Atmospheric particulate matter (PM) sampling was recently conducted at the Lower Kaweah monitoring station (10 km west of Emerald Lake, 1905 m asl), which had access to power required to operate the Stacked Filter Unit and Micro-Orifice Uniform Deposit Impactor(Vicars et al. 2010; Vicars and Sickman 2011; Vicars 2009). Total P (TP), inorganic P (IP), and Al, Fe, Ca, Mg and V were determined. Aerosol concentrations were elevated, primarily due to transport from offsite and emissions from local and regional wildfires. The dry depositional flux of TP ranged between 7 and 118 μg m-2 d-1 (mean of 40 ± 27 μg m-2 d-1). Relative rates of dry deposition of P and N are consistent with increasing N limitation of phytoplankton. PM concentrations were highest during the dry season, averaging 8.8 ± 3.7 and 11.1 ± 7.5 μg m-3 for the coarse and fine fractions, while winter months had PM concentrations < 1 μg m-3. Fe/Al and Fe/Ca (Fig. 3) ratios suggest a mixture of dust from regional agriculture and long-range transport of dust from Asia.

An autosampler is collecting stream samples on approximately a 3-day basis during snowmelt and field personnel are making monthly collections at other times for analysis of major solutes and nutrients at all gauging stations. Samples from Emerald Lake are collected about monthly, and include samples for nutrients and major solutes, chlorophyll a as well as in situ profiles of temperature, dissolved oxygen and light. Analyses of nutrients (NO3-, NH4+, DON, DOC, soluble reactive P, DOP, particulate N, P and C) and dissolved ions (Cl-, SO42-, K+, Na+, Ca2+, Mg2+) are performed using our established methods. We are sampling zooplankton and will re-census the brook trout. We are using a mass balance approach based on diel fluctuations in dissolved oxygen to estimate rates of gross primary production, ecosystem respiration and net ecosystem production (Sadro et al. 2011 a,b). Our model includes wind and convection-driven estimates of gas exchange with the atmosphere (MacIntyre et al. 2010) and takes into consideration the depth of the mixed layer.