CZO Southern Sierra CZO snowline processes CZO Southern

CZO

Southern Sierra CZO: snowline processes CZO

Southern Sierra CZO Water balance instrument cluster

Southern Sierra CZO team Principal investigators Research team Roger Bales, UC Merced Beth Boyer, UC Berkeley Martha Conklin, UC Merced Mike Goulden, UC Irvine Jan Hopmans, UC Davis Dale Johnson, U Nevada Reno Jim Kirchner, UC Berkeley Christina Tague, UC Santa Barbara 9 students, TBD Field hydrologist/geochemist Data manager Education/communications scientist Carolyn Hunsaker, USFS-PSW Cooperating investigators & students, TBD

Proposed research investigations 1. water cycle & response to perturbations: rain vs. snow dominance, baseflow response, soil moisture, ET & snow patterns/responses 2. coupled hydrologic & (bio)geochemical processes/cycles: soil moisture controls on C/N cycles, weathering & landscape evolution 3. extreme hydrologic events in hydrologic & biogeochemical cycles: linking weathering & nutrient fluxes to fire/rain/snowmelt 4. vegetation control over fluxes of water & nutrients: linking ET, synthesis, respiration to soil moisture & water cycle 5. pathways for transport of water, heat & mass: subsurface pathways, role of meadows, nutrient response to rain vs. snowmelt 6. role of seasonal snowpack in determining critical zone processes: role of snowpack (duration) in N cycling & weathering Education: train YI instructors & bring more CZ science into their curriculum – about 13, 000 middle/high school students cycle through YI 3 -5 day courses in the Sierra Nevada annually (near UC Merced)

Gradients in hydrology & geochemistry Cumulative discharge for 3 catchments, water year 2004 Major ions in streamwater

Southern Sierra CZO measurements KREW measurements by PSW Instrument grant & CZO additions stream stage & discharge stream channel stream condition inventory stream physical habitat survey erosion & sedimentation geology soils & litter shallow soil water chemistry snowmelt & rain chemistry stream water chemistry riparian & upland vegetation fuel loading stream invertebrates algae & periphyton flux tower, eddy correlation snow depth soil moisture sap flow cosmogenic nuclides high-frequency, high-resolution stream temperature water levels, piezometers stable isotopes carbon & nitrogen cycling Digital library: https: //eng. ucmerced. edu/snsjho/ KREW is a USFS long-term integrated watershed study

Southern Sierra CZO: snowline processes

Goal: understand how critical-zone processes control fluxes & stores of water across the landscape & how the water cycle modulates (bio)geochemical, biological, geomorphological & soil processes Five questions define & focus the core measurements & research: i) how do coupled hydrologic & biogeochemical fluxes vary across the rain-snow transition ii) what is the role of extreme hydrologic events in water & biogeochemical balances iii) to what extent does vegetation modulate or actively control the primary subsurface fluxes of water & nutrients, vs. act as a passive agent iv) over what time & space scales, & during what seasons, are macropores & other short-circuit pathways dominant in the critical zone v) how does the presence of a seasonal snowpack affect soils, geomorphology, biogeochemistry & hydrology in Sierra watersheds & hillslopes, & how will the relevant processes & reservoirs respond as the climate warms & snowpacks recede

Instrument sites soil moisture, snow, sap flow

Soils grid

Sediment grid

Vegetation grid

Riparian transects