The broad objective of this project is to study the interrelationships among surface fluxes of heat, radiation and CO2 over a fast ice system and seasonal changes in both the surface ice/snow volume and atmosphere.
The goal of this project is to determine how marine bacteria in sea ice adapt to changing brine salinities as temperatures drop in winter and increase in warmer seasons. Our working hypothesis is that, as brine salinities increase in winter, bacteria take up and retain organic compounds in intracellular pools (to act as compatible solutes to protect against an otherwise damaging efflux of dissolved salts from the cell), later respiring these same compounds as an energy source when salinities freshen in spring and summer and compatible solutes are no longer needed; in the respiratory proces
To protect against damaging UV radiation (UVR; ~280-400nm), many marine phytoplankton are known to produce UV-absorbing mycosporine-like amino acids (MAAs), but little is known about their presence in sea ice-covered Arctic waters. Understanding MAA presence and prevalence will aid in our understand of coping strategies of algal and phytoplankton communities to UVR exposure. With current changes in climatic conditions we are seeing decreasing trends in ice cover and thickness as well as increases in first-year ice.
Coincident measurements of bottom-ice algal and bacteria production will be made using traditional and oxygen based incubations. Changes in community productivity over the spring bloom and between different snow covers will be assessed this coming spring in Cambridge Bay, Nunavut, while environmental factors potentially driving variability are documented. Collaborations will also be made with Dr. Brent Else and his eddy covariance system to assess potential nutrient limitation in the bottom ice.
Fieldwork site: Field camp, Cambridge Bay, Nunavut, Canada
The timing of the phytoplankton spring bloom plays a critical role in the trophic dynamics of the Arctic ecosystem. Such blooms were previously thought to be insignificant. This is mainly due to strong light limitation occurring due to the overlying snow, sea-ice and algae. Past observations also support this concept. However, there have recently been observations of under-ice phytoplankton blooms in different areas of the Arctic, meaning that these blooms could actually be of some significance but also quite common.
The timing of the phytoplankton spring bloom plays a critical role in the trophic dynamics of the Arctic ecosystem. Such blooms were previously thought to be insignificant. This is mainly due to strong light limitation occurring due to the overlying snow, sea-ice and algae. Past observations also support this concept. However, there have recently been observations of under-ice phytoplankton blooms in different areas of the Arctic, meaning that these blooms could actually be of some significance but also quite common.
This project will investigate the long-term response of marine primary producers to sea ice variability in high Arctic Greenland. A network of climate and biological proxies will be applied to marine sediment records retrieved from fjord areas in NE and NW Greenland, covering the past millennium, and combined with state-of-the-art molecular tools to obtain an integrated view including the functional (productivity), structural (community composition and diversity), and genetic level.
The aim of the field campaign is to collect snow depth and density data in three different snow regimes in Qaanaaq, North Greenland; Tasiilaq, East Greenland; and Qassiarsuk, South Greenland which will be used in snow modelling work on Greenland scale.
Field Site: Qaanaaq, North Greenland; Tasiilaq, East Greenland; and Qassiarsuk, South Greenland.
Snow cover in North East Greenland
The aim of the fieldwork is to validate snow modeling work (SnowModel, Liston and Elder 2006a,b) by collecting snow depth and snow density in a region from the east coast of Wollaston Foreland to the ice margin of the Greenland Ice Sheet. This will cover a coast–inland gradient in snow depth and snow cover duration. The location of snow depth and density observations will span the variations in landscape features, elevation gradients and aspect in order to answer the question:
The changing climate has resulted in a significant increase in melting rates of the Greenland ice sheet as well as a reduction of sea ice cover in the Arctic Ocean. However, information on the variability of sea ice is limited to the satellite period (i.e. ca 30 years), and ice sheet melting rates is known from an even shorter period. This hampers our understanding of the natural, background state of the climate and environment in the East Greenland region.
