Bio-optical characterization of under-ice primary producers
Bio-optical characterization of under-ice primary producers
In the Arctic, following an initial bloom of bottom ice algae in early spring, primary producers can start their spring bloom in the water column below a melting sea ice cover. Snow melt and the formation of melt ponds on the ice surface lower the ice surface greatly increase light transmission through the ice. The levels and spatiotemporal variability in the transmitted light levels are not well understood at present, particularly for ultraviolet (UV) wavelengths. In addition, melt water from the ice (and potentially from nearby land and rivers) strongly stratifies surface waters, placing under-ice phytoplankton in growth favorable environment. My project seeks to examine processes influencing spectral light transmission through a melting ice-covered water column in order to improve our understanding on how a warming Arctic could affect primary production in the future. In situ light transmission profiles of upwelling and downwelling spectral irradiance will be conducted to estimate spectral light transmission and water column diffuse attenuation. These profiles will be made under a variety of different types (snow-covered, drained ice, and melt ponds) in order to characterize the under-ice light field as the system proceeds through different melt stages. Through analyses of these in situ data as well as detailed bio-optical properties measured on discrete depth water samples, we will be able to investigate the spatiotemporal variability of the system and quantify the influence of primary producers on the under-ice light climate.
This research project aims to: (1) investigate variability in the under-ice light climate during the melt season, (2) determine the spatial (horizontal and vertical) and temporal variation in bio-optical properties of primary producers and dissolved matter, and (3) examine the two-way causal influence of primary producers on the under-ice light climate and nutrient concentrations.
Fieldwork site: Baffin Bay near Qikiqtarjuaq, Nunavut
PI's: CJ Mundy/J. Ehn
Project lead: C. Quiring
Project participants: C.J.Mundy (CEOS), Jens Ehn (CEOS), Christine Quiring (CEOS), Nicole Pogorzelec (CEOS)