Characterization of nitrogen dynamics in an aquaponic system
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An aquaponic (AP) system combines a recirculating aquaculture
system (production of aquatic animals, mostly fish) with a
hydroponic system (production of plants) and recycles water and
nutrients between these two main components. Nutrient-rich water
from the aquaculture component is directed to the hydroponic
component and provides nutrients for plant growth, while
nutrient-poor water is returned back to the aquaculture component.
One of the key nutrients in AP is nitrogen, which is introduced
into the nitrogen cycle of the system via fish feed and subsequent
fish excreta. Ammonia and nitrite are both harmful to fish. The
transformation between these forms as well as the production of
nitrate are mediated by bacteria. Other components of the AP, such
as the biofilter, solids removal unit, settler, sump, piping, as
well as their physicochemical conditions, further affect microbial
community and nitrogen dynamics. The spatial distribution of
microbial communities and the dynamics of the nitrogen cycle in an
AP system are poorly understood.
This project aims at quantifying nitrogen fluxes between different components of the AP system as well as quantifying the nitrogen losses from the system. In addition, microbial communities that are involved in the nitrogen cycle will be characterized. The main forms of nitrogen in all AP system components (fish feces, fish tank, biofilter, solids removal unit, digester, sump, piping, and rhizosphere) will be quantified. Bacterial community composition and function will be described with a metagenomics approach and by using quantitative PCR for specific populations of bacteria involved in N-cycling. Finally, nitrogen fluxes among system components will be traced using a 15N isotope in order to parametrize the nitrogen dynamics in the system.
Archives of microbiology.
Verfügbar unter: https://doi.org/10.21256/zhaw-1593