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Stoichiometric Investigation of the Relationship between Ecosystem Metabolism and the Plant Community. Rachel L. Douglass. November 12, 2010. Ecological Stoichiometry. Investigates the balance of multiple chemical substances involved in ecological interactions and processes Carbon-C
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Stoichiometric Investigation of the Relationshipbetween Ecosystem Metabolism and the Plant Community Rachel L. Douglass November 12, 2010
Ecological Stoichiometry • Investigates the balance of multiple chemical substances involved in ecological interactions and processes • Carbon-C • Nitrogen-N • Phosphorus-P • Used to increase mechanistic understanding of: • Trophic interactions • Population dynamics
Research Objectives • 1) To characterize overall ecosystem metabolism and individual species stoichiometry at varying timescales • 2)To examine consequences of species stoichiometry, abundance, and distribution on overall ecosystem metabolism • 3) To measure across time, seasons, flooding episodes and locations to quantify relationship between plant tissue stoichiometry and stoichiometry of ecosystem metabolism
Hypotheses • H1: Individual taxa possess unique C:N:P stoichiometric signatures; yet these signatures exhibit daily, seasonal and episodic variation. • Plants within the mixing zone at the 2500 site of the Santa Fe River exhibit temporal changes to their stoichiometry on episodic time intervals related to the stage of the river.
Hypotheses • H1: Individual taxa possess unique C:N:P stoichiometric signatures; yet these signatures exhibit daily, seasonal and episodic variation. • H2: There will be a direct quantifiable relationship between ecosystem metabolism stoichiometry and the stoichiometry of the primary producers within the system with the ability to partition overall ecosystem metabolism by producer groups.
Hypotheses • H1: Individual taxa possess unique C:N:P stoichiometric signatures; yet these signatures exhibit daily, seasonal and episodic variation. • H2: There will be a direct quantifiable relationship between ecosystem metabolism stoichiometry and the stoichiometry of the primary producers within the system with the ability to partition overall ecosystem metabolism by producer groups. • H3: Changes in species abundance and distribution lead to changing ecosystem metabolic stoichiometry and alter nutrient cycling efficiency within the system.
Field Methods Year 1 • In-situ nutrient sensors • Monitor DO, NO3- and SRP concentrations • Field collection of vascular plant and algal species • Collection on a seasonal basis • Used to analyze specimens for C:N and C:P ratios Year 2 (in addition to all Year 1 activities) • Mesocosm experiments • Collection before, during and after flooding episodes
Anticipated Results and Contributions • Quantification of the relationship between ecosystem metabolism and the plant community • Information on patterns including • Changing abundance and distribution of plant species • Nutrient cycling efficiency changes • Model of ecosystem metabolic changes