Angelo Coast Range Reserve

15 Jun, 05 AM - 30 Jun, 03 PM

The main objective of this project is to understand how stream network position influences spatial patterns in the feedbacks between multiple nutrient cycles, stream metabolism, and consumer-resource interactions. This research is a natural extension of previous work on food web controls on algal productivity and pathways of energy flow in the South Fork Eel watershed to include feedbacks between these interactions and downstream propagation of their effects on biogeochemical cycling. In essence, we ask where and when are biotic interactions and biological stoichiometry important determinants of nutrient transport and retention in river networks, and what are the consequences for downstream communities? Recent theory addressing consumer-driven nutrient recycling suggests that shifts in elemental content of consumers are driven in part by resource availability and in part by the emergence of specific life history traits in response to changing environmental conditions along gradients of physical variables. The effects of shifts in stoichiometric imbalance between consumers and resources on nutrient spiraling have yet to be studied. We believe this to be an exciting frontier in the study of stream ecosystems. The proposed work will contribute to the development of these ideas by establishing 1) empirical relationships between stoichiometric imbalances and changing environmental conditions along a drainage area gradient in a river network; and 2) experimental determination of the effects of stoichiometric imbalance in consumer-resource interactions on nutrient spiraling. We will use spiraling as a tool to examine feedbacks between stream metabolism, consumer-resource interactions and biogeochemical cycling at plot and reach scales at several network positions and during algal succession. We will measure uptake length and net retention of nitrogen (N) and phosphorus (P) over reach scales at different channel network positions. These measurements will reveal changes in nutrient uptake and regeneration with changes in network position, light and temperature. On smaller (1-10 m) scales, we will manipulate algal and detrital biomass, consumer densities, and stoichiometric imbalances to determine their individual and interactive effects on uptake rate. We will ultimately use these measurements to estimate whole-system effects of changes in algal and detrital biomass and consumer-resource interactions on spiraling of multiple nutrients by exploring their specific effects on nutrient uptake and regeneration.

Visit #20755 @Angelo Coast Range Reserve

Approved

Under Project # 8715 | Research

Ecological stoichiometry and biogeochemistry of stream food webs

undergraduate_student - St. Olaf College Minnesota

Reservation Members(s)

Nichole Turner Jun 15 - 30, 2009 (16 days)

Reserve Resources(s) | Create Invoice

Fox Creek Lodge 1 Jun 15 - 30, 2009