Lake Pusiano field experiment: first preliminary results Greg Attwater & Diego Copetti, Supervisors: Giannni Tartari & Jorg Imberger

PART 1: CWR Equipment SCAMP Measures extremely small scale fluctuations (few mm) in temperature and conductivity (Carter & Imberger, 1986) by Greg Attwater

Lake Diagnostic System (LDS) LDS combine a weather station measuring wind, air temperature, relative humidity, short wave radiation and net long wave radiation with a thermistor chain. Using the LAKEMON software, the system is used to monitor the strength of mixing activity in a water body by using Lake Number concept. Robertson & Imberger (1984).

F-Probe A fine scale profiler using commercially available sensors for the measurement of temperature, conductivity, oxygen, pH and turbidity (Fozdar et al., 1985) In this experiment the F- Probe has been dropped with the Fluoro probe in order to obtain information on the distribution of 4 algal groups, total clorophyll a and DOC.

Why? Scientific goals: to investigate on the bluegreen – green algal shift between 2002 and 2003; to study the mechanism involved in the formation of the plankton patches. Distinguishing between physical, chemical and biological causes; Applied goal: to study the ecology of the Lake Pusiano during the stratification period in order to obtain a detailed description of the nutrients circulation and their effect on the phytoplankton population and suggest adequate strategies in order to obtain an ecological recover of the lake. Part 2: Scientific Issues by Diego Copetti

LDS meteorological parameters thermal structure SCAMP water column stability F-Probe Transport process WQ sampling nutrient availability Biological response Biological samplingFluoro probe Phosphorus bioavailable experiment PAR

Experimental plan LDS SCAMP hydrochemical parameters: P6, P18, P21 biological parameters P3, P19, P11, P15, P21 PAR P3, P6, P21, P11, P15, P16, P18, P20 Bioavailable phosphorus concentration experiment WE transect NS transect

ELCOM - CAEDYM

Results: meteorological data and thermal structure

During 25 July 2003 intense wind produce regular high frequency wave

SCAMP profile 209 day

2002 hydrodynamic model (DYRESM)

The data collected during the Pusiano field experiment 2003 appear very consistent; The first elaborations of the physical dataset underline the production of regular high frequency internal wave; It is evident an anisotropy distribution of the phytoplankton community aggregated in patches; The results obtained during the field experiment will be the starting point of the restoration plan of the lake, particularly in the evaluation of the nutrient internal load. Conclusion