DEVELOPMENT AND APPLICATION OF NEW MODEL ALGORITHMS OF THE BIOLOGICAL CARBON PUMP IN THE NORTH ATLANTIC: A STUDY ON PARTICLE EXPORT, SINKING AND DECOMPOSITION

2017-1-24
Yumruktepe, Veli Çağlar
A 1D lower trophic level pelagic ecosystem model, NAGEM, was developed to investigate processes moderating productivity, algal community structure and resulting carbon export at BATS, ESTOC and PAP time-series stations in the North Atlantic. At each site, the relative effects of community structure, sinking rates, physical and biological aggregation, mineral ballasting and diel vertical migration on carbon export were explored. Simulated carbon export rates were evaluated using in situ sediment trap data collected at the 3 time series stations and model algorithms were modified in order to best represent observed differences in export rates between stations. The observed 3-4 fold difference in carbon export between BATS and ESTOC is partially explained by differences in hydrographic conditions. The deeper and more prolonged vertical mixing at BATS results in efficient particle transport, whereas slower particle sinking at ESTOC results in a relatively higher remineralization pressure. This work highlighted the benefits of adequately describing plankton community structure in models to define the magnitude and structure of particle export and nutrient decoupling. Modelled carbon export was highly sensitive to changes in particle sinking rates, although these changes did not introduce variability in export. Temporal and spatial variability was achieved when specific sinking rates were assigned to detritus from each community. This resulted in relatively higher export efficiency at the PAP site due to the presence of larger plankton. Further improvements to model performance were achieved through adjusting aggregation, mineral ballasting, community specific remineralization rates and diel vertical migration of zooplankton.

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Citation Formats
V. Ç. Yumruktepe, “DEVELOPMENT AND APPLICATION OF NEW MODEL ALGORITHMS OF THE BIOLOGICAL CARBON PUMP IN THE NORTH ATLANTIC: A STUDY ON PARTICLE EXPORT, SINKING AND DECOMPOSITION,” Ph.D. - Doctoral Program, Middle East Technical University, 2017.