In the project a newly developed method will be used to characterize the molecular weight spectrum of dissolved carbohydrates in the ocean and under laboratory conditions by selected phytoplankton species. The new method is based on the fractionation of carbohydrates according to their molecular weight by capillary electrophoresis and laser induced fluorescence detection resulting in unsurpassed resolution and accuracy in the quantification. The overall hypothesis is that the bio reactivity of dissolved carbohydrates is related to their molecular weight spectrum, with highest bio reactivity in the mid-size range (\'1000-10,000 Ad) and decreasing towards both, the low and the high end of the molecular weight spectrum of the carbohydrates. This hypothesis is based on recent findings formulated in the size-reactivity model of oceanic DOM.
In Objective 1, coastal North Sea water will be collected at weekly intervals and the dynamics in the molecular weight distribution of dissolved carbohydrates assessed and quantified. These data will be related to other relevant biological and chemical parameters determined at the same time in the frame of an ED funded project (BASICS) in which particularly the functional diversity of the prokaryotic community is investigated.
In Objective 2, dissolved carbohydrates will be collected during a cruise along a transect off the Mauritanian coast from the up welling area towards the open ocean. We expect to find distinct patterns of the molecular weight spectrum of dissolved carbohydrates with a dominant mid-size pool in productive surface waters, decreasing in size with depth and towards less productive waters.
Objective 3 deals with the production of dissolved carbohydrates by identically grown selected phytoplankton species under different nutrient conditions (N vs. limitation). These phytoplankton-derived dissolved carbohydrates will be characterized and quantified according to their molecular weight spectrum, etc.
Field of science
- /natural sciences/chemical sciences/electrochemistry/electrophoresis
- /natural sciences/biological sciences/microbiology/bacteriology
- /natural sciences/biological sciences/biochemistry/biomolecules/carbohydrates
- /natural sciences/biological sciences/biochemistry/biomolecules/proteins/enzymes
Call for proposal
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