Guilherme Duarte Ferreira:
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The conceptual basis upon which management tools for our ocean, seas and coasts have operated are out-of-date. Development of management tools and policies to predict fish production and global change in marine waters operate within a paradigm that builds on a simple division between “plant-like” phytoplankton and their main consumers, the protozooplankton at the base of the food chain.
The new revised paradigm recognises that most phytoplankton and as much as half the protozooplankton actually combine both plant-like photosynthesis and animal-like consumer activity within the same single cell. This form of nutrition, phago-mixotrophy (also defined as mixoplanktonic organisms), supports the growth of organisms important for food chains and biogeochemical cycles removing atmospheric CO2.
As a consequence of this revised paradigm, traditional laboratory and field research approaches, management policies and allied computer modelling tools are arguably no longer fit for purpose.
The objectives of this PhD were: 1) to develop and implement new methodologies for evaluating the relevance of mixoplanktonic grazing in the field 2) to evaluate, in the laboratory, differences in feeding rates amongst different mixoplanktonic functional groups and the main factors affecting them (e.g., light and temperature).