Aquatic Biogeochemistry

1
Aquatic Biogeochemistry

• The coupling of biogeochemical processes to
  dynamic hydrologic events must be understood to
  determine rates and trajectories (increase or
  decrease) of constituent concentrations (e.g.
  mercury, selenium, pesticides, nitrate) within
  any given watershed.

2
Aquatic BiogeochemistryScience Drivers

• How are the dominant biogeochemical processes
  governed by hydrologic processes?
• snowmelt pulse (pulse introduction of new
  constituent fluxes)
• lake level fluctuations (cyclic lake sediment
  saturation-aeration and reduction-oxidation)?
• How will land use-driven and climate-driven
  changes in the magnitude and timing of dynamic
  hydrologic processes alter the above?

3
The Weber Basin/East Shore/GSL

• Rates of constituent increase or decrease within
  the Weber Basin/East Shore/GSL carry important
  implications for
• biota in wetlands (of hemispheric importance for
  migratory waterfowl)
• policies for utilization of impaired water
  (disposal of reverse osmosis concentrate from
  treatment of mine-impaired groundwater)
• freshwater (importation of Bear River to the
  metropolitan Wasatch Front).
• These issues are representative of western
  watersheds.

4
Initial Infrastructure Metals Speciation
Analytical Capability

• Trace metal species concentrations in complex
  matrices (hypersaline water and wetland
  sediments)
• High Performance Liquid Chromatograph (HPLC)
  interfaced to Inductively Coupled Plasma Mass
  Spectrometer (ICPMS) with an Octopole Reaction
  System

5
Obvious target constituentsMetals and metalloids

• Hg - immune, sensory, neurological, motor, and
  behavioral dysfunctions.
• Se teratogen that bioconcentrates due to
  chemical similarity to sulfur.
• Pb - anemia, neurological, kidney and motor
  problems including mental retardation in
  children.
• Zn - interferes with the metabolism of other
  minerals in the body.
• Cu - gastro-intestinal problems in humans, can
  cause severe problems in ruminants.
• As skin conditions, sensory and motor
  impairment, elevated risk of skin cancer.
• Sb relatively little known regarding its
  toxicity

6
Obvious target constituentsOrganics, etc.

• Dioxins carcinogens, bioconcentrated, found in
  the general US population at near-adverse levels.
• Polycyclic aromatic hydrocarbons (PAH)
  carcinogens, bioconcentrated, ubiquitous products
  of incomplete combustion of fossil fuels.
• Nitrogen nitrates substitute for oxygen in
  hemoglobin. Nitrites above moderate doses are
  highly toxic to aquatic species.
• Natural organic carbon mediates the transport of
  many dissolved and particulate constituents,
  drives drives redox conditions.
• Bacteria and viruses fecal contamination

7
Monitoring atmospheric flux (down and up)

• Hg, (CH4)2Se, Pb, Zn, Cu, Dioxins, NOx
• D and 18O to aid determination of storm track
• Passive monitoring
• Lichens at 25 sites along urban and elevation
  gradients
• Air
• 2-5 sites, continuous to weekly
• Rainfall
• Co-located with precipitation gages
• Snowpack
• snow pits co-located with SNOTEL sites sampled
  annually (spring), 5-10 cm increments, snow
  density

8
Monitoringstreams, lakes, shallow groundwater

• All target and context constituents
• Samples co-located with
• stream gages
• lake and reservoir inflow-outflow gages
• streambed piezometers (hyporheic zone in gaining
  and losing streams)
• groundwater monitoring wells
• multi-depth lake reservoir samples (to reflect
  vertical variation in redox and salinity)
• Sampling frequency must capture
• runoff events, inversions, diurnal variations
• Aided by deployable sensors and flow-activated
  and water quality-activated refrigerated
  automatic samplers (e.g. ISCO).

9
Monitoringsediments

• Determine target constituent histories
• lakebed samples for histories will be coordinated
  with paleohydrology component
• Sample catchment lakes, intermediate lakes and
  reservoirs, and terminal lakes
• Determine present constituent fluxes to from
  lakebed sediments
• exposure-submergence cycles
• Contrast deltas of three contributing basins to
  GSL
• Differing land use histories

10
Develop testable hypotheses neededto refine
choices

• Focus on the influence of the dynamic hydrologic
  system on biogeochemical processes
• Inputs
• snowmelt pulse and runoff events, constituent
  evolution with transit through system
• Outputs
• burial (sedimentation equals preservation?)
• Methylation and volatilization from sediment
  governed by lake area fluctuation
• Capitalize on rapid development in upper basin
• Capitalize on accumulated histories offered by
  closed basin
• Capitalize on contrasts offered by adjacent
  records of 3 distinct basins

11
Strategy for refinement

• No initial set of hypotheses will suit everyone
• No initial deployment of infrastructure will suit
  everyone
• Make a system that adjusts to and grows by
  genuine involvement from national community
• A compact HO will allow a better support,
  involvement, and adaptation plan

12
Tradeoffs - costs

• Radar in Weber (other basins better?)
• Deep monitoring wells
• Change characterization
• Long term sediment records

13
Tradeoffs - disciplines

• Heavily engineered Weber not workable for river
  geomorphologists