OPTICAL PROPERTIES OF LAKE VENDYURSKOE

Abstract

We conducted a field study on light conditions in a small boreal Karelian Lake Vendyurskoe over two years. Albedo of ice-covered lake varied from 0.9 to 0.1, and the euphotic zone depth exceeded 3.5 m during the melting stage. The Secchi disc depth changed from 2.5 m after ice-break to 3.7 m at the stage of early summer. The vertical distribution of the photosynthetically active solar radiation (PAR) attenuation coefficient for water Kw was characterized by high spatial (vertical) and temporal (seasonal and interannual) variabilitywhich can be connected with the dynamics of plankton cells. The highest values of Kw eached 2–2.8 m–1 in the upper 0.5 m layer of a water column, and decreased to 0.5–1.5 m–1 with increasing depth. The highest values of Kw were marked in the end of ice-covered period.

Keywords

• ice-covered lake
• albedo
• photosynthetically active radiation
• under-ice irradiance
• par attenuation coefficient