Purchase of an upright fluorescence microscope

点击翻译按钮获取中文摘要

This proposal is to purchase an upright bright field Leica DM5000 B microscope equipped with differential interference contrast, fluorescence, digital camera and image analysis software. The system will be used in several research projects combining geological, biological and ecological approaches over the next 3 years to document and understand microalgal communities in various marine ecosystems. The fluorescence microscope allows for detailed studies on the identification, morphology, viability and trophic character (ability to photosynthesize or not) of dinoflagellates and other marine microalgae. One project will focus on dinoflagellates (unicellular protists) and their cysts in Arctic regions. The potential increase of shipping due to the melting of sea ice in the Arctic will be accompanied by increased shipping and intense ballast water intake/exchange, which is necessary to maintain the ships stability. Dinoflagellates and their cysts can survive several weeks in the ballast water and invade new areas when the ballast reservoirs are emptied or flushed. Therefore, we need to document their abundance and distribution in Arctic regions in order to monitor potential invaders and to effectively help developing mitigation measures. Dinoflagellates can produce toxic blooms (e.g. St. Lawrence Estuary in 2008) and cause massive deaths in the fish, bird and marine mammal populations. In the St. Lawrence Estuary, Alexandrium tamarense produces resting cysts that may germinate several months after being formed, lying dormant in the upper sediment layer, and acting as a "seed bank" for future toxic blooms. Therefore, we need to document the spatial distribution of the cyst beds within the Estuary/Gulf of St. Lawrence area to help anticipate future bloom episodes. Another project will be providing paleoceanographic reconstructions (temperature, salinity and sea ice cover) for the last 2000 years (with particular emphasis on the pre-industrial/industrial transition) based on dinoflagellate cyst assemblages. This will provide precious data on the oceanic conditions that prevailed prior to the onset of the actual global warming, and contribute to future climate scenarios.