Physiological and metabolic characteristics of polar diatoms: insights into cold adaptation and potential for biotechnology

• Main Author: Coffin, Sam
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: University of Cambridge 2022
• Subjects: Polar; Antarctica; Diatoms; Physiology; Thermal tolerance; B12; Arctic; Antarctic; Antarctic Peninsula; Antarc*; Climate change
• Online Access: https://www.repository.cam.ac.uk/handle/1810/334336; https://doi.org/10.17863/CAM.81750

The polar regions represent two of the most extreme environments on Earth, with sub-zero temperatures, sustained light in the summer and complete darkness in the winter. Marine diatoms are prevalent in the polar oceans, significantly contributing to primary productivity and ecosystem functioning. They are characterized by having optimal growth at low temperatures (<10°C) and have developed various genetic adaptations to cope with these extreme environments. The polar regions, however, are experiencing unprecedented environmental changes because of regional climate change. We currently lack detailed knowledge on polar diatom ecophysiology and metabolism, which means we do not know how these species may be impacted by future environmental changes. One barrier to our understanding of polar diatoms is the availability of living strains for experimental study. The number of polar diatom strains in public collections is low and of those that are available, many have been kept in culture for many decades. Hence, there is an urgent requirement to isolate new environmental strains that have not been exposed to artificial conditions for many decades and also to increase the number and diversity of species available. In this project I conducted fieldwork in Antarctica to isolate several new Antarctic strains and used these alongside Arctic and Antarctic strains from culture collections to study whether physiological and metabolic characteristics are conserved between diatoms from the two regions. My studies focused primarily on the response to temperature with the aim of predicting the effects of future climate change on polar diatom physiology and metabolism. The project also aimed to identify potential candidate strains for biotechnological exploitation. Conducting fieldwork on the Western Antarctic Peninsula, I isolated 36 strains encompassing 12 different species of polar diatoms. These have been genetically and morphologically identified and representatives deposited in the Culture Collection for Algae and ...