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Antarctic sea ice algae : primary production and carbon allocation

Ugalde, SC (2015) Antarctic sea ice algae : primary production and carbon allocation. PhD thesis, University of Tasmania.

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Abstract

Sea ice is a semi-solid matrix of brine-filled channels, typically displaying strong
vertical gradients in temperature, salinity, light, and space. Prolonged biological
activity within the confines of the brine channels itself alters the microenvironment
and physicochemistry. To be able to cope with these changes, ice
algae display a complex suite of physiological and metabolic adaptations. One
such adaptation is the exudation of photosynthetically-derived organic carbon.
Research undertaken for the thesis details primary production and carbon
allocation of ice algal communities in laboratory and field conditions, and
discusses the relationships between microbial growth dynamics, responses to
physicochemical change, and ecosystem dynamics.
The thesis finds that sea ice algae are capable of exuding large quantities of
photosynthetically-derived organic carbon. Allocation to exuded organic carbon
is highest during times of adverse conditions, such as challenging biochemical and
physicochemical conditions. The composition of exuded carbon varies between
defined pools, including dissolved organic carbon, colloidal organic carbon, and
extracellular polymeric substances. The observed magnitude of changes in carbon
allocation indicates that each extracellular carbon pool imparts different
ecological roles and/or benefits to the producer organism.
The thesis highlights the complexity of sea ice primary productivity, subsequent
carbon allocation, and the driving factors within the diverse sea ice habitat. With
an increased ability to quantify direct exudation of organic carbon, the
contribution of sea ice algae to total primary production and carbon flux dynamics
across ice-covered seas could now be estimated.

Item Type: Thesis (PhD)
Keywords: Antarctica, carbohydrates, microalgae, photophysiology, nutrients, biomass, extracellular organic carbon
Copyright Information:

Copyright 2015 the Author

Date Deposited: 20 Nov 2016 23:53
Last Modified: 20 Nov 2016 23:53
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