The studies described in this thesis were designed to answer several problems relating to the recovery of a salt marsh heavily polluted by an accidental spill of Number 2 fuel oil. Field and laboratory studies were ...
Tetrachlorobiphenyl metabolism, toxicity, and regulation of cytochrome P50 expression in a marine teleost fish White, Renee D. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1994-11)The effects of 3,3',4,4'-tetrachlorobiphenyl (TCB) were examined in the marine fish scup (Stenotomus chrysops), focusing on the interactions between TCB and the CYP 1 A 1 enzyme system. A low TCB dose (0.1 mg/kg) elicited ...